Do I need a bypass valve

[Ghost88]

I have a SN93 running 8-9 lbs of boost. Do i need a bypass valve?

[Buck-Strickland]

Can't hurt. I always use one, no matter the boost level. My 2cents.

Is there a reason you don't want to run one?

[Ghost88]

It didn't come with one. Cliff at Cundn racing said I didn't need one because the boost don't come in as fast as the other chargers(Vortech) etc.

[gooberzx2ta]

I had to use one because any pressure between the TBI and the Paxton would "hang" the throttle blades open. Without being able to return to idle, the engine RPMs would increase, creating more pressure, increasing the RPMs, and increasing the pressure -- until the ignition key was turned off.

I first added an additional return spring. This corrected and idle to 3k range. However, the first run to about 4k RPMs, again resulted in hung open throttle blades.

I used the plastic OEM-style Bosch by-pass valve configured to recirculate back into the s/c inlet to reduce/eliminate noise.

Mike

[lotar_6]

yeah... you have to relieve the pressure or you get what Mike is seeing. If you are running a mass air flow system, then you should divert the metered air back into the system... not vented to atmosphere. Otherwise you will run really rich and have stalling problems. The plastic bosch is a good stop-gap, but they wear out easily. There's lots of options out there, though.

GL!

-Kyle

[JPJP]

I recommend you go w/ CUND racing's advice and leave it alone.

[Ghost88]

I recommend you go w/ CUND racing's advice and leave it alone.

Why you say leave it alone. Just want to know your reason.

[JPJP]

Reasons:
1. CUND racing says to leave it alone - they are the professionals. They would love to sell you something even if you don't require it. If they say you don't need it, it is safe to say you don't need it.
2. "Don't fix what ain't broke"
3. Another part = one more thing to go wrong

[Ghost88]

Reasons:
1. CUND racing says to leave it alone - they are the professionals. They would love to sell you something even if you don't require it. If they say you don't need it, it is safe to say you don't need it.
2. "Don't fix what ain't broke"
3. Another part = one more thing to go wrong

Understood.

[winfred]

maybe its because i am running it on a 2.8 inline 6 instead of a 5.0+ v8 but i had insane flutter with one 38mm valve, forcing the blower to choke on all of that back pressure on a shift i doubt is doing the shaft/bearings any favors, i know if you bark a turbo enough you kill the bearing/seal or on some units break the shaft with the cavitation, i ended up adding a 2nd valve and its much happier now and only chirps for the 1/2 second or so before the valves open and am going to work on that with improved plumbing to the diaphragms, couldn't imagine my rig with no BOV

this was just before it hit the road before i added the 2nd valve, not is bad on a free rev as the engine slows quickly but on a down shift or just lifting at high rpm it would make any ricer proud the quantity of noise it made http://www.youtube.com/profile?user=.../7/KypF_3W5iBY

[novi306]

I installed one on my paxton novi 1000 when it was at 5 to 6 lbs because at idle it still flowed enough to create problems with backflow resonating enough to cause the maf to read funny , so when i added the bypass valve it idled like a champ.