How does the ECM know whether to go to the PE % Change to Air/Fuel Ratio vs. RPM table or the PE % Change to Air/Fuel Ratio vs. Coolant Temp table??? Which one am I supposed to be changing to achieve maximum power? Also, do the regular VE tables have any effect on WOT performance? To combine all my questions into one, what should I be changing to achieve maximum power at WOT?? Thanks in advance.

 

The VE tables are your fuel tables, the ECM uses the VE values + any PE values in the chip. If you change the VE tables it will effect your WOT also.

PE vs coolant temp and PE vs RPM are added together as far as I can tell.

 

PE vs Coolant temp ( adjust for colder engie temperature where more fuel is needed
pe vs rpm ( overall enrichment)
the VE table is the main fueling table. i would not worry about WOT till the BLm and INT are close to 128 and the timing is squared away. that means no nock counts and yet again BLM and INT around 128.

the PE vs Coolant temp is always added to the PE vs RPM from the expericnes ive had so far with tunning it. PE vs Coolant temp is a gloable change but PE vs RPM is a WOT change.

so if the engine tmep were say 40c you would need more PE fueling than at 109c.

 

So what you're saying is leave the PE tables alone, and just screw with the VE tables to get 128 for all values including at WOT, then mess with the PE tables? Also, does an increase in this percentage equate to an increase in fuel?? Thanks again.

 

no id say work out all the PT till its sorted to 128 blm int. then once thats done work on the PE tables.

 

For what its worth,

pe formula is AFR=14.7/(change cool/100 + change RPM/100 + 1)

I like to set my PE tables to the desired AFR that I'm seeking. Then I modify the upper VE table until I get it. I believe the computer still has an ablity to seek different fuel ratios in PE.

For Supercharged or turbo cars

I'll set the VE tables to something then modify PE until I get it. In the latest case I tuned a speed density camaro with no FMU 42lbs injectors. By the time I was done this 7psi car had PE AFR's values of between 6:1 and 8:1. The car stays 12.3:1 in real life and has 128 INT and block learns at wide open.

 

This is probably a dumb question, but what is the PT? Thanks for all the replies.

 

pt= part throttle.

 

Every car has INT and BLM of 128 at WOT. THat's what it does when it engages PE. THere is no adjustment being made to the VE tables, hence 128 at WOT. This is why it is stressed to achieve 128 in PT before attempting PE tuning.

 

thats not true,

get a car thats far off and you'll see INT values begin to change as soon as you hit WOT then it will start pulling BLM