500 Horsepower Mod for a 03-04 SVT Mustang Cobra

Ah, the 03-04 supercharged SVT Ford Cobra, the one the street racers call the Terminator; and there's a good reason, because the Cobra is and should be the king of the road. From the factory the SVT Cobra comes with all the goodies, a supercharged 4.6 modular V8 making 340whp mated to a more than capable T56 Tremec 6 speed transmission with independent rear suspension. From the factory the SVT Cobra achieves 60mph in just 4.5 seconds and blasts the quarter mile in 12.9 seconds at 111mph. So what else could you want from a SVT Cobra other than the beautiful two tone leather and suede seats? How about more horsepower! What if I was going to tell you the simplest and most effective methods for achieving just over 500 horsepower on pump gas. Well, I am and you're most likely going to be able to do the work yourself, I'm not saying it won't be time consuming; however it will be worth it. There's nothing like the squeal of the Eaton blower on a SVT Cobra, but with new pulleys it will really whine for you; it's like a calling card for death to other cars. So, what are you going to need to do this? A few principles, hand tools, a little automotive knowledge, two jack stands, patience, and some good old fashioned SVT Cobra performance parts (that I will include links to the companies that supply the parts) and I'm going to tell you why.

The SVT Cobra parts you will need include: A PCM (engine computer) flash tuner (such as Diablo Sport or Superchips), performance throttle body and upper plenum, long tube headers, x-pipe, cat back exhaust, some tune up items such as: new direct fire coil packs, spark plugs, low temp thermostat, an upper and lower crank and supercharger pulley upgrade, a new alternator pulley and two new idler bearing pulleys, and a Goodyear gator back serpentine belt.

Optional SVT Cobra parts highly recommended include: Centerforce dual friction clutch kit with new pilot and throw out bearing, lightweight aluminum flywheel, IRS brace (independent rear suspension brace), RPM Outlet stage 3 cooling kit which includes a heat exchanger, coolant holding tank and power steering cooling accessories, some Evans Coolant.

**The flash tuner--Your going to need on your SVT Cobra this so you can tell the engines computer what modifications you have done in order for it to adjust fuel delivery and timing curves as well as other operations such as modify fuel cut off, max mph, and rev limit. Some of these devices have USB ports so you can upload different tunes for your modifications to your SVT Cobra from different performance dyno tuners. This is a must have.

**Performance throttle body and upper plenum--These two parts were designed to be restrictive from the factory, by limiting the amount of airflow to the supercharger they were able to lower the horse power output of the engine in order to make it safer, more fuel efficient, and fit into certain insurance categories.

**Exhaust system--Whether you choose to put a racing x-pipe in the exhaust system is up to you depending on emission legalities in your state (I live in Florida where they don't test, so I would want to get more power); Having long tube headers and a complete free flowing exhaust system is an excellent way to get free horsepower from the restrictive nature of the factory manifolds and exhaust, remember they were trying to detune the SVT Cobra motor from the factory not make more power. When putting a free flowing exhaust system on your SVT Cobra you will be doing two things, first you will be lowering the amount of back pressure in the exhaust system and effectively lowering your egt's (exhaust gas temperature), this means that you're going to be making your SVT Cobra engine run cooler and more efficiently thus gaining power. The less restriction an exhaust system has the more capable it is of removing "dirty" (or already ignited air/ fuel mixture) exhaust gases from the combustion chamber, when there is an exhaust gas restriction it causes the spent gases to build up pressure and stagnate near the cylinder heads exhaust port; when there is pressure in this are and the exhaust valve opens not all of the exhaust gas (after combustion from the power stroke) is divorced from the combustion chamber, leaving the combustion chamber overly hot and filled with unusable spent gases that will fill the potential space of clean and new air/ fuel mixtures when the intake valve opens. So, when having a forced induction engine a free flowing exhaust system is a must have to keep the egt's down because there is so much pressure during the combustion process in the cylinder chamber and a immense amount of heat and pressure you want out of the engine to keep the engine reliable and maintain longevity. A good exhaust system on a SVT Cobra will gain you about 45 horsepower and 50-55 ftlbs of torque.

