Maf VS Maf

[ZR2_350]

Is there a difference in performance if using the V6 maf versus the V8 maf?

Here is a comment made by someone, and for some reason it just doesn't seem to be true. I could be wrong, If anyone could confirm or deny this statement that would be great.



My ecu is programmed for the v8. It didnt make two shits which mass air flow sensor was installed because I had both in and it ran the same. I THOUGHT it would make a difference so I did get the v8 one, but it didnt do shit. I made no gains on the switch.

[GAMEOVER]

The V8 MAF is larger in diameter than a V6 MAF.... at least it was in my S-10 compared to any V8 Silverado....

[ZR2_350]

Yes it is a bit bigger. I am trying to find out if his statements old true,or false

Here is a reply from another member... Again, True or False.



You ran the same G/S table for both MAF and you say there is no difference? Are you scanning your PCM at all? Just because you don't feel a difference doesn't mean your fuel trims aren't pegged at max + or -, in either case your PE fueling will be shit and so will your economy, and I know that from experience. If you have a basic flash from some where, they usually are conservative on timing and pretty rich to keep people from blowing their stuff up. I've had lots of people bring me cars that were tuned like that.

There is a lot different in the table for the GM 75mm and the LQ4 maf, especially over 4000-5000 hz. Maybe it doesn't matter much on your application since you aren't moving enough air to get it up that high except under very heavy throttle, where Acceleration enrichment dumps make up for it, and you're not WOT long enough to completely lean out.

On my car typically @6300 rpm I'm hitting 11,300 hz on the Lq4 maf (gm 85mm) which is at the effective limit for my pcm (the MAF can go up to 15,000 but the pcm's table stops at 11,500 IIRC), so either i have to go to a larger MAF or scale the entire MAF signal and lose resolution.

A 1% change in your MAF value, will have a 3% change in your front O2 sensor reading.


IE, if I'm targeting .950 O2, and i have .880, it would mean i would want to increase the MAF cell that i was at during that o2 reading by ~2.6%... like wise, if your pcm is reading only a few percent off at any given range, it will had triple the effect on your o2 reading.

Changing your MAF sensor with out recalibrating the table will throw your entire tune off. Fuel trims is the cushion for this discrepancy, which can compensate up to 16%+ to 21%- (it can add 16% more fuel than what the table is calling for or remove 21%), but a change from the 75mm to the 85mm is outside of this range (on the + side). At wide open, if you were reaching the upper range of the MAF you would be ~6.5-7% too lean if your pcm is 'tuned' for the 75mm.