Whats everyone using to tune their MAF curves? I went the STFT route with LTFTs disabled. But now that I have the wideband can I use it to tune the MAF curve more accurately, and if so how do I go about setting this up?
Whats everyone using to tune their MAF curves? I went the STFT route with LTFTs disabled. But now that I have the wideband can I use it to tune the MAF curve more accurately, and if so how do I go about setting this up?
2019 Ford Raptor Tow Rig Scarab 195 Open 250HO
2008 Shelby GT500 VMP Gen II-R (17psi), JLT 123mm CAI, Ford SCJ Monoblade Throttle Body, 56# Injectors, BoostAPumps, VMP triple pass heat exchanger (dual fan), 170* thermostat, BBK long tube headers, Dual resonators, Magnaflow Catback, LC2 Wideband, RXT clutch
Depends on how far off your MAF is, most likely, with a base adjustment the car will be fairly driveable. If so, you can use LTFT's. I don't know if this is a simple, use STFT or LTFT question, but I thought I might as well include the how to info.
Take your stock inner intake tube diameter, assuming you have a 5.0 Coyote Mustang, it has a stock inner intake tube diameter of 86mm (inner radius of 43mm)
The surface area of the inside of the intake tube can be calculated using pir^2 : (pi)(43^2) = 5808.8
Take the inner tube diameter of the new intake, assuming you have a JLT Intake, has a inner tube diameter of 107mm(inner radius of 53.5mm)
The surface area of the inside of the intake tube can be calculated using pir^2 : (pi)(53.5^2) = 8992.02
8992.02 /5808.8 = 1.548
Multiply the entire MAF Airflow vs. Period table by 1.548 and flash this tune to the car. Doing this with my V6 Mustang right away got the MAF Curve within 3% in most driving conditions, but the car was 12% rich at idle, so there was still work to do.There is no need to disable any form of adaptive learning in the tune when using LTFT's, which is nice. STFT's switch quick and LTFT's consistently build fueling correction. Also if I don't datalog the car, the computer does it for me by remembering the LTFT during different driving conditions, the next time I datalog the car, the learned LTFT data is there.
The next thing to do after that base correction is made, is to setup a histogram to log MAF Period.
2.25 Scanner may or may not support all of the parameters needed to tune the MAF, here is how I did it in 2.24
1. Define a custom PID for MAF Period
SUCCESS5.PNG
2. Setup the table display to include the following parameters at a minimum: LTFTB1(SAE),LTFTB2(SAE),MAF Hz and the user defined PID you created for MAF Period.
3. Setup a histogram to relate LTFT's to MAF Period.
General & Plot
SUCCESS2.PNG
Row & Col Axis
The data in the labels box is simply copied from the period axis inside the MAF Airflow vs. Period Table in your tune. You have to use commas in between values in the labels box!
8.PNG
4. Go on a drive, let the car learn and generate LTFT data in as many different driving conditions as possible. As it records, it will populate your histogram table. You can now use this data to tune your MAF.
Idle issues.PNG
Last edited by AKDMB; 11-09-2015 at 12:18 PM.
Here is my stock MAF Curve vs. the new MAF Curve after two tunes. I think it turned out pretty well, you can go back and forth between the two captures and the shape of the curves are near identical.
Stock
maf1.PNG
Modified
MAF2.PNG
If there are any issues with the approach above, PLEASE LET ME KNOW!!! I want to learn as much as possible about this stuff!!!
Last edited by AKDMB; 10-15-2015 at 04:28 PM.
Good writeup! When the car goes into open loop fueling does it still look at the MAF curve for fueling? Just curious as to if I should be concerned about the upper limits of my MAF curve if I am in open loop fueling.... ?
