Using PE to madify AFR

[Chalky]

Newbie here but curious to know if I can adjust PE table to get AFR smoothed out? I have dyno runs showing AFR using wide band.
While my PE table does not match my actual AFR ratios from the dyno pulls, can I adjust my PE table to lean or richen up where needed based on the dyno AFR's?

[Redline Motorsports]

What kind of mods? If the motor has a cam in it, modifing the PE table will only be accurate if the VE tables is correct. From what I have learned what happens in the VE table directly effects PE tuning. How far off is the commanded value you have set in PE vs. the WB readings?

[foff667]

What kind of mods? If the motor has a cam in it, modifing the PE table will only be accurate if the VE tables is correct. From what I have learned what happens in the VE table directly effects PE tuning. How far off is the commanded value you have set in PE vs. the WB readings?

I thought maf took over after 4k rpms?

[Chalky]

Dynatech Headers, Hi-Flo cats, Blackwing Intake.

LABELS PE Modifier Based on RPM (AFR)
RPM {link: SAE.RPM} Value
WB
3200 12.707818 13.15
3600 13.072478 12.90
4000 13.187148 12.81
4400 13.303849 12.81
4800 13.894038 12.89
5200 13.580261 12.82
5600 13.507052 12.55
6000 14.681005 12.83
6400 14.195797 12.73

WB results are numbers on the right.

[ringram]

As I understand it you can do that.
Its not ideal as it applies to WOT settings only. Say for example WOT one day due to ambient conditions is 0.80g/cyl and 100kpa you can dial in PE to be correct that day, but because VE on another day might take you up the 90kpa path it will be wrong.

You might get closer, but its only a plaster on the problem, its not really a fix.
Best idea is to dial in your ve by loading the engine over all load points and rpm and then do PE.

[joecar]

If you first make sure the IFR is correct, then dial in the VE using your WBO2, then toss the MAF (or dial it in later (using VE and WBO2) when you're bored), you will find the WBO2 will reflect the richer of OLFA or PE (wysiwyg).

[Chalky]

Joe:

OLFA? Open Loop but not sure of what FA stands for.

[MN C5]

At WOT you can use PE to control your AFR. It is also useful if you blow past the limits of the MAF

[joecar]

Joe:

OLFA? Open Loop but not sure of what FA stands for.
Sorry, I should have used the reference numbers, that's what they're for...

B3605 "Commanded Fuel When in Open Loop" commonly a.k.a. "Open Loop Fuel Air".

[Chalky]

If you first make sure the IFR is correct, then dial in the VE using your WBO2, then toss the MAF (or dial it in later (using VE and WBO2) when you're bored), you will find the WBO2 will reflect the richer of OLFA or PE (wysiwyg).

Joe, if you don't mind me asking but @WOT, AFR's are determiend by either PE or OLFA, why wouldn't one table control that function exclusively?

TIA.

[bink]

toss the MAF (or dial it in later (using VE and WBO2) when you're bored.

:muahaha:
:cheers:
joel

[joecar]

Joe, if you don't mind me asking but @WOT, AFR's are determined by either PE or OLFA, why wouldn't one table control that function exclusively?

TIA. It seems to me that the commanded AFR is determined by the richer of the 2.

In my log, the OLFA is red circles, PE is green circles.

The curved portion in the AFR is the PE, and then it goes flat because that's the OLFA.


http://img516.imageshack.us/img516/1558/olfape1cr.png


BTW: I put in some 104+ octane booster and I'm running higher timing than previously, but what you don't see here is that a a few 100/1000 frames later, I got more audible knocking.

[MN C5]

The PE value has to reference something for fueling. Part of that is the VE table.

[Chalky]

I have a lot to learn.:Eyecrazy: :help2:

[onfire]

If the right hand column that you posted is results from a wideband on a NA car, I would not change it. It's a safe af that will make good power.

[Bruce Melton]

If the right hand column that you posted is results from a wideband on a NA car, I would not change it. It's a safe af that will make good power.

Thanks:D