LNF - Calibrating MAF frequency

[oldskool]

How do you do it? Will calculating the percent change in cross sectional area and multiplying the table by that percent work?

Does anyone have a formula to get close when going from the stock intake piping to 3" or 4" piping?

[Baldturbofreak.com]

THats how I do it. % change in cross section. Then fine tune using %error in afr, Always works.

[oldskool]

THats how I do it. % change in cross section. Then fine tune using %error in afr, Always works.

do you actually have a large %error in afr under load? I have not changed the intake yet, but as it is my %errors in afr are quite low. What about STFTs instead?

[Baldturbofreak.com]

In the LNF all I do is use the ltft's as a global offset, then use the stft's to dial the AMf correction vs/load map.
All other Gm vehicles are WB less so I have to use % error. in combination with an external WB.

[cobaltssoverbooster]

how do we tune the ltft in the lnf? and % error where is this screenshot perhaps?
try 1 percent thats what i got on my 3" cobalt pipe should be around same for you 1-2 %

[Terminator2]

My LTFTs are -5% across the board with my Dejon SRI, but mine has a 3.25" inlet not a 3". I just multiplied the MAF airflow vs frequency table by 1.05 all the way across. I hope that fixes it. I think my reasoning is correct: 5% more MAF flow for the same frequency should mean 5% less fuel added for the same MAF flow which should make for 0% LTFTs. Someone please correct me if I am wrong.

[kuprito]

My LTFTs are -5% across the board with my Dejon SRI, but mine has a 3.25" inlet not a 3". I just multiplied the MAF airflow vs frequency table by 1.05 all the way across. I hope that fixes it. I think my reasoning is correct: 5% more MAF flow for the same frequency should mean 5% less fuel added for the same MAF flow which should make for 0% LTFTs. Someone please correct me if I am wrong.

-5 LTFT means the PCM is removing 5% percent of fuel
Multiply by 0.95 to remove the fuel and you will have almost 0 LTFT

If the PCM is removing, multiply by 100-X%
If the PCM es adding, multiply by 100+X%

Make the same with the STFT values, it takes more time to adjust...

[Terminator2]

-5 LTFT means the PCM is removing 5% percent of fuel
Multiply by 0.95 to remove the fuel and you will have almost 0 LTFT

If the PCM is removing, multiply by 100-X%
If the PCM es adding, multiply by 100+X%

Make the same with the STFT values, it takes more time to adjust...

Thanks man. I realized that I did it wrong when the LTFT went to -10. It was my first time MAF tuning and I second guessed myself I had it correct at first then I changed it. I have had HP tuners for only a couple weeks now. I learned something new yesterday.

[oldskool]

My LTFTs are -5% across the board with my Dejon SRI, but mine has a 3.25" inlet not a 3". I just multiplied the MAF airflow vs frequency table by 1.05 all the way across. I hope that fixes it. I think my reasoning is correct: 5% more MAF flow for the same frequency should mean 5% less fuel added for the same MAF flow which should make for 0% LTFTs. Someone please correct me if I am wrong.

Doesn't your method here assume that all the the LTFT is from the larger intake? I though the MAF frequency was to adjust for the diameter at the sensor, and the MAF calibration table was the actual fueling compensation for the MAF?

[Terminator2]

Doesn't your method here assume that all the the LTFT is from the larger intake? I though the MAF frequency was to adjust for the diameter at the sensor, and the MAF calibration table was the actual fueling compensation for the MAF?

Apparently I did it wrong because now my STFTs are all over the place and I put it back to stock for now my LTFTs are -4 to -6 (-5 avg.) all rpms ranges and loads and my STFTs are insane.They are anywhere from +17 to -20

[kuprito]

Terminator, look at averages, not max or min. Is not the same cold or hot engine, it has different STFT...

[Terminator2]

Terminator, look at averages, not max or min. Is not the same cold or hot engine, it has different STFT...

Thanks man still learning. I Have a histogram now of LTFT+ STFT as well as a STFT vs MAF frequency and STFT VS load and rpm and LTFT vs load and rpm. I have it better now and the car runs a ton better now but I have +7 STFTs at WOT so I need to make a slight adjustment to the high load areas. -1 LTFTs now instead of -7.

[cobaltssoverbooster]

so maf correction table is for ltft? i know my stft were perfect when i adjusted the maf cal. table

[oldskool]

I think MAF Calibration is to adjust for different intake diameter, MAF correction factor is to adjust fueling (LTFTs) after the correct calibtation is set.

[Terminator2]

so maf correction table is for ltft? i know my stft were perfect when i adjusted the maf cal. table

Seemed to work well for getting my LTFTs close to 0.

[oldskool]

So if you get an aftermarket intake with a LARGER diameter, will your MAF readings be artificially HIGHER or LOWER

[CalebL]

I need help in this area too. I purchased an aftermarket intake and now after logging my LTFT's are in the negatives (-8 last), they used to be spot on at zero. I attached my log for reference. How exactly do I go about trying to correct this? Do I use the MAF correction table?

[cobaltssoverbooster]

yay this is good info cause the port job and stage 2 on of a k custom k04 will def be freakin my ltfts and i didnt know what to change till now. all i had to do stock was move my stft and the ltft stayed 0 lol lucky me
thanks

[Terminator2]

So if you get an aftermarket intake with a LARGER diameter, will your MAF readings be artificially HIGHER or LOWER

Artifically low I would think because the air velocity through the intake would be reduced for the same amount of airflow.

[oldskool]

Artifically low I would think because the air velocity through the intake would be reduced for the same amount of airflow.

Lol I HATED physics. I was seeing it as you are getting more airflow for the same velocity. 1000 Hz through a 3" tube vs a 4" tube - which has the greater mass flow?