If you are building a high output boosted motor at what point will you need to change the MAF or trick the PCM into reading higher flow rates.Some guys are claiming to max out their MAF readings with what I would consider mild setups,at least they are when compaired to a 650 or 700hp turbo setup.

 

the maf will only read something like 57lb's of air, if you swap it out to a diferent type then it can goto something like 64lb's of air. this would probably be a little over 500rwhp.

that is when the maf maxes out, you can still tune the truck to run and add fuel, it just wont be nearly as adaptive. you have to pick your max boost and even tune on a cool day, this will give you prety much the max air flow you will see, then you just tune based on rpm.

problem is a warm day with air that isn't as dense or you turn the boost down a little, the pcm wont know and will add too much fuel.

edit.. seth at cmotorsprts told me if you tune for lets say 12psi and good gas and then turn the boost down to 9psi but keep the 12psi tune it will still run good, might be down 20hp from a perfect 9psi tune

 

What about a Pro-M MAF?I've seen posts where these are used with a conversion that tricks the stock PCM to read higher.

 

can you link me? seems like harlen tried that and he gave up on it for some reason, that would be sweet if someone had it figured out and was actualy using it. if you do that you may need to get a seperate IAT sensor.

 

The max on the stock maf appears to be 59.9lb or 454 gm. You can actually see the peaks get chopped right off.

This place claims to custom calibrate mafs pro-flow . I have a couple of emails from them, but have not gotten any definitive answers on what they can actually do. Just need to call I guess, but don't know that I'm educated enough on it to even know what the hell I would be asking them for. I believe this is the same place mentioned above. A few guys in the FI section refer to them on occasion.

 

I don't know of a link,but Pro-flow shows a GM MAF converter and a MAF calabrator that they claim make tuning their 90mm MAF for use with a GM PCM possible.

 

The stock computer can read up to 512gm/s(~68lb/min) of airflow. The stock MAF can read more but, I hear the resolution starts to go away with higher flows.

If you edit your MAF table in edit so the max value is 511gm/s you can then adjust the IFR to get your Ltrims back in check. I think the timing tables will need to be adjusted a bit also since they are linked to the MAF table(load calc). If you really want to confuse yourself add a MAF translator on top of that and you can eek out a little more with the stock computer without relying on the PE table.

The Pro-M Maf is nothing more than a Ford MAF(guts at least) that outputs a voltage(0-5V) instead of a frequency. Pro-Flow can calibrate these MAFs to read whatever you want and sell you a voltage to frequency converter to make the signal compatible with our computers. Harlan ran this setup on his car until he switched over to DUAL stock GM MAFs. Before it's asked he runs the dual MAFs with a custom signal "averager" box he built.

I like the dual MAF deal Harlan is running since two stock truck MAFs would be able to register over 900gm/s(~120lb/min) Start tweeking them with the trick above and bump that up to 135lb/min. That's ALOT of power.

 

All sounds way above my head, but most of all way above my needs. I don't believe I would be capable of hitting 511gm/s, but hard to tell. I'm holding the peak of 454 for a little over a second.

 

Let's hear more about the dual MAF deal. How would you wire that up to the PCM?

 

How do you get it touch with Harlan and will he sell you a"averager"box to run with the 2 stock MAFs?