maf flow rate

[02blackfoci]

what are you guys seeing for your lbs per minute? I am seeing 73 at wide open in 3rd gear on the street.

my car is on an 82mm and e85 measures e90 has an offroad mid pipe and a roush cold air.

I feel as if it is a little low compared to a friend of mines car with the same mods. for reference he pulls 83 to 86. same fuel and elevation only mod that he has on me is kooks shorty headers. we have different plugs he runs ngk 6510's and I run brisk's rr14ys. both are gapped at .028. hell we even have the same tuner lol so I'm stumped here

I'm trying to figure this out. so any help or input would help out

 

[imeyers302]

Just checked my last datalog I did for Lund when tuning for my Procharger. MAF flow rate was just over 86 @7500rpm. Also running Brisk plugs gapped to .030.

 

[02blackfoci]

I'm about to do another datalog pull to get my final revision and ill post up shortly

 

[jn2]

We need to know the LTFT and STFT you are giving up the lbs/min for. For example,

73lbs/min@7300rpm w/a LTFT+STFT of +5%

Thats an example, but your MAF flow rate can be skewed by your Fuel trims, unless your trims are zero then the number is not accurate, My example above reads as 73lbs/min but would actually be flowing ~76.6lbs/min since fuel trims needed to add 5% more fuel to achieve the desired lambda.

 

[02blackfoci]

my short term fuel trims are .97 on both banks 75.36lbs/min @7602.50 rpm

 

[jn2]

my short term fuel trims are .97 on both banks 75.36lbs/min @7602.50 rpm

What about LTFT?

The equation would be "[LTFT1+LTFT2]+[STFT1+STFT2]/2", You then take that value and multiply it by 73, this would get you a more accurate number.

Also your friend having headers will play a major role in power output, he is able to expel exhaust gasses and lot better than you can.

 

[02blackfoci]

my ltft are flat lined at 1.0. even being shorty headers. figured they wouldn't play that much of a roll in it. it seems every where I look people with blowers are making 86lbs/min lol I was thinking something must be wrong with my shit! ill have it on the dyno Saturday morning so we will see exactly what it puts down. but I'm still curious to see why I don't make as much flow rate as the others

 

[jn2]

my ltft are flat lined at 1.0. even being shorty headers. figured they wouldn't play that much of a roll in it. it seems every where I look people with blowers are making 86lbs/min lol I was thinking something must be wrong with my shit! ill have it on the dyno Saturday morning so we will see exactly what it puts down. but I'm still curious to see why I don't make as much flow rate as the others

If the car runs good and pulls hard you shouldn't worry much about it. Go to the track, get a half way decent launch and post up your trap speed. You'll prob be somewhere in the 130 range +/- a few MPH

 

[mastwolf]

86lb/min is the max that the PID will read. You would have to look at MAF freq in hz then reference that table in the tune and unless you can open you tune up your not gonna be able to see the true lb/min.


Also if your injector data is off or not perfect comparing lb vs lb will not always be the same. Close but not the same always.

 

[02blackfoci]

I got the tires on it and will be going to the track tomorrow... pray for no broken parts lmao

 

[Shaun@AED]

86lb/min is the max that the PID will read. You would have to look at MAF freq in hz then reference that table in the tune and unless you can open you tune up your not gonna be able to see the true lb/min.


Also if your injector data is off or not perfect comparing lb vs lb will not always be the same. Close but not the same always.

Correct.
And inferred fuel pressure programmed is also used in this calculation. If the tune is set for fuel pressure drop of 3psi vs 13psi there will be a big difference in the lb/min calculated.

86lb/min with a TVS on the 82MM pulley is not normal. 75 is about what I see out of most on the dyno at 7500-7700RPM.