I just put in a bigger IC (it happens to be a Treadstone that I fabbed in). Nice quality Spearco-style IC, but a bit difficult to get installed due to the generic mounts. Anyways, all I changed is the IC...nothing else. I was previously running 17-18lbs of boost on a regular, daily-driven basis. Now, the car will hit 18lbs on the first run to redline, then is decreases progressively on each run. By the time I go around the block, the boost is only hitting 12lbs at redline. I've checked for boost leaks, but there are none large enough to see, and no squeals or audible hisses during a boost test. Any ideas anyone?

Btw, this forum is an invaluble resource for us Evo owners. I don't post a lot, but I've learned much from reading.

 

Who exactly makes the core?

 

So your car will peak at 12 psi, or it tapers down to 12 psi after going around the block?

 

becasue u have a bigger volume of air........its like pumping 10psi into a 20oz bottle then making the bottle a 2lt.....u loose pressure.

 

^^^what he said. If it's hitting 18 and rapidly falling off to 12 then you've got a leak somewhere. If not it may just be the turbo not being able to hold boost through the new core. Where do you live (what altitude)?

 

Yeah, a local guy went to the track with me and he lost .5 second in the 1/4 after putting a new IC on without tuning. The air volumes are all messed up.

 

I don't think he's talking about a boost taper. It sounds like after a few WOT runs the car won't peak at more than 12 psi. That doesn't sound normal at all for just adding the intercooler. Could the car be knocking and pulling so much timing (more and more after each successive run) that it can't even hold any boost? The stock FMIC isn't bad. Maybe this one is worse than stock and you are getting bad results from it? I believe DSMotorsport tested a Spearco core on their shop Evo and posted on here that the car slowed down vs. the stock FMIC. I'd beg/borrow/steal a datalogger of some sort and see what's really going on.

 

evo8ltw has got it right...it's not a boost taper. During WOT runs, the car starts to hold less and less boost. So, I have 18lbs to redline during the first couple pulls, then it gets less and less, and by the time I get home, it's only 12lbs. Here's a link to the company's website that makes the intercooler:

http://www.treadstoneintercoolers.com/index.htm

It's very similar to a Spearco. I hadn't heard about negative results from them, but not saying it isn't possible. Does it sound to anyone like it could be a boost leak? I've never had an issue like this before. Maybe it is a timing issue... I live in AZ and can go back to Dynocomp and we can fine tune it again. They really hate my Greddy Profec-E01 though...it's a ***** to tune. I could always throw the stock IC back on and see what happens too.