Setting up a/f ratio correctly

[zo6racerx]

PLEASE Excuse me for asking these questions.

I have searched through all the how to's and I've gotten bits and pieces of my answers but I hoping all you could please help me out.

Situation: Tuning 2006 Z06:
WOT tuning
Actual air to fuel doesn't match PE eq/rpm commanded.
I'm seeing a true 12.9 but I need to command 11.9 to get it there.

I have Zero'd out my Add ECT and IAT parameters.

What is the correct way to adjust this?

#1 What paramters should I first start tuning WOT with when starting from scratch? Should I disconnect the mass air meter and adjust the VE tables so that under WOT the VE tables dial in the a/f? Should I start with the mass air curve? The mass air curve is stock and hasn't been changed. Is there a particular order you should adjust these parameters in when starting from scratch on a WOT tune?

#2 Are there any other fuel adders that can contribute to the a/f other than PE, VE, and mass air?

#3 I'm reading that the computer only looks at the PE Eq ratio vs rpm parameters and the mass air curve at 4000 and up? Is this correct? Should I not waste my time with VE affecting a/f in this range?

[Russ K]

If your retaining the maf, then set the pe to 1.13 at all rpm's, then rescale the maf table using the maf error histogram. The idea is to have a commanded/actual 13.0 afr.

Russ Kemp

[zo6racerx]

If your retaining the maf, then set the pe to 1.13 at all rpm's, then rescale the maf table using the maf error histogram. The idea is to have a commanded/actual 13.0 afr.

Russ Kemp

Thanks for the input. Can you tell me what rpms does the mass air control the a/f? Should I unplug the mass air and do any tuning via VE first?

Any help is appreciated.

[S2H]

well..1.13 is not ideal on all cars...and its definaltelly not ideal as a flat curve....
you need more fuel at peak torque and less at peak HP
in general I star with 12.5 up till peak torque...then I hit 12.8 at peak HP and ail back to 12.5 again by redline

on a dyno you can push teh A/F around till you see what your car likes...
.1 A/F can be the difference of 10 HP in some cases

in general most cars like this NA...sometimes they like it a litle leaner...like 12.7~13.0 or even a few I have done liked it leaner than that...
but they always like more fuel for peak torque and less for peak HP


if OLFA is a higher value then PE...then it will take control..pcm always uses the higher of teh 2 values..
MAF controls A/F at all steady state operation..
meaning that you can look on teh dynamoc airflow tab on your car for find out what is considered "steady state"
I personally like to push those values around so that the MAF takes more control for tuning..then set it back to stock later..
gurantee that MAF has more control for tuning...

you have to do your VE table first either way

[zo6racerx]

if OLFA is a higher value then PE...then it will take control..pcm always uses the higher of teh 2 values..
MAF controls A/F at all steady state operation..
meaning that you can look on teh dynamoc airflow tab on your car for find out what is considered "steady state"
I personally like to push those values around so that the MAF takes more control for tuning..then set it back to stock later..
gurantee that MAF has more control for tuning...

you have to do your VE table first either way

Couple questions regarding this just so I understand please.

1. What is OLFA?
2. You say to tune VE table anyway, does that include WOT?
3. YOu say the dynamic air flow tab on the car our you referring to the dynamic cylinder air function on the datalogger? See how steady it is?
4. What values do you move around?

[Russ K]

well..1.13 is not ideal on all cars...and its definaltelly not ideal as a flat curve....
you need more fuel at peak torque and less at peak HP
in general I star with 12.5 up till peak torque...then I hit 12.8 at peak HP and ail back to 12.5 again by redline

on a dyno you can push teh A/F around till you see what your car likes...
.1 A/F can be the difference of 10 HP in some cases

in general most cars like this NA...sometimes they like it a litle leaner...like 12.7~13.0 or even a few I have done liked it leaner than that...
but they always like more fuel for peak torque and less for peak HP


if OLFA is a higher value then PE...then it will take control..pcm always uses the higher of teh 2 values..
MAF controls A/F at all steady state operation..
meaning that you can look on teh dynamoc airflow tab on your car for find out what is considered "steady state"
I personally like to push those values around so that the MAF takes more control for tuning..then set it back to stock later..
gurantee that MAF has more control for tuning...

you have to do your VE table first either way

OLFA=open loop fuel air (ratio)
There is no ve table as of yet on the 2006 ZO6. Also under Dynamic Airflow there is a blank page.The OLFA tables are quite different than the earlier cars.
So you need to rescale the maf calibration tables to get your actual afr to match the commanded afr.

Russ Kemp