Originally Posted by Bill W

I think from some of the post he has made he is a lawyer. His specialty is the ethical treatment of spider monkeys, there are alot of cruel spider monkey breeder that do nothing but sit around and spank their monkeys all day long.

Originally Posted by Zippy

I'll give it a shot, but Markski has the full answer. Please don't be insulted if too simple for you (or not 100% correct) .

The OEM MAF has a voltage that runs through it in a direct relation to the airflow that passes over it. It is this variation in voltage by which the MAF reads the amount of air coming into the engine. When about 550-600 HP, it is also at it's maximum voltage capacity. Air flow increases above this level are not registered by the MAF. Said another wat, the OEM MAF has very poor resolution in the upper HP range. Some tuners use a MAF that can handle a much higher voltage and hence the engine can be tuned better in the higher HP ranges. I believe Protomotive use this approach. Other tuners use a larger diameter MAF tube, in conjunction with the OEM MAF. The larger MAF tube mean less air flow at the same HP as a norrower diameter tube. With this approach, you can get better resolution in your tuning in the high HP ranges. I believe UMW and Sportec use this approach.

If pushed too far, the voltage increase running through the MAF can cause it to "pop". Strangly, some cars experience this much more than others. I, unfortunately, have a MAF eater. With the added air flow of the having a V-Flow installed, I can blow a MAF in 20 mins. With the OEM air box installed, the MAFs seem to stay alive.

As was posted by Mike at EVO, several months ago, EVO are working on a MAF solution for the GT700+ cars. As to thier progress, I haven't heard.

Originally Posted by yellowturbo

I believe Protomotive uses a MAP flow sensor (does anyone know if MAP=Manifold Air Pressure?) and uses a different way to calibrate the ECU. I just found this on the Protomotive website:

http://www.geocities.com/protomotive/psvsaf.htm

If Protomotive uses the first column - then I wonder how they get the temperature value (volume is easier) unless there is a sