03 04 Cobra Whipple Blower Upgrade

Over the last several years Alternative Auto has had a performance package for the supercharged ’03-’04 Cobras that brought improvements of over 100 Rear Wheel Horsepower – With just simple bolt-ons like a K&N filter kit, pulley change for the blower and some exhaust work along with our own custom SCT Dyno tune. We’d typically see about 450 RWHP on these cars with stock drivability.

If 440 to 460 RWHP isn’t enough for the power greedy, then we at Alternative Auto have the answer for you. Whipple Industries has come up with complete 2.3L twin-screw replacement blower for the stock Eaton on the Cobra capable of producing 600 RWHP on a ’03-’04 Cobra.

For the guys who are looking for a very reliable “premium unleaded fuel” boost level and tune, we’re setting up these new screw type blowers to make 17-18 psi of boost, and we’re seeing no less than 575 to 600HP at the Rear Wheels!  This is 125+ HP more at the rear wheels then our first bolt-on package for the Cobra and as much as 200+HP more at the rear wheels than a totally stock ’03-’04 Cobra.

We’ve come up with a well rounded package that consists of more than just the replacement blower unit. We’re also switching to 60 lb injectors.  These new, large 60’s, with the right tune can have totally stock-like idle quality and drivability. When these 60 lb injectors are coupled with SCT’s new BA-2600 90mm Mass-Air-Meter, and a proper tune, we’ve accomplished what we would have never thought possible just a few years ago in terms of over-all performance/RWHP and stellar drivability with Ford’s modern return-less EFI fuel system.

We also add a Boost-A-Pump  (voltage enhancer) to help the stock twin Cobra pumps keep up with the additional power.

The key reason these new screw type replacement blower’s make so much more power is that the boost doesn’t fall off at higher rpm’s like the stock Eaton does. Additionally, screw type blowers run cooler than roots-type compressors when moving larger volumes of air at higher rpms.

This is the best thing yet to happen to the ’03-’04 Cobra besides being born with a supercharger from the factory. 

The dyno graphs shown are a comparison of a very typical stock ’03 Cobra and an ’03 Cobra with our first stage of mods plus one with 16 psi of boost produced by either a Kenne Bell or Whipple replacement blower. As the graph shows you can see how the boost falls off on the stock Eaton at higher rpms, where as the screw type blower shoots up to peak boost and stays there, making for a huge gain in RWHP and mid/high Torque as well.