Boost problem - Boost Forum

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Boost problem
Thursday, May 30, 2013 5:23 PM
So with my rear mount setup I boost with no problem with just a straight piece of pipe in place instead of the intercooler. When I put the intercooler on it would barely boost at all. Its a cheap ebay intercooler so I figured that maybe it was just too much volume or something. So I started pinching off sections of the intercooler thinking that if I lowered the volume that it would work better. Totally opposite effect. No boost whatsoever. My IATs are only at 120 degrees and get down under 100 with the meth injection. Id still like to have an intercooler on the car so did I just get one thats poorly made or what? Or should I just say F it and not worry about running one? Any suggestions for small intercoolers?


3400 SWAP DONE. 187WHP 212TQ (14.2 @100MPH NA) 240WHP 310TQ (N2O)


Re: Boost problem
Thursday, May 30, 2013 5:44 PM
It's gotta be leaking somewhere. Are the couplers snug on the inlet/outlet before you tighten the clamps? I know a lot of ebay stuff tends to have odd metric sizes for inlets/outlets that don't fit standard couplers.

In any case I think you'd be best off to just buy a decent one somewhere even if it's small.



"In Oldskool we trust"
Re: Boost problem
Friday, May 31, 2013 10:27 AM
Go with a cxracing ic cheap. Is it to big of a intercooler?
Re: Boost problem
Friday, May 31, 2013 11:59 AM
I'm guessing the intercooler has a leak, but in order to create no pressure, it would have to be huge!
I mean bigger than 1/4".
My intercooler is huge, and Im running a 16G, volume of intercooler really wont affect that as much as people think.
Are you running a good size turbo?
Its possible with just straight piping, you have enough of a restriction to build pressure, with the intercooler in place it allows for rapid expansion just before the engine.
This would mean that the turbo would be undersized, not to keep enough CFM feeding the engine to create positive pressure.

I would leak check the intercooler for starters, it will cost about $20 for a homemade tester.
Go to home depot buy two pvc rubber couplers to fit intercooler, two pvc caps to fit couplers, 4 gear clamps, and air chuck quick connect, and JB weld.
Attach one coupler, and cap to one side of the intercooler, drill a hole in the other cap, and JB weld the aid chuck to it (in assuming you don't own an NPT tap set, if you do, tap it and avoid the JB weld)
Attach other cap to intercooler as well.
Turn air compressor regulator down to 1-3 psi, attach air hose, and spray with soapy solution.
You should be able to find it!

Good luck!
Re: Boost problem
Friday, May 31, 2013 11:30 PM
Why are you running a fmic with a rear mount turbo anyway there isn't really a need for it. your prob.
experiencing a @!#$ ton off pressure drop from all the intercooler piping you have ran.
Re: Boost problem
Saturday, June 01, 2013 3:53 AM
What size is it? It may be too small and is a restriction. Also, where is the wastegate referenced to? If its anywhere on the compressor side or IC piping, change it to the manifold and then try again. If its a restriction at all, then it will cause the wastegate to open sooner if its referenced anywhere on the IC piping or compressor. I tried a small ebay IC on a rear mount setup of my truck and it had the same effect of killing boost. It was too restrictive for a rear mount which is already pushing the air harder than a front mount is. You could deff tell it was a restriction when out of boost as well in my case. The one I used was maybe 2.5x7x24 or something close to that.



12.6 @ 114.6 MPH

Re: Boost problem
Sunday, June 02, 2013 7:00 PM
I think thats what is happening its building too much pressure behind the intercooler and pusing the wastegate open prematurely. My wastegate boost ref is right off of the compressor housing. Do you think I should run a VAC line all the way back to the waste gate? I have my waste gate right by the turbo in the rear.


3400 SWAP DONE. 187WHP 212TQ (14.2 @100MPH NA) 240WHP 310TQ (N2O)

Re: Boost problem
Sunday, June 02, 2013 7:16 PM
You should run the wastegate off of the intake mani
Re: Boost problem
Monday, June 03, 2013 10:03 AM
Yeah, run the line from the mani back. My rear mount SUV has about 7-8ft of 1/4" line for the wastegate. Works great. Not any slower to react like you may think. If that doesn't do it, then the IC is just too restrictive or there is decent sized leak somewhere.



12.6 @ 114.6 MPH

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