Air/Fuel Ratio
08-18-2005, 02:28 PM
#1
Thread Starter
Join Date: Jul 2005
Location:
Posts: 23
Air/Fuel Ratio
I had my car dyno'd the other day and the air/fuel ratio showed my car running very rich. I've only put a CAI on my car, but stock the car should dyno 240 rwhp. With the CAI I SHOULD be making 250 rwhp. MY car dyno'd 225 rwhp. My Air/Fuel was around 12:1 up until 4000 rpm where it dropped dramatically and by the time I hit peak power at around 4800 rpm my ration was 11.2:1. Other dyno charts I've seen for the same model show running around 13:1. The tech told me the only way to fix this problem is by getting a chip from steeda or jet....he said reseting ECU by disconnenting the battery wouldn't do the trick. Can anyone help me out here, will reseting the ECU fix my problem or do I really have to spend the $400 for a chip? I am driving a 2001 Mustang Bullitt GT.
08-18-2005, 02:50 PM
#3
Join Date: Aug 2005
Posts: 15
RE: Air/Fuel Ratio
Just to throw an idea out there, is it possible the ecu might have learned some bad fuel curves? Is it absolutely necessary to spend $400 to completely re-tune the car? BlueBullitt, did you notice any decrease in performance before you saw the A/F results? Are you having any problems running on a normal basis? or starting? I guess the question I have is this, is it even possible for an ECU to just go bad? or possible the factory tuning varied that badly between the same cars?
08-18-2005, 03:01 PM
#4
Gentleman's Relish
Join Date: Feb 2005
Location: AZ
Posts: 13,090
RE: Air/Fuel Ratio
ORIGINAL: BlueBullitt
I had my car dyno'd the other day and the air/fuel ratio showed my car running very rich. I've only put a CAI on my car, but stock the car should dyno 240 rwhp. With the CAI I SHOULD be making 250 rwhp. MY car dyno'd 225 rwhp. My Air/Fuel was around 12:1 up until 4000 rpm where it dropped dramatically and by the time I hit peak power at around 4800 rpm my ration was 11.2:1. Other dyno charts I've seen for the same model show running around 13:1. The tech told me the only way to fix this problem is by getting a chip from steeda or jet....he said reseting ECU by disconnenting the battery wouldn't do the trick. Can anyone help me out here, will reseting the ECU fix my problem or do I really have to spend the $400 for a chip? I am driving a 2001 Mustang Bullitt GT.
I had my car dyno'd the other day and the air/fuel ratio showed my car running very rich. I've only put a CAI on my car, but stock the car should dyno 240 rwhp. With the CAI I SHOULD be making 250 rwhp. MY car dyno'd 225 rwhp. My Air/Fuel was around 12:1 up until 4000 rpm where it dropped dramatically and by the time I hit peak power at around 4800 rpm my ration was 11.2:1. Other dyno charts I've seen for the same model show running around 13:1. The tech told me the only way to fix this problem is by getting a chip from steeda or jet....he said reseting ECU by disconnenting the battery wouldn't do the trick. Can anyone help me out here, will reseting the ECU fix my problem or do I really have to spend the $400 for a chip? I am driving a 2001 Mustang Bullitt GT.
Also, have you done anything else to the car after which you did not have a dyno done? Like exhaust? Doesn't sound like it but sometimes people forget to mention things in their original post.
08-18-2005, 03:26 PM
#7
Gentleman's Relish
Join Date: Feb 2005
Location: AZ
Posts: 13,090
RE: Air/Fuel Ratio
ORIGINAL: code3GT
I really don't want to burst your bubble, but even at running it's best, I don't think you will see 250RWHP with just a CAI. The Bullitt is rated at 265 at the crank.
I really don't want to burst your bubble, but even at running it's best, I don't think you will see 250RWHP with just a CAI. The Bullitt is rated at 265 at the crank.
Code3GT, have it redynoed with the stock air intake, then put the CAI back on (without a reset) and see what happens. If the same thing happens then a chip or tuning program may be the way to go. The MAF might be getting thrown off by the larger volume of air passing through it.
08-18-2005, 03:34 PM
#8
Join Date: Aug 2005
Posts: 15
RE: Air/Fuel Ratio
I really don't want to burst your bubble, but even at running it's best, I don't think you will see 250RWHP with just a CAI. The Bullitt is rated at 265 at the crank.
08-18-2005, 04:40 PM
#9
Mustang Nazi
Join Date: Sep 2004
Location: Texas, baby
Posts: 13,444
RE: Air/Fuel Ratio
ORIGINAL: AFAccord
Even with a very low 15% loss, 225whp would equate to a sad 260 crank hp, no where near correct specs for a even a stock Bullitt. A bone stock '00 GT that ran an hour before BlueBullitt's run, produced 231whp. I don't see a CAI reducing power like that. Maybe on a civic, but not on a mustang. I haven't seen a stock Bullitt put down less than 240 on a dyno. Which ever way you look at it, the A/F ratio is way off. Not tryin to be an ***, just making sure you're correctly informed before you give your best opinion.
I really don't want to burst your bubble, but even at running it's best, I don't think you will see 250RWHP with just a CAI. The Bullitt is rated at 265 at the crank.
What kind of crank HP do you think a stock Bullitt makes?
