http://forums.bradbarnett.net/index.php?ac...e=post&id=21648

Just wondering how safe this A/F is, as I don't particularly want to get a tune now but if it should be lower (maybe 12.9ish) it would be worth it to me for piece of mind.

 

ur air fuel shoudl be somewhere between 12.4 and 12.8 with 12.8 being on the lean side

 

I was under the impression most people with N/A motors tried to get more in the 13-14 range where was the 12.4-12.8 was more for those with boosted applications. The dyno operater basically told me this a/f was 'perfect', but I wanted opinions of those who also own the car.

 

Your a/f should be fine at 12.9.


Paul

 

Supposdily (sp) the perfert A/F ratio is 14.7:1. Weither or not that is true for the Mustang I dont know. Id just check it with someone else's and smell your exhaust.

 

Exactly what smell am I looking for?

 

Would you guys pretty much say a aftermarket tune is in order then? :/

 

You should not require a tune due to the installation of a Magnaflow X pipe and catback.


Paul

 

every tuner ive spoken to says that 12.1 on a FI motor is safe and 12.4-12.8 on a NA motor is retty safe... this is comign from Jeremy at HPP and an LS1 tuner at LG motorsports who used to work at Dallas Mustangs

 

I thought the same thing, but im being told that my A/F is a little bit too lean. Probably not at the point im going to break anything, but at the point that im not really comfortable driving it around all the time with what people are telling me.

 

I am tuned to 13.1

 

Lean is mean but from that graph it looks like you do need to richen it up a bit. Get it around 13 or under.

 

Thanks guys, seeing as how im selling the car im probably just going to put the stock h pipe back on to get the A/F back to normal (amazes me how exhaust adjusted A/F so much, wtf!!) and not spend $500 on a tune.

I really appreciate it.

P.s. I havent been driving the car aside from the dyno unless absolutely necessary just in case the a/f hasnt been safe.