80 Camaro Z28 - 550hp AFR 383 / T56 6spd (Holley HP EFI)
91 Beretta "SS" - 260hp 3400 MPFI / HM282 5spd (7730/$A1) sold! for crazy money...but I miss it
94 Silverado Z71 - 300hp Vortec 357 TBI / NV4500 5spd (7427/$0D) gone but not forgotten
96 Beretta "T56" - 4.8 LS RWD swap / 6spd (0411/2156)
01 Silverado 2500HD - stock Vortec 8.1 / ZF6 6spd (0411/8322)
https://www.youtube.com/c/GEARHEADdezign
Ok, I cleaned the MAF really well and double checked for unmetered air leaks. (No leaks and the MAF looked pretty damn clean, but it did change my AFR a bit after the cleaning.) However, what I really noticed was the angle of the tube right after the MAF. It has a much more noticeable bend than you really see while installed in the truck. I wouldn't be surprised if that skews the sensor readings.
The intake was an ebay special for "2500HD" but it turns out it's for 4.8/5.3/6.0 and I had to modify it a bit to fit 8.1. Unfortunately, I already tossed the stock stuff so I can't do a sanity check on the sensor.
What I did see though, was the idle was high 11s until the LTFT hit 80 and STFT hit 95. So that's pulling out 25% to hit 14.7 right? Steady state low throttle at 2000ish rpm the LTFT was about 90-92. WOT was 100 LTFT and 13.0-13.2 AFR. So math-wise it seems like the calibration is non-linear.
So I'm going to disable the MAF, take a log and make sure my VE tables are pretty good with a historygram. Once I'm happy with the VE tables, I'm thinking of adding 6% to the stock MAF curve, re-enabling and taking a look at the LTFT historygram again.
Then, will I be able to use LTFT in a newly built historygram of RPM vs g/sec to tune in the MAF? Since I can't get the wideband to report to the datastream, I can't do an AFR error calculation like I keep seeing in how-tos for MAF scaling.
80 Camaro Z28 - 550hp AFR 383 / T56 6spd (Holley HP EFI)
91 Beretta "SS" - 260hp 3400 MPFI / HM282 5spd (7730/$A1) sold! for crazy money...but I miss it
94 Silverado Z71 - 300hp Vortec 357 TBI / NV4500 5spd (7427/$0D) gone but not forgotten
96 Beretta "T56" - 4.8 LS RWD swap / 6spd (0411/2156)
01 Silverado 2500HD - stock Vortec 8.1 / ZF6 6spd (0411/8322)
https://www.youtube.com/c/GEARHEADdezign
Made a huge datalog at varying RPM with the MAF disabled (attached). LTFTs are much closer with the MAF disabled. +/-2% for most of it...up to +5-8% at the top of the log. I adjusted the VE table and I'll log & retune another couple times.
Then I can work on the MAF. LTFT with the a history table for g/sec sound like a solid plan?
80 Camaro Z28 - 550hp AFR 383 / T56 6spd (Holley HP EFI)
91 Beretta "SS" - 260hp 3400 MPFI / HM282 5spd (7730/$A1) sold! for crazy money...but I miss it
94 Silverado Z71 - 300hp Vortec 357 TBI / NV4500 5spd (7427/$0D) gone but not forgotten
96 Beretta "T56" - 4.8 LS RWD swap / 6spd (0411/2156)
01 Silverado 2500HD - stock Vortec 8.1 / ZF6 6spd (0411/8322)
https://www.youtube.com/c/GEARHEADdezign
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