I've owned an '04 GTO m6 for about 2 years now, and ever since i had the car i have been thru many different tuning iterations, trying to optimize performance and get rid of an annoying part throttle light pinging/detonation issue.

First, all i am doing is disclosing my findings about this, and i'm not here to start any post wars, insults, arguments, whether it's technically correct or incorrect, or whatever, so save it for someone else.

I just thought that this info may help someone here who is experiencing a seemingly unsolvable pinging issue.

Well here it goes.... i did a search on this forum and on ls1gto.com, and found many opinions and theories about passive vs active crankcase ventilation. Our cars are active of course, for the purpose of government regulated emission control. i capped off the two inlets on my ls1 TB, and capped the outlets coming from the valve covers, and left the engine valley cover outlet open. Of course this allowed oily mist to vent thru the tube coming out from the bottom end of the engine temporarily. What I was trying to do is figure out how to design an effective crankcase evacuation system that prevents oil ingestion, releasing/balancing any internal pressure in the valve covers and outside of the combustion chambers, that would be simple and low cost. In this process, i ran my engine for two days so far (passively), and i noticed something- NO MORE PINGING. I also noticed my throttle response was sharper, and it seemed to come off the line a little bit harder. No power gains here, just better response. At first i was skeptical that i was imagining this, so i put the stock setup back on, and guess what.... the slight pinging came back and the car was slightly more sluggish off the line.

i am convinced now that after 1+ years of pulling my hair out trying to find out why this ls1 was so hard to tune, that my problem all along was the stock PCV setup, of course since under vacuum it's pulling in that oily stuff into the intake trying to digest and burn it off in the cylinders. Excessive oil in the combustion chamber causes pinging, period. I'm just happy that this wasn't worn valve guides leaking oil into the chambers.

Now i might be able to add a little more timing and fuel, and get more driveability out of it, as it was mean't to be in the first place. The car is running great right now.

I still have the problem of figuring out how to handle crankcase ventilation though. This is a work in progress for me, and i'm still undecided if i want passive (breather oil cap) or active setup (small vacuum pump emptying into a catch can of some type). This is worth pursuing for me, i do not claim to be an expert with this or anything in the LSx world. i just wanted to share this with all.

 

I installed elite's catch can. Fits nice, and catches a few oz of oil
between oil changes.


http://www.eliteengineeringusa.com/Catch_Can.html

Russ Kemp

 

thanks Russ!
this looks like exactly what I need to solve my problem.

 

I never had an oil consumption problem, but regardless I went with a Moroso Catch can and breather.

 

thanks. i noticed your sig, wow... you cut a 1.40 60ft'er, and doing low 10's with an m6?? that's impressive to me. i doubt that i could get my heavy gto to ever do that with just a h/c setup. Are you runnin stock gears or 4.11/4.56's?

 

I recently did a H/C swap and while I was in there I put in the LS6 valley pan with integral PCV/oil separator box. That turned out to be a pain in the behind because my 01 LS1 block requires cutting so the pan will fit, not sure about the block in your 04 GTO. Check out this link for details:
http://www.ls1howto.com/index.php?article=18

If you don't need to cut the block I think the LS6 pan is a good mod. Otherwise I would just recommend getting a catch can. I got the one from thunder racing:
http://www.thunderracing.com/catalog...vid=3&pcid=316

 

i think i already have the LS6 pan. i saw a pic of it on somebody else's '04 gto which was stock. with my setup, i think i'm going to add a catch can anyway.