When I put my LQ4 together I had the stock 317's milled .020" because one of the heads had some scratches on it. Can someone tell me how many cc's it took off of the combustion chambers and how much crank and rwhp that it probably gained me?

 

1cc for every .007 milled, HP that you have gain, idk maybe 5 to 15.

 

Thanks. Anyone else?

 

I have a friend sayin i gained at least 20 hp... I want to get to the bottom of this, so anyone with some hard proof would be much apprecieated! Thanks!

 

 

What ^^he^^said!

Was that friend from Great Bend? If you use their math, and corrections, you still wouldn't get 20 hp...

Maybe 5-8...at the flywheel

 

Thats exactly what i had calculated. I had figured 6 to 8 hp... Thanks man. If anyone disagrees with this please post up and explain why.

 

Hey buddy from what we have seen, I would say at least 10-15 fly. These motors love compression. remember people on the ls1's go to the ls6 head which flows in the 255-260 range vs the ls1's 220-225 and is 64cc vs 66cc for the ls1 head and the average gain is around 15-20 rwhp gain. You went from around 71-72cc down to 68-69cc. So ya id say 10-15 fly. Maybe 5-10 at the wheels. And yes I am from Great Bend. We don't know what we are doing. We have slow crappy cars. lol

 

I don't agree with you guys not knowing what you're doing at all! You guys have the fastest chit for mods I know of around here!! lol I was not trying to offend you or say that you were lying in any way, I was just trying to get some other opinions and try to get some cold hard facts with proof to back it up, but no one seems to have any...

I wish I could remember which HOTROD magazine it was that I read it in, but they tested how much HP was gained from compression. They increased the compression exactly 1 point, like from 10.0 to 11.0 and gained exactly 16 crank HP... BUT, I don't remember what kind of motor it was on. Probably an old school SBC. But results could be completely different on an LS. Thats what I wanted to find out, if it is the same on an LSx based motor.

 

Also remember that the only difference from the lq4 to lq9 is compression and they dyno around 8-12 more at the wheels. That is a half point of compression. They have 10 and the lq4 is 9.5. You should be around 9.8 give or take for what gaskets you used. My 2004 Escalade Had the same tune as my Lq4 engine. same timing, same P.E. Same wideband tuning 12.8 AFR. Everything was the same on the same day and My injector duty cycle on my escalde was 4-5% higher.. That shows that the lq9 has more power the my lq4 did. And the only difference is the half point of compression. And by your track numbers compaired to My old lq4 and Chrises notch which is a stock lq4 you are laying down like 6-10 rwhp over us. All else is the same. Hope this helps. See you soon