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Boosting the 3v with Positive Displacement Superchargers – Almost Everything You Need to Know
 

Department Of Boost’s Commitment to Fact

The performance automotive aftermarket industry, especially the forced induction portion, is littered with “fuzzy math”, half-truths, and in some cases outright lies. We see it every day, all day. In some cases, we think this problem is from ignorance on the part of the industry. In others, it’s obviously an attempt to muddy the water or a blatant lie to drive sales. It makes us crazy. It should make you crazy, too.

We commit to you to always tell you the full truth and relay the facts as we know them. Do we know everything? No, of course not. No one knows everything about an entire subject. And new theories and methods are continually being discovered. Additionally, more and more “wives tales” or “internet truths” are being debunked daily. But we’ll give you the unvarnished truth as we know it at the time. And with a healthy fear of coming off as arrogant, we know a lot.

We’ll always provide you with technical data to the best of our abilities. We’ll never give you half-truths. And we’ll never lie to you so we can sell more product. This is our commitment to you.

If you find something we wrote that’s not fact (that’s possible), and you have evidence it’s not, please email us and let us know. We’ll take a look at it and, depending on circumstances, update the article.

Disclaimers/Notes

Before you read this, there are a few things to get out of the way.

-The 4.6L 3v found in 2005-2010 Mustang GTs has been around forever at this point. There’s no mystery left to it. It’s a known quantity and there are enough of them in enough states of tune to know what works and what doesn’t. What follows is information based on all of our experience/data.

-We quote horsepower (HP) at the rear wheels on a Dynojet dyno.

-All HP numbers quoted (if not otherwise noted) are while using 93 octane gas.

-All the HP numbers quoted are REAL HP numbers. Not fantasyland “hero run” numbers. Not a number from an optimistic dyno. Not a number that someone inflated in a post on the web. Not rounded up. All numbers are based on the car being at full operating temperature. The numbers quoted are based on a ton of examples we have seen with our own eyes and are numbers that you can achieve with your car in the real world.

-Most statements you read are to be regarded as “most of the time.” There are a zillion and one variables when dealing with motors/boost. You’ll probably be able to dig up one example that applies to every statement in here that makes it “untrue”. We’re aware that those variables are out there. But it would be impossible to write something like this and cover every single variable. What you’ll be reading is what you can expect most of the time. It’s not meant to cover wild combinations or “flyers.”

For example, we consider the pump gas octane limit on the 3v to be about 650rwhp. But we’ve gone from 650rwhp to 775rwhp on a 3v (the same car) with just a blower/manifold/CAI change. Both combos were run at 20lb of boost. How is that possible you ask? Well, it involved a “unicorn” combination. The 650rwhp was made with a 2.3L Whipple/Whipple manifold spinning 18,500rpms running a twin 72mm throttle body and a 127mm cold air kit/mass airflow meter. The 775rwhp was made with a 3.4L Whipple with a Crusher inlet/R-Spec manifold spinning 11,900rpm’s running a twin 72mm throttle body and a 156mm cold air kit/mass airflow meter. There are a lot of factors as to why this is possible that this article can’t cover. At the end of the day, it comes down to efficiency…………………..and money. It happens that piles of money will get you more. Imagine that!

Anyway………statements in this article should be considered as “most of the time.”

-This article will have some “sales” in it. There really is no way for us to get all the information across without mentioning our own products. Additionally, we got started as a company by offering stuff for the 3v motor, so our first product was targeted specifically at what was already in the marketplace. Because we got to assess the existing playing field and design products directly to compete in it, we ended up with some really good solutions for the 3v. So yeah, we’re going to mention our stuff.

 

Why We Wrote This

We wrote this for two reasons:

Even though blown 3v’s have been around for about a thousand years now, we still see absolutely horrible information posted up on forums, Facebook, in magazine articles, etc. It’s still treated as a little bit of a mystery. And that’s not the case at all. We wanted to provide one spot where people can get all the information they need about supercharging the 3v. Well, supercharging using positive displacement blowers. But a lot of the information applies to centrifugal blowers too.

It pains us to see so much false/ contradictory information out there. Superchargers aren’t inexpensive. And it frustrates us to see people spend their hard earned money, a lot of hard earned money, on blower kits that don’t fulfil their needs/expectations, mods they don’t need, combinations that don’t work, etc. Many many moons ago, before we were in the business, we bought a garbage supercharger system for a 3v that didn’t fill our needs. And then we threw all the wrong parts at it to get where we wanted to be…..and never got there. It sucked. Hopefully we can help you not to make the same mistakes we did.

The other reason is that we, of course, want to sell more product. And we’re hoping that by shining light on the realities of blown 3v’s more people will choose to go with what we offer. We do this to make money after all!!!

Terms and Abbreviations

We use the words supercharger and blower interchangeably. For this write-up, they’re the same thing.

We’ll be using a lot of abbreviations in this write-up. Here is what they are and what they mean.

BAP = Boost a Pump

PD – Positive Displacement. This is the type of supercharger we’re talking about in the write-up.

IAT – Intake Air Temperature. This is the air temperature measured after the intercooler right before it goes into the cylinders. This is very important.

ECU – Electronic Control Unit. This is your car’s computer. It’s sometimes also referred to as PCM, ECM, etc.

FPDM – Fuel Pump Driver Module. This/these are what “drives” the fuel pumps for the ECU. Think of them as the fuel pumps’, brains.

IC – Intercooler. The intercooler is what cools the air coming out of the blower before it enters the cylinders. It’s in the intake manifold and you can’t see it unless you have the blower off.

HE – Heat Exchanger. The heat exchanger is part of the intercooler system. It’s the “radiator” that mounts up in the nose of the car and it sheds the heat that’s picked up at the intercooler.

NA – Naturally Aspirated. A motor with no forced induction (blower or turbo) is naturally aspirated.

OEM – Original Equipment Manufacturer. This means stock. The parts, systems, etc. the car came with.

HP – Horsepower.

TQ - Torque

rwhp – Rear Wheel Horsepower. This is the horsepower measured at the wheels on a chassis dyno.

lph – Liter Per Hour. The unit of measurement generally used when describing the abilities of a fuel pump.

Duty Cycle – The Duty Cycle is an expression of how hard a fuel injector or fuel pump is running in comparison to its maximum ability. A 50% duty cycle means that a particular component is running “half way” maxed out.

VVT – Variable Valve Timing.

 

Overview

The 4.6L 3v in the 2005-2010 Mustang GT likes boost. It likes it a lot. Let’s face it, NA the 3v is a bit of a dog. Even when you throw the entire catalog of go-fast NA parts at it, you still won’t have a ton of power. $10,000 worth of NA go-fast goodies/built motor will get you about 420rwhp and not much torque. Not only is that a lot of money, that also represents a lot of time. It’s no wonder why most people go for a supercharger kit. They’ll make 450rwhp and 450rwtq for far less money and far less time.

 

The Limits of the Stock 4.6L 3v Motor

Hard Parts

Connecting Rods and Pistons:

The stock 4.6L 3v connecting rods and pistons will take up to 450rwhp at 6,000rpm. Anything above that puts you firmly in the danger zone. The likelihood of chucking a rod out of the motor is high if you push the limits.

Crankshaft:

The stock 4.6L 3v crankshaft is surprisingly robust. It’s been run up to 800rwhp in a few combinations we’ve seen and not let go. Most builds don’t need a forged crank.

Engine Block:

The stock 4.6L 3v engine block is very robust. The stock block has been run up to 1350rwhp and held up. Can it handle more? Maybe, we don’t know of anyone making more power than that with the 3v though.

Valvetrain:

The stock 4.6L 3v valvetrain, when used in conjunction with the correct valve springs and VVT lockouts, will hold up to 7,800rpm. This is where the ECU stops being able to “calculate,” so, as far as we know, no one has tried to spin one faster. You won’t be concerned with this many RPMs though. When running a PD blower, you simply don’t need or want to spin the motor that fast in anything short of a full-blown dedicated drag car. Then MAYBE you would spin the motor that fast.

Heads:

The cylinder heads actually flow quite a lot for a stock “non-performance” head. And big flowing heads are not as critical as they are on NA motors. We don’t think that it’s worth porting heads until you’ve eclipsed 700rwhp.

Exhaust Manifolds:

The stock exhaust manifolds aren’t THAT bad. They certainly aren’t an old school “log manifold”. They’re more of a cast shorty header in design. On that note, don’t ever buy shorty headers for the 3v. If they make any more power, it’s 1-3rwhp. Not nearly worth it. Anyhoo, the stock manifolds are pretty good up until about 600rwhp. Headers certainly don’t hurt. But they’re expensive, a PITA to put on, and add heat to the engine compartment, which you don’t need. Best to hold off on them until you actually need them.

