Bluevette85

I am using the ARAP bin on a Superram L98. The AFR in PE mode uses two tables for fueling (coolant and RPR). It looks like this:



Why are those AFR transitions there? Should I try to have 12.5 across all RPM's or some type of transition from low to high RPM's? I will be getting a wideband soon.

Grumpy

I understand the labels, but where did you get this from?.

AFR is whatever makes the engine happy.
It's also somewhat touchy, rich being better then lean in case of an error.

Starting at 12.5 is GENERALLY a safe AFR. But you have to sneek up on things carefully. Read the plugs.

Do a commanded 12.5 and make sure with all things being correct or close to that you have a reasonable DC. Since if your going to rely at all on the ecm for generating a AFR, you want it to be able to. ie if you set the AFR to 12.5 and run a 100% DC your too far out to even get things back in without some mechanical work.

On my car I started at 11.5 and have been taking it lean from there. But, I also had run it at 11.8 and knew that was a happy zone for my combo.

Bluevette85

Grumpy,
The graph is based on a formula I found here:

PE AFR = 14.7/ (1+(%added Coolant table/100) + (% added RPM table/100))

I'm using the value of 22.66 from the Coolant table because this is the temperature I operate at.

If this formula is wrong, please correct me.
Thanks.