[PO1SND U]

Hey guys! I know the efficientcy with the stock Eaton's are horrible at high RPM's with the smaller pulleys. I've currently got the 2.76" w/ idlers on my 03 Cobra and it runs 13 PSI untill it hits about 4,750 RPMs and drops to about 9 PSI at redline. I was just curious to see if anyone else has drop off as bad as mine and if changing to a different pulley would help my cause. Thanks!

[crazyhorse7749]

did you check to see if your belt might be slipping

[soundwave3100]

If you dont have the boost bypass kit installed with your smaller pulley it could be the culprit.

[PO1SND U]

It's defiantly not a slipping belt. I have the 4 100mm idlers as well and the belt is in perfect shape. If it was the belt then the blower wouldn't be winding out as high as it does when the RPM's increase.

Boost bypass valve? What's that? I've never heard of this because I'm new to the 03 Cobra scene...

[PO1SND U]

Ok I looked up boost bypass and they show a little thing you can do where you switch a few vacuum lines to bypass that soleniod they use to get rid of extra boost and the previous owner already had that done.... Hmmm...

[annivcobra03]

what web site did you find this out on I am interested in reading up on it....

[cobra_03svt]

The boost bypass cutout is a good mod. There is a black accuator on the side of your blower that operates an internal butterfly valve that will open up at high rpm and dump boost. It's also open at idle and when the motor is not under any load. All u have to do is swap the two hoses around "will need a little extra vaccume line and an in line connector because one hose comes up a little short". This will permenatly keep the valve closed at all rpm. Also blower will be alot louder at idle and will not drop off at all on top end and expect to have instant boost as soon as u hit the pedal. U can also have your tuner just tune it out via the controll module. Eithor way. I had mine tuned out so u should be weary of running your a/f lean at wide open throttle if you just swap the two lines.