A/F Ratio
04-22-2009, 09:44 AM
#1
Senior Member
Thread Starter
Join Date: 10-28-07
Location: Tall Timbers, MD
Posts: 3,713
Likes: 0
Received 0 Likes
on
0 Posts
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.
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.
04-22-2009, 10:32 AM
#2
Senior Member
Join Date: 11-12-07
Location: Maryland
Posts: 1,537
Likes: 0
Received 0 Likes
on
0 Posts
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
i think im correct on this...im still learning tuning so i might be wrong
04-22-2009, 10:42 AM
#3
Senior Member
Thread Starter
Join Date: 10-28-07
Location: Tall Timbers, MD
Posts: 3,713
Likes: 0
Received 0 Likes
on
0 Posts
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?
04-22-2009, 10:45 AM
#4
Senior Member
Join Date: 11-23-06
Location: Texas boy stuck in an Iowa Cornfield
Posts: 2,855
Received 0 Likes
on
0 Posts
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
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
04-22-2009, 10:50 AM
#6
Senior Member
Thread Starter
Join Date: 10-28-07
Location: Tall Timbers, MD
Posts: 3,713
Likes: 0
Received 0 Likes
on
0 Posts
04-22-2009, 10:56 AM
#8
Senior Member
Thread Starter
Join Date: 10-28-07
Location: Tall Timbers, MD
Posts: 3,713
Likes: 0
Received 0 Likes
on
0 Posts
04-22-2009, 11:29 AM
#9
Senior Member
Join Date: 11-12-07
Location: Maryland
Posts: 1,537
Likes: 0
Received 0 Likes
on
0 Posts
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
04-22-2009, 11:34 AM
#10
Senior Member
Thread Starter
Join Date: 10-28-07
Location: Tall Timbers, MD
Posts: 3,713
Likes: 0
Received 0 Likes
on
0 Posts
^^^ 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.
04-22-2009, 02:25 PM
#13
Junior Member
Join Date: 10-26-06
Location: SE VA
Posts: 454
Likes: 0
Received 0 Likes
on
0 Posts
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.
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.
04-22-2009, 02:33 PM
#14
Senior Member
Thread Starter
Join Date: 10-28-07
Location: Tall Timbers, MD
Posts: 3,713
Likes: 0
Received 0 Likes
on
0 Posts
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.
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.
Thread
Thread Starter
Forum
Replies
Last Post
Jmc007
2.0L LSJ Performance Tech
91
12-04-2005 05:22 PM