Osmosis

I recenlty rebuilt my engine to almost the exact spec's as the old engine. The only difference was that I had my block decked .010. Same cam, AFR 190 heads, All forged internals. MY old engine...the crank busted at the snout, hence the new engine..with forged internals.

Now, I run 9psi with a procharger 3 core intercooler, 8/1 fmu, crane hi6s igniton with boost retard. My engine always ran top notch, never pinged notta! Well, I just turned 3000 miles and put the charger on yesterday. Now, I get detionation when i get around 7psi? my timming is set at 6 deg advanced.

I"m thinking

bad gas?
increase my fmu pressure
retard my timing to 4 deg advanced
maybe retard my timing in the chip if need be.

Any thoughts our suggestions would be appriciated

97WS6SCharged

What are the specs on the engine?

1bad2k2ta

If nothing has changed in the fuel system and s/c setup (pulleys, etc.), and there are no obstructions in front or behind the intercooler, then could be bad gas, fuel filter, or possibly increase in CR due to milling block .010 and maybe thinner head gaskets. This would lilkely only cause a problem if you were already at the edge on last build. If all this is the same and fresh good gas and fuel filter don't fix it, then are you sure the cam was indexed correctly, might be off a tooth. The FMU could also be suspect. Almost nobody is using them on the LS1s, at least not on anything over 7 psi, they just never worked right.

Tom

Osmosis

Well, I think I'm on the road to recovery. First thing, I recently got a code 43 again. That would explain tons. If the knock sensor is not working, it is not pulling out timming when I get a knock, hence detionation in the upper rpms. Also, I think bad or low octane fuel is partially the problem. I put a bottle of 104 in plus 1/2 tank of 94 and the knock has been cut in half. I think I was putting 87 octane in while I was breaking in the engine. I'm going to check my KS today and see if it is bad or not, that will tell me a lot.

Thanks for the help! I'll keep ya informed!

Steven

huffin Z

I would say maybe your timing!, but don't go on my word..