LY6 compression test is 93 a waste?
Thread Starter
Staging Lane
Joined: May 2014
Posts: 80
Likes: 1
LY6 compression test is 93 a waste? Hey everyone.
I have a LY6 that has LQ9 flat top (4.030") pistons with a TSP cam 231/236@0.50" and .615"/.641"and 111LSA.
I am running an LS3 intake and NW 92mm throttle body.
The car made around 405whp and 395 ft lbs on the chassis dyno through a T56 and 8.8 rearend
I recently did a compression test and leak down to make sure cylinder break in went well and just verify over all engine health.
All cylinders were between 180 and 185 doing a cold compression test with cylinders sprayed with some WD40.
I also did a leak down on the cylinder. They were between 15 and 22% which I am happy with.
With the lower cylinder compression do you think it is a waste for me to be running 93 octane and should I consider 89/91 or am I over thinking it?
Timing at WOT is around 24* but when the guy dyno tuned the car he did not go past 24 since he said generally all LS engines run best under 25*. Not sure if maybe there was some power left on the table at WOT due to the higher octane and lower cylinder pressure.
I have seen a lot of setups closer to 200-210psi running on pump gas.
I figure the compression is around 10.2:1. I would like to have the heads milled down to get the compression up but that will have to be a project for next year.
Just curious what you guys think.
Thanks
Shane
I have a LY6 that has LQ9 flat top (4.030") pistons with a TSP cam 231/236@0.50" and .615"/.641"and 111LSA.
I am running an LS3 intake and NW 92mm throttle body.
The car made around 405whp and 395 ft lbs on the chassis dyno through a T56 and 8.8 rearend
I recently did a compression test and leak down to make sure cylinder break in went well and just verify over all engine health.
All cylinders were between 180 and 185 doing a cold compression test with cylinders sprayed with some WD40.
I also did a leak down on the cylinder. They were between 15 and 22% which I am happy with.
With the lower cylinder compression do you think it is a waste for me to be running 93 octane and should I consider 89/91 or am I over thinking it?
Timing at WOT is around 24* but when the guy dyno tuned the car he did not go past 24 since he said generally all LS engines run best under 25*. Not sure if maybe there was some power left on the table at WOT due to the higher octane and lower cylinder pressure.
I have seen a lot of setups closer to 200-210psi running on pump gas.
I figure the compression is around 10.2:1. I would like to have the heads milled down to get the compression up but that will have to be a project for next year.
Just curious what you guys think.
Thanks
Shane
