We were tuning my H22 at the shop saterday and seemed to hit a wall at 21 to 22 psi.It just to seem that it stopped making power efficiently.The more we turned the boost up the worse it seemed.I have one of those huge ebay intercooler and it flowed good till about 580 or so wheel.Has anyone else ran into this problem or does it seem something else is going on.The iat seemed good..
H22A1
9.1 CP PISTONS
MANLEY RODS
SUPER TECH VALVE TRAIN
FULL PORT AND POLISH
GE INTAKE MANIFOLD
70MM TB
t67 h.o

 

The ebay intercoolers are good up to about 400hp, if your running that much horse power invest in a good intercooler.

 

we have used the big ebay one 24xwhateverx4" nd it handled 738whp and was not even hot..

 

I just ordered a 24x12x3" core off there, hopfully it will get me to 700 without problems.

 

The problem is that not all ebay IC's come from the same source. I agree there's not many sources, but each will have several different types in their lineup.

One way is to check the pressure drop on the IC. You could get a motorola/freescale MAP sensor that reads differential, which could be logged with any 5 volt logging soft/hardware. Hook one nipple to the turbo, the other to the manifold and you'll see the pressure drop of that entire section of the piping/IC. You could do it with a 2nd gauge, but its hard to focus on 3 gauges at once (rpm & 2 boost) while doing the mental math for pressure drop.

My bet is your turbo can pump out a good deal of pressure, but the cheap IC's pressure drop becomes expotential above 20psi, such as 3psi @20psi, 6psi @22psi, 12psi @ 24psi; a 12psi pressure drop would give you 24psi in the manifold, while the turbo is pushing out 36psi. Meaning your turbo compressor is still efficient, but the big increase in exhaust mani pressure is killing power. Thermodynamics and fluid mechanics can get real complicated with a turbo motor.