I'm playing around with a GM/Hitachi MAF sensor off an aussie VS commodore (buick V6 derived engine, 3.8L). I'm wondering if anybody has access to the calibration details (mass flow vs frequency) for these airflow meters.
This one gives out about 180-190Hz with no flow and maybe 1.8-2kHz at idle.
Cheers,
Duncan
GM high frequency MAF cal curve
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jakobsladderz
- MegaSquirt Newbie
- Posts: 11
- Joined: Tue Mar 15, 2005 9:08 pm
- Location: Ballarat, Australia
GM high frequency MAF cal curve
Exeter: (noun) the nut or bolt always left over after putting something back together (Douglas Adams, The meaning of Liff)
-
jakobsladderz
- MegaSquirt Newbie
- Posts: 11
- Joined: Tue Mar 15, 2005 9:08 pm
- Location: Ballarat, Australia
I guess I can answer my own question now after relocating the info from way back.. I have found this to be fairly close..
It was one I found on the old DIY-EFI site apparently read out of an ECU Cal Rom. I figured a line-of-best-fit onto it (was originally 100 times smaller units, I wanted the resolution) and extrapolated somewhat. It's not perfect but it's probably within 2-3% over most of the curve, although each sensor is different. Flow Units - couldn't say, although I can say a 2 litre engine idles at around 500-600 of them.. The sensor seems to be temp compensated I think, the cal is as good on freezing mornings as after a hot soak.
Doesn't seem to obey King's law even remotely, it's a bit odd in my mind, but who am I to argue with the numbers..
Sensor has AC written on it, although it's a high frequency output that I thought were made by Hitachi. 3 pins, active low open collector signal output. 12V (car battery) supply.
Enjoy
Freq Flow
336 20
464 32
592 47
720 65
848 86
976 111
1104 140
1232 173
1360 210
1488 252
1616 298
1744 350
1872 408
2000 471
2128 540
2256 616
2384 699
2512 789
2640 886
2768 991
2896 1104
3024 1225
3152 1356
3280 1495
3408 1645
3536 1804
3664 1974
3792 2155
3920 2347
4048 2551
4176 2767
4304 2995
4432 3237
4560 3492
4688 3761
4816 4045
4944 4344
5072 4658
5200 4988
5328 5334
5456 5698
5584 6079
5712 6478
5840 6895
5968 7332
6096 7788
6224 8265
6352 8762
6480 9281
6608 9822
6736 10385
6864 10972
6992 11582
7120 12217
7248 12877
7376 13563
7504 14274
7632 15013
7760 15780
7888 16575
8016 17398
8144 18252
8272 19136
8400 20050
8528 20997
8656 21976
8784 22988
8912 24035
9040 25115
9168 26232
9296 27384
9424 28574
9552 29801
9680 31066
9808 32371
9936 33716
10064 35102
10192 36529
10320 37999
10448 39513
10576 41070
10704 42672
10832 44321
10960 46016
11088 47758
11216 49549
It was one I found on the old DIY-EFI site apparently read out of an ECU Cal Rom. I figured a line-of-best-fit onto it (was originally 100 times smaller units, I wanted the resolution) and extrapolated somewhat. It's not perfect but it's probably within 2-3% over most of the curve, although each sensor is different. Flow Units - couldn't say, although I can say a 2 litre engine idles at around 500-600 of them.. The sensor seems to be temp compensated I think, the cal is as good on freezing mornings as after a hot soak.
Doesn't seem to obey King's law even remotely, it's a bit odd in my mind, but who am I to argue with the numbers..
Sensor has AC written on it, although it's a high frequency output that I thought were made by Hitachi. 3 pins, active low open collector signal output. 12V (car battery) supply.
Enjoy
Freq Flow
336 20
464 32
592 47
720 65
848 86
976 111
1104 140
1232 173
1360 210
1488 252
1616 298
1744 350
1872 408
2000 471
2128 540
2256 616
2384 699
2512 789
2640 886
2768 991
2896 1104
3024 1225
3152 1356
3280 1495
3408 1645
3536 1804
3664 1974
3792 2155
3920 2347
4048 2551
4176 2767
4304 2995
4432 3237
4560 3492
4688 3761
4816 4045
4944 4344
5072 4658
5200 4988
5328 5334
5456 5698
5584 6079
5712 6478
5840 6895
5968 7332
6096 7788
6224 8265
6352 8762
6480 9281
6608 9822
6736 10385
6864 10972
6992 11582
7120 12217
7248 12877
7376 13563
7504 14274
7632 15013
7760 15780
7888 16575
8016 17398
8144 18252
8272 19136
8400 20050
8528 20997
8656 21976
8784 22988
8912 24035
9040 25115
9168 26232
9296 27384
9424 28574
9552 29801
9680 31066
9808 32371
9936 33716
10064 35102
10192 36529
10320 37999
10448 39513
10576 41070
10704 42672
10832 44321
10960 46016
11088 47758
11216 49549
Exeter: (noun) the nut or bolt always left over after putting something back together (Douglas Adams, The meaning of Liff)