gear based AFR targets necessary? (XFI)

Blazer406

Mechanical Engineer
Joined
May 2, 2002
Wondering if there is a way to alter AFR targets to make it more lean down low.... where the engine is under less load..... or if that is even necessary....or possible....doesn't appear to be any way to do this....for the XFI

seems like a lean down low would aid spoolup.... and 60' times..... might be a desireable thing....

Obviously... lean in high gear is not a good thing..... so some way to have some sort of way to lean it out....down low without affecting up top..... might be desireable....
 
A few months ago, Craig Smith discussed an interesting way to use the knock retard to back off timing off the line, which would also help spool-up. Did you see that post?

-BC
 
I use the a swtich on the shifter and add fuel from a simulated nos input on a time delay feature on the gen 7 to add fuel as i switch the car from park to drive so it does not stall. I am sure you can do the same on an xfi with the inputs.........
 
I use the a swtich on the shifter and add fuel from a simulated nos input on a time delay feature on the gen 7 to add fuel as i switch the car from park to drive so it does not stall. I am sure you can do the same on an xfi with the inputs.........

Why would you have to do that?
Sounds like one of your idle parameters and or VE table is not setup correctly.

As far as blazer its not necasary,Use your target a/f table.You can setup
your a/f based on load right there.

As far as leaning out for spoolup spend the money on the correct convertor and make sure your tune during spoolup is spot on.
Playing with a/f and timing during your particular spoolup is crucial to
quicker spoolup,running it leaning the car way out and taking timing out is not the way to do it.

Look at the fastest cars out there,They are now running tight convertors and the spoolup is tremndous with no type of spoolup aid,Just proper tune and convertor matching for combo.

Go listen to Don Cruz car in the video section and see how well a 70GTQ can spool when setup properly
 
Playing with a/f and timing during your particular spoolup is crucial to
quicker spoolup,running it leaning the car way out and taking timing out is not the way to do it.

Look at the fastest cars out there,They are now running tight convertors and the spoolup is tremndous with no type of spoolup aid,Just proper tune and convertor matching for combo.

Go listen to Don Cruz car in the video section and see how well a 70GTQ can spool when setup properly

I agree. Pulling timing will just lower the engine power output and the converter will stall less. It may help in a stick car but not ours. I run as much timing as i can at all points and ramp in the fuel as the boost comes in.
 
Sounds like I don't need to look any further in that direction......

We are exploring any and all ideas to help us get quicker in the IROC.... I was just curious if there was something to be gained.... evidently not....

Thanks....

FWIW.... on the wish list.... is a PTC 9" converter....and an AMS 1000..... this will definately be real high on the list...

We went low 10.40's @ 133 at Reynolds.... with a sorry high 1.60 short time.... on 22 psi....with champion irons and champion ported intake.... not too bad IMHO... all things given.....We really didn't have any time to work on launching.... hence the sorry 60' time....the car has been low to mid 1.50's before.... We have no real boost controller other than a RJC bleeder on an internal wastegate.... and a ?? converter.

We will get there....eventually..... I'm just trying to learn and read all I can from the smart people here.

Thanks guys.
 
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