A/F question
Thread Starter
11 Second Club
Joined: May 2003
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From: Glasgow, Ky
A/F question My power is down a bit from my best but, my A/F is supposedly in the optimal band. I use HPTuners, and I think I'm lacking something, I've been tunning off of the stock o2's, but I have access to a wideband and a dyno, where should my a/f ratio be?
Last edited by 99FormulaWs6; May 24, 2005 at 12:24 AM.
Thread Starter
11 Second Club
Joined: May 2003
Posts: 764
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From: Glasgow, Ky
I'm happy with anywhere around 400 but I had 402RWHO before I started tuning! and on a hotter day! This is what's tripping me up. I should be a bit closer to 410 even through the 12 bolt.
Idealy, from what I've read on here, you want your AFR to follow the peak paths of your hp and tq. Many people command a 13.0 AFR except around peak tq (where 12.8 is good) and slightly after peak hp to redline (where 12.8-12.9 is good). If you can flatten out your AFR at a solid 13.0 aside from your peak tq and post peak hp, you might be able to squeeze a hair more out of it.
Launching!
Joined: May 2003
Posts: 290
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From: Canadian West Coast
Your A/F seems reasonable.
I had a similar experience on the dyno the past week. I see your #'s are SAE, so that should help. I Dyno'd 4 weeks ago and pulled 412 rwhp with a 12.2 A/F - and that was after being in traffic for 2 hours. So, I went back two weeks later, similar type of day, but no traffic, so my drive was only 30 minutes and I had time to cool down. First run on the dyno was about 13 rwhp and 20 rwtq LESS than my prior best, and A/F was still the same. After tuning to 13.0 I got it back to 410 rwhp or so, but I couldn't figure out why my #'s were off so much. I figured (guessed) it was just the dyno that day.
I guess even the same dyno can vary from day to day.
I had a similar experience on the dyno the past week. I see your #'s are SAE, so that should help. I Dyno'd 4 weeks ago and pulled 412 rwhp with a 12.2 A/F - and that was after being in traffic for 2 hours. So, I went back two weeks later, similar type of day, but no traffic, so my drive was only 30 minutes and I had time to cool down. First run on the dyno was about 13 rwhp and 20 rwtq LESS than my prior best, and A/F was still the same. After tuning to 13.0 I got it back to 410 rwhp or so, but I couldn't figure out why my #'s were off so much. I figured (guessed) it was just the dyno that day.
I guess even the same dyno can vary from day to day.
Thread Starter
11 Second Club
Joined: May 2003
Posts: 764
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From: Glasgow, Ky
Thanks guys I actually have a bit of research to do, I didn't have my tuners with me, so I didn't watch and see if I was picking up any knock, that may be an issue also. But I was also told since I was at a different dyno than my first runs that might be the issue.
