limiting boost with adj. bypass valve?

[big5_ohstang]

hey guys i was wondering: since i have no personal experince with adjustable bypass valves. how do they work? this is my thoery please tell me if im way off here... i have a sq-trim with a draw through maf, and am using the stock bypass valve from vortech. couldnt i installed and "calibrate" a adjustable valve to un-seat at a certain psi-which would in effect limit max boost? it would just recycle back to the intake side of the charger just like when letting off the gas right????
thanks guys for any input!
ps.ive done a search but didnt really find much

bryan

[underpsi68]

I have always wanted to try something like that. This way you could put a smaller pulley on the blower to build boost sooner and keep the same max boost pressure that you where running before. It should add a lot of mid range power.

Anyone else?

[speedytang]

That would be a BOV. Been used for years just exhaust it back into the system. Your factory turbo units have been using them that way for 30 years to meet federal noise level laws.

[regattacoupe]

I'd really be interested in trying somehting like this. Running a wild pulley combo on my T-trim to get my 60' where i want it but then only having about 14 psi up top. Do you have any ideas aaron? I guess it would have to be pretty fancy for a high horse application.

[big5_ohstang]

yea i ask because i just installed a UPR boostmaster sc inlet pipe i havent gotten on it real hard yet (leaning out up top) but i saw at least 13.5-14psi of boost! and i nknow as it gets cooler outside ill easily see 15+. IMHO thats just toooo much for a stock block and pump gas. if i cant limit the boost with some sort of valve i think ill slow the charger down with a pulley change. i dunno...

bryan

[blown1989saleen]

That would be a BOV. Been used for years just exhaust it back into the system. Your factory turbo units have been using them that way for 30 years to meet federal noise level laws.

turbo cars use a wastegate to regulate boost NOT the BOV, the BOV just releases the boost when the throttle is shut suddenly ;)



Scott

[speedytang]

I guess the turbo word should not have been used since they do use a wastegate also. Sorry. You can use a BOV with adjustable spring and a reference vacuum port. Most BOV have both on top. You will just have the BOV set to open at 10psi and let it blow back into the system or use a remote wastegate like the Turbo system it can handle more pressure 20psi+. The problem with all these methods are your working the supercharger just as hard to produce less. Your better off on a supercharger to use the pulley to regulate that way your not producing more heat for less power.

[big5_ohstang]

The problem with all these methods are your working the supercharger just as hard to produce less. Your better off on a supercharger to use the pulley to regulate that way your not producing more heat for less power.

yea i know what your saying, im just not sure if the added boost down low and then to bleed/recirculate say 2 psi off the peak boost would be more benificial ultimately rather than changing pulleys and have all around lower boost-but with less heat. you see the thing is, ive still got the stock pulleys on there right now and before the new pro-m 80mm maf,upr boostmaster pipe i was making everybit of 11psi. now im seeing at least 14psi-prolly more. my point is that i havent changed pulleys or anything to add heat but just made the supercharger able to breath more efficently. do you still think slowing the charger lower than "stock" would be more beneficial than limiting peak boost?
plus the charger is still in warrenty, so me changing the charger pulley isnt going to happen. and i aint gonna pay vortech to change a stupid pulley! so that means i need to change crank pulley sizes. :(
anyone have any ideas or experince with my problem?
thank you for the replys so far guys!
bryan

[vortecS2000]

I was going to ask the same question on here. I have an s2000. I want to run an 11 psi pully but have it bleed off at 8psi. So basically it would be at full spool around ~6k rpm and I could hold the 8 psi to 9500 rpm.

My question was how reliable are the pop off valves at being able to hold constant boost while the pressure increases within the system.

[Stangonline.com]

Been talking to a friend about this too. I think what you are after is a turbo wastegate mounted on the boosted side. You would also need to use a large bypass like a mondo in between the wastegate and the TB.

IMO, this would work best on a FAST tuned car, or some other speed density setup, as you would likely be wastgating so much "metered" air that it might cause tuning issues.

[big5_ohstang]

thanks but that sounds way too involved and costly. (not that i couldnt figure it out) i think a pulley change would be easier and cost effective