Boost “Limits” and Fuel Octane

Something that’s not widely understood in general and about the 3v specifically is the boost/fuel octane limit.

Octane in simple terms is the fuel’s ability to resist detonation (or, more specifically, pre-ignition). Pre-ignition/detonation is when the fuel explodes/ignites inside the cylinder before the piston is at the top of its stroke and before the spark plug fires. This is bad. Detonation happens when the fuel octane can’t prevent that “explosion.” When you add boost, the pressure inside the cylinder increases dramatically over what you would see NA. Add to that the heat generated as the byproduct of making boost, and, at some point, the fuel octane won’t be able to prevent detonation. You’ll punch holes in pistons, break connecting rods, and sometimes break blocks. So clearly detonation is bad. For this “exercise,” we’re going to assume that the IC system is working correctly and the IATs aren’t too high. We’ll simply be talking about boost pressure and the fuel’s ability to prevent detonation.

The boost limit on 93 octane gas for the 4.6L 3v is about 18psi. This is assuming that the motor has at least forged rods and pistons. But not all forged motors have the 3v’s stock compression ratio (9.8:1). So the 18psi figure can go up or down depending on what the compression ratio of the actual motor in question has. We’ve run 20psi safely on 93 octane at a compression ratio of 9.25:1. There’s no hard and fast rule for how much boost you can run with X.XX:X compression ratio. That’s something you’ll need to discuss with your tuner.

Why bring up the octane limit? There are a couple of reasons. It’s obviously not bad knowledge to have. And if you’re planning on going for big HP and you’re limited to running 93 octane pump gas, you’ll be riding the edge of the fuel’s limit. You need to understand what’s going on so you can safely achieve your goals.

The “good news” is that most of the blowers available for the 3v don’t move enough air to make 18psi. That’s not really “good news” if you’re trying to make big power. But it does make the whole octane limit thing a moot point for a lot of blowers/most people. There’s information later in this write-up about what blowers will make for boost and their maxed out HP capabilities.

For those that have a blower that can make over 18psi and want to run 93 octane gas, there are things you can do to make that possible.

Boost is simply a measurement of restriction. We’re not going to go into the entire concept of boost in detail here, it’s very complex. But in short it works like this: the more restrictive the motor (the ability to push air through it), the more boost you’ll make for a given blower speed. If you reduce that restriction by using ported heads, big cams, a stroker kit, big exhaust, etc., you’ll reduce the restriction and boost will drop. You’ll still be moving the same amount of air through the motor so you’ll make the same power, but it will be at a lower boost level.

If you have a blower that will make 22psi on a 4.6L 3v (which is about 775rwhp) and you want to use everything that blower has to offer but still run 93 octane gas, you need to reduce the motor’s restriction. You could, for example, run a BOSS block stoked to 5.3L, big ported heads, big cams, big headers, and big exhaust. That reduction of restriction will drop the boost to about 18psi (lots of factors here, these numbers aren’t set in stone) and allow you to run 93 octane and still have your 775rwhp. Those engine mods you did didn’t “make” more power. They allowed you to run the blower at a “775rwhp blower speed” and stay under the octane limit. You may pick up a few HP because you’re decreasing how hard the blower as to push, which means it’s more efficient, but that’s very small and a subject for another time.

Most people won’t need to worry about octane limits with the 3v. Most of the blowers won’t make enough boost/move enough air to make it an issue. And very few people are shooting for over 600rwhp. Well, not many people make it. But if you’re one of the people planning on “going big” but running 93 octane gas you need to plan your combination right from the start to achieve that goal.

 

What Will the Blowers Make?

This is a tricky question and quoting power numbers these days is very difficult because the industry and the public as a whole use “fuzzy math” when making claims. What does “How much power will it make?” really mean? Are we talking about a stone stock motor with stone stock exhaust? Are we talking about a built motor with ported heads, big cams, high compression pistons, monster exhaust, a huge throttle body, and cold air intake? Or somewhere in between? Are we talking about 91 octane gas or 93? Are we talking about E85? And then just to make things really fun you can take the same car to 5 different dynos on the same day and get five different power readings that can be as much as 75hp apart! Don’t believe us? Check out this article from Hot Rod Magazine. As we’re sure you can tell, there’s going to be a huge difference in “what it makes” between stock and wild. And if you’re adding E85 to the mix, it blows the whole estimate right out of the water.

That said, here are some reasonable numbers that are based on the blowers running on stock 4.6L 3v motors (aside from forged rods/pistons so parts don’t fly out) running 93 octane gas, on the same dyno, on the same day. These numbers are based on the blowers spinning at 18,000rpm, which is their effective safe limit. These numbers can move up or down depending on other variables.

Keep in mind none of these blowers will make this power out of the box. At an absolute minimum, they would all need fuel injectors and fuel pump upgrades to see these numbers. Some will need more supporting mods than that. None of the kits are capable of running the maximum power the actual supercharger can make when you get one.

On 93 octane gas, listed least to most:

-Roush M90 1.6L will make about 400-420rwhp.

-Magnuson Magnacharger 1.9L will make about 570-580rwhp.

-Edlebrock EForce 2.3L TVS will make about 580-590rwhp.

-Kenne Bell 2.6L Stage I will make about 585-595rwhp.

-Kenne Bell 2.6L Stage II will make about 590-600rwhp.

-2007-2012 GT500 2.0L M122 (ported) will make about 605-615rwhp.

-Saleen Series VI 2.3L will make about 620-640rwhp.

-Whipple 2.3L will make about 625-645rwhp.

-Roush R2300 2.3L TVS will make about 625-645rwhp.

-Kenne Bell 2.8L and 2.8LC will make about 680-695rwhp.

-2013-2014 GT500 2.3L TVS will make about 685-700rwhp.

-Kenne Bell 3.2LC will make about 715-725rwhp.

-Department Of Boost 3.4L 3v R-Spec will make about 750-775rwhp.

On e85 these blowers will make:

The following blowers (which are also in the list above) are capable of making more boost than can be safely run on 93 octane gas. That means to run them all out on E85 or race fuel is needed. E85 is by far the best choice because E85 has amazing cooling properties and is incredibly inexpensive compared to race fuel. Here is a list of those blowers and what they can make on E85. Keep in mind getting these numbers will require very, very high dollar fuel systems and a truckload of supporting mods. Listed least to most:

-2013-2014 GT500 2.3L TVS will make about 810rwhp.

-Kenne Bell 2.8L and 2.8LC will make about 850rwhp.

-Kenne Bell 3.2LC will make about 1100rwhp.

-Department Of Boost 3.4L 3v R-Spec will make about 1200rwhp.

-Department Of Boost 4.0L 3v R-Spec will make about 1300rwhp.

-Department Of Boost 4.5L 3v R-Spec will make about 1400rwhp.

“But, but, my uncles plumber’s brothers Walmart greeter girlfriends dog groomer knows a guy that saw a post on a forum where XYZ blower made 1000hp more than that on a 3v!!!! Those numbers aren’t right!!!!! You’re full of crap!!!!”

The numbers listed above can go up or down based on conditions, fuel used, how safe they’re tuned, how happy the dyno they were on is, other supporting modifications, etc. They’re simply a representation of what you can expect out of the above blowers when they’re compared to each other under the same conditions.

Fueling/Fuel Systems

Fuel systems can get extremely confusing because there are an incredible number of choices and different combinations for different power levels and fuels used.

We’re going to leave this section to our friends at S&H Performance (sandhperformance.com). They specialize in fuel systems, and they’re who we go to for our fuel system needs, suggestions, requirements, help, etc. This is their specialty, not ours.

Here is something that Jeremy from S&H wrote up for us:

S&H Performance – Pump Gas (93 Octane) Systems

So first off. Don't come at me with the “I made 520rwhp with just 39lb injectors and a BAP” crap. So what? So the stars aligned and you had a generous dyno, 18.5 volts at the pump, and perfect weather. That was on the ragged edge. Running stuff on the ragged edge is asking for trouble nor smart for anyone else to follow because you got lucky and swear by it on YOUR car. This goes for any example and not just the one above. Setups can vary as much as 25-50% from one another on the extreme end. In reality, on healthy systems, 10-20% difference is not uncommon.

Disclaimer. Throw manufacturers’ claims out the window! XXX product will never perform on the car as well as it did in a controlled lab test, period. Nuff said? Yes, on a healthy system, XXX product should support YYY power on ZZZ setup. That doesn't mean it will when you get it on YOUR car.

These stats will be averages for most power I’ve seen with some safety put it because I'm not in the business of helping people blow their cars up. These are my numbers that I’ve seen personally on my car or on cars I’ve worked on or built systems for and received feedback from customers.

HP numbers are at the wheels (rwhp) with 93 octane gasoline.

