bobby.is.rad

With spring coming up, we've got temperature swings from the 50's up to the 80's in NC, and I've noticed that the weather is affecting my AFR's. Is this normal? If so, is there any way to fix it automatically without having to retune for temperature changes? (Something like the RAX IAT vs. WGDC for boost, but with AFR's instead?)

Here's two runs, on two different days, with the exact same tune. As you can see, it's much leaner when the ambient temp is in the 80's vs. when it's in the 50's. I did quite a few back to back runs on both days and these charts are what I was generally seeing on each day.

sstevojr

iTrader: (7)

11.5, I personally wouldn't worry about it. The 10.8 up top was a bit too rich anywho, for me atleast. I try to keep it ~11.2-11.7.

tonyboy

iTrader: (4)

you are in direct boost aren't you? the reason why your afr's changes is because you are hitting different load cells..

at least from what i read and understand about the RAX patch and IAT BWGDC, it will help indeed..although that will require thorough testing and/or tuning..at least for the load cells that you're going to hit from different temperatures..good luck and have fun tuning!

bobby.is.rad

Thanks Tony. I am using direct boost. I took a look and my load was a bit different between the two runs, which could have definitely caused me to hit different load cells. Looks like I just need to work on getting the fuel maps consistent between 240 through 280 load.

tephra

iTrader: (6)

you need to log things like ECT, MAT and MAFIAT to pin point your issue.

there are HEAPs of temp corrections already built into the ECU.

Hiboost

iTrader: (9)

Chances are the different load cells are tuned quite a bit different in each run and when it's cooler and higher load the tune is richer. Just one reason I like to tune for more boost levels than just the final one so that when seasons change there are minimal AFR differences. Only problem with smaller turbos is usually the boost is locked in above 5500 so while boost is identical, the load may still be different because load changed.

Most tunes are setup to get richer as load increases which is a built in safety measure, I prefer to tune the load cells 20 higher then where it is currently hitting and then worry about making it richer if it somehow gets beyond that range through uncontrolled boost for safety. Loads below that should already be smoothly transitioning as well but some tuners only change the load cells you are currently hitting so you get some inconsistancies.

bobby.is.rad

Just wanted to update the thread and say you guys were right on the money. Once I evened out the AFR's at the load cells immediately adjacent to my previous loads, I was where I needed to be. Thanks!