Multi-post

 

It's tough to scale a MAF and injectors at the same time. Although for the injectors, there are a lot of numbers already published on evoM that make the process easier. Even if you borrow someone's FI scaling and latency numbers, it is still a good idea to verify that they work on your car before you scale the MAF.

 

Yeah I hear ya. I tried starting with several injector scalings and latencies from many of the evoM members. I ended up with a higher injector scaling with horrible openloop accuratcy between acutal AFR and what is set in ecuflash. After reading throuh several forums at least one person in each thread mentioned MAF but didn't really get any support. Apparently MAF Scaling is just as necessary as injectory scaling and AFR tuning.

So please if I am wronge, The "best" most accurate order to tune the different systems would be to:
1 Start with last known "good" injector, intector scaling and injector latencies combo used
2 Tune MAF scaling to bring Fueltrim_Low and Fueltrim_mid as close to 0 (zero) as possible in respective Hz range
3 Change Injectors and adjust injector scaling and latencies to bring Fueltrims back to 0 "zero"
4 Finally adjust MAF Hz range for openloop till actual AFR equals projected in ECUflash fuel table

Thanks for hanging in there with me. I am mostly new to tuning the evo. Been tuning AFR with mostly stock set ups for a couple years but never got into depth like this.

 

The "best" method above is close.

You really don't want to mess with me MAF until you have your injectors scaled as perfectly as you can get them. So some injector tweeking is usually necessary before you start messing the MAF.

Then you use the MAF scalings to bring the injectors even closer to 0 LTFT.

 

Just to add my 5cent.

I did as said in the first post. First looked at my new scaling and it looked a bit funny. Well went through this topic and saw that others have had similar results so will test mine tomorrow.

Though my fuel map will have to be redone as I have mapped it with the wrong scaling.. :P

I have Evo 6 GSR with HKS intake, HKS HiPower Silend (dp, mid-part + silencer ) with cat and stock turbo.

So will be back to tell my results. My guess is that I will run REALLY RICH AFR's.

 

I read this whole thread several times and my brain hurts

Anyhow, I plan on switching over to e85 tomorrow night. I'm installing a fuel pump and fic1100 injectors. My question is, should I rescale the maf with the stock pump and injectors that are in the car, then install new pump and injectors, work on the scaling for the new injectors and latencies and then finally adjust the maf again?

Thanks in advance!
Christian

 

Absolutly not....once you have your MAF scaled to work well with your intake you shouldn't have to mess with it any more.

But, you may need a slight adjustment here or there for fine tuning.

Paul

 

Thanks Paul. That makes sense to me. I'll rescale the maf before I do injectors and pump, then work on dialing in the injectors.

 

So I read this thread through and I have a couple questions...

First, I understand that we are supposed to adjust the MAF Compensation table rather than the MAF Scaling table at this point. However I noticed that while doing this it is not a direct correlation of STFT + LTFT addition as a percentage that you add or decrease the MAF Compensation table. It appears that the MAF Compensation table as a percentage works great if you are calculating the difference between actual AFR and Map AFR as a percentage. To clarify, if your fuel trims sumed (LTFT + STFT average) are + positive than you add to your MAF Compensation table, and if your fuel trims sumed (LTFT+STFT average) are - negative than you subtract?

Second, beyond closed loop, if your Actual AFR are lower than the map AFR than you lower the MAF Compensation value as trial and error until you measure the values in your AFR Map compared to reading from the wideband?

Any help and direction appreciated,

George

 

what you mean in 'lower afr' ? if you mean richer, then yes, if aafr is richer than mafr you lower maf scaling at corresponding hz. haven't dealed with compensation table, tweaked only with scaling and worked perfectly

 

Small changes to the compensation table equates to larger changes in the fuel trims, atleast in closed loop is what I have determined. A 3% change in the compensation table equalled roughly a 8% change in the fuel trims, this is for my car, and I'm at an altitude close to 6000 feet.

Thank you for your assistance!

George

 

I know this is an old thread. Great thread at that. My question, that seems not to be directly answered, though danced around, is this: WHat do you do to calculate MAF Scaling, when you rescale the HZ side of the MAF Scaling above 1600 HZ. It is suggested that stock, if the car pushes above the 1600 HZ frequency, the ECU just uses the last table of 232 units. So it seems it is suggesting that you just leave/use 232 when above 1600 HZ. However, when the MAF Scaling table is opened, and in graph mode, the curve is dorked after 1600 HZ and just is a flat line. This seems odd or off. Does anyone have an actual calculation one can do to calculate what the units should be per hz above 1600?

I have also been made aware, that the MAF Scaling Table, does use load in its calculations. Suggesting that a Scaling that is wrong in units per HZ, would equate to wrong loads being achieved in logs. Can anyone clarify this?