i was wondering if i should get rid of my cats and replace them with test pipes. i heard that this may cause boost creep and ruin my motor. ive got a 90 tII with minor modifications. should i do it??????

 

if you feel comfortable with taking off the turbo and doing some grinding, then go for it. The reason the boost "creeps" through the wastegate is because the stock hole doesn't allow enough air out. This is mainly a problem on the 87 and 88. Since your 90TII has a different style wastegate, it shouldn't be much of a problem. If you have other "minor modifications" and add the test pipes, yo're gonna be hitting fuel cut (probably booost around 8psi with a functioning wastegate), so you'll need a fuel cut defense.

 

My '89TII with Bonez DP & hi flo cat hits just over 8. I'm sure with cats completely removed, you'd hit fuel cut.
Hope upgrades include fuel system components.

 

I am running with the pre-cat just emptied out and then custom piping (stock diameter) out the rear through the stock mufflers. I still have the stock air box.

I only ever hit 8 PSI, '89 Turbo II. With the exhaust being stock diameter and the intake being stock, there is no boost creep (the boost actually starts going down after 5500 RPM due to air flow restrictions).
Might be different if I had a good down pipe.

 

just put in a 3" test pipe where the cat used to be.


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