Ok, with the holidays and all i haven't been able to really take care of the issues with the EVO. But this past week i have been fixing all the little issues and getting the car ready so it can get tuned.

Background on the car, 2.3L JAM, Stock Turbo, Hallman MBC, Intake Filter, Turbo back exhaust. The car has been set to the lowest the MBC can go which is about 12lbs. Just for safety reasons until it gets tuned. The car is also running rich, also for safety reasons.

Recently the car has been acting funny, this is something that just started happening a couple weeks ago. Lets say i take off in first gear, and start boosting. It will hit the set 12lbs very quickly, as it has since i got the car. Once i shift in to second, it seems like the turbo hits a brick wall, or its some huge GT42R or something. Takes for ever to spool up. Even if i am lets say in 5th gear, if i boost to the set lbs, then let off. If i attempt to boost again. BAM Holly Lag.

I first i thought it was a stuck BOV, so i replaced it with an OEM IX valve. Nope.
So i sorta think it might be a stuck Wastegate actuator maybe? I dont hear any exhaust leaks or anything like that. But i do know i had a loss exhaust manifold nut. I am going to double check all of those today after work.

Any ideas would be great?

Thursday i am replacing the noisy Megan Racing Test pipe with an APS High Flow Cat. Friday i am doing an Oil change and spark plug change. So ill be working on the car all week, Hopping i can get the car tuned over the weekend.

 

I might replace the Wastegate actuator at the end of the week if i cant figure it out.

Maybe the FP upgraded one.

 

Sounds to me like the wastegate actuator arm needs to be tightened down some. More than likley when they were doing your 2.3 they did not put it back right. Easy Fix

 

Yea, i am going to take a look at that when i get the chance. Its just crazy that it just started happening. I have had the car back for over 2 months.

 

Any other ideas what could be causing this?

I have checked the IC piping twice already, so there aren't any leaks.

Is there anyway to test my Actuator while its on the car?

 

Yeah, you should start by adjusting the actuator rod to put more tension on the flapper valve. If as you say you have the MBC at lowest possible setting and are seeing 11-12 PSI, then you should shorten the rod to achieve about 17 PSI preload with the wastegate for starters.

With the actuator rod at its longest length and the MBC at it softest setting there is insufficient tension on the flapper valve, so it is being allowed to lift off its seat. With the increased displacement you are moving a lot more air through the stock turbo's relatively restrictive turbine housing. So, there is considerably more flow out through the wastegate bypass port and with the MBC at its softest and the actuator rod at the loosest setting the flapper valve is being forced off its seat.

 

I really appreciate you taking the time to help me.

Its strange how it just randomly started happening, after it being set to the softest setting for a while now. I don't plan on keeping it at its softest setting for long. I just want to make sure the car is ready for its tune. I dont want to take the car to the shop and it need more work just to tune it.

I will take a look at the actuator and try adjusting it. I also plan on taking it off the turbo and gently running some air into it, and see if it holds and what happens after the air is released.

 

I havent been able to test the actuator but i did raise the boost to about 18lbs, instead of the 12lbs..

If i drive the car and hold it at 12lbs, shift then step on it again.. its fine.
But if i step on it, hit the set 18lbs, when i shift and step on it again it lags.

So, i definitely think its the actuator... Chad has one, so when i take the care to him we might give that a try and see if that solves the problem.

 

Tom, It sounds just like the false knock thing to me. It will pull tons of timing and make the turbo spool very slowly!
In different gears at different loads this will happen, till you get it fixed.

Do you have a EGT on your car?