Trying to figure out how to describe this. My car seems to go no where when it's boosting suddenly, like it's currently getting to 15psi and doesn't really pull at all. It just started this. Only recent things done are new head gasket, arp studs, new intake mani gasket, new injector o rings. timing is correct, compression check checked out, boost leak on IC piping no leaks. coolant and oil look fine. Someone mentioned my turbo might be going out, seems theres some oil in the piping and not sure not much play the shaft should have, this is my first Evo so i'm trying to take care of her. Stock Evo 8 turbo tuned by previous owner.

 

Probably clutch slipping.... It goes a bit until boost kicks in then it goes nowhere but kinda catches when you let off the gas and lurks forward?

Clutch might need bled, or adjusted, but it's probably time for a new one.

 

I don think clutch it seems pretty good, but I guess not to Ryle it our. Car drives like an NA car. Manifold sees post but car doesn't respond like a boosted car.

 

where in pa are u located?

 

Trainer

 

Check your stock cat. It might be "clogged" up.

 

Forgot to mention mods. lol. header, downpipe, testpipe, catback. SES due to no cat. HKS 272/280 cams, injen UICP/LICP, descreened maf, meth,evo 9 BOV (I currently have a Blitz on there thinking it was a leaking bov, no dice),turboxs FMIC.

Car boosted fine, then head gasket, lifters, intake and exhaust gaskets all replaced, and now i get this. Car is tuned at 28psi, but stopping at 15psi.
If boost is being measured at the manifold, but not being 'forced' into the engine, should I assume a leak somewhere or a bad turbo?

 

Check for exhaust leaks pre turbo. I had two small cracks in my manifold under where it couldn't be seen and mine would only hit 15 and felt like it was a honda. After time it got to where it would only hit 10 psi at redline. Any small leak in a gasket or manifold before the turbo will cause this

 

When you say there is no boost leak by the intercooler piping, do you mean you did a boost leak test?

 

This is why I said clutch. If there are leaks, obviously fix that first. I figured he said there were no leaks.

 

+1 esp if your "header" is an ebay one cause they crack and leak like its going out of style. imo id find a stock ported one and put that on.

 

Slipping clutch he would have an RPM issue as well.

 

yes my friend had made a test and we didint find a leak.

I'm pretty sure it's a megan racing header. Yes I'll have to find whatever I can get my hands on I guess to replace it.

 

I've had clutches that only slip under peak torque or peak horsepower but catch almost instantly producing a hesitation that feels like a misfire. Not all of them slip for hundreds of RPM where you can just watch the needle rise with no movement.

Mine would engage and hold normally until 4200rpm then slip just a tiny bit, then catch for another 600-700rpm before slipping again and immediately catching again. It was almost exactly the same as a misfire, except a trained ear could tell there was none. The power delivery would only cut out slightly, feeling like a single ignition event failed.

It was like that for nearly 15,000 miles in my Cobra. Before I figured it out, I thought if it was the clutch slipping, it would slip more within a few hundred miles of aggressive driving..... not so, in fact I kept chasing a misfire. The clutch always held down low, and only slipped with high rpm and only for milliseconds. That is before it exploded.... no damage to anything, I got lucky...

My Evo's clutch is getting replaced within the next week or two. Just started slipping but this car slips exactly at peak boost and will continue slipping until I let off the gas before it catches and lurks forward. Unlike the Cobra, this was obviously the clutch and now she's parked .

But I wanted to share that story because I've had more clutches fail ever so slightly, than the obvious ones that slip for a long time. Although at this point I don't think this is the OPs issue since he's cast more doubt into the equation.

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haha thank you, very interesting i'll have to keep an eye for this if its same thing or not.

i'm also wondering if maybe my turbo kicked the bucket? how long can you run a stock turbo 28+ psi? car is tuned by previous owner at that psi and theres no MBC so i guess its computer controlled.