I was studying my most recent mpscan plot and noticed that above 4000 rpm boost was dropping while rpm continued to rise. It wasn't much, about a pound of boost over time. Is this a pressure leak somewhere or is there some other cause.
Thanx
I was studying my most recent mpscan plot and noticed that above 4000 rpm boost was dropping while rpm continued to rise. It wasn't much, about a pound of boost over time. Is this a pressure leak somewhere or is there some other cause.
Thanx
The only substitute for cubic inches is cubic dollars, how fast can you afford to go?
What is the setup of the car? There's a lot of things that can cause a dropping boost curve.
What specifically do you want to know?
The only substitute for cubic inches is cubic dollars, how fast can you afford to go?
a manual controller will spike and then level out.
Brian
Originally Posted by turbovanman
Definitely need more info on the setup of the car; what engine, turbo setup, intake/exhaust manifolds, downpipe/exhaust, hows boost controlled, ecu type, etc..
Reason for needing this info is some setups just don’t flow enough at higher rpms and will cause this, or it could be part of boost controller, etc..
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^^This
I do have a manual boost controller, im sure that is what is happening.
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Reaper. Thanks for your response.
The only substitute for cubic inches is cubic dollars, how fast can you afford to go?
Could be a few reasons for that. One of the more common reasons is that exhaust backpressure overcomes the wastegate as RPM rises. If this is the issue, you can add some wastegate spring tension and that can help.
Mike Marra
1986 Plymouth Horizon GLMF "The Contraption" < entertaining sponsorship offers
Project Log:
http://www.turbo-mopar.com/forums/showthread.php?69708-The-Contraption-2013-14&highlight=
Yes, exhaust backpressure is most likely going to be a major contributor given what we know.
That is interesting, if I have to get the wastegate solenoid off to put a spring on it somehow, that could be a problem. I can see where this could be a tuning problem if the boost spikes into detonation range and then drops back a bit.
The only substitute for cubic inches is cubic dollars, how fast can you afford to go?