Thanks for the measurements. Unfortunately its too big to fit in our little actuators. Ill keep hunting.
Still cheaper than the $120 replacement valve I had to get for my Whipple. I should have it this week. I'll test with a hand operated vacuum pump the difference between the two.
I'm very interested in this....I am seeing unusually high IAT2s like you mentioned earlier in the thread. Also before my whipple install my cruise control didn't work. The shop that put my blower on managed to fix the issue (not sure what it was) and now when I have the cruise on, any little deviation in loss of mph will cause a hard surge to maintain the mph that the cruise is set to. Do you think this could be the issue? I just hate to pull the blower and get the spring installed.
*edit*....what are your IATs looking like now that you have the new spring in there?
Jr.
Stock cams....cant remember the vacuum at idle but it seems pretty normal for stock. I was just curious about this due to my high IATs and the surging while having the cruise set.
Jr.
Well Update: - the low pressure spring bypass valve allows the car it idle out of boost and not be surging but it has a horrible side affect when driving.
As you accelerate and vacuum reduces the car starts to run out of air as it passes the 10 inches of vacuum point. I can see why the stock bypass valve would open at this point. So what happens is the car runs out of air and when it hits the 3 ~ 4 Hg point the valve opens and it gets a sudden rush of air and the car jerks or lunges as it gets a sudden rush of air. A lean spike is seen on the wideband too right as it snaps open. It is extremely annoying to drive with. I'm not sure what a good fix to this is.
I've since swapped cams and went to slightly milder cams and now have 11 ~ 12 inches of vacuum at idle. I'm thinking of switching back to the prior bypass valve and if the valve still flaps or it surges at idle then adding a mini vacuum helper pump to pull on the bypass valve when idling.
Open to ideas?
Interesting, my car drives really good with the low pressure spring. It does have a tiny bit of what you are taking about, but with the stock spring it did it way worse. I am going back to my tuner on Friday to play with this. He was very confident he could tune it out by playing with what he called pump shot.