Whipple is down on boost

[Yellow_rag]

hey, I have a 2.3L whipple on my 03 Cobra and the boost will not build past about 15 lbs. I can feel it's down on power too. I'm getting same boost readings from the analog dash gauge and my AeroForce OBD gauge. I have a 3.1in pulley which should be about 18 lbs. The boost dump actuator is removed (think they call it boost bypass mod) and the manifold pressure goes straight to the Whipple bypass valve actuator. The other side of bypass goes to atmosphere.

I dont think there's a manifold leak cause it would probably throw a code. I think maybe the bypass is not closing all the way but i dont know how to check it. You cant see it. I put a vacuum pump on the atmosphere side of the bypass valve actuator and saw no difference.

I emailed Whipple and after a lot of back and forth they said the boost isnt getting past the rotors, meaning they dont think rotors are the problem. They wouldnt tell me how to confirm it's not the bypass valve though.

Anybody know how to check it? Other suggestions, other that pull the blower? thanks!

 

[01yellercobra]

How old is the belt and tensioner? Is there a lot of black dust around the blower pulley?

In order to test the bypass you need a vacuum pump and a way to reach the bypass. You need to put the vacuum on the side of valve that has the hose running to the blower. Generally if it holds vacuum it's good. If it doesn't the diaphragm is shot.

 

[Yellow_rag]

yeah, should have mentioned there is no belt slip. I have Reichard pulley. No dust. Also the bypass actuator does hold vacuum. I put a hand vacuum pump on it. Thansk for suggestions though.

 

[BlckBox04]

there's nothing clogging the intake right

 

[Yellow_rag]

no, nothing in the intake.

 

[Deceptive]

Did it make 18lbs before or are you just going on what Whipple says it should make?

Does anything sound funny?

Have you data logged?

Did you do anything to the car recently?

Have you ensured the engine is good?


Sent from my iPhone using svtperformance.com

 

[Yellow_rag]

yes it is down on boost like the title of the post says. It does not sound funny. I did not datalog. I can see it on the gauge!

Really just asking if anybody knows how to confirm the bypass is closing completely or if there is some other way it could be bleeding off pressure. thanks!

 

[jbou91]

Not sure if this helps but 3.0" pulley is for 17-18psi and 3.1" is for 15-16psi

 

[Yellow_rag]

Yep, you're right - i misstated the situation. I had a 2.9 on it when i first noticed the boost drop. I put a 3.1 on it and boost tops at same 15 lbs as the 2.9in. No difference at all.