I have been having an intermittent issue with the Whipple Bypass valve. It doesn't always open when the engine is hot. The rod that operates the valve is not moving much when stabbing the throttle. My maggie would move a lot. Also, moving it by hand seems tight, I can't remember how tight it was when I installed the new valve a few months ago though.

On the Camaro5 forum, I saw a thread from a car done by Haddad a few years ago and the SC had to be changed. I sure hope this is not the issue!

Here is short video. It closes once and then stays stuck open.
http://s19.photobucket.com/user/j_po...wvxx2.mp4.html

Ideas anyone??

 

For some reason the video is not working.

 

I uploaded to YouTube, let me know if the link works.

http://youtu.be/RVE_RHVYDuc

 

That link works. Its hard to judge. In neutral it takes a pretty heavy foot to get that to move. It's hard to build boost, or remove all vacuum behind the TB in neutral. Does it seem to not make boost when it should while driving? That would be the biggest sign there is a problem.

 

I would remove the hose and apply vacuum or pressure to make sure it is not leaking first. Next I would move it without the actuator connected to see how easy it moves. Im not sure how the Whipples are set up, so im not sure if you can do that. If I had to guess by looking at the video, it looks like it slammed shut and the butterfly got stuck in the hole from closing slightly too far.

 

What is your vacuum source? (Tee, vac block, single line to lower manifold, etc...) Also how much vacuum does that cam pull at idle? I am not sure if the Whipples are the same but the KB bypass needs at least 10in vac to fully open. They do offer a lower vac bypass for those with large cams and low idle vacuum.

 

Hard to do anything with two little ones under two years old.

Went for a drive today and the actuator is not working correctly. If I stab the throttle it will close and make boost without a problem. If I roll onto it, it does not close. Once open, it is fine. Will make boost to 6k rpm's.

Talked to Whipple yesterday, they told me to see if the actuator arm closes when the engine is off. It does not. The actuator seems to be stuck in the open position.

I am going to put a vacuum pump on the actuator and go from there. This sucks, I was hoping to put in the Walbro 450 in and dyno the truck.

No it does not always make boost when driving. It opens like normal when cold, but as soon as it gets up to operating temp (180 degrees), it does not.

I am going to pull it off, just a pain in the *** since I have to move the alternator bracket. I think it is open too far and has trouble coming back. Open means no boost, right?

Pulling vacuum from the lower manifold. 50 KPA at idle. I bought the light spring in the actuator for use with aftermarket cams.