Bone Stock the Cobra was rated at 390 hp. It had a stock boost of around 9psi with the Eaton supercharger. Here’s a stock graph of my 04 Cobra:
- Cat Back exhaust ( Magnaflow is a very good option)
- K&N FIPK intake or JLT
- 2.76” upper pulley (Billetflow) which will increase boost to about 15psi.
- Billetflow snub Idler tensioner
- NGK TR6 plugs gapped at .035”
- Performance Dyno Custom tune
Here are the results:
- Add a 4lb lower pulley and 2.93” upper pulley
- High flow cats.
This will keep the boost at about 15psi but increase torque because of less belt slip. By increasing the lower drive pulley we can turn the blower the same speed with a bigger upper and reduce belt slip. Here are the results over the 2.76” upper only, notice the torque is huge but peak power is not there. That’s because the boost is high during the lower rpm’s where you develope torque but noses over at high rpm’s:
If you want to increase peak hp then the blower will need to be ported. Cobra’s have a fuel system that will support about 470rwhp before everything maxes out. In order to be able to port the blower you’ll need the following:
- Kenne Bell Boost-a-Pump OR dual GT pumps
- SCT BA2600 Mass airflow sensor
- 60lb injectors
This will allow the blower to maintain closer to 15psi at high rpm’s.
Here’s a graph to show the differences:
Whipple Supercharger upgrade. The advantage to the Whipple supercharger is it will hold the boost to up to 20psi on the Cobras. You can use the supporting mods you did with the Stage 3 and just swap the blower itself. Here’s what you get:
2003-2004 Cobra Tuning Package:
This is one of the best motors ever put into a Mustang! Ford was still bruised from the ’99 Cobras. Remember the big recall because they were down on power? Ford lost money and hurt their performance reputation with that one. The ’01 was better but just didn’t sell many and couldn’t beat the Camaros and Firebirds. When Ford decided to pull the trigger on the 03’s they decided to install a supercharger and cure the anemic 4.6L’s high revving motor with low torque. Problem was, they couldn’t build a motor with stock production parts that would stay together during their durability testing and they were running out of time. The engineers decided to buy the rods and pistons to speed up the timeline. That’s why the Cobra has H beam rods, forged pistons, ARP hardware and steel crank. They are capable of nearly 800 rwhp in stock form. We have tuned over 120 03-04 Cobras in virtually every form from stock superchargers, turbos, and aftermarket superchargers. We data log as many as 20 parameters when tuning to make sure your fuel pressure, pump duty cycle, intercooler temps and other sensors are working properly.
There are many tricks to tuning these cars correctly and we’ve got over 12 years experience in doing them. We offer the same Drivability Guarantee! Not happy with the way the car drives? We’ll retune it NO CHARGE as long as there are no mechanical issues! Need to pass emissions? With the introduction of the OBDII Readiness tests in New England it’s harder than ever to get heavily modded cars to pass! We can help! We’ve done extensive testing and if you’ve got High flow cats or other mods and are throwing a “check engine light” call us! We can almost always help you get the “tune” you need to pass! As a matter of fact, if we tuned your car we’ll guarantee you’ll pass the test and get your sticker. We even run a “simulated obdii readiness test” on the car when you leave to make sure it’s ok.