Pump Wire Upgrades

-10awg wire upgrade to FPDM plug will get you an 8-12% drop in duty cycle.

-8 wire a few percent more.

-If you run two pumps on one FPDM, -10awg is fine, -8awg is optimal.

Always run the fuse closer to the power source, and always run a larger amperage relay than what you need. My wire setups use a 30amp fuse and a 40amp relay.


16-18Volt Pump Boosters (BAPs)

I personally would never run a BAP on a stock fuel pump past 475rwhp. It’s a temporary solution that's easy to install until you can afford a better solution. Don't install a BAP without running a wire upgrade feed for it, period.

Fuel Pump Combinations Using the OEM Fuel Hat

-OEM pump. 180-200lph, 375-400rwhp capable on boost. Don't do this!

-Walbro 255lph pump. 450-475rwhp capable like the BAP.

-340lph pump. 525-550rwhp capable. Don't mess with any brand besides DeatschWerks (DW) or AEM; they’re the proven most reliable with quality components. Any other brand is a crapshoot. Wire upgrade required at this point.

-Walbro 400lph pump. 575-600rwhp capable. Wire upgrade required at this point.

Fuel Pump Combinations Using the GT500 Dual Fuel Pump System

-OEM pumps. 650rwhp capable. Comes with harness second fpdm and wire/relay upgrade already. A lot claim it can handle more, but I’ve seen them max at 600-625rwhp, so I can’t justify a higher rating.

-Two 255 pumps. 700rwhp capable.

-Two 340lph pumps. 800rwhp capable. Again AEM or DW. DW is direct fit. Any other pumps are a pain to fit but can be done.

-You can add a fuel pump booster (BAP) to these higher flowing pump combos and make an additional 100hp on top of what’s listed.


800rwhp, the Return-Less/Return Threshold

What’s the difference between a return-less and return fuel system?

Return-Less Fuel System – The OEM system is return-less. And it’s exactly what it sounds like. The fuel goes from the tank to the motor and never comes back. The amount of fuel sent to the motor is controlled by the computer which pulses the fuel pump(s) to get just the right amount.

Return Fuel System – This style system is also exactly what it sounds like. Fuel is sent from the tank to the motor. The fuel that’s not used is returned via another fuel line back to the tank. The amount of fuel returned is metered by a fuel pressure regulator that maintains a pre-set fuel pressure in the system.

The discussion/reasoning on why one system is better than the other under what situations and why is very complex and very long. Way too long for the purpose of this article.

At 800rwhp, I like to see the OEM fuel system converted to a return system. At 800rwhp, your stock lines, rails, and filter become a restriction. And the pulse modulated return design is bumping into its maximum capabilities.


Return Fuel Systems

You do make a little more power per pump than the same pump(s) in a return-less system due to the design and regulator returning fuel to the tank…so I didn’t relist any of the pumps I already spoke about above. Keep in mind, as you run higher power numbers, your system can start to vary more wildly from the average. Over-building your fuel system at this point is not a bad idea.

-2 400lph pumps. 1000rwhp capable.

-2 450lph pumps. 1200rwhp capable.

-3 255 pumps. 1000rwhp capable.

-3 340lph pumps. 1200rwhp capable.

-3 400lph pumps. 1600rwhp capable.

-3 450lph pumps. 1800rwhp capable.


Fuel Line Size

8AN or 10AN? Planning on more than 1000rwhp? Then go 10AN. 1000rwhp and below, go 8AN.

Wire Size

10awg minimum wire for return pumps Consider 8awg for more than 2 pumps.

Fuel Injectors

Gasoline rating on boosted setups. I highly recommend reading this link if you want to learn more about selecting injectors.

http://performanceparts.ford.com/download/charts/Fuel_Injectors_and_Adaptors.pdf

Ford/Bosch 24lb. Newer design, available in ev6 body/internal design with uscar connector. Excellent spray pattern for 2v/3v/4v heads. Great control/mileage. Original equipment on the 3v.

Ford/Bosch 39lb. 20+ year old ev1 body/internal design injector that can be found with either jetronic or uscar connector. Subpar pulse angle and control by today’s standards. Cheap entry level injectors with fair control/mileage. 450-475rwp rated. Don't recommend using them on a 3v personally or at all for that matter. A lot of imitation versions of these out there as well.

Ford/Bosch 47lb. Newer design, available in ev6 or ev14 body/internal design with uscar connector. Excellent spray pattern for 2v/3v/4v heads. Great control/mileage. 550-600rwhp rated. Excellent injector choice for a stock block boosted setup. 

Ford/Bosch 55lb (580cc). New design, available in ev14 uscar connector. OE on the 2013 GT500. Requires height spacers for GT use. Excellent spray pattern for 2v/3v/4v heads. Great control/mileage. 675rwhp rated.

Ford/Siemens Deka 60lb (630cc). 15+ year old design available in ev6 body with uscar connector. Fair spray pattern/mileage and good control. 650-700rwhp rated. Common/good choice still used widely today.

Bosch 65lb (650cc). Newer design, available in ev6 or ev14 body/internal design with uscar connector. Excellent spray pattern for 2v/3v/4v heads. Great control/mileage. 700rwhp rated. Less commonly used injector due to higher price over the SD 60lb.

Bosch/ID/DW 750cc. Newer design, carry over from ls/gm world. Available in ev14 compact (39mm ls) or ev6/ev14 body/internal design with uscar connector. Excellent spray pattern for 2v/3v/4v heads. Great control/mileage. 800rwhp rated. Less commonly used injector due to higher price point.

Ford/Siemens Deka 80lb (875cc). 15+ year old design available in ev6 body with uscar connector. Fair spray pattern/mileage and poor control at low pulse widths requires more fines to tune. 900rwhp rated. Common choice still used today due to cheaper price point compared to other injectors in this size range. I don’t personally recommend them.

Bosch/ID/DW 95lb (1000cc). Newer design, available in ev6 or ev14 body/internal design with uscar connector. DW1000s are for the 2016 Cobrajet. Excellent spray pattern for 2v/3v/4v heads. Available in 4 hole or single ball orifice tip. Excellent control/mileage (single ball orifice tip being optimal). 1000rwhp rated (850rwhp E85). Excellent injector choice for any built motor application up to this power rating. 

Bosch 127lb/ID1300 (1330cc). Newer design, carry over from BMW world design. Available in ev6/ev14 body/internal design with uscar connector. Excellent spray pattern for 2v/3v/4v heads. Great control/mileage. 1200rwhp rated (1000rwhp E85). Less commonly used injector due to much higher price point over the 1000cc. Common choice for E85 use due to all stainless steel internals.

Bosch 160lb/ID1700 (1700cc). Modern design, available in ev1, ev6, or ev14 body/internal design with uscar or jetronic connector. Excellent spray pattern for 2v/3v/4v heads. Excellent control/mileage in E85 (fair with gasoline) 1800rwhp rated (1200rwhp E85). Not too commonly used due to similar pricing as the 2000cc.

Bosch 210lb/ID2000 (2225cc). The biggest on the block. Carryover from the import world. Available only in ev14 compact and denso connector so spacers and plug adaptors required for Ford application. Good control/mileage in E85, fair to poor in gas. 2000rwhp+ rated (1600rwhp+ in E85). Controllable up to 100psi base pressure (3350cc). 3700cc max flow rating at 130psi base pressure. $$$$$$$$

E85 Fuel Systems

E85 fuel systems are pretty easy to figure out. They take roughly 25% more fuel than when you’re running on gas. For example, if you have a fuel system that will make 700rwhp on gas, it will be able to support 525rwhp on E85. 700 minus 25% (x .75) equals 525.

If you want to know what injectors/pumps will support E85 at your target power level, simply go to the section above and multiply the horsepower numbers by .75.

End of S&H Fuel section……..Thanks Jeremy!!!

Variable Valve Timing - Lockouts- Limiters

We see a lot of discussion/questions pertaining to cams, variable valve timing (VVT), limiters, and lockouts. This is a bit of a grey area because some of these choices come down to personal preference. Here’s what we think:

The first thing to get out of the way (and you’ll see below) is that we’re not big fans of running aftermarket cams with PD blowers until you’re playing with big power. It’s not because we don’t like cams, we love them. Who doesn’t like the rumpidy, rump, rump of a cam? It’s just that non stock cams on PD blown cars don’t do anything for you until you’re making big power (more on this below). This means that you’re spending money/time on something that doesn’t show up in actual performance. We’re fans of HP/$$$, and cams are a pretty bad value for most PD combinations.

But if you’re going to run cams, here are some things we’ve learned over the years:

Keep the VVT As Long As You Can

If you don’t have to lock out or limit the VVT…………..don’t. Some cams require it (you have to with these), some don’t. The VVT works great, and it really improves midrange torque. And if you have a street car, that’s where you’ll spend most of your time…in the midrange.

