Unwanted: high boost
07-02-03, 05:00 PM
#1
Rotary Enthusiast
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Unwanted: high boost
Car ran fine yesterday. All of a sudden today, when I go full throttle, instead of 10 pounds of boost, I have 15. Motor is street ported but otherwise stock, with no computer mods. at 15 pounds, after about 2 seconds, the motor bogs like the computer shut it down or not enough fuel to support the boost. Any ideas as to what broke or stuck?
07-02-03, 05:12 PM
#3
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Join Date: May 2002
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STOP GOING WOT!!! You're experiencing boost creep from your streetport and Bolt on's....Do you even have an aftermarket ECU?!
14psi means significant trouble (I blew my motor with about 12-13psi due to boost creep), you have 15! You better pray...
Originally posted by Flybye
Boost creep occurs when the wastegate can not bleed enough exhaust away from the turbo. This generally happens when you have a free flowing exhaust and intake system. The turbo spins fast enough to quickly build boost and the wastegate can't keep up by bleeding the necessary amount of exhaust for your desired boost amount. You can either port the wastegate or restrict your exhaust. The cheapest way to restrict the exhaust is by putting a small restrictor plate between the DP and the MP. It's better than popping your engine.
This can also occur at 4500rpm in sequential mode. You can get the famous boost spike. This happens because the 2nd turbo is getting prespooled TOO much, and when 4500rpm hits, all that boost pressure get's bleed in giving you a boost spike. This can also be fixed by playing around with the prespooler and the wastegate.
You better hope you don't have the factory ECU. 14psi means trouble.
Boost creep occurs when the wastegate can not bleed enough exhaust away from the turbo. This generally happens when you have a free flowing exhaust and intake system. The turbo spins fast enough to quickly build boost and the wastegate can't keep up by bleeding the necessary amount of exhaust for your desired boost amount. You can either port the wastegate or restrict your exhaust. The cheapest way to restrict the exhaust is by putting a small restrictor plate between the DP and the MP. It's better than popping your engine.
This can also occur at 4500rpm in sequential mode. You can get the famous boost spike. This happens because the 2nd turbo is getting prespooled TOO much, and when 4500rpm hits, all that boost pressure get's bleed in giving you a boost spike. This can also be fixed by playing around with the prespooler and the wastegate.
You better hope you don't have the factory ECU. 14psi means trouble.
Last edited by Chronos; 07-02-03 at 05:15 PM.
07-02-03, 05:15 PM
#4
Dont like it? I dont care
Join Date: Jan 2003
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Wow, you're motor is gonna pop dude. I seriously hope your ECU is modified in one way or another.... hell I don't see how you could have a stock ECU with a street port...
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