ullose272

so i know that most of the power difference between the lq9 and the lq4 6.0s is the tune. now i havent messed with tuning the timing, but im fairly familiar with tuning the air/fuel. so if i wanted to put the lq9 timing tables on my lq4 i would basicly compare my file against a lq9 stock file and change everything that is different to the lq9 tune? id imagine id want to do everything under the spark tab (advance, retard, dwell, and knock sensors?) then retune my fuel tables?

George C....

first off the tune isnt the main difference, the difference is the compression

and you cant just simply copy one tune into next

youre better off just tuning your motor for what it wants and not what another motor has

ullose272

the compression is only about .6 higher. the research that i have done says you MIGHT see 3-5% hp increase with a full point of compression increase. so were talking 5-10 hp max from the compression. the rest is in the tune. this has been hashed out many times on this forum. from looking at the timing tables it looks like the lq9 timing comes on a bit faster (more timing on bottom) and has 2-3 degrees more through mid and top end. i know my **** when it comes to carbs and distributors but im new to tuning efi. now i figured since the lq9 has a hotter timing table, yet is still a factory tune, i could load that up and still have a safe tune, but a little better to start from. what im really concerned with is if i change the high octane table, should i change all the other tables in the SPARK tab to the lq9 tables so everything is the same.

George C....

old rule of thumb is for every .5 in SCR youll see about 15-20 hp which shows to be true for the LQ9 vs LQ4


tune is different cause its stated to run 93 only for the lq9 cause of the compression

with said dont copy and paste, tune the lq4 as its needed

and just cause something is on the net doesnt mean its correct

ullose272

man i wish you could get 15-20 hp out of .5 point of compression. its 3-5% per point

http://www.bgsoflex.com/cgi-bin/crch...9.4&newcr=10.1

simple calculator

How Much HP, Per 1 Compression Increase - LS1TECH

Eaton Balancing » Milling Heads for a Horsepower Gain

How much power does adding compression make? - LS1TECH

George C....

showing posts from ls1tech is like believing everything obama says, do you believe everything obama says?


FYI that number figure has been around way before Ls1tech was ever created there bud


but to your timing topic, tune the motor for what it wants and not just copy and paste..

ullose272

anyone else?

2xLS1

iTrader: (25)

Yea, better not disagree with George C....

Ah, screw it, Yes you can copy the LQ9 high and low octane tables to your LQ4 tune. I would suggest running a min of 91 octane gas if you do.

And GM recommends 91 octane with the LQ9.

Oh crap, I did it again.

GREENSIERRA

I have always believed the same thing as George on compression, .5 give around 15-20hp
when I talked to some reputable vendors when I was planning out my stroker they all told me those numbers aswell

2xLS1

iTrader: (25)

More like 2%-3% for each 1 point increase. I've never heard or read of it being stated as a specific hp number.