VersaTune User Forum

Is it possible with VT? I'd like to go 15.2 AFR @low load/low RPM (half of closed loop basically). Do u guys know how to do it with VT, or is not even possible?

Cheers

I tried to go that lean with the 2.3DISI-T/MPS platform and apart from wearing out the sparkplugs faster and making the throttle response a bit more hysteric we did not get much. I do not recommend going leaner than 1.03LAMBDA on piston engines, with rotaries it may be even trickier. Anyway, to go leaner than 1.03lambda you will have to disconnect the secondary O2 sensor.

No big deal for the 2nd o2 sensor, since I have it disabled since day 0 of having VT. It's kinda safe to go leaner than 14.7 up to 15.5 on race extensions since it won't get that hot (plus, it's in closed loop and up to 0.4 load), but I don't find the way of doing it since the limit on the fuel map is 14.7, and nothing else.

but thanks for the answer, I can try going from there

EDIT: Forget what I said..... yeah, I found it. Just modding the stoich, in theory, will do.

Thanks a lot for the answer tho

Ok, a little update on this. So I did it....... 15.1 AFR at idle and cruise loads/rpm, I got 7.1 L @2900 RPM/15% load, and 7.9L @3600 RPM/35% load (120 km/h, 65 or 70 mph I'm lazy, I'm not converting it). aaaaanyway, I got what I wanted. It's not enjoyable at all (I have many other tunes for that) but for what I'm planning this weekend, I guess I'll be doing it in 1 or 1.5 tanks.

For a more normal measurement, I got 150km done with not 1/4 of the tank (reading the stock fuel gauge), when before, with any other map or even stock, I wasn't able to get 50km with less than 1/8 of a tank.... so yeah, huge improvement!