My car is acting weird when it hits full boost (10psi)...

Spooling up until that point the car is pulling good/hard, but as soon as it hits full boost the car just feel like it ran into a brick wall. It is NOT boost cut, a boost leak or the turbo, because both the boost solenoid (AEM) and the MAP sensor (SoS) are showing that its holding at full boost (and it doesn't feel like boost cut... I've felt that before, waaay different). It is NOT the clutch, because the RPMs are not going up rapidly. If anything they are increasing too slow (like I said, feels like I hit a brick wall). The car is fully warm, but not overheating (~180 coolant temps). Oil level is fine. AFRs are fine (low 12s)...

Everything seems normal... but the car just isn't accelerating as fast as it should be.

The only things I can think of is ignition/misfire (really doesn't seem like that though, as any other time it is running smooth, AFRs are always normal and I'm not pushing the limits of the system), transmission issue (no weird noises though?), or something weird in the tune. What other possibilities can you guys thing of?

I rarely hit full boost on a daily basis, so I'm not sure when the issue arose, but I know it wasn't happening when I was on E85 (since I was at the track and it ran great there and on the way home). Thus I can only assume it started after I switched back to 93 (and changed my tune).

I'm going to take some logs soon and send them to my tuner and maybe that will answer some questions, but I thought you guys might have some insight until then.

Any help/suggestions would be appreciated.

Thanks.

 

If everything checks out mechanically then that points to the tune. What is the ignition timing doing when you're experiencing this? Post a screenshot of your ignition table and/or log

 

When is the last time you changed your plugs?

 

I agree with soul coughing

 

Just b/c it's hitting full boost doesn't mean the turbo isn't out of it's effective boost range. The turbo could be spinning it's guts out to make 10lbs if you have a boost leak.

Do a boost test, and a comp test. Eliminate a motor/leak issue.

 

Its run fine on this tune before. It shouldn't be anything to do with the ignition table. I'll see what my tuner says though after I send him a log.

Can't remember exactly... Hasn't been that long though... ~10k miles maybe?

Guess it wouldn't hurt to go ahead and change them anyways...

Thanks for the advice. Going to have the tuner check the log first. If that doesn't answer any questions then I'll likely change the plugs and then if that isn't it, I'll do what you suggested.

 

good luck let us know how things turn out!

 

Good luck, you won't be the last person to have this problem, keep us posted.

 

10k miles is a long time if you're on copper plugs...

 

Not using copper plugs.