Tune is scheduled for end of the month...operator stated he will get the A/f 12.4-12.6 from start to finish. Question is would this be optimal for an N/a setup? If I recall correctly the 12.6 was to be the wot ratio and 12.4 everywhere else.
Well stype thanks for the bump anyways!!
Dons...so you would consider this safe but resonable for a power curve? I do run 16* initial and summer temps here average 80-90 so IF these factors are important (not sure if they even matter)then would the above stated A/F be aggressive enough..or too rich?
No I have always run 91 (company gas card...boss loves it.. loves it..really he does) So is it my understanding that the ratio provided at 16* would be a reasonable setting.
Why is he setting it rich?It should make best power at 12.8-13.2 across. I tune my car from a low 13 and work its way down to a high 12 up top. But I make more power, run much more compression than you and I rev higher. It should make best power around 34* total timing.
Is he tuning part throttle and medium throttle too or only WOT? I tune all loads with my PMS.
Tune is scheduled for end of the month...operator stated he will get the A/f 12.4-12.6 from start to finish. Question is would this be optimal for an N/a setup? If I recall correctly the 12.6 was to be the wot ratio and 12.4 everywhere else.
I had to read this through a couple of times to get a feel for what he might have been describing. No idea what your setup is or how aggressive your cam is or what your compression ratio is.
What I think he's saying is that he want to keep your AFR between 12.6 and 12.8 from the bottom of the rev range to the top @ WOT. He's not talking about part power or idle settings. As eluded to above, those AFR settings are too rich for just cruising down city streets but are great for WOT. It's a nice safe ratio to be in.
I agree with GRN92LX that overall, that may be on the rich side for an N/A application but again... cam and compression will have allot to do with where exactly, the "sweet spot" in your AFR will be.
Richer = safer
Leaner = more power
Since it's a street car... and if I were the tuner... I'd tune it after it were good and warmed up with the hood closed and a fan blowing in through the front end. I'd tune the AFR for peak power @ WOT (no pinging) then add between .2 and .4 (richer) to the AFR @ WOT across the entire power band. That would leave you with a good compromise between max power output and safe tune with a little fudge factor built in for the occasional crappy gas.
I will take the info above and have a chat with him regarding it..not having a background in dyno tuning I go in blind..but with a little info in the back pocket from here helps me understand the basics of it.
I thought this was a good summary of a/f settings. I didn't write it, and don't remember where I found it now though.
6.0:1 Rich run limit
9.0:1 Low power, black smoke
11.5:1 Rich best torque
12.5:1 Safe best power
13.2:1 Lean best torque
14.7:1 Chemically ideal
15.5:1 Lean light load, part throttle
16.2:1 Best economy, part throttle
18:1 Lean run limit