Limiters Can Be Scary

We’ve seen TONS of situations where limiters have failed. There are two “styles,” and we’ve seen both of them fail multiple occasions. Yes, some people run them with no problem. But there is a potential problem out there. And it’s not uncommon. If you have cams that require limiters, we suggest simply locking them out.

Lockouts Hurt Torque

There’s no two ways about it. If you can’t affect the valve timing through the VVT, you give up one thing, HP or TQ. Obviously most people choose to give up TQ. Expect to see a 30-40 ft lb loss at about 3000-3500rpm when running lockouts. With PD blowers, this isn’t a huge deal because they already have so much torque. And, in some of the big HP situations, it’s actually an advantage to kill some of that low end. But most people in most situations want that TQ.

High RPMs and Heavy Valve Springs Kill VVT

If you chose a big lumpy cam or you’re even revving the guts out of the stock cams, the VVT starts to show its weaknesses. And sometimes fails. If you’re running heavy valve springs or consistently spinning the motor past 7,000rpms, you want to lock out the cams.

Compression Ratio

This could turn into an article all by itself. There are a lot of factors at play here. We’ll keep this as brief as possible.

In the past couple of years, it has become “fashionable” to run higher and higher compression ratios on boosted motors. There are some reasons for this. But frequently it’s done because it’s the cool new thing to do (not that there’s anything wrong with that).

If you’re going to build a forged motor so you can safely make over 450rwhp, the biggest question you’ll have to answer is “what compression ratio should I make it???”

A quick tutorial on compression ratio and boost

A motor’s compression ratio is how much the air/fuel in the cylinder is squeezed before the spark plug fires. A compression ratio of 10 to 1, commonly written as 10:1, means that, when the piston travels upward in the cylinder, it compresses 10 “units” into 1 “unit” before the combustion cycle (spark plug firing). This compression of air/fuel created pressure (duh!). If this pressure gets too high, the air/fuel will detonate before the spark plug goes off and before the positon gets to the top of its travel. This is called pre ignition or detonation and is BAD. Imagine putting your piston(s) on the workbench and slamming a ball peen hammer into the top of them. That’s what’s happening.

There are a lot of factors that determine when you get detonation. Heat in the block/heads, fuel quality/type/octane rating, cam timing, etc., etc., etc. But assuming everything is working correctly, detonation basically comes down to having too much cylinder pressure. The higher the compression ratio is, the more pressure is created. You want your cylinder pressure to be as high as it can be without detonation. More pressure equals more power.

When you put a blower/turbo on a motor, you’re adding more pressure to the motor “artificially.” So you’re raising your “effective” compression ratio. This puts you closer to the point where you’ll get detonation.

Years ago when fuels weren’t as good/consistent and fuel injection systems weren’t nearly as precise as they are now, you were pretty much forced into running “low” compression ratios with boost to keep from melting motors down due to pre ignition/detonation. Back in 2007, the 5.4L GT500 had an 8.4:1 compression ratio. In 2013, the new 5.8L GT500 motor got a 9.0:1 compression ratio. This is all due to Ford being able to safely fuel/time the 5.8L with the new ECU that was put in that year. It’s much “smarter” than the previous ECU. But 9.0:1 is still “low” by today’s NA standards. The 2005 Mustang GT had a 9.8:1 compression ratio, and the 2011 Mustang Coyote got 11:1 stock.

But people put blowers on the 3v and Coyote and they have “high” compression ratios without detonating them into scrap, don’t they? That’s correct. But the 9.8:1 in the 3v isn’t “that” high. The 11.0:1 in the Coyote, on the other hand, IS high. The Coyote has an advantage with its twin variable cam timing though. Tuners can set them up to bleed boost off through the midrange, where you see most detonation, to control cylinder pressures/detonation. If you couldn’t bleed off the pressure in the Coyote, you wouldn’t be able to run very much boost. 11.0:1 is high for boost and pump gas. Additionally, we (manufacturers and consumers) will do things in the aftermarket that the car manufacturers won’t because they have to warranty it under the assumption that the dumbest person in the world is driving the car, could put crap gas in it, etc.

So Why Do You Want a Higher Compression Ratio for a Boosted Motor?

More Power - More pressure equals more power. But with everything related to motors, there are trade-offs, and limits. There’s a point where you’ll simply have too much compression to run on pump gas (93 octane). Yes, you can run E85 or race fuel and run more compression/boost. But that means you won’t ever be able to run it on gas again unless you drop the boost. Not ideal for most people.

You Can Make a Small Blower Act Like a Big Blower – Depending on what your goals are and how much power you ultimately want to make, the blower you have/choose won’t be big enough. For example, if you have a Roush 2.3L TVS and you want to make 750rwhp, you need high compression. Higher compression will take whatever volume of air the blower can put out and squeeze it even more. Which will make more power. We’re in E85 or race gas territory here though. You can’t get 750rwhp out of almost all of the 3v blowers on pump gas, period. So, if you already own a blower that won’t make the power you want it to and you don’t want to/can’t replace it, bump the compression ratio and run it on E85 or race fuel. “How high can I go?” you ask? Right now it looks like the most people are pushing it to is 12.5:1.

Torque – For turbo or centri setups, a higher compression ratio is nice because the motor will make more torque when not in boost so it will be nicer to drive in real life. A centri or a turbo takes some RPMs before they start to build boost. Punch it at 3,000rpm and you’ll be waiting around a bit for it to start rolling hard/building boost. If you add compression, the power will come in sooner. No amount of compression will get a centri or turbo to act like a PD blower, though. If you punch it with a PD blower, you get full power RIGHT NOW. Yeah, a high compression PD setup will hit sooner/harder than a low compression combo. But realistically that extra torque would probably end up as tire smoke.

IATs – If you have your blower maxed out, this is probably a moot point. And most people are going for high compression because their blower is maxed out. But, if your blower isn’t maxed out and you’re not going to be putting yourself in a position of only being able to run E85 or race fuel, high compression will allow you to reach your power goals at a lower boost level than low compression. And lower boost levels mean lower IATs. How much of an IAT improvement can you expect? We weren’t able to find any concrete data on this anywhere. There are way too many factors that ultimately determine IATs for it to be a simple math problem. One car’s combo could result in wildly different results than another. We can’t imagine the IAT reduction is very much though. And if you’re going high compression/E85, it’s almost irrelevant. E85 has incredible cooling properties. A couple more deg of IAT will get “lost” in the cooling effect of E85.

So Why Don’t You Want a Higher Compression Ratio for a Boosted Motor?

Flexibility – If you go high compression and force yourself into E85 or race fuel, you just turned the car into a “race car.” Most people don’t want to be in this position.

Power/Efficiency – Raising the compression ratio one point (9.0:1 vs 10.0:1 for example) gets you about a 3% increase in power. This extra power is from the air/fuel being squeezed more. More squeeze equals more bang. If you add 1psi of boost, you’ll see a 3.4% increase in power. This is because you’re getting more squeeze (you’re compressing more air). But, more importantly, it’s because you’re getting more air into the cylinder. And more air means once fuel is added you get more bang. In this example, the motor with more boost vs more compression will make .4% more power. That doesn’t sound like much. But it’s more than if you simply bumped the compression. It will almost always be more efficient to add boost opposed to adding compression.

Safety – Your safe tuning window gets narrower the higher the compression ratio goes.

Compression Wrap Up

This section wasn’t put together to answer the question of “what compression ratio should I run?” There are way too many factors, pros/cons, etc. for that to be something that can be answered by someone other than yourself. But we’ll tell you what we’d do in a few situations.

Blower Is Not Big Enough and It Will Always Run on E85 or Race Fuel – In this case, we’d run the compression ratio at 12.5:1.

Blower Is Big Enough for My 600-650rwhp Goal, and I Want to Be Able to Run On Gas (93) and E85 - In this case, we’d run the compression ratio at 9.5-10.0:1.

Blower Is Huge and I Want to Be Able to Run on Gas (93) and E85 - In this case, we’d run the compression ratio at 9.25:1.

One Last “Food for Thought”

These days “What will the blower make?” is becoming more and more irrelevant. As time goes on and blowers get bigger, what the blower can move for air is becoming less and less of an issue. Currently, in some cases, the blowers can move more air than the motors can handle on pump gas (93) without detonation. So the question isn’t what will the blower make, the question is how much power can you make and still remain on 93 octane? In the real world, most people aren’t doing E85 or race fuel setups. So what you have is a fuel limit not a blower limit. Here’s an example that sheds light on that as well as how compression affects power.

