Ok, so I'm having a very very very wierd problem with my car. About 6 months ago I had been fighting a problem for a few months on my car. The car spooled up a teensy bit slower than the rest(I"m comparing to my 5 friends with evo's), and had a nasty taper problem. The boost would taper very quickly and quite drastically(1.5 to 1.1-1.2), also the car would not make power.

I had it dyno'd with 272's and an AEM EMS and it put down a ground pounding 288awhp on a dynojet.j

Since then I have swapped turbo's with a known good one, and added alky and 280's. The car immediately felt better after the turbo swap and was able to put down 397whp 398wtq.

The car felt awesome for a whole 2 days, and now its back to its old self again. Boost taper from about 2 bar to 1.5-1.6 if I can even get it to hit 2 bar w/out a HARD load in 3rd-5th. Even at its 2 bar the car feels like absolute crap. It doesen't ring through the gears like it did, and even got slightly pulled on by a 264/272 non alky evo.

I have no idea what the crap is going on, I've called multiple shops and multiple people all with no real explanation or ideas. I am ceartain I have no boost leaks as I've tested it myself. AEM is not pulling timing and a/f's are completely proper.

Anyone with any ideas please feel free to give me some info or suggestions, sorry that it is so long. Thank you.

SETUP:
HKS 280
10.5 housing
AEM EMS
Greddy profecB
Greddy RS BOV
ARP headstuds
SMC ALKY

 

how's your idle?

Perhaps your timing is out of phase or you skipped a timing belt tooth. Checking your timing.

And of course check the normal stuff like compression and do a leak down test, it's pretty easy.

 

timing is dead on, I got back home from the dyno on sat evening, drove the car for about 20 min sat nite. Drove the car for roughly 1.5hrs on sunday. Then on Monday this **** started.

 

You might want to list all you mods champ ... because after all the mods you have, you can not, not have TBE .... are you also using the stock boost solenoid?

 

Maybe do a compression check?

 

Full 3" TBE w/ no cat
Greddy Profec B boost controller
Walbro 255lph


Sorry, I only listed the more important, I assumed everyone would assume I had the neccesities

 

Compression is 150(yes, I know a lil low) all across the board, it has been since I got the car.

Thanks for the help guys, keep it coming

 

Have you tried checking all the I/C piping? And is it misfiring at all?

 

Anyway you can find out what your EGTs are?

 

I assume your knowledgeable enough to know if the clutch is slipping or not so i will rule that one out.

2 bar is a little high for the stock turbo, you may be wearing it out pretty good.

Other than that the only other thing i can think of at the moment is a boost leak if all those other things are good to go like timing and so on. I assume you pressure tested the whole system from the lower i/c pipe and left everything else on?

Good luck.

 

Have you also checked for exhuast leaks before the turbo? That can lead to slow spool up and less boost. Check the gasket between manifold and turbo hotside, and the manifold for any cracks.

 

I pressure tested by attatching a coupler to turbo inlet and put ~29lbs of pressure in the system, no leaks.

And yes thank you for giving me benefit of the doubt, I work on cars all day long so the usual **** I know very well. The clutch is not slipping and I'm not having any misfures.

They're are no exhaust leaks anywhere in the car except out the back

Unfortunately I can't figure out the EGT's b/c I don't have a guage

 

So you did check your base timing *after* this problem came up?

Any chance of plugging the stock ecu back in?

 

can't say that I have yet, however i've not noticed any difference in the way the car idles or anything.

Stock ecu...hmmm....first I'd have to find it..second I think my MAF plug is in my fenderwell now and I know it would throw a couple of lights..not sure it would be all that happy with the current setup, lol.

 

I gurantee you its your EBC ... It bleeds and dosnt hold boost good ... Sell that and get yourself a MBC - call it done ... That and do a boost leak test - fix all of those boost leaks .. You probably have anywhere from 3-4 ....

But most def the EBC .. Do a search on your EBC ..