Are OTS maps inherently lean? (log included)

[theweebabySeamus]

So I ran a log the other day on my BM3 CS+ map and I noticed the AFR is pretty lean lower in the powerband, but I also notice its hitting the AFR target consistently and both banks are even, so I'm wondering if I have an issue or if PTF just runs them that way?

I sent them a log and they responded that it's bad quality fuel. Sure, CA is terrible, but my ACN91 has at least 25% Sunoco 100 in it. Also, fuel quality shouldn't affect lean/rich.

**Log not included, I made a mistake **

[Jmk508]

If the fuel is not as advertised then YES it effects the engine performance. Your vehicle will pull all timing if it detects knock until it doesnt.

[theweebabySeamus]

Originally Posted by Jmk508

If the fuel is not as advertised then YES it effects the engine performance. Your vehicle will pull all timing if it detects knock until it doesnt.

You're saying that quality of fuel will affect how lean an engine is? Should only be affected by O2's, vacuum lines or fuel delivery in my experience.

EDIT: I understand that fuel quality affects timing, I'm speaking specifically about AFR.

[Jaizero]

It should be ~14.7 except under enrichment at WOT where it will be more rich (around 12.5-13.0 AFR)

It will always swing lean/rich as staying perfectly at 14.7 is impossible.

These cars use lambda for fueling, so regardless of stoichiometry of the current fuel in the tank you should always see somewhere around 14.7 on a basic AFR gauge.

Post a log.

[theweebabySeamus]

Originally Posted by Jaizero

It should be ~14.7 except under enrichment at WOT where it will be more rich (around 12.5-13.0 AFR)

It will always swing lean/rich as staying perfectly at 14.7 is impossible.

These cars use lambda for fueling, so regardless of stoichiometry of the current fuel in the tank you should always see somewhere around 14.7 on a basic AFR gauge.

Post a log.

Thanks, that definitely helps as it does start getting richer as the rpm goes up, and stays in the 12's from about 5k on.

[wheela]

Yes, that certainly could be normal per the tune, the tune adjusts AFR target based on load% and rpm. If actual aligns with target I wouldn't worry. For reference, here's some n55 fuel maps from a different thread (anjuna's n55 tuning thread). I've read that a lot of OTS maps will run a little leaner than stock, but it depends on the tuner and what tradeoffs they're shooting for.

[Jaizero]

Originally Posted by theweebabySeamus

Thanks, that definitely helps as it does start getting richer as the rpm goes up, and stays in the 12's from about 5k on.

This sounds about right for PTFs OTS tunes.

When you are logging make sure you log "actual" and "target". This way you will know if the car is doing what it's told to do.

I have a post floating around somewhere on here that shows what you should be logging to get the best information. There are others with similar dashboard setups as me, just search if you have any questions.

[Jaizero]

Originally Posted by wheela

Yes, that certainly could be normal per the tune, the tune adjusts AFR target based on load% and rpm. If actual aligns with target I wouldn't worry. For reference, here's some n55 fuel maps from a different thread (anjuna's n55 tuning thread). I've read that a lot of OTS maps will run a little leaner than stock, but it depends on the tuner and what tradeoffs they're shooting for.

Good lord the stock tune runs rich up top lol

[theweebabySeamus]

Greatly appreciate it guys, helps my mind rest a little easier. But kind of makes me want a custom or pro tune also, I just can't wrap my mind around running that lean.

[WeekendWarriorz]

BM3 off the shelf tunes are terrible. Heard from multiple shops in the SoCal area who have reported the same thing. Lean AFR, timing pulls, HPFP crashing.

MHD OTS are much, MUCH better

[theweebabySeamus]

Originally Posted by WeekendWarriorz

BM3 off the shelf tunes are terrible. Heard from multiple shops in the SoCal area who have reported the same thing. Lean AFR, timing pulls, HPFP crashing.

MHD OTS are much, MUCH better

Odd, I just reviewed an MHD log and the target AFR was similar to BM3...but the car ran a little richer.