Good AFR for 3V Mustang?

[jakesmithpbr]

Hey guys want to start by saying you're all extremely helpful, ever since I got my MVPI2 I've been non stop messing with my MAF tables and tuning stft and ltft and can't wait to learn more about VCM editor. Got a quick question.

I got my maf tables pretty dialed in I think, so I ordered an AFR gauge and headers, now I want to start tuning my MBT and BLK tables. From what I've read everyone is saying that they are stock set at 14.64 which I believe is 1 lambda. Is that the number I should shoot for seeing when I do WOT pulls and cruising? Also, keep in mind I'm running on 91 octane. Can't find 93 in California.

Not really sure where to start with tuning my spark, I don't want to blow my motor up just yet. Any advice would be appreciated on where to start. I'll attach my current tune and scan. Please if there is anything on my tune that looks wrong and sketchy, please tell me. This is my first tune and I want to learn from my mistakes, although I don't know if I'm doing something wrong just yet, except for common knowledge.

Thanks guys

Car: 2007 Mustang GT 5 speed manual
Current mods:
100mm CAI
Gutted cats, cherry bombs no muffler
2007 mustang GT scan.hpl
2007 Mustang GT First Tune.hpt

[JuiceNA]

Do NOT shoot for 14.64 afr WOT you will melt pistons.
I start at 12.0 WOT afr on naturally aspirated and 11.5 for forced induction.

[jakesmithpbr]

Do NOT shoot for 14.64 afr WOT you will melt pistons.
I start at 12.0 WOT afr on naturally aspirated and 11.5 for forced induction.

14.64 is what my stock Stoich AFR is set to. It changes to 12.0 when I go WOT?

[decipha]

no

the stoich is the stoichpoint of the fuel your running it should be ~14.1 or so if your running e10.

The commanded lambda at WOT is from the stabilized fuel table in stock tunes. So you can go to the base fuel table and change the commanded AFR at wot there. Typically the stock values are going to be somewhere in the mid .80s. You can command .86 or so and dial it in. Once you've got the maf dialed in and your wideband matches lambse (STFT) then you can go command any value you want and you'll get it. You can then toss it around to see what your engine likes best for AFR at wot.

Oh and btw, I would highly recommend changing your wideband to show lambda since its then immune to any fuel your burning. That way your fuel error is never skewed by the fuel your burning and you don't have to cross calculate anything. Makes life much easier and will make you a much more proficient tuner long term.

[JuiceNA]

Yes. Full power/WOT afr must be rich or engine damage will occour.
You should find the best WOT AFR on a dyno.

[jakesmithpbr]

Alright so running 91 pump gas I should change my Stoich AFR to around 14.1? Once I do so, is that what my afr should be reading idling? What about WOT? I'm not sure if it shows lambda. Its a 52mm prosport gauge.

[jakesmithpbr]

I'll make sure to watch it on the afr. is there a range that is considered ok like 12.0-12.5 or something?

[cpeek96]

When I was N/A, I ran .88 at WOT on 93 octane with no issues. That being said, my combo was different than yours. Don't slam that number into your tune and expect it to work.

Get your MAF curve dialed in using a wideband O2 sensor first, so you're actually getting what you're commanding. The narrowband O2 sensors in your exhaust manifolds can't respond to the richer WOT mixture, so your ECU switches to open loop fueling. Simply put, it takes the amount of air entering the motor, determined by your MAF sensor, and injects a certain amount of fuel. There is no feedback to "close" the loop.

There's plenty of information and opinion out there about WOT air-fuel ratios, what's best, and what's safe. Do some research and decide for yourself what's best.

[SultanHassanMasTuning]

really depends on fuel quality, and it will be a combo of ignition and fuel for best power

[decipha]

Alright so running 91 pump gas I should change my Stoich AFR to around 14.1? Once I do so, is that what my afr should be reading idling? What about WOT? I'm not sure if it shows lambda. Its a 52mm prosport gauge.

thats why you should use lambda as its significantly easier and immune to those mistakes.

the wideband will show which ever value its programmed for stoich at when its at stoich.

if your wideband shows 14.7 now for stoich in closed loop (lambda==1.000) then it will continue to when you change the stoich point value in your tune.

To dial in the maf your wideband afr should be the lambda your commanding in your fuel table at wot BUT the wideband will always be referencing 14.7 stoich.

Thus if u plug in .86 in your fuel table, 14.6 * .86 == 12.64 is what your wideband will read at wot when you have your fuel dialed in correctly.

changing the stoich value for the fuel your running should have been your first change when setting up your base tune