A turbo Mustang just might be the ultimate power adder for the buck. Not only that, with advances in kit engineering, installing a turbocharger in your pony car is within the capability of the mechanically inclined enthusiast.
As we mentioned in the performance parts section, a turbocharger is a quick way to bolt on a lot of horsepower. Even on a stock Mustang, a basic single turbo kit is enough to transform your everyday stocker into a beast!
Turbo Mustang theory:
A turbocharger works to compress the air/fuel mixture into a denser charge. And the more air and fuel you can cram into the engine on each intake and compression stroke, the more power you can make. A turbo Mustang uses waste exhaust gasses to turn a turbine to an extremely high speed (upwards of 100,000 rpm). A second chamber with another turbine draws incoming air into the turbine and forces a positive pressure into the intake plenum. A separate powered fuel nozzle injects more fuel into the stream of pressurized air in a specified ratio and the mix is forced into the cylinder under pressure. By comparison, in a normally aspirated engine, air and fuel are drawn into the engine under vacuum.
In stock form, Ford managed to increase the wimpy 88 horsepower inline four cylinder motor in early fox body turbo mustang cars to 140 hp, which was equal to the 5.0 liter V8 at the time. Just think what a Mustang turbo kit could do for your V6 or V8 car!
With standard hot rodding techniques, a whole lot more power is available. Lower compression forged or hypereutectic pistons a free flowing set of heads and other mods coupled to a dual turbo set up can turn an already decent GT into a twin turbo Mustang screamer.
Quarter mile times in the 9's and 10's are not dreams with a twin turbo kit.
On purpose, I'm not going to spend a lot of time explaining the difference between a T3 and a T4 turbo, or a T3/T4 combination, or maps for turbos, as I'll leave that to the turbo geeks.
The nice thing these days is that unlike the old days, when you slapped a turbo on your motor held your breath and dropped the hammer, waiting for either more power or an explosion, its easy to find the right kit without much effort.
However, I'm going to give you a quick and dirty way to figure out roughly what you're looking to get from different turbocharger boost levels and sizes.
Some Basic Rules:
When we say that you can produce X horsepower with a certain combination, its important to remember that engines don't make the same power at all rpms. Camshaft profiles, head flow and other things determine where power comes in and goes out on a naturally aspirated engine and adding a Mustang turbo kit can add a few more.
Smaller turbos make power sooner (ie. lower rpms)and larger turbos make more power overall (at higher rpms).
Street and Strip Turbocharging
A good street turbo kit can start making horsepower at say, 2,000 rpm, while a full-on race unit may make maximum power at 5,000 rpm. so, while a big unit might be just what you need on your drag car, it will probably be disappointing on a street Mustang.
Pressure Makes Power
Keeping that in mind, lets figure out what you can achieve given that you know now, what power your pony car is making.
At sea level, air like everything else has weight. Air stacked on air, from the top of the atmosphere down to land exerts a pressure of 14.7 pounds per square inch (psi). So a stock 289 V8 that makes 210 horsepower at sea level takes an intake manifold pressure to produce that output.
If you've ever taken a vintage Mustang up into the mountains, you've probably noticed that power isn't what it was at sea level. You've heard that the air was "thin", which means it had less oxygen, which reduced output. The higher pressure packs more oxygen in the same amount of space and the result is more power.
Hmmmm.... so if we could pack more air into a motor at sea level we make more power?
Well... yes and no. To a point we can make more power, but since power is also a function of the ratio of air to fuel, adding more air but not more fuel means we run lean, which reduces power and can wreck an engine.
So knowing how much more air gets packed in, we can figure out how much more fuel to add to take full advantage of all that extra air.
How much boost is enough?
But installing a Mustang turbo kit, do we really need to know what that is? Nope. They figured it out already.
So what we really need to know for the most part,is only how much more power over the non-turbocharged base we are looking for, to get the right kit.
When we get to a certain point, at the higher end of a street or strip motor, the manufacturer is going to tell you what you need, and may include parts like a larger throttle body,bigger injectors, freer flowing heads or a computer modification.
So in our classic Mustang example, lets say we are looking for 400 horsepower from that stock 289 V8. We know that at the atmospheric pressure of 14.7 psi we produce 210 hp, so adding another 14.7 lbs of boost pressure, should produce approximately 420 horsepower.
How to Calculate Horsepower Output
If you want a different number, here's how to figure it out:
We know we can get roughly 210 more horsepower with 14.7 lbs of turbo boost. Then take that 14.7 and divide it by 210 (the extra horsepower). The answer = .07 which you can now multiply by your desired extra horsepower to see how much boost is needed.
( .07 X 100 (the extra horsepower you want) = 7 lbs of boost for a total horsepower of 310 )
Easy like pie!
But we wanted 400 horsepower, so lets take .07 X 190 ( the extra horsepower to up it to 400) and we get 13.3 lbs of boost pressure.
So you could just look for a turbo kit that makes about 13.3 lbs of boost. Does that work? Yep. Our little 210 horsepower 289 V8 gets another 190 horsepower at 13.7 psi for a total of 400 horsepower.
Put the power where you want it
The last part of the equation is where in that power band you want that extra power and that comes down to how you drive, where you want it and where the original motor makes its power.
And that is where you start to look at turbo Mustang kit specs. Find the kit that suits you. If you want lots of power and you already have trouble getting traction, get a bigger body turbo, which will take longer to make the extra power.
If you have lots of top end, but no low end grunt, a smaller turbo mustang kit will probably make you a lot happier. Or maybe a twin screw setup would work better.
Types of Mustang turbo kits:
Single turbo kits:
A single turbo Mustang set up, consists of one turbocharger, mounted to the exhaust outlets on one side of the motor.
Depending on the age of your car, some turbo kits for computerized cars, include a computer tuner chip to change the fuel map of the motor and time injector pulses, a blow off valve, plus larger injectors. Earlier packages simply use what's called a waste gate, to bleed off excess pressure when required and a single injector to add the additional fuel.
The amount of extra power is determined by the size of the turbo and the amount of boost that is set.
Twin turbo Mustang kits:
Twin turbo mustang kits provide more total power, as well as the potential to improve overall throttle response and driveability.
The two typical offerings fall into one of two categories:
Two smaller turbos:
Smaller turbochargers spool up faster, which means when you mash the throttle, you get that extra boost and power faster than you would with only one big unit.
One smaller and 1 larger turbo:
The idea here is that the smaller turbo gets to speed faster and you get a more instant throttle response, then as power and engine speed increase, the second turbo kicks in and delivers the one-two punch when getting traction is less of an issue.
Turbo Kit Sources
The next page has some sources of kits to turn your pony into a
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