DSMTalk Forums: Mitsubishi Eclipse, Plymouth Laser, and Eagle Talon Forum banner
1 - 18 of 18 Posts

·
Registered
Joined
·
761 Posts
Discussion Starter · #1 ·
I'm so tired of this. Have a FP bigt28 and can't hold boost. After many boost leak test, I have zero boost leaks. I replaced all of my exhaust gaskets and put all the preload in the world on the wastgate arm and still I lose boost. It will start out at 21 psi and by about 4000rpm it will drop to 15. I don't know what it could be. Any ideas or thoughts would be helpful as I am totally stumped. Why am I losing boost??:mad:
 

·
Registered
Joined
·
5,386 Posts
What did you use to boost leak test with? Some people try a bike pump or a small compressor and that is not enough.

Wondering if this may be a problem with FP turbos as a buddy of mine is having trouble holding boost on his FP T-28.
 

·
Registered
Joined
·
183 Posts
My t28 (stock) does the exact same thing and I had no boost leak. (I got rid of boost leak by switching to a bigger turbo. :p)
*Just an input.
 

·
Registered
Joined
·
2,094 Posts
Hate to sound like a broken record but what did you use to test for leaks and did it build 21psi on your boost gauge?? So many people think they're doing a properly blt and there doing it half assed..
 

·
Registered
Joined
·
761 Posts
Discussion Starter · #5 ·
I was using a big compressor to do the test it held 21 just fine and slowly faded off. So other people are having trouble holding boost as well with the FPt28? Mybe its the turbo, but I have heard of people on here holding 21psi just fine. Don't know. Sucks to go out and buy a different turbo since I just payed 900 for this one. Any other ideas though? I can't think of anything else that I havn't checked.:dunno:
 

·
Registered
Joined
·
761 Posts
Discussion Starter · #7 ·
Yeah, I thought about that. But its not. If I set it to 21 psi it will go up to 21, stay there for a second and slowly fade to 15. Sometimes it fades to 15 then goes back up to 17. Not matter how high I set the BC it will always fade to 15 and this is with the FP upgrade 17psi actuator. I recently preloaded that crap out of the actuator and now I hit 23psi falling to 18 and holding for the most part. But now the turbo makes a wirling noise. I think its becase the wastgate is shut so hard and bearly opens that the air is trying to rush by the flapper. But I think I'm missing something. Not sure. No boost leaks, no exhaust leaks. I have a evo o2 and 3" all the way back. So no restrictions. If my actuator was bad I would think it wouldn't open at all. So agian, I'm lost. Is there anything I could be missing?
 

·
Registered
Joined
·
761 Posts
Discussion Starter · #8 ·
It seems that my wastgate flapper is blowing open. But everytime I adjust the wastgate to try and stiffin it I get spike. But not sure if that is the problem or not.
 

·
Registered
Joined
·
50 Posts
Do you have a hard pipe from the MAF to the turbo inlet? Clean and unobstructed air filter? Banana in the tailpipe? :) It sounds like there has to be a restriction in the system somewhere, especially since you cranked down the boost controller and didn't blow it up!:D
 

·
Registered
Joined
·
2,420 Posts
Dman95awd said:
Do you have a hard pipe from the MAF to the turbo inlet? Clean and unobstructed air filter? Banana in the tailpipe? :) It sounds like there has to be a restriction in the system somewhere, especially since you cranked down the boost controller and didn't blow it up!:D
I wouldn't think it would be an obstruction. I would lean toward a bad boost controller before that, and I think that is even pretty unlikely. Have you replaced the actual wastegate actuator? I know its new, but sometimes you can have a bad spring....:dunno:
 

·
Registered
Joined
·
761 Posts
Discussion Starter · #13 ·
I have the new joe P. pro Z MBC and if the spring was bad on the wastgate actuator wouldn't I be getting unlimited boost? But I do have a hard pipe from the MAF and my filter is clean. Obstruction? I just recently put on a new road race engineering downpipe with evo exhaust mani and o2 with all new gaskets. So not sure what could be obstructing anything. I do however have minimal blow by in my engine. Meaning when I do a boost leak test some air comes out the VC breather, but its very minimal. Not enough to drop my boost like it is I wouldn't think. I would hate to buy another 100 actuator from FP. Maybe its the turbo itself? Its only 2 years old. Not sure though. But when I put alot of preload on the wastgate, I get this wisling noise coming from the engine. Exhaust leak maybe? But would that be enough to cause that much boost drop?
 

·
Registered
Joined
·
363 Posts
n0rthendtr00per said:
Hey bump on this because I Can't get boost above 5K rpms. I believe its my Boost Controller.. Rocking a HBC pro.
I too am running that same controller and isn't working for shit either. In order to hold 14 psi with the heavy spring I had to set it to spike to around 18psi @ throttle tip in. So today I tried the softer spring (the one that comes installed) and with it turned all the way in it will hit about 15-16 then still only hold about 13psi at higher rpms. I am pretty sure I dont have any boost leaks besides the 1g bov (need to crush more) but I am not venting so that shouldn't matter right. My turbo is capable of at least 20#'s and is still like new so I don't think it could be that.
 

·
Registered
Joined
·
363 Posts
n0rthendtr00per said:
Bought a Forge BC... GOing to try it out later tonight. Fingers crossed.
Let us know if it makes a difference so I know if I should try a different one. Thanks.
 
1 - 18 of 18 Posts
Top