I cant figure out do the formula on the help page for wot%change to fuel/ air ratio vs coolant . it says that the two are summed to arrive at the wot air /fuel ratio.I want the a/f ratio to be around 12.9 and lean out to 13.2, can someone tell me how or tell me the #s to fill in the for these tables? thank you

 

oh no no don't everyone answer at once

 

The 2 tables (RPM and Coolant @ WOT) do add together to give the percent change that the computer should make when these two engine parameters are met. The question is; what is the uncorrected air/fuel ratio at that RPM and Coolant temp? If you knew that then you could change these tables to get the air/fuel ratio to the range you are looking for. This is why people use a dyno. It will tell you what your baseline air/fuel ratio is. Because you have a pretty common setup, I can email you a bin that will get you close if you want it.

Jeff D.

 

There is a spreadsheet that was posted some time ago about this that uses the formula in TC to adjust the A/F ratio at WOT. Just do a search for it. All you need to do is look in the help files for the equations, also.

 

Fbody1...YGM

JEff D.

 

Man,

I've looked at the charts on %change to fuel/air ratio Vs. RPM at WOT, and every chart I look at isn't smooth.

They start out around 2 to 3, take a nose dive to negative numbers between 1000 to 2000rpms, come back around 2 to 3 again up to around 4500rpms, then sky rocket up to around 7 to 9%from 4500 rpms to 5500rpms, and fall again when it gets to 6000 rpms down around 6.

It isn't smooth at all, is everyone else's chart look like this?


Thanks.

D Moss

 

yea that sounds like mine, but from 4500 up they are like +2 or 3 , is that good ? dont know yet still tuning, they wer at 6 &7 +, but what you are saying that sounds stock

 

Well I looked at another file, and thier file was maxed out from 4500 to around 5500. I'm going to have to do some more research around this.

I guess a trip to the dyno will help alot.

thanks

D Moss

 

AFR = {1- {# in Temp Table} + {# in RPM Table}} / 100} *14.7

The PE vs coolant table # should be 16 for an operating range of around 180 degrees. Plug in 16 for the PE vs coolant number and then do the math for the PE vs rpm part.

AFR={1-{16} + {Plug in a number}}/100} * 14.7


By plugging in different numbers you will be able to arrive at the desired AFR
Hope this helps
Skip

 

Guys, if it was as easy as just using a spreadsheet and those 2 tables than why do some of us pay to use a dyno and a wideband O2 sensor?
Use those spreadsheets and tables at your own risk. There is more to that formula than just the 2 pe tables. Things like injector constant and maf reading are taken into account. I've got pe tables that I can show you guys that give 13:1 on a dyno/wideband but if you throw them into one of those magical spreadsheets you'll end up with a/f ratios in the 10's!
I'm assuming this is mostly due to maf table calibration errors, right Ben?