Thoughts on Tuning and the LNF.

[Iam Broke]

Oldskool - I translated my E48 tune to the stock MAF freq table and added the 14.x % needed to the MAF correction table in all cells. It was very well dialed in so we'll see how this works out. Thanks for posting the idea.

[T-Man]

Ok, here's a discussion point that i've seen elsewhere as well. Why use the "MAF Calibration" table to adjust for E85, knowing that it will throw your airflow readings out of wack? I thought the point of that table was to make adjustments when there is an airflow track change to get the most accurate airflow readings possible. Why not use the "MAF correction" table to adjust for E85? We have a two-fold factor of increase in that table, so the 30% needed off the bat is no problem. I personally try to leave the calibration table alone when tuning fuel trims, since i have the stock airbox in place. That included tuning my water/methanol injection set up.

Great point... Thanks for the tip oldskool

Oldskool - I translated my E48 tune to the stock MAF freq table and added the 14.x % needed to the MAF correction table in all cells. It was very well dialed in so we'll see how this works out. Thanks for posting the idea.

I did the same when I saw oldskool post this ealier and decided to experiment. I multiplied the entire MAF correction table by 1.075 as the largest swing in LTFT i've seen is 7.8

From what I've seen thus far, it looks to be a more accurate way of dialing in the extra fuel needed. Obviously the MAF correction table will need to be dialed in a bit more but I've found that with this method there's less of a swing in my STFTs and it brought my LTFT into the 0.8 to -0.8 range.

Will keep you posted.

[Gimpster]

For some reason I always thought the correction table didn't have that large of an adjustment range.

Will have to give that a try too.... if I ever put a clutch in the car.

[oldskool]

It may have been in the LTFT/STFT tuning thread, but wasn't it suggested at some point with a stock air box to leave the calibration table alone, set the correction table to "1" across the board, and tune LTFT on the correction table? basically the E85 (or Exx) guys would set it to 1.30 (or whatever percentage of fueling is affected) across the board and tune from there.

[Iam Broke]

Ran well with the fueling adjusted the oldskool way. LTFT stayed 0 to +0.8 on a 50 mile commute, same as the MAF freq offset after adding my bias to every cell in the MAF correction table. MAF flow and VE flow log close again.

I learn something here every day.

[Iam Broke]

Gimp - With the MAF relocate at idle and the Emix I have 1.3x in some low rpm low load cells in the MAF correction table, it took it fine.

[Terminator2]

Ok, here's a discussion point that i've seen elsewhere as well. Why use the "MAF Calibration" table to adjust for E85, knowing that it will throw your airflow readings out of wack? I thought the point of that table was to make adjustments when there is an airflow track change to get the most accurate airflow readings possible. Why not use the "MAF correction" table to adjust for E85? We have a two-fold factor of increase in that table, so the 30% needed off the bat is no problem. I personally try to leave the calibration table alone when tuning fuel trims, since i have the stock airbox in place. That included tuning my water/methanol injection set up.

You coud make a 28% change to all the cells in the correction table to tune for E-85 or you could make that same 28% change to the calibration table for the E-85 either way it does the same thing if you are needing a global offset like you would when tuning for E-85 or a blendof E-85 and gas. I personally like to adjust the calibration table (make sure you multiply the whole table by the same percentage to keep the steps between the cells smooth) then tune the correction table until the total fuel trims are within 1-2% everywhere.

When tuning for water/meth with the stock airbox it makes a lot more sense to tune using the correction table only because the meth is injecting only at certain loads so tuning the correction table only makes sense unless you have modded the stock airbox and the LTFT is off by more than 3% then it would be a benefit to make a slight adjustment to the calibration table first then tune the correction table.

[T-Man]

What still baffles me is that everyone talks of 14% and 30% swings in fueling errors and the most I've ever seen was 10.x and that was right after a rain storm here recently. What I've seen on the last 4 days or so when trying to re-tweak the fueling for shits and giggles was a consistent 7.8.


1:1 mixing too...

[Terminator2]

What still baffles me is that everyone talks of 14% and 30% swings in fueling errors and the most I've ever seen was 10.x and that was right after a rain storm here recently. What I've seen on the last 4 days or so when trying to re-tweak the fueling for shits and giggles was a consistent 7.8.


1:1 mixing too...

14% average change is seen with a 50/50 mix but if you were -4 on the LTFT before you would now be +10 with a 14% change.

[Ch1ck3n]

Total change of topic, but something I've been wondering lately. Cam angle adjustment; yay or nay?

I've read advancing the intake cam can make power easier to build, but then (I forget who it was) someone had some serious valvetrain issues with changing those tables, even just the warm intake cam table.

Any thoughts?

[Iam Broke]

Many combinations have been tried by several of us, stock tables work best here.

The only issues would be if you didn't make smooth changes and had the cam phasers slapping them around. I remember reading something about that over a year ago.

[Gimpster]

If I have any gripes with trying the correction table method.... it would be the lack of resolution above 190+ load. I wish this table let us change the scalar beyond that.

Otherwise its kinda nice having sane MAF and VE airlow data without a custom PID.

[Iam Broke]

Agreed. My fuel trims are damn near the same 190% load to 350% though anyway. I log them out to 370% in the LTFT+STFT histo. Since tuning the correction table and putting the MAF freq back to the stock curve I've only hit 330% load to date.