I was pulled over in Maryland for exhaust and given a repair ticket. I put my silencer on the car and the mechanic said the car was legal. After taking the silencer off after 2.5 days I noticed my oil pressure was maxing out at 4-5k rpm. Is this a carbon build up or coincidentally a sensor? Side note the car ran like **** with the silencer on it; bad acceleration.

I have:
kinteic high flow cats
stock y piece
megan single

 

It could be instrumentation, or it could be mechanical/gasket obstruction related. I'd get a manual oil pressure gauge and test it with that to eliminate the faulty instrumentation possibility first. Then move on from there..

 

I believe this is normal. There is a sprung diaphragm pressure relief valve in the oil pump that bypasses the oil galleys once it's set pressure is reached. Same idea as an external fuel pressure regulator. What isn't needed is dumped back into the pan.

This pressure is reached before redline (especially when cold) as pump flow increases with RPM's.

Typically you'll see an additional 10 PSI/1000RPM above idle pressure once system is warmed up. Typical relief pressure is ~60 PSI but more will be seen when driving or idling a cold engine due to fluid viscosity.

 

^Right. But this just started happening, so what's "causing" the relief valve to bypass oil now...

 

Pure coincidence - there is no connection of any kind which exists between the exhaust and oil pressure. Troubleshooting procedure is in the FSM.

 

Question... Define maxed out, you talking 120?

And what did it do before you noticed anything abnormal?

 

well to put in in perspective, when I hit 4-5k rpms the needle looks like I'm bouncing off the rev limiter, 120+

 

so normally the car would idle around 2.5 rpms and oil psi 80 cold and when warm 3rpm at 60psi. Now it idles at 2.5 at 120 cold start and the 4-5 rpm at 120 when warm.

 

Yeah change out that transducer man, I just bought this one from czp a few weeks ago, perfect.

https://conceptzperformance.com/niss...0a_p_28462.php

 

Test your pressure with a manual gauge first before throwing parts at it.