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Discussion Starter #1
Hey guys. Ok, I've got a couple of general questions about bleeder valves, blow off valves, funny turbo noises, and decreasing boost at high rpm. First, what's a bleeder valve? What does it do? Why would I want one? Second, what advantage does a blow off valve give you? Does it make you spool faster? Third, my turbo makes a weird humming in first gear as it spools, not always, just sometimes. The boost also drops at the top of first and second, down to about 8 or 9. Is that normal? How can I fix it? One more question, what's a turbo timer, what does it do? Sorry for all the questions, I'm just curious! Thanks.
 

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bleeder valve bleeds pressure out of the lines that go to
your wastegates to let more boost creep into the plenum.

You have a mbc so you don't need one

blow off valve helps keep your commpresser wheels
spinning at optimum rpm during closed throtle.

turbo timer keeps your car runnin after you shut it
off for a predetermined amount off time in order
to cool turbos.:)
 

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Beast said:
blow off valve helps keep your commpresser wheels
spinning at optimum rpm during closed throtle.
A blow off valve vents air either to the atmosphere or back into the air box (open vs. closed loop, respectivley) during shifts when the throttle plate is closed. This prevents the boosted air from surging back ("compressor surge") and damaging the turbos.

.jon
 

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With stock turbos it's normal to slowly loose boost at higher RPMs I go from about 14psi to probably 9 or 10 by the time I get to redline.

Adam

92 Laser AWD
94 Stealth RT/TT
 

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Discussion Starter #5
quote: blow off valve helps keep your commpresser wheels
spinning at optimum rpm during closed throtle.

What are compressor wheels? Does that help boost faster on the uptake?

quote: A blow off valve vents air either to the atmosphere or back into the air box (open vs. closed loop, respectivley) during shifts when the throttle plate is closed.

Whats the advantage of a closed loop or open loop? What do they do?

Thanks for helping me out here, I want to go faster, and playing with the turbos tends to be a pretty handy way to do it!
 

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Check out this page, very informative
http://www.team3s.com/FAQturbobasics.htm for impelers, wastegates, intercoolers, basically everything to do with a turbo system.

The 3/S cars come with blow off valves that vent back into the intake. There are several threads here and on dsmtalk about whether it is better to vent to atmosphere or to keep it closed loop. An open blow off valve sounds cooler, but with the air meter where it is on the 3/S cars you are releasing metered air, meaning the computer had adjusted the fuel to burn with the air and so you will run rich if you let the air out of the system. Also our stock blow off valves are slightly open at idle, so a vented blow off valve will allow UN-metered air into the system at idle allowing the car to idle very poorly due to a lean condition, sometimes even dying. A speed density system like a VPC will allow you to vent to atmosphere and get some really cool looking intake systems.

There is much more to learn about these cars and the turbos and how they work together with your ECU and piggy back computers and different metering systems, much more than I can get into here, best thing to do is get reading!

Adam

ps. When it comes to going fast, the only thing you can do to the turbos (aside from upgrading) is turn up the boost. After that you want to open up the intake and exhaust to allow the boost to come on quicker.
 
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