A/F Ratio
 

Okay so I got a DashHawk this week and I have played around with the settings and done some data logging. I know I don't have a wideband but I have been logging the command a/f ratio and it does stay at 14.7:1 for most of the time. but under WOT I have seen it drop to the low 11.x:1.

The reason I am asking is it doesn't normally do this until 5500 rpm or so. is it a mile per hour thing or an engine load setting? I am not tuning anything, yet, and only have an intake in terms of power mods.

when you go to WOT your car goes into power enrichment mode, which commands and differant afr... and just because its commanding 11.5 for example does not mean your accual afr is 11.5...

i think im correct on this...im still learning tuning so i might be wrong

right i know it isn't my a/f ratio but it is what the PCM is telling the car to aim for. But BennyHHR told me it is the PE delay and that is can me removed. But I need tuning software first. But is the low 11s to low for WOT at high RPMS?

not really, some wil argue yes and like to be in the 12's. I'm a little conservitive and have my PE set to 11.5.




edit: I just looked at what type of car you have and yes 11's are a little rich for N/A cars, I have my truck PE set to 12.8

Your forgetting he is n/a not s/c. Its a rich, but thats a gm tune for you. Most n/a cars shoot for a 12.8~13.0 afr when fine tuning.

and what all does having the PE set to a lower ratio do/mean. keep in mind I am pretty much a n00b when it comes to tunes.

sorry Power Enrichment, PE, is a table on HPTuners to adjust the AFR during WOT, or past a certain % Throttle Position

got ya is that only for HPtuners?

not sure... ive got hptuners... sounds like your local... havnt messed with any NA cars but im sure someone could hook you up with a toon... or i can lean it out for you. thats not a problem... just need a afr gauge

^^^ since I am an 08 HPtuners doesn't work for my ECU yet. LSedit and Trifecta and JET are the only PCM/ECU tunes i can get at the moment.

NA should be tuned for 13 or so like people ahve said .. cruise/ idle should be 14.7 ..

also like said jsut because you're commanding 11 AFR at WOT doesn't mean thats what you're getting .. however. it shouldnt be commandin that low either lol

damn GM tune!!!!!

The low 11's you're seeing is likely COT (Cat Over Temp) algorythms kicking in on a hard pull.

A normal GM tune will hold stoic (14.7) for a bit due to PE delay. Then it will go richer in a more normal range (about 12 - 13), then when COT enables, you'll see it go pig rich.

The PE delay helps GM perform well for standard smog and MPG tests, but will loose power during that. COT protects the catalyst (and GM).

IOW, good for GM, but not for best power. Hey, that's why we tune!!

Dunkin, you mentioned your's is an '08 (E37 ECM), not supported by HPTuners yet, and available choices. It all depends on what your goals are. Learning good tuning takes a LOT of time and effort. Stay away from the Jet crap. Either invest in EFILive, LS2Edit and be ready for a learning adventure, otherwise your best bet would be to just go with Trifecta. He's good.

yeah I am leaning towards LS2edit, and I am very willing to crunch numbers and do some trial and error.