Hey guys, I just got protuned by a reputable shop. Afterwards the tuner said that he noticed my car preferred to run on the lean side, and that there would be no problems. He is very experienced in tuning evos. The car seems to run very good, but I wanted to check by you guys.

Y axis is Boost/AFR and X axis is RPMs.


As you can see from the graph, at 3k rpms, I'm at ~21 pounds of boost, but my AFR is ~13.5. Towards redline, my target AFR seems to be about 12, instead of the normally suggested 11 here on the forums.

Some advice would be appreciated. Am I worrying too much? Should I trust the expertise of my tuner?

 

Wow, well I'm no tuner and I suspect that some others that have more direct experience with tuning will chime in, but that seems pretty lean to me. Knock count would be an important data element as well. For a road race tune I believe our tuner shoots for an afr around 11.4-6. Again though, smarter people than I will have more specific advice.

 

that graph if correct ,
your car is running way to lean if you are on 93 octane.

most tuners will tune between a 11.1-11.6

second most tuners would have a very stabilized fuel trim.. that fuel trim to me looks like he never gets it under control. Just look at the min/max/avg numbers..

I look at it and I shiver.

saying that , like johnr352 said, i would be interested to know the knock count on that run and at what timing you are also running.

 

I'm also not a tuning expert but if you're running e85 then those afr's are acceptable. If on 93, then I'd venture a guess and say that's pretty lean.

Also you can still fry your piston being lean and not necessarily be having a lot of knock.

 

I'm not a tuner, I just feel I do my due-diligence when it comes to my hobbies. IMO that is too lean. If you do start knocking, it's going to have issues really quick. My X is tuned for 11.5-11.7.

I wasn't surprised when my tuner set it up like that either, because many other turbo cars find a sweet spot around the same AFR for power and safety. Which makes me think he's full of **** even more, because that's also a healthy tune spot for the 4G63 too. All my friends I can think of tuned by different tuners have their AFRs targeted around 11.5ish.

Seriously a 13+ AFR is only cool if you're tuning for power on an N/A engine.

 

14.7 is way too lean. As others have stated about 11.5 - 11.8 is the sweet spot. I would get your car retuned asap. I would also lay off of WOT until you do get it tuned.