MAF Scaling - Open/Closed Loop Fueling info

[steve99]

Originally Posted by Turdinator

I updated to OFM 1.08.0 last night and then did my log today. Could it be it just hasn't been updated on the 700G roms? Or do I need to download something extra?

download and apply latest template file as well

[phrosty]

Originally Posted by wparsons

C# is what I do, porting to a web app would be trivial!

Sorry for the delay, car's been in the shop after being vandalized. Took some time to clean up the code and added OL scaling too:

https://github.com/scalablecory/scalemaf

[solidONE]

Originally Posted by Kodename47

The simple solution is to zero out the IAT compensation table while scaling the MAF. You should really do that to all compensation tables while calibrating for that very reason.

On ECUtek you fill the table with values of 1, RR is 0.

The IAT compensation isn't a simple hot/cold +/- as it reverses as air volume increases too. I would return the stock table when you've done calibration.

Now I'm getting really anal with my MAF scale, I've found that the intake air temp correction to be somewhat inconsistent to what I found earlier with around 95 vs 75 temps once the IAT get lower than 68 degrees... now the question is to zero or not to zero the IAT compensation tables or not. What do you guys think? Any thought or advice on the temp compensation, or just deal with it as is?

[vgi]

fyi, updated proggie is now posted.

[phrosty]

Originally Posted by solidONE

Any thought or advice on the temp compensation, or just deal with it as is?

We have the compensation tables... it seems like we should be able to anti-compensate to get more accurate corrections.

[solidONE]

Originally Posted by vgi

fyi, updated proggie is now posted.

Link?

[solidONE]

Originally Posted by phrosty

We have the compensation tables... it seems like we should be able to anti-compensate to get more accurate corrections.

I would think so, but the compensation tables are a bit strange. It is zeroed at 68 degrees and at 11.23 g/s. At temps of 104 or above the compensations below 11.23 g/s is negative, but anything over 11.23 g/s it goes to positive. The inverse is true for temps below 68 degrees. Not sure of the logic behind this. I'd like to learn more about why it is done this way before making any changes.

[Kodename47]

Originally Posted by solidONE

I would think so, but the compensation tables are a bit strange. It is zeroed at 68 degrees and at 11.23 g/s. At temps of 104 or above the compensations below 11.23 g/s is negative, but anything over 11.23 g/s it goes to positive. The inverse is true for temps below 68 degrees. Not sure of the logic behind this. I'd like to learn more about why it is done this way before making any changes.

I can't work it out, it must be due to the behavior of air at those temperatures.

As for zeroing out the IAT comp, just do it while doing the MAF and then put them back as stock would be my recommendation.

[steve99]

Originally Posted by Kodename47

I can't work it out, it must be due to the behavior of air at those temperatures.

As for zeroing out the IAT comp, just do it while doing the MAF and then put them back as stock would be my recommendation.

I suspect the table is correcting for errors in the maf sensor behaviour due to temperature rarther than trying to compensate for air density changes, i suspect that calculation is done in ecu code somewhere using iat.

[vgi]

Originally Posted by solidONE

Link?

Same place, link is on RR forum and I believe has been posted here.

[Turdinator]

I noticed a while ago that the car felt the nicest to drive when the outside temps were around 20c. If we could tweak the table for more performance when cold and a tad safer when warm I'd be very happy.

[solidONE]

Originally Posted by Turdinator

I noticed a while ago that the car felt the nicest to drive when the outside temps were around 20c. If we could tweak the table for more performance when cold and a tad safer when warm I'd be very happy.

If there is a temp compensation table for ignition advance, it can be done. The nicer feeling you're getting at 20c is probably just the increased power from cooler iat. Though, this engine seems more knock prone when temps are higher. The iat compensation for maf scale will only dictate how much or little fueling correction the computer will make to hit your target afr.

[Kodename47]

Originally Posted by solidONE

If there is a temp compensation table for ignition advance, it can be done. The nicer feeling you're getting at 20c is probably just the increased power from cooler iat. Though, this engine seems more knock prone when temps are higher. The iat compensation for maf scale will only dictate how much or little fueling correction the computer will make to hit your target afr.

The IAT is a load compensation table, not MAF.

There are 2 ignition timing vs IAT tables, one that changes timing depending on IAT and the other determines the % of that applied depending on RPM and load.

[solidONE]

Originally Posted by Kodename47

The IAT is a load compensation table, not MAF.

There are 2 ignition timing vs IAT tables, one that changes timing depending on IAT and the other determines the % of that applied depending on RPM and load.

Really? So it's the load that gets adjusted... that would explain the relatively low % of adjustment in the table, I guess. I've decreased the entire IAT compensation table by .4%. I'll see if it has the desired result.