Avengeance

iTrader: (4)

I jumped on the dyno the other day and my car was down on power... well.. we think its probably the POS Spec3 slipping across the board. I was advised by my tuner to do a compression test and leak down just incase.... just for ***** and giggles. I did the compression test.. the low was 186psi and the high was 191psi. So that turned out fine. Before I go and rent a leakdown test tool I was wondering what signs would my car have that would warrant a leak down? Oil in the intake? Burning oil?

Ive never done a leak down before and Im not quite sure what signs, besides being down hp, would warrant a leak down.

Any help would be appreciated. TIA.

brad8266

iTrader: (23)

Since you compression readins are so close together I wouldnt even bother doing the leak down test. Your engine is fine.

Oil in the intake is normal for an LS1 with the PCV susterm still installed and it wont kill power.

bczee

iTrader: (12)

A leak down test will let you know the health of a the engines seals, rings and other item. With a correctly done Leak down test, you will find where and what is leaking and what percentage should tell you the health or how bad it is.

Once you have a cyl on leakdown test, you will listen for air leakage. If you hear it coming out of the intake, you know your valves are leaking. If you hear if from the oil filler or valve covers, then it is the rings that are bad.

I forget how much leakage percentage is acceptable, but I had 3-5% leakage on my 99 LS1 which I think is good.

oange ss

iTrader: (50)

i believe the serviceable limit is 13%

hammertime

iTrader: (1)

3-5% is very good.

I agree with Brad, if your compression numbers are that consistant, you should be fine. A leakdown test would backup those results, but probably isn't necessary.

A slipping clutch is power that ends up generating heat instead of making it to the wheels. If you know it is slipping, I would start there.

Avengeance

iTrader: (4)

Thanks for the info guys. Much appreciated.