**Tune up items--You are going to want to do a tune up on your SVT Cobra engine in order to make absolutely sure it's in perfect running condition, especially you SVT Cobra's ignition system, you want to replace the factory SVT Cobra direct fire coil packs with aftermarket higher quality ones, these are known to fail and while you're at it you are going to want to put fresh spark plugs in your SVT Cobra's engine that have a colder heat range. You're doing this to prevent possible detonation from extremely high combustion chamber temperatures in your Cobra's engine. It's also a good idea to put a lower temperature thermostat in your SVT Cobra's cooling system so that it opens up earlier and allows coolant to pass through the radiator sooner cooling the SVT engine down a few degrees.

**Upper and lower pulleys--This is where you're going to get almost all your power from, what were trying to achieve is to spin the supercharger much faster than it usually rotates thus making the rotors inside the supercharger move faster and compress air at a much faster rate; the faster this process goes the more air will enter the chamber. One drawback to over spinning the factory SVT Cobra's supercharger is the temperature increase in the air going into the combustion chamber, the supercharger is only meant to be so effective at certain speeds to maintain proper intake air temperatures. So, in order to remedy this situation we don't want to force to much boost pressure into the SVT Cobra's engine and we want to be able to cool these temperatures down more. So, when purchasing pulleys you are going to want to get the upper supercharger pulley in 2.8" or 2.93" this will create an additional 5-6psi over your stock boost levels (you need to purchase a vacuum/ boost gauge so you can read how much boost your SVT Cobra engine is producing). Lower pulleys are larger in diameter and the come in boost increase increments of two such as: 2, 4, 6, and 8psi increases. Now we all think bigger is better, but you have to be careful with the 6psi and the 8psi crank pulleys on your Cobra as they will heat up the air considerably in conjunction with the upper supercharger pulley and possibly cause engine damage without the proper cooling equipment. So, if your not going to upgrade your SVT Cobra's cooling system stay away from the 6psi and 8psi crank pulleys. Don't forget to buy the optional alternator pulley, changing the other pulleys and not changing this one will cause your alternator to run to fast and damage it.

**RPM Outlet stage 3 cooling kit- This is a must have if you're using the higher psi pulleys, it includes a larger capacity and better designed heat exchanger to get that cool air moving through it to lower the temperature of the superchargers internal exchanger and it offers a larger capacity coolant tank to lower the coolant temps more. I suggest using Evans coolant because it is built for hot engined race cars and is perfect for a way over boosted SVT Cobra, it will lower your coolant temps considerably as well as draw heat out of the cylinders. It's like magic, it affordable and requires no checking or refilling; they use it on ambulances, fire trucks, and drag racing engines.

**Clutch--Get the Centerforce dual friction clutch kit, your factory SVT Cobra clutch will no hold an additional 160 horsepower and you shouldn't expect it to. It may hold for a while, but it will fail in a short amount of time. If you have some extra coin get a lightweight aluminum flywheel for your Cobra, this is free horsepower and your engine will rev faster with more response.

**IRS brace--SVT Cobra's are notorious for wheel hop when you increase their horsepower so it is a wise decision to install one of these braces to prevent the rear differential from moving around and changing the independent rear axles geometry. Without this piece of hardware you can break your rear end or your axles, both will leave you stranded.

If 500 horsepower isn't enough then add a small 50-75hp shot of nitrous on top of that, the engine can take it and it will cool the intake temps to a chilling temperature, but the factory fuel system will be inadequate and I'll describe the parts and modification necessary for high horsepower SVT Cobra fuel systems and more power increases that you can bolt on in my next article.

http://www.rpmoutlet.com/03cobra.htm
http://www.teamjdm.com/shop/index.php?cPath=10