looking at the PE table, say if tuned correctly, u really dont need the PE correct? problem is i quite dont understand how it works. i see a PE mode spark advance table which makes sense but then when i see PE vs temp and PE vs rpm and it displays a %. is this a percent of spark advance as shown in the PE mode spark advance table?

 

You need PE. One major issue will be that the car will be prone to detonation at leaner AFRs and itll run hotter. It could also damage the cat as well since you wont be in closed loop.

PE basically richens up the AFRs to help improve power, and provide a safe AFR for the engine and catalytic converter to operate at under high loads.

EDIT: With that engine, you could be picking up pieces of it out of the oil pan without PE. Definatly need to have it with a hot combo, or any standard engine for that matter.

 

That's PE fuel. PE fuel makes it go from 14.7 to whatever, like 12-13:1.

There's 2 PE fuel tables that you have. The PE vs RPM, and PE vs Ctemp that combine to make the final PE A/F. I know in an older version of $6E definition, that one of them was calculated incorrectly. I posted the fix a while ago.

Not safe to turn off for long times. I wouldn't recommend turning it off at all. Once your MAF tables are good enough, the PE commanded A/F should work itself out pretty closely, except at very high RPMs and load, where the MAF reaches its limit, then PE is used to fudge in some extra fuel.

 

thanks! now that i understand more of what it does. im happy! so its the % from coolant PLUS the % from rpm equals how much richer the afr is? is this shown in target afr? when datalogging?

 

The combination of the two is something like that.

Here's how I do it in my .xdf which seems a little more intuitive:

PE vs RPM (in A/F): 1470/((0.390625*X -50)+100)

PE vs Temp (in %): 0.390625*X

You can zero out the PE vs Temp at warm engine, and the commanded A/F will be just as in the PE vs RPM in A/F. The PE vs Temp will richen it when colder by the percent in the table.

It's not PLUS when dealing with A/F. Like 10:1 PLUS 2.5:1 does NOT equal 12.5:1. Minus is more like it, but it's not that simple.

In the way I do it, it's the base A/F vs RPM, and then divide by (100+ (PEvsCtemp))/100), so for example 12.5:1 and 10% goes to A/F=12.5/(110/100)=11.36:1 A/F

It's something close to that anyway. I lost the proof when my hd crashed.