I am just looking for some input on e.t. changes to expect when you change the AFR. I got my LM-2 working and the first time to the track i was at 10-10.4. I dropped 2 jet sizes rear and 1 jet in the front and the next week the AFR was 10.9-11.3. The thing is, after correcting the e.t. to sea level for both runs there was prett much NO difference in e.t.

I will say I did take 1* of timing out for the leaner set up so it probably picked up a hair, but nowhere near what I was expecting. I was looking for .05 or something.

My original plan was to keep leaning it down until I got to mid to high 11's but if that is all the e.t. gain to expect then it is not worth trying to get that close to the ragged edge. If I am only going to pick up .01-.02 I'd rather stay well into the safely rich zone.

What change in e.t. would you guys expect for a .5 change in AFR?

 

i never tried a pass after changing AFR's, but on a dyno, i was making 698 RWHP at 10.8-i pulled a little jet out, and made 733 at 11.2
so i gained 35 HP, not sure if that would result in much et gain, i didnt go any further down, as the engine had already blown up once,
and the plugs looked safe at 11.2

 

If you are tuning a car, and you made your tune "safe" with 10.2 AFR and XX timing and then you decide to change the AFR to say 11.5, you cant just assume the engine is going to need less timing to be "safe". you have to re-tune the whole thing, reading plugs, changing them to the appropriate temp range and gap, set the timing and its ramp rate to a proper range and of course make sure there is enough fuel and octane to get the job done. if you are running 87 octane at 10.2 and max timing, then sure, you lean it out, u better back down the timing. but if you are now running 116 and 10.2afr and then go to 11.5, you may still get away with even more timing! too much fuel is not good! cylinder wash down , oil contamination, plug fouling etc etc. you are better off running the proper AFR and back off the timing if you have bad fuel in the tank.

 

Right now I am running 93 Octane, 33* timing locked and not pulling any out, 8 PSI boost, one 14 GPH and two 3 GPH water/meth nozzles running 70/30 water meth.

The car kept picking up MPH with timing but I got spooked and stopped at 33/34*. It would probably like even more with this tune.

Here is the plug on the low 11s AFR pass. On the low 10 AFR passes there was no white at all on the porcelin. The black soot went all the way to the top.

 

If that plug reading was taken from a clean shut off, then its way too rich and over timed.

 

It was a clean shut off. The AFR was low 11 so yes, it was rich. In terms of the timing, I showed this plug because it was the "worst case" and the only one with the timing indicator in the bend of the strap. All of the rest had the timing mark well up on the flat part of the strap. If you look where the mark stops on the SIDE of the strap on this one, that is where it stopped on all of the rest.

Either way, I thought you want the mark in the bend? The picture had a bit of glare from the flash but the mark stops right in the middle of the bend.

 

Yes, right around the bend is correct. Sometimes in photos the timing is hard to see, but for sure that is way too fat.