If you have a 3v with the stock 9.8:1 compression ratio, you can safely put about 18psi to it (assuming the blower is big enough) and still run on pump gas. It will make 625-650rwhp. These numbers are based on a stock motor with forged rods/pistons, headers and big off road exhaust.

If you have a Coyote with the stock 11.0:1 compression ratio, you can safely put about 10.5-11psi to it and still run on pump gas. It will make 625-650rwhp. These numbers are based on a stock motor with headers and big off road exhaust.

Interesting that both motors make almost identical power when constrained by 93 octane gas, huh? This is because, in both cases, you’re running out of octane, not how much air the blower can move. So, if you’re going to be running on 93 (most people), it really doesn’t matter that much what your compression ratio is. You’re going to ultimately make the same power.

Belt Tensioners

We’re not going to go into a ton of detail here because we already have an entire tech article on belt systems and they’re very, very, complex. To read that article click here: Belt Tensioner Tech

Here is the short version. We have never seen (and we think we have seen them all) a tensioner aside from ours that works correctly. End of story. Nothing out there that we have seen has enough spring pressure, enough travel, or both. And without those two things your belt system will never work right. Oh, you may not chuck belts, but you will be slowly hurting parts (the tech article linked above has that information).

We came up with a very inexpensive solution, the Frankentensioner. It’s $90 and works far better than anything else out there. It’s not pretty though. We could produce pretty ones, but they would be $400+. And frankly a $400+ tensioner is silly for most people.

There are details in the Combinations sections below about stepping up to 8 rib best systems as the power goes up.

 

Combinations

The Basic 450rwhp Combo

-Cost from stock to 450rwhp - $4,000-6,500

-Cost per horsepower from stock to 450rwhp - $22-37 per HP

The 3v’s stock rods and pistons are good for about 450rwhp and 6,000rpm. After that you’re in the danger zone. They’ll eventually throw a rod out of the motor if you push it much past that. Just ignore people that say they’re good for “XX boost.” Boost isn’t horsepower and RPMs. It may or may not correlate to what power is being made, and it certainly doesn’t correlate to how fast the motor is being spun. To make more than 450rwhp, you need forged rods and pistons, so most people, we estimate 90%, stop there. 450 real deal HP on a street car is a lot of HP despite the internet telling you otherwise. There aren’t many cars in the real world that are faster. That’s 600cc sportbike fast, which is FAST! If you’re not looking for bragging rights on the internet or a specific 1/4mi time, save yourself piles of money, work, and aggravation and stick with 450rwhp.

What do you need to make 450rwhp? Nothing really but a blower kit. You can stick any of the out of the box blower kits (aside from the Roush M90) on your car with no other changes and make an easy 450rwhp. Of course, not many people go straight to the blower (it’s the most cost effective route though) and have some bolt ons. Let’s see how those bolt ons affect a blown combination and the HP they’ll make you at the 450rwhp point.

Exhaust/Off Road X/H Pipe

A cat back system or X/H pipe will make the car sound different (better), but it won’t “make” more power. You’re limited to 450rwhp anyway, which the blower will make all by itself. So exhaust gives you no measureable power advantage.

Headers

Headers will make the car sound different (better), but they won’t “make” more power. You’re limited to 450rwhp anyway, which the blower will make all by itself. So exhaust gives you no measureable performance advantage. Headers can cause some problems though. Depending on where you live, they may not be emission/inspection legal. That’s a huge pain to deal with. If they don’t make power and they’re a pain to deal with, do you want them? A secondary problem and a real one is that headers add a lot of heat to the engine compartment, even the ceramic coated ones. Heat is a very real enemy…you’ll hear us mention heat a LOT. That’s for a reason. In our opinion, all headers should be wrapped with header wrap or ceramic coated then wrapped. Wrapping headers is tedious and, if not done correctly, doesn’t last long. Best bet is to skip headers and save yourself all the problems and the money.

Cold Air Intake

As long as you don’t get a blower kit with a sealed box style airbox (there are a few out there, usually “50 State Legal” kits”), cold air intakes, or “bigger” ones than the one that comes with your blower won’t make one more HP. Skip it.

Throttle Body

A bigger throttle body, you guessed it, won’t make one more HP. Skip it.

Ported Heads

Ported heads, you guessed it, won’t make one more HP. Skip them.

Cams

Cams won’t allow you to make more than 450rwhp either. And, depending on what cams you choose, you’ll hurt torque production down low. We agree good lumpy sounding cams are fantastic to the ears. But considering they’ll make no power or you’ll lose torque, they’re a tough pill to swallow.

Other Supporting Mods at 450rwhp

Well, that’s the big stuff. And it’s all pretty much useless at the 450rwhp level. An argument could be made that, if you were to run a huge cold air intake, huge throttle body, ported heads, cams, headers, and exhaust, you could make 450hp at less boost (this is a whole different subject, just roll with it), which would net you lower intake air temps (another whole different subject, just roll with it). But the drop in boost/intake air temps would never be anywhere close to worth it considering the money involved. You would be much better off spending 25-30% of that money on intercooler system upgrades that will give you much better results for your money.

Summary: 450rwhp

So what do you need to do to make 450hp with your 3v? Put a blower on, that’s it. And it’s that easy. You can spend more money on go-fast widgets, but they won’t do you any good. Take that money and spend it on something that will give you real performance gains. Like cooling mods, suspension mods, wheels/tire mods, brake mods, etc.

All the systems out there (except the Roush M90) will make 450rwhp easily and reliably. The only performance difference that you’ll actually notice is how they control intake air temperatures, which can KILL power if too high. This mainly boils down to intercooler design. In our opinion, choosing a supercharger for the 450rwhp level/application should come down to two things. How well it handles intake air temperatures and cost. Aside from how they look, that’s the only thing that will separate them when in use.

 

The Next Step – 450-575rwhp

Going Straight from Stock to 575rwhp?

-Cost from stock to 575rwhp - $7,225-17,930

-Cost per horsepower from stock to 575rwhp $36-89 per HP

Going from 450 to 575rwhp?

-Cost from 450rwhp to 575rwhp is another $3,225-11,430

-Cost per horsepower from 450 to 575rwhp is another $25-91 per HP

Must Have Mods:

Forged Motor - $2,225-5,000

Above 450rwhp you need to run forged rods and forged pistons. It’s nice to have a forged crankshaft but not actually necessary. A lot of people have made 800+rwhp on stock cranks. Going forged isn’t inexpensive, especially if you’re unable to do your own work. Here’s what forging the bottom end looks like from a cost perspective. For the most part, this is the LEAST expensive way to do it. You could easily spend a lot more money going with better components:

H-Beam rods - $400
Forged pistons/rings - $530
Bearings - $40
Block machining/balancing - $500
Head gaskets - $185
Exhaust gaskets - $26
Main bolts – $50
Head bolts – $90
Billet oil pump gears (a real good idea) – $400

Total - $2,221

This represents the absolute least expensive way this is going to happen. This is if you do all of your own work, you have all the equipment, you have all the tools, etc. And, unless you’re a seasoned mechanic, that probably isn’t going to happen.

-If you can’t build the shortblock yourself, add about $750 for your shop to do it for you.

-If you can’t build your whole motor, add about $1,000 for your shop to do it.

-If you can’t remove/replace your motor yourself, add another $1,000.

You’re looking at $2,225-4,225 for a forged shortblock, depending on your abilities. And this can easily grow by $1,000 going with better components, etc. If you were to walk in a shop and ask for a forged shortblock and have them do all the work, you’re probably looking at a $5,000 bill.

Fuel System - $1,000-1,400

Most blower kits don’t have big enough fuel pumps and fuel injectors to get you up over 500hp. And, if they do, they’ll be on the razors’ edge. So you’re looking at fuel system upgrades (pump and injectors). There are a lot of options here but it’s a pretty safe $1,000. And another $300-400 for installation if you’re not doing it yourself.

Supporting Mods You Really Want:

These aren’t 100% necessary, but they’re pretty close.

8 Rib Belt System - $400-800

The 2005-2010 Mustang GTs come with a 6 rib belt system stock. This system was never meant to run a supercharger, just the accessories. A stock GT500 comes with a 10 rib system…that should tell you something. All of the supercharger kits available (but one) jump the supercharger in to the existing 6 rib system. And if the blower isn’t being spun too hard and your belt tensioner is good, a 6 rib system will work at 450rwhp. But, when you start to spin things up and go for more power, the 6 rib system simply doesn’t cut it, it’s way out of its league. At the 500+hp level, it’s a good time to start thinking about an 8 rib system for the car. An 8 rib system offers 33% more belt, which is significant. Because you don’t need to spin the supercharger real fast at this HP level, you can get away with using a low cost harmonic balancer/lower pulley. It’s actually a stock unit off of an Explorer. An 8 rib conversion will run you about $400. And another $300-400 for installation if you’re not doing it yourself.