2019 Ford Raptor Tow Rig Scarab 195 Open 250HO
2008 Shelby GT500 VMP Gen II-R (17psi), JLT 123mm CAI, Ford SCJ Monoblade Throttle Body, 56# Injectors, BoostAPumps, VMP triple pass heat exchanger (dual fan), 170* thermostat, BBK long tube headers, Dual resonators, Magnaflow Catback, LC2 Wideband, RXT clutch
From what I know these cars only operate in open loop right after startup at idle, even then, only for a short amount of time, a little bit longer if the car is cold. Someone more knowledgeable than me can answer this question, but I'm pretty sure coyote's pretty much stay in closed loop 24/7.
Regardless of closed or open loop. Fords ALWAYS use the MAF sensor directly for fueling calculation (unless MAF is failed).
Open loop just means no correction to errors in fueling.
I used the fuel trims for the low end of the MAF, and the wide band for the high end. An 08 GT500 would go open loop for WOT, so no fuel corrections.
2. Setup the channels to include the following parameters at a minimum: LTFTB1(SAE),LTFTB2(SAE),MAF Hz and the user defined PID you created for MAF Period.
What exactly do you mean by this OP? I am only familiar with 2.25 unfortunately.
Kris
2.25 has the MAF Sensor Period PID already set up. No need to set up a user defined.
What I meant was that you need to include those PID's in the channels, because those PID's have to be recording to make the histogram work. A histogram that uses LTFT's for example can't work if LTFT's aren't even being recorded in the datalog. If your histogram uses a PID, that same PID needs to be present in the channels. I hope the way I am explaining this makes sense. I can't remember what the channels are called in 2.25, away from my computer right now. It has been forever since I have used 2.25 to datalog, I am forgetting the terminology between 2.24 and 2.25.Originally Posted by kris5597
EDIT: I was wrong, they are called "channels" in 2.25 and in 2.24 they are called the "table display".
Unfortunately MAF Period hasn't been defined yet for my vehicle. I am missing a lot of PID's in 2.25 so it useless for my application at this point. I don't even have knock retard. It's not that big of a deal though, I know that Eric and everyone at HP Tuners has a lot on their plate getting everything added for every vehicle, can't imagine having to get everything to work for every vehicle. I have a 3.7 Mustang which uses the ESYS PCM not the Copperhead. Eric hasn't gotten everything added for the ESYS PCM's. I thought I would do the above explanation with 2.24, 2.25 doesn't work for everyone but 2.24 pretty much does.
Last edited by AKDMB; 11-09-2015 at 12:20 PM.
Yea, I'm missing a few PIDs for mine too but I do have MAF Period and KR. Would like to have fuel pump duty cycle, oil temperature and VCM controls. I'm sure they will be coming along. Like you say, so much to add with so many vehicles.Unfortunately MAF Period hasn't been defined yet for my vehicle. I am missing a lot of PID's in 2.25 so it useless for my application at this point. I don't even have knock retard
I wish there was fuel injector duty cycle...
I log Inj. pulse width and convert. http://www.stealth316.com/2-calc-idc.htm
Ah, very nice. Didn't even think of that.
Subbed
If there an update on how to log MAF period in v3.0? The screenshots are from the older version and I cannot get mine to populate values...
Below are screenshots on how i configured it. Only the first row populates.
You need to log either ltft or stft for the sensor (Parameter), and use the MAF Period Sensor for the row, and populate the row values to match your MAF vs Period table. The column doesn't matter, (I don't have a sensor selected at all for the column in mine).This will populate fuel trim correction of your choice to the maf period table for doing correction.
Last edited by toyoguru; 02-27-2016 at 08:23 PM.
Current toy- 97 SCSB OBS chevy forged 6.0/4l80 combo with a bit of boost..currently back under the knife
To many previous vehicles to list
Thank you, that worked. I picked LTFT and they now populated. So now my question is, these numbers that populated, how i use them to modify the "MAF airflow vs period"?
For example on the third row labelled "107.0" has a value of "41.34". Based on the log, which shows a "-6.3", would I change the cell in the tune for that row to "35.04"?
My logic behind that is just basic subtraction, 41.34-6.3=35.04. Or am I wrong?
Copy all results, paste special multiply by % - Half
good info
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