VersaTune User Forum

Lolmooses wrote: ↑August 2nd, 2020, 11:55 am I still have these weird lean spots during a 2nd and 3rd gear pull. The lean spots are now occurring at the same MAF volts range, so I went to adjust the MAF cal, but the numbers just don't make sense.

If the MAF cal is not spot on you may notice such weird situations in lower gears where the load and RPM ramp faster which means there's also less time for corrections. Also, even with upgraded internals below like 4000rpm such lean sports are not unseen if you shoot for high load (and also reach it) in the lower gears if you don't have some sort of aux fuelling that can also react to some input (boost usualy).
So what intake do you have? Maybe I have a good MAF cal for it somewhere in the dozens of tunes I made for various people...

The intake is a corksport stage 2. Updated my signature to list what's been done to my car.

So an update, I tried a maf cal from Cobb for the CS intake I have and.....bad idea. It ran very lean under WOT. I went back to my last revision. Strangely enough, the pulls with the Cobb MAF cal exhibited the same pattern of really rich and then really lean right spool up. The AFR curve very similar to pulls I posted last time except much leaner. Just for shits I adjusted the MAF cal for the spots that go lean and rich. I now have values that are larger than the one coming after it and the AFR curve is better but this obviously isn't the right way to do things. Could it possibly be something outside of the tune at this point?

The MAF cals from Cobb or even CS for some intake they have are absolute disaster. It's safer to scale a factory MAF cal and account for air filter permissivity than using those. I've found weird flaws even in the ones from Stratified.

I can now see why LOL. It was not even close. I have a new air filter and MAF cleaner coming in today. I'll try those and see if it helps. I bought the car with this intake on it so who knows how long it's been since either have been done.

Here it is, use this one.

This looks much better than the Cobb one I used, definitely a lot richer comparatively. I'll give it a shot tomorrow and let you know. Thanks again!

So I did a few pulls with that MAF calibration. Car runs fine but unfortunately its doing the same thing, dips rich on spool up (low 10's) , then goes lean (12's) at full load and evens out slowly to what it's supposed to be.

Still commanding loads above like 2.2-2.25 at 3000? Can you post another log?

Yeah, I'm targeting 2.22 at 3000 rpm and 2.3 onwards, but its going a little bit higher than that since its not so hot out like it has been. I attached two logs and the tune itself.