Urethane Engine Mounts - $130-230

The stock engine mounts are liquid filled pillowy messes. They were designed for your average Mustang buyer, which you’re not. The problem with the stock mounts is that they flex like crazy. On the dyno you can actually see the motor twisting in the engine compartment quite a bit. This presents two problems. The stock mounts weren’t designed to handle the torque that a blown motor puts out, and eventually they’ll break/pop. Obviously not great. They also allow the motor to move enough while under load for things in the engine compartment to start contacting the engine. The engine can contact the hood, headers can contact all sorts of stuff, etc. And to add insult to injury, when the motor is twisting around like that, it makes the trans hard to shift because it puts a twisting load on the shift linkage. So you really want some urethane mounts. Good thing they’re only about $130. And another $100 for installation if you’re not doing it yourself.

Clutch - $300-1,500

Your stock clutch won’t hold up to this power level. And if it does, it won’t be for long. Budget yourself $300-1,000 for one. And another $400-500 for installation if you’re not doing it yourself.

Intercooler System Upgrades - $300-2,500

More power is made with more boost. More boost means more heat. The intercooler system components that come with supercharger kits out of the box are barely adequate at best. This is standard across the industry. At 450rwhp, it sure doesn’t hurt to run better components. When you start to play with 500rwhp+ you really want a better working system. Well, at least you want to if you want all of your power. There’s a wide range of ways to upgrade these components. You can put a bigger heat exchanger on for $300-1,000 and get better results. You can put a higher flowing water pump on for $300-500 and get better results. Or you can go full bonkers and upgrade the system size from the standard .75" to 1.25” with a 1.25” heat exchanger, degas tank, lines, and pump for about $2,000. There are lots of ways to go. The good news is that you can get much better performance than what you have (supplied with your kit) for as little as $600. And another $200-500 for installation if you’re not doing it yourself.

As far As Other Supporting Mods, This Is How It Looks:

Cat Back Exhaust

When playing with 450rwhp+ a cat back will give you a couple of HP. Nothing dramatic though. You’ll make your power at slightly less boost though, so that’s not a bad thing.

Off Road X/H Pipe

When playing with 450rwhp+ an off road X/H pipe will give you a couple of HP. Nothing dramatic though. You’ll make your power at slightly less boost though, so that’s not a bad thing.

Headers

When playing with 450rwhp+ headers will give you a couple of HP. Nothing dramatic though. You’ll make your power at slightly less boost though, so that’s not a bad thing.

Cold Air Intake

A bigger CAI certainly won’t hurt. Do you “need” one? No, not really. But a big CAI used in conjunction with a big throttle body will net you a few HP and/or allow you to run the supercharger slower for better intake air temps. You don’t need to go out of your way to use one at this point. But if one drops in your lap, run it.

If your supercharger kit has a sealed box style “airbox” CAI (usually “50 State Legal” kits”) you do want to switch out to one of the “open element” style CAIs. There aren’t very many of the sealed airbox style CAIs out there though, so your chances of running into one are slim.

Throttle Body

Like the big CAI, going with bigger TB than the one that comes with your blower will allow more air into the blower (when combined with a big CAI), which makes the blower’s job easier. Which will net you a few HP. Big CAIs and TBs up at this HP level are not a bad thing to have. Not worth selling a kidney for, but you don’t want to kick one out of bed for eating chips either.

Ported Heads

Ported heads won’t make measurable HP. They’ll drop your boost a little though. But that’s not enough reason to spend $2,000+ on ported heads. We’ve seen 650+hp combos with stock heads, lots of them. Skip them at this point.

Cams

Cams will make more power at this point, sorta-maybe. Cams are tricky and work/don’t work in a lot of different ways. And even if we understood everything about cams, which we don’t, we wouldn’t be able to go over it here.

With some cams you will see a shift in the power curve more than an actual power gain/loss. For example, you may pick up 30hp after 6,000rpm but at the same time you lose 30tq at 3,000rpm. With another cam you may actually see that 30hp gain with no loss of TQ. Then you start throwing the whole limiter/lockout thing at it and your results can be all over the place. We have seen cams that didn’t make power, cams that shifted power and cams that made some power up top with no loss down low. This is something that you need to “gamble” with yourself. We don’t have enough experience in this segment to be the last word.

We’ve been a part of many, many combinations that have made 600+rwhp with stock cams. And they retain mountains of torque. Our “go to” stance on cams at this level is leave them stock. But if you do the research and get good information and you gotta have cams go for it. We love the sound of cams. And we love more HP. We get it. We wouldn’t skimp on other necessary items to stay within a budget though, that’s for sure. You can always put cams in later.

Summary: Other Supporting Mods at 450-575rwhp

Well, that’s the big stuff. And it’s all pretty much useless at the 450-575rwhp level. An argument could be made that if you were to run a huge cold air, huge throttle body, ported heads, cams, headers, and exhaust you could make 450-575hp at less boost (this is a whole different subject, just roll with it), which would net you lower intake air temps (another whole different subject, just roll with it). But the drop in boost/intake air temps would never be anywhere close to worth it considering the money involved. You would be much better off spending 25-30% of that money on intercooler system upgrades that will give you much better results for your money.

Dollar Per Horsepower

You’ll spend $22.85-37.14 per HP to get from the stock 275rwhp to 450rwhp.

You’ll spend ANOTHER $25.80-91.44 per HP to get from 450rwhp to 575rwhp.

If you can do all of your own work and you go entry level on everything, the $$/HP isn’t very bad at all. Just a touch more per dollar than it costs to get from stock to 450rwhp. But at the other end of the spectrum, it’s pricey at $91.44/hp. You’ll probably land somewhere in the middle of that range because you’ll be able to do some things yourself but have to farm other stuff out. Is that HP between 450 and 575 really worth it to you? When it’s broken down like this we’re sure you can see why a lot of people stick with 450rwhp.

What Is Our Suggested 575rwhp Combo?

This is what we would do for a 575hp combo:

-Department Of Boost GT450 Phase I
-Eaton M122 supercharger (stock 07-12’ GT500)
-Stock GT500 throttle body
-Stock 2010+ GT500 CAI

-Forged H beam rods
-Forged pistons (9.5-10.5:1)
-Stock crank (balanced)
-Bearings
-Block machining/balancing
-Head gaskets
-Exhaust gaskets
-Main bolts
-Head bolts
-Billet oil pump gears

-Stock heads

-FRPP 52lb/hr fuel injectors (stock 13’ GT500)
-FRPP dual “GT500” fuel pump kit

-8 rib belt system
-Urethane engine mounts
-Clutch
-13’ GT500 heat exchanger
-13’ GT500 intercooler water pump

Why This Combo?

This is the least expensive way to make 575rwhp. If you start with a complete blower kit you will at a minimum be upgrading the fuel injectors, fuel pump(s), heat exchanger and water pump. That means you bought them twice. If you build a kit around the GT450 manifold you buy that stuff once. And the GT450 is simply less money to begin with. Most of the blowers will make the 575rwhp. You will just spend more doing it that way.

This is the “coolest” way to do it. The GT450 IC is better than the rest. No matter what you use for a water pump and HE the GT450 will always perform better than the others. And that means more of your power, more of the time.

 

 Things Just Got Real
575-700rwhp

 

Going Straight from Stock to 700rwhp?

-Cost from stock to 700rwhp - $11,355-36,060

-Cost per horsepower from stock to 700rwhp $26-84 per HP

Going from 575 to 700rwhp?

-Cost from 575rwhp to 700rwhp is another - $4,130-18,130

-Cost per horsepower from 575 to 700rwhp is another - $33-145 per HP

 

When you’re looking at over 600rwhp things just got “real”. Despite what the internet tells you there are not very many 3v’s out there making this sort of power. Lots of claims yes, lots of hero runs on the dyno, yes. And lies? Yes, lots of lies. 2013 GT500’s make about 585-600rwhp stock and about 700rwhp with pulleys, big TB, big CAI, injectors, BAP and headers/exhaust. Stock the GT500’s were $65,000ish and to get to 700rwhp those guys are spending another $5,000-8,000. This is “not screwing around” power and it costs real money no matter how you go at it.

Actual 3v’s making this sort of power in real life are few and far between. The main reason is money and effort. But a secondary reason is you’re getting into “race car” territory. And “race cars” are just plain harder to deal with. You’ll not be jumping in, hitting the key, and driving it like a daily driver. It needs more attention, maintenance, etc., etc., etc. If you want this sort of power great!!! Who doesn’t right? But be aware that this sort of power is not “keeping up with the Jones’s,” it’s more than what the Jones’s have. And be aware that you are firmly in the zone of diminishing returns. You’ll spend a lot of money, time, anguish, etc. playing on this particular playing field. And lastly, be aware that some of the superchargers for the 3v can’t make this sort of power. Depending on what supercharger you have you may not be able to make these numbers no matter how much money you throw at it.

