timing help

[Josh2562]

Hello all. I'm new to tuning. I have a lq4 with 243 heads that have been milled .030. cam specs .610/.606 224/232 114 ls. tbss intake with 92mm t/b and long tube headers. This engine is on my airboat. My max engine rpm is 5800rpms due to gearbox ratio and max prop rpm. Right now I'm running 23 from 2200 rpms to 4000rpms. running 25 from 4000rpms and up. With this timming I can get the engine up to 5200rpms. I started with 21 from 2200 to 4000rpms and 23 from 4000 and up. with the 21 and 23 my max rpm was 5000rpms. I'm picking up around 100 rpms with each timing change. I don't want to hurt the engine by running to much timming. I'm watching my knock reduction and have none so far. The prop acts like a dyno. The more rpms I'm able to turn the prop at a set pitch the more power I'm making.
The tune that I'm working off of was done by a shop but I changed the intake/injectors/throttle body.
I'm running a SD tune. I've tuned the Ve table and have it running great but would like to make the most safe power I can. Thanks for any Help

[Ben C]

Spinning a prop is heaps good for tuning, so many variables of tuning a car are removed.
With your approach you are on the right track.
You will likely see that when adding more timing from the best point the rpm won't increase, and adding timing from that point would cause knock.
Are you using the real time tuning function?that would save heaps of time flashing and re testing.

[Josh2562]

No I'm not using RTT yet. I just learned about it the other day. I'll check in to it more. Thanks for the help.

[Hutchinson]

Airboat huh? What neck of the woods you in,....u near me in Florida? Airboats,....that's right up my alley ��

[Josh2562]

I'm in Crystal river Florida. Do you run a Ls engine on your boat? Once I get the tune down I'm going to put a turbo on it.

[blownbluez06]

26-27 isn't unreasonable. If you're able to create more load than a typical vehicle, it should take less timing

[Hutchinson]

Apologies Josh2562,...this one slipped right past me. I don't currently have an airboat,...the ones we had were simply carb 350's and 454's (haulin fat *sses), or going light with a O-360 or O-540. I used to hang out/work with Larry Whited (airboat association) and run the back flats of Tampa Bay.
Crystal River,.... that's some nice airboat runnin' area round there. Let us know how she runs,....especially after the turbo,...that should be cool and quick,.... Some guys spend thousands on a motor, yet, leave a lot of top end on the table due to prop selection. Bet you've already got a Sensenich or Whirlwind Prop on there.

[Area47]

the peak efficient range of the lq4/ls9 runs about 25-26 degrees of peak timing. from my findings its not worth it to push it to 28 for 1-3 hp gain.

[Fast4.7]

the peak efficient range of the lq4/ls9 runs about 25-26 degrees of peak timing. from my findings its not worth it to push it to 28 for 1-3 hp gain.

It depends on the engine setup to be honest. My buddy has a LQ4 with very thick cometic head gaskets on it for boost and a turbo grind cam. Running NA it makes peak power at 30? of timing. Increasing from 26? to 28? was about 8 rwhp and 28? to 30? about 7 rwhp more. I could certainly see a stock engine running best in the 25-27? range. The MSD controllers that Edelbrock uses for the carb conversion run all day long at 36? total advance.