Those with H/C over 420RWHP, what's your A/F ratio?
03-18-2002, 05:49 PM
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Those with H/C over 420RWHP, what's your A/F ratio? I don't have much time to dyno tune, so I wanted to get a close figure to what people are finding to be the best A/F ratios. How much power would running too rich rob (let's say 11.8 A/F)?
Also, what's the maximum timing advance you guys have?
Thanks!
Also, what's the maximum timing advance you guys have?
Thanks!
03-19-2002, 04:09 PM
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Re: Those with H/C over 420RWHP, what's your A/F ratio? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by akw408:
[QB]Also, what's the maximum timing advance you guys have?
[QB]</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Sorry, I dont know my A/F ratio.. but I can tell you i run 29 degrees of timing (dyno tuned).
30.5 was the best performer on my stock motor.
[QB]Also, what's the maximum timing advance you guys have?
[QB]</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Sorry, I dont know my A/F ratio.. but I can tell you i run 29 degrees of timing (dyno tuned).
30.5 was the best performer on my stock motor.
03-19-2002, 05:12 PM
#3
Re: Those with H/C over 420RWHP, what's your A/F ratio? Ive gotten a few responses on this over the last year or so.
Most like to see the A/F run at approximately 13.0 at low RPMs (<4000) and then ramp down to 12.5 at the torque peak. Then after the torque peak, a ramp back up to 13.0 before the redline.
Others have implied the same system, but 13.2->12.8->13.2 (slightly leaner).
Please not that the A/F will likely be about .3 lower on a dyno than it will be on the street, and you are presumably tuning for the street <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
\chris
Most like to see the A/F run at approximately 13.0 at low RPMs (<4000) and then ramp down to 12.5 at the torque peak. Then after the torque peak, a ramp back up to 13.0 before the redline.
Others have implied the same system, but 13.2->12.8->13.2 (slightly leaner).
Please not that the A/F will likely be about .3 lower on a dyno than it will be on the street, and you are presumably tuning for the street <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
\chris
03-19-2002, 06:30 PM
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Re: Those with H/C over 420RWHP, what's your A/F ratio? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Visceral:
<strong>Ive gotten a few responses on this over the last year or so.
Most like to see the A/F run at approximately 13.0 at low RPMs (<4000) and then ramp down to 12.5 at the torque peak. Then after the torque peak, a ramp back up to 13.0 before the redline.
Others have implied the same system, but 13.2->12.8->13.2 (slightly leaner).
Please not that the A/F will likely be about .3 lower on a dyno than it will be on the street, and you are presumably tuning for the street <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
\chris</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Thanks guys. I'm looking at about 28 degrees of timing, so 29 isn't too far off. I doubt I can run 30.5 degrees with the CA 91 octane I have to run off of.
I'll be looking to get my A/F #s close to around what you described. I have been using my Autotap to monitor the O2 sensor and I'm looking at high 11s at lower rpms gradually coming into a 12.5 at 5000+ rpms. This is a stock PCM program with just using the MAFT. I'll be going to a real dyno with a real WB O2 sensor soon, just wanted to get my car running as close to the right number as possible before the dyno because I will only get 3 runs to get it right. Why do you suggest the A/F will be off 0.3 from the street? The ram air effect? Or the catalytic converter burning off some excess gas? Thanks!
<small>[ March 19, 2002, 06:54 PM: Message edited by: akw408 ]</small>
<strong>Ive gotten a few responses on this over the last year or so.
Most like to see the A/F run at approximately 13.0 at low RPMs (<4000) and then ramp down to 12.5 at the torque peak. Then after the torque peak, a ramp back up to 13.0 before the redline.
Others have implied the same system, but 13.2->12.8->13.2 (slightly leaner).
Please not that the A/F will likely be about .3 lower on a dyno than it will be on the street, and you are presumably tuning for the street <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
\chris</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Thanks guys. I'm looking at about 28 degrees of timing, so 29 isn't too far off. I doubt I can run 30.5 degrees with the CA 91 octane I have to run off of.
I'll be looking to get my A/F #s close to around what you described. I have been using my Autotap to monitor the O2 sensor and I'm looking at high 11s at lower rpms gradually coming into a 12.5 at 5000+ rpms. This is a stock PCM program with just using the MAFT. I'll be going to a real dyno with a real WB O2 sensor soon, just wanted to get my car running as close to the right number as possible before the dyno because I will only get 3 runs to get it right. Why do you suggest the A/F will be off 0.3 from the street? The ram air effect? Or the catalytic converter burning off some excess gas? Thanks!
<small>[ March 19, 2002, 06:54 PM: Message edited by: akw408 ]</small>
03-20-2002, 05:23 PM
#5
Re: Those with H/C over 420RWHP, what's your A/F ratio? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by akw408:
<strong> Why do you suggest the A/F will be off 0.3 from the street? The ram air effect? Or the catalytic converter burning off some excess gas? Thanks!</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Dynojet dynos are roughly equivelent to the load of a 2800 lb. car. Being a 3600 lb car with you in it, the increased load leans things out a bit.
\chris
<strong> Why do you suggest the A/F will be off 0.3 from the street? The ram air effect? Or the catalytic converter burning off some excess gas? Thanks!</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Dynojet dynos are roughly equivelent to the load of a 2800 lb. car. Being a 3600 lb car with you in it, the increased load leans things out a bit.
\chris
03-21-2002, 12:05 AM
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Re: Those with H/C over 420RWHP, what's your A/F ratio? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Visceral:
<strong>Ive gotten a few responses on this over the last year or so.
Most like to see the A/F run at approximately 13.0 at low RPMs (<4000) and then ramp down to 12.5 at the torque peak. Then after the torque peak, a ramp back up to 13.0 before the redline.
Others have implied the same system, but 13.2->12.8->13.2 (slightly leaner).
\chris</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">That seems to be about right by me also. I put down 400 with an Unlocked Vig 3600 so locked is a little over 420. I had the PCM tuned via Ed W. and I still used a MAFT to dial it in perfect.
<strong>Ive gotten a few responses on this over the last year or so.
Most like to see the A/F run at approximately 13.0 at low RPMs (<4000) and then ramp down to 12.5 at the torque peak. Then after the torque peak, a ramp back up to 13.0 before the redline.
Others have implied the same system, but 13.2->12.8->13.2 (slightly leaner).
\chris</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">That seems to be about right by me also. I put down 400 with an Unlocked Vig 3600 so locked is a little over 420. I had the PCM tuned via Ed W. and I still used a MAFT to dial it in perfect.
