As the subject says, how do I richen up the a/f ratio using Tunercat? I'm using the % Change to Fuel/Air ratio Vs. RPM at WOT and Coolant Temp at WOT.

 

There's a formula in the help menu of Tunercat

 

Be very careful with that formula!
There is more to it than what is shown in the help section in tunercat. I can't prove it, but I'm rather certain that it takes into account, long and short term fuel trims, maf afgs, and injector constant.
Another frequent contributor to this board has done some experimenting with his own car in order to try and make the formula shown in tunercats help section a little more usable.
What he did was disabled pe mode completely in order to try and correct the maf tables and get consistent 128 long term fuel trims across the entire maf table/range.
Then when the % change to wot tables are applied that formula is a little closer to being usable because the actual airflow coming into the engine is really close to what the maf table is expecting.
Confused?

 

Dan K, I've used that formula to change A/F ratio at WOT going richer & leaner and have not had any problems. Why is it bad if it takes long and short term fuel trims, MAF AFGS and Injector constant into account? I know the only truly accurate way to tune WOT is on a Wide band O2 dyno which I will be doing soon but so far I have not seen any KR

 

I think he was saying that the formula and resulting AFR will only be as accurate as the data given to it.

So, if your MAF sensor is reading incorrectly at the higher RPMs, because the BLMs are locked at WOT, there will be no compensation for this offset.

Therefore, tuning your BLMs at all RPM/MAP ranges (turning PE mode off), before you program/tune the WOT AFR, will give more accurate results since you'll have more accurate input.

 

Bingo!

 

JSK333 & Dan K, Thanks for the input