What is boost creep


Pro Tuner
Staff member
2002 Clio 172
Heard someone talking about a boost problem they were having and they said about boost creep but I don't have a clue what that is!

Can anyone explain to me what boost creep is?
A. Boost creep is a condition of rising boost levels past what the predetermined level has been set at. Boost creep is caused by a fully opened Wastegates not being able to flow enough exhaust to bypass the housing via the Wastegates itself. For example, if your boost is set to 12psi, and you go into full boost, you will see a quick rise to 12 or 13psi, but as the rpm's increase, the boost levels also increase beyond what the boost controller or stock settings were. Boost creep is typically more pronounced at higher rpm's since there is more exhaust flow present for the Wastegates to bypass. Effective methods of avoiding or eliminating boost creep include porting the internal Wastegates opening to allow more airflow out of the turbine, or to use an external Wastegates.
It is due to the waste gate not flowing /draining off enough gases TO BYPASS the turbine wheel and keep the boost level at the correct level so the turbine sees more exhaust gasses that cause it to turn even faster and this increases the positive pressure above the desired setting.

A faulty gate that is not operating properly and /stuck closed or partly closed OR simply too small for the engine will cause overboost and lead to engine damage if not rectified ASAP
Thanks for the answers, as always I'm learning a lot from you guys.
And you thought boost creep was where someone came up to you and said they "really like your turbo car and it's one of the best forced induction cars on the road and looks stunning!"

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