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Old 05-02-2003, 08:12 PM   #21
Austin
Scooby Guru
 
Member#: 7089
Join Date: May 2001
Chapter/Region: NWIC
Location: Western Wa
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Quote:
Originally posted by silvercharged
It involves using an industrial micro pressure relief valve just prior to your MBC.
Congratulations, you've just created a type of dual stage MBC... But it won't do anything for boost creep.

Boost creep is when, even running a straight line from the compressor outlet nipple/pressure source to the wastegate actuator, boost level creeps up. Some amount of boost creep is okay, but too much can be a problem.

With an 8 pound wastegate spring, a car running a straight line from the compressor outlet nipple to the wastegate actuator should run 8psi boost pressure. Boost creep causes that car to build more than 8psi boost pressure - it's when the wastegate is unable to physically flow enough gas to limit the flow through the turbine wheel, causing excessive flow through the turbine wheel, causing the turbo to spin faster than intended.

If your car (with a straight line to the wastegate actuator) creeps to 12psi, but you intend to run 16psi, then it's not a problem for you... but no form of boost control will enable you to run <12psi.

If your car boost creeps to, say, 21psi when you intend to run 16psi... then it's a problem.
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