VersaTune User Forum

I recently installed a GWR 1.8 header and started going down the tuning rabbit hole. I've made a lot of mistakes along the way and even though I'm closer I'm still very lost.

After logging a few WOT pulls I noticed that the car runs very lean on higher RPMS. Initially I thought I could adjust the MAF sensor and increase the g/s on higher voltages to get actual lambda to match desired (or what is on my fuel map because desired is always 1 in the logs).

This worked and I was able to get my lambdas down to .85, but after reading multiple docs on tuning headers I believed I followed the wrong approach and should have been changing the Volumetric Efficiency Load Multiplier Table.

For my second attempt. I set all the OL Partial WOT table , OL APP WOT, OL Global AFR fuel tables to target .85 lambda so that I always target .85 lambda on OL. I then did multiple WOT pulls, calculated how off in % actual is from desired. Made the corrections on the Load Scaling table (Increased values) and then verified with another WOT pull.

I did the procedure mentioned above 4 times and I was not able to get actual lambda to match target. I'm at a loss right now. I'm not sure what I could be doing wrong.

Can you post your tune and some logs.

I remembered some more details about the desired being stuck at one. I don't use Versatuner to log so I don't know if it'll allow you to change the logged decimal point.. In ForScan and the OEM software, you've gotta change this in the parameter settings. Other wise it's just rounding up to 1.. You need 2 - 3 decimal points.

Leave the Volumetric Efficiency table stock and just modify your MAF calibration to keep your AFRs in check.

Also on a side note, targeting 0.85 lambda on NA with headers (assuming deleted cats) is probably a bit richer than I would go, try around 0.88-0.90 lambda.

Any logs would be sweet too.