AOD guys and bypass...

Do you guys hear your bypass valve release air when your tranny shifts? It doesnt seem like they should since the throttle body valve is still wide open (even if the load is taken off the motor for a split second). However, I keep hearing what sounds like a "whoosing" air sound as I climb past 5500 RPM's or so. And it seems to make it as the RPM's are still climbing but its damn close to right before my tranny shifts.

It may be a slipping belt but I tightened it up the other day and while the "whoosing" sound did seem to get better its still doing it and the belt is really tight. I'm not running a super small blower pulley or anything (stock size on a Novi 1000) and I even have an 8" crank pulley, which should reduce belt slip even more.

I see about 10 lbs of boost max but when I hear this sound I can also see my boost drop to about 8 lbs. So I was also wondering if when your tranny (auto) shifts do you normally see a boost loss of a couple pounds or should it stay pretty much pegged? B/c either my belt is slipping or something is wrong with my brand new Bosch bypass valve. Thanks for any input, Ryan

I've never noticed that before. Do you have a good shift kit? The tranny isn't slipping or dragging out the shifts, is it? Maybe your throttle body is too small. Just some ideas.

Tighten the belt. If it has slipped too much you'll need a new belt as it will never grab in the areas where it has slipped before.

I dont think the TB is too small, its a 65mm Accufab. While it could stand to be a 70mm I know plenty of guys making big power with 65's. The tranny does have a shift kit, valve body, hardened input shaft, and a fluid cooler. I didnt have it built though so I cant give you too many details. It survived 100 and 150 shots of nitrous though. It is suppose to hold 600 HP.

And while the belt may not be slipping now I think it was before so maybe I should get a new one. I'm probably going to try some anti belt slip spray/solution first though or at least for the track.

But I am guessing the noise and/or the boost dropping is not a "normal" thing with auto's then? Thanks again, Ryan

Have you double-tripple checked all your connections and hose clamps? how about the sillicone or rubber connectors for rubbing or holes? Maybe there is something wrong with the bypass itself? Just a couple more ideas.