In the p.e. a/f ratio vs rpm table, with the stochiometeric ratio
being 14.7, I would think the entries in p.e.would be approx. 9 %
(doing the math it would get you the 13.23 power ratio (or higher depending on the car's needs) that is optimal. Does this make
any sense and if not why.

 

could you please explian how yr arriving at this #.

 

9% of 14.7(ratio) is 13.37 ratio.Which is also a very good starting point for the power ratio.Will vary from car to car.(up or down maybe .25 %

 

I think the only way to answer this is by sending you to do some research in the archives as it is a little confusing. Type the words "pe change formula" or variations of it and see what you see. I'm still confused with all the damn math.

 

Im wondering how you got 13.25 a/f as the perfect ratio???? Thats pretty lean to make good power. Most of what ive seen made beter power around 12.5-12.7. Ive seen some stuff a little richer than that also. There really isnt a magical a/f ratio, as alot of variables enter into what each motor wants. ve, parasitic losses, etc all play a roll. On the dyno, bsfc will vary between 2 "identical" motors for max power. And with the same carbs, they will sometines require different jetting and/or timing.

 

https://www.thirdgen.org/techbb2/sho...threadid=37236

Tim

 

First off it depends on what mask you're using.

If you look in the tables, there is probably a PE AFR vs temp.
Often the warmer setting are like 13.5.
SSooooo.
In the PE by % TPS, that reads 0-12-25-37-50-62-75-87-100% TPS you might run 1 2 3 4 5 5 5 5 5 5. That way when you first crack into the gas your at 13.5, then as you rollinto the gas you'll get 5% richer or about down to 12.9.

Then you might have a PE by RPM, again same thing.
0-1% at the lower rpm and going up to 5% at the higher rpm.

That way you PROGRESSIVELY get richer as the loads by TPS, MAP/MAF get higher.

Or just unplug things till it kinda runs the way you want, and not worry about getting anything correct.

 

Tim,
Did TC every redo their calculations? or do we have to do that calculation that you came up with? I didn't see any follow ups so I figured I would ask instead of assuming.

Brendan