Must Have Mods:

Forged Motor - $2,225-5,000

Above 450rwhp you need to run forged rods and forged pistons. It’s nice to have a forged crankshaft, but not actually necessary. A lot of people have made 700+hp on stock cranks. Going forged is not inexpensive, especially if you are unable to do your own work. Here is what forging the bottom end looks like from a cost perspective. For the most part this is the LEAST expensive way to do it. You could easily spend more money going with better components, ARP fasteners, etc.:

H-Beam rods - $400
Forged pistons/rings - $530
Bearings - $40
Block machining/balancing - $500
Head gaskets - $185
Exhaust gaskets - $26
Main bolts – $50
Head bolts – $90
Billet oil pump gears (a real good idea) – $400

Total - $2,221

This represents that absolute least expensive way this is going to happen. This is if you do all of your own work, you have all the equipment, you have all the tools, etc. And unless you’re a seasoned mechanic, that probably isn’t going to happen.

-If you can’t build the shortblock yourself add about $750 for your shop to do it for you.

-If you can’t build your whole motor add about $1,000 for your shop to do it.

-If you can’t remove/replace your motor yourself, add another $1,000.

You’re looking at $2,225-4,225 for a forged shortblock depending on your abilities. And this can easily grow by $1,000 going with better components, etc. If you were to walk in a shop and ask for a forged shortblock and have them do all the work, you’re probably looking at a $5,000 bill.

Fuel System - $1,300-1,700

Not one blower kit has big enough fuel pumps and fuel injectors to get you up to 575rwhp. And nowhere near 700rwhp. So you’re looking at fuel system upgrades. There are a lot of options here, but it’s a pretty safe $1,300. And another $300-400 for installation if you’re not doing it yourself.

8 Rib belt system - $850-1,250

The 2005-2010 Mustang GTs come with a 6 rib belt system stock. This system was never meant to run a supercharger, just the accessories. A stock GT500 comes with a 10 rib system that should tell you something. All of the supercharger kits available jump the supercharger in to the existing 6 rib system. And if the blower isn’t being spun too hard and your belt tensioner is good, a 6 rib system will work at 450rwhp. But, when you start to spin things up and go for more power, the 6 rib system simply doesn’t cut it, it’s way out of its league. At the 500+hp level, it’s a good time to start thinking about an 8 rib system for the car. An 8 rib system offers 33% more belt, which is significant. Another thing is that, at this HP level, you need to spin the blower really fast, and that tales an overdrive (larger) harmonic balancer/lower pulley. Getting an overdrive balancer is a two-fer though. You can spin your blower faster, and you get the engine safety of running a good quality balancer (your motor will thank you). An 8 rib conversion will run you about $850. And another $300-400 for installation if you’re not doing it yourself.

Urethane Engine Mounts - $130-230

You’ll destroy the factory liquid filled engine mounts in short order with this sort of power.

Clutch - $450-1,650

Your stock clutch won’t hold up to this power level. Budget yourself $450-1,000 for one. And another $400-500 for installation if you’re not doing it yourself.

Intercooler System Upgrades - $600-2,500

More power is made with more boost. More boost means more heat. And, at these power levels, you’re looking at quite a bit of boost. The intercooler system components that come with supercharger kits out of the box are barely adequate at 450rwhp/9-10psi. This is standard across the industry. At these power levels you need to make some upgrades if you want all of your power. Even if the car is stone cold when you launch it at the drag strip, you won’t make it through the lights before the intake air temperatures are too high and the ECU starts to pull timing. And that kills power. And that’s perfect conditions. You’ll be pulling timing almost all the time in real life.

There’s a wide range of ways to upgrade these components. You can put a bigger heat exchanger on for $300-1,000 and get better results. You can put a higher flowing water pump on for $300-500 and get better results. Or you can put a bigger heat exchanger and high flow water pump on together and get even better results. You can also go full bonkers and upgrade the system size from the standard .75" to 1.25” with a 1.25” heat exchanger, 1.25” degas tank, 1.25” lines, and pump for about $2,000. There are lots of ways to go here. The good news is that you can get much better performance than what you have (supplied with your kit) for as little as $600. And another $200-500 for installation if you’re not doing it yourself.

Cat Back Exhaust - $550-1,100

When playing with 575rwhp+ a cat back will give you some power. Somewhere in the neighborhood of 10-20 HP. The stock cat back simply can’t move all the gases that are generated making this sort of power. Additionally, the stock mufflers have been known to “explode” when making big power. This is why you “have” to have one. It will also drop your boost a little bit, which is a good thing, because at these power/boost levels, you’re getting to the point where 93 octane pump gas won’t be enough. Cat back systems run $450-1,000. And another $100 for installation if you’re not doing it yourself.

Off Road X/H Pipe - $250-450

When playing with 575hp+ a, off road X/H pipe will give you a couple of HP. Nothing dramatic though. But, at these HP levels, catalytic converters have been known to come apart, block up the exhaust, and destroy the motor. It’s standard operating procedure to run an off road mid-pipe at these HP levels. It will also drop your boost a little bit, which is a good thing, because at these power/boost levels, you’re getting to the point where 93 octane pump gas won’t be enough. Off road X/H pipes run $150-350. And another $100 for installation if you’re not doing it yourself.

Cold Air Intake - $0-400

None of the CAIs that come with supercharger kits are real happy about making more than 600rwhp. Well, two kits have enough CAI, more on that in the kit review section. Some of them won’t make 600rwhp at all. Inlet restriction to the supercharger is a big deal at these HP levels. You really want a big CAI to reduce inlet restriction. This will allow you to make more boost at the same blower speed and reduces intake air temperatures. With some blower kits you really want one, with other kits you have to have one, and with other kits you can’t actually get bigger ones. Taking into account that you can’t get big CAIs for some supercharger kits, the price range is $0-400.

Throttle Body - $0-800

Like the CAIs, none of the throttle bodies that come with supercharger kits are real happy about making more than 600rwhp. Well, two kits have enough throttle body, more on that in the kit review section. Some of them won’t make 600rwhp at all. Inlet restriction to the supercharger is a big deal at these HP levels. You really want a big throttle body to reduce inlet restriction. This will allow you to make more boost at the same blower speed and reduces intake air temperatures. With some blower kits you really want one, with other kits you have to have one, and with other kits you can’t actually get bigger ones. Taking into account that you can’t get big throttle bodies for some supercharger kits, the price range is $0-800.

Mods You Want, But Don’t Have to Have:

Headers - $0-1,500

When playing with these big power numbers, headers sure don’t hurt. They’ll be worth 10-30hp but, most importantly, they’ll reduce the boost level and make it easier (or possible) to run on 93 octane gas. Because you don’t have to have them, the cost scale starts at $0. Price range $0-1,000. And another $300-500 for installation if you’re not doing it yourself.

Ported Heads - $0-4,100

When playing with these big power numbers, ported heads sure don’t hurt. They’ll be worth 10-30hp but, most importantly, they’ll reduce the boost level and make it easier (or possible) to run on 93 octane gas. Because you don’t have to have them, the cost scale starts at $0. Price range $0-3,600. And another $300-500 for installation if you’re not doing it yourself.

Cams - $0-1,900

Cams will make you any more power at this point, sorta-maybe. Cams are tricky and work/don’t work in a lot of different ways. And even if we understood everything about cams, which we don’t, we wouldn’t be able to go over it here.

With some cams you will see a shift in the power curve more than an actual power gain/loss. For example, you may pick up 30hp after 6,000rpm but at the same time you lose 30tq at 3,000rpm. With another cam you may actually see that 30hp gain with no loss of TQ. Then you start throwing the whole limiter/lockout thing at it and your results can be all over the place. We have seen cams that didn’t make power, cams that shifted power and cams that made some power up top with no loss down low. This is something that you need to “gamble” with yourself. We don’t have enough experience in this segment to be the last word.

We’ve been a part of many, many combinations that have made 600+rwhp with stock cams. But we’re starting to get to the point where you really want to consider them. Certainly at 600+. At this point shifting the power up in the curve is not a bad thing. You will be making MOUNTAINS of torque. Shifting the power up will make the car a lot easier to drive. There aren’t many tires that won’t instantly turn to smoke at this level with stock cams. You will also see a slight decrease in boost, which is a good thing. If you pick the right cam you will see more of a top end charge (more power). There are a lot of good reasons to go for cams at this point. But you don’t NEED them. If your budget is constrained skip them for now and do them later.

Price range $650-1,400. And another $300-500 for installation if you’re not doing it yourself.

