THADD

iTrader: (12)

We have a mini pulling tractor with a LS swap in it. The motor is stock except for Vic Jr intake with a 650 carb. For now there is no map sensor and I am wanting to plot my own timing curve. I have been reading and I think I will got with 22 degrees at idle(750 or so), ramp to 30 by 2000 rpm, then by 3000 rpm go to max timing at 34 degrees. The tractor might weigh 2200 lbs and we pull a max weight of 2000 lbs. It has a 5000 stall but shouldn't stall that high from the start because we don't just floor it off the start plus the weight of the tractor isn't that heavy to flash the stall. Also we only pull in 1st gear with a th350 and 580 rear gears. Here is a pic to give you an idea of what's going on. Any input or suggestions on timing would be great!

89gmcs15

iTrader: (7)

Sounds to me like your right on track for the timing, just keep a ear out for signs of too much timing if ya can. In a application such as this it would be best to test and tune and tweak and adjust as needed. With your ever changing track I don't know how you will be able to consistently and accurately repeat a run to get back to back data tho. Good luck!

THADD

iTrader: (12)

Yeah it will be hard to get back to back data but I guess as long as it sounds clean, throttle response is good, and no sign of detonation I will be good. Once the max timing is figured out I think the only time we would really change anything is the timing at the start of the pull based on track conditions

speedtigger

iTrader: (16)

No good definitive way to know best timing that I can think off. Since there is no performance testing unless you are going to strap that beast to a dyno and you most likely have an exhaust system that is loud enough that you would not hear the engine rattle if it did, I would error on the side of caution and run 30 degrees.