Should I hear my bypass right before shifts?

[NothinButNotch]

I think the sound I am hearing is from my Bosch bypass valve but I thought it was only supposed to relieve pressure when you let off the throttle. The noise I am hearing sounds like a really fast pulse or a whoosh of air. Its coming from the corner under my hood where my bypass valve is so that is what I'm assuming the noise is.
Anyway, I am hearing this right before my car shifts, seemingly as the rpm's are still rising. I have an AOD by the way. But does the bypass valve see the tranny shift as a "letting out of the gas" or a lessening of load and start to open just prior to a shift? Or is something else going on here. Thanks for any info, Ryan

[swilldup]

if you have it hooked properly it should only open when you let off the gas....as long as the vac. line has boost there is no way it should open

[Krwy]

You'll hear it as soon as the car sees vacuum.

[NothinButNotch]

Well good news.... it wasnt my bypass it was my belt slipping. Having never heard belt slip before I didnt know what I was hearing. Unfortunately this wasnt suggested to me as a culprit until right when the track closed today so I didnt get time to tighten the belt and make another pass. But when I got home I tightened it up and went for a spin real quick and sure as hell no more noise and more boost! :) Now I cant wait to get back to the track and with some stickier tires. She went 12.0 @ 116 mph today on 17" street wheels and some DR's. My best 60ft was 1.9 so there is much improvement. So I hoping for mid 11's with some ET Streets on my Weld wheels next time out. Thanks again for the good info fellas, Ryan

[ISLANDLX]

Hey Ryan,
What type of work did you do on your AOD? Is it a stock AOD with a different valve body?

Thanks,
Troy

Well good news.... it wasnt my bypass it was my belt slipping. Having never heard belt slip before I didnt know what I was hearing. Unfortunately this wasnt suggested to me as a culprit until right when the track closed today so I didnt get time to tighten the belt and make another pass. But when I got home I tightened it up and went for a spin real quick and sure as hell no more noise and more boost! :) Now I cant wait to get back to the track and with some stickier tires. She went 12.0 @ 116 mph today on 17" street wheels and some DR's. My best 60ft was 1.9 so there is much improvement. So I hoping for mid 11's with some ET Streets on my Weld wheels next time out. Thanks again for the good info fellas, Ryan

[NothinButNotch]

Troy,

I actually didnt have any of it done. The buddy I bought the notchback body from actually sold me the tranny with it for really cheap so I took it (and have actually enjoyed it more than I thought I would). However, I know it does have a hardened input shaft, a different valvebody, a B&M shift kit, a cooler up front, and a higher stall (2600-2800). It is suppose to hold up to 600 HP and knock on wood so far has done just fine for me. I wouldnt mind having a touch higher stall, like a 3000-3200, but probably wont change it unless something goes wrong. I do plan to put in a fully manual Lentech valvebody though sometime in the near future.

Sorry I cant provide you with any specifics but thats the info I have, Ryan