Valve Springs - $0-400

If you’re going with cams you will already be getting valve springs. But if you’re retaining the stock cams you still want to consider them. At these boost levels the intake valves can be slightly unseated (open) by the pressure if the valve springs aren’t stiff enough. Add to that you will be spinning more RPM’s (probably) than your average person which will “bounce” the valves if there isn’t enough spring pressure and you have a recipe for power loss. Springs aren’t very expensive and on a build like this not a big deal to add to the list of things to do.

ARP Fasteners (Motor) - $0-550

You don’t have to use ARP fasteners at this power level, the stock fasteners will hold up….barely. They run about $550.

 

Dollar Per Horsepower

You’ll spend $22.85-37.14 per HP to get from the stock 275rwhp to 450rwhp.

You’ll spend ANOTHER $25.80-91.44 per HP to get from 450rwhp to 575rwhp.

You’ll spend ANOTHER $33.04-145.04 per HP to get from 575rwhp to 700rwhp.

The small end of the scale ($33.04) is not entirely representative. That would be for a combination that you’re going to do all the work on and is based on a supercharger that can’t make 700rwhp, and therefore don’t need/can’t use some of the parts/options. That amount is more representative of roughly 600-620rwhp. Playing up at the big end of the scale gets a lot more expensive.

Even if you can do all of your own work and you go entry level on everything, the $$/HP at 650ish rwhp is getting real ugly. You’re looking at about $120/hp. But the top end of the spectrum is getting a little bonkers at $145.04/hp. Is that HP between 575 and 700 really worth it to you? When it’s broken down like this we’re sure you can see why a lot of people stock with 450rwhp. Or even 575rwhp.

And don’t forget, when playing with big power you need all sorts of other supporting car mods. Transmission, driveshaft, rear end, brakes, suspension, etc., etc., etc.

 

What Is Our Suggested 650-700rwhp Combo?

This is representative of what we would do as a minimum for this power level. This will work very well, but everything can be better right? If we were going to throw more money at it, we would spend it on the intercooler system components (heat exchanger, pump, etc.), a return style multi pump fuel system ,and cams.

This is what we would do for a 650-700hp combo:

-Department Of Boost GT450 Phase I
-Eaton 2.3TVS supercharger (stock 13-14’ GT500)
-Cobra Jet or VMP TB
-JLT Big Air CAI

-Forged H beam rods
-Forged pistons (9.25-10.5:1)
-Bearings
-Block machining/balancing
-Head gaskets
-Exhaust gaskets
-ARP Main bolts
-ARP Head studs
-ARP rod bolts
-Billet oil pump gears

-Stock heads

-1 3/4" long tube headers
-3” off road X pipe
-3” cat back system

-iD1000 fuel injectors
-FRPP dual “GT500” fuel pump kit
-Boost A Pump

-8 rib belt system w/ OD balancer
-Urethane engine mounts
-Clutch
-13’ GT500 heat exchanger
-13’ GT500 intercooler water pump

Why This Combo?

This is the least expensive way to make 575-700rwhp. If you start with a complete blower kit (assuming it will make this much power, some won’t) you will at a minimum be upgrading the fuel injectors, fuel pump(s), heat exchanger and water pump. And maybe the TB, CAI, MAF, etc. That means you bought those parts twice. If you build a kit around the GT450 manifold you buy that stuff once. And the GT450 is simply less money to begin with.

The 13’ GT500 TVS blower makes the most power out of all of the 2.3L blowers. It was designed last, it makes sense. It’s also relatively inexpensive.

This is the “coolest” way to do it. The GT450 IC is better than the rest. No matter what you use for a water pump and HE the GT450 will always perform better than the others. And that means more of your power, more of the time.

 

Big Big Horsepower E85/Race Fuel Combinations
700rwhp+

This is the point where things go bonkers. You’re pretty much in full race car territory here. We won’t get into specific combinations. There are way too many variables at this point.

At this point, you’re in BIG DOLLAR territory. Especially if you want it to make big power for more than one hit when the car is stone cold. There aren’t many 3v’s on the planet that truly make more than 700rwhp consistently despite it seeming that way on the interwebs. We’d take a wild guess and say it’s maybe 25 cars. If you want to play on this playing field, keep in mind you’re playing with the “Pros.” It’s not easy, it’s not cheap, and there are sacrifices to be made.

Two Major Things Crop Up - Heat and Belts

Heat is always going to be an issue with forced induction. But, up at this level, it’s a major factor. If you want a car that will run a fast 1/4mi time or put down a big number on the dyno, it’s not a huge problem to solve. Especially because you can run an ice chest in these situations. It still needs to be solved though. And, depending on what system you’re running, even with an ice chest, it will still run hot and pull power in as little as 8-9sec. Street or street/strip cars on the other hand need everything and the kitchen sink thrown at them as far as cooling goes if you want to have full power even most of the time. If you want a road course car at this level, get your wallet all the way out. You’ll most likely be looking at custom parts.

Belt systems can be very problematic. There are a lot of factors in if the car will eat belts, have belt slip, etc. If you have relatively high gearing (3.55s for example) and a manual trans, things are going to be rough on the belt. The large RPM drop between gear changes is really tough on the belt. If you have an auto trans and shorter gearing, the belt has a much easier time. But, at the end of the day, it’s just plain tough on belts. All the blowers but one that will make this power jump the blower into the existing belt system. This makes for a very long belt, and long belts stretch a lot. You can go with an 8 rib conversion, which will help. But using the bigger blowers and running them hard on a system with an 8 rib 125”+ belt will never actually work 100% right. You can get them to sorta “live” depending on a lot of factors, but, in most cases, the only reason they’re staying together is that a tensioner is being used that bottoms out hard on its maximum travel stop. This may keep the belt on, but it’s no good for your oil pump gears, crank snout and every bearing in the belt system. You can read more about that situation in our Belt Tech article.

GT500s use a 10 rib belt that’s about 85” long (which stretches a whole lot less than an 8 rib 125”+ belt…..about 45% less), and those guys have belt problems. If you talk to the belt manufacturers, they’ll tell you at this point you need to be running a 12 or 14 rib belt. Do we get away with 10 ribs? Yes, but it’s because we run them a lot tighter than they were designed to. And if a short 10 rib can barely get the job done, a long 8 rib is in for a tough day of work. We’ve seen multiple people that make big power running at the track that go through a belt per run. Belts can be a huge deal.

Dyno Queens don’t see nearly the issues that a drag car does. The dyno is really easy on belts.

What Kind of Combo Do You Want?

People want different things from their cars. Especially at this point. Some people want a car they can drive to/from work every day, cruise on the weekend, etc. Something low maintenance and reliable. Other people may want a car they’re going to trailer to/from the drag strip and are looking for a good 1/4mi time. Another person may be tearing up the twisty back roads or doing track days at the road course. And some people want a big fat dyno number they can post up on Facebook. All of these needs will require a different combination.

Getting this combination right from the start is key to not spending a fortune and doing things 2-5x until you get the performance you want in the environment you want to be in. More people than not fall short of their goals because they don’t know what they’re getting into and eventually their budget kills them. This means there are a lot of cars out there with a pile of go-fast goodies on them that don’t work very well anywhere but the dyno. And sometimes not even there.

The first thing to do is set realistic goals. This is not just a HP goal. This is what you want from your car. You’ll not be very happy if your car makes 900rwhp on the dyno but falls flat on its face when you’re driving it. Or you’re working on it more than driving it. Or it’s just plain not fun to drive.

Once you have your goals set in your head, map out what it takes to get there with help from someone WHO HAS DONE IT BEFORE. Which is about 25 people.

Now figure out how much that costs. Unless you’re one of only a handful of people (we’re not in that handful), you’ll find you don’t have the budget to build an 800rwhp car that will drive around on the street with no problems and make power in situations other than the dyno. It’s going to be a boatload of money. Better to find out now you don’t have the budget before you’re half way in. Not having a budget is what dooms most projects.

If you want advice on reaching goals in this range, drop us an email. We’ll be happy to help you meet your goals on your budget. Or at least get you as close as you can to your goals with the budget you have.

Wrap Up

We hope this is helpful to those of you looking to add boost or add more boost. We, of course, aren’t able to cover absolutely every situation, but this is the broad strokes and will give you a good idea what the playing field really looks like.

In our experience, unreasonable/unattainable expectations are what kills most projects or prevents them from becoming what they were supposed to be.

Modding your car is supposed to be fun, right? Driving you modded car is supposed to be fun, right? Unfortunately a lot of people don’t end up having nearly the fun they thought they would. But they could have with a solid plan based on “realities.” If you stay realistic and have a solid plan, you can have fun, a LOT of fun.

If you have any questions, shoot us an email at departmentofboost@yahoo.com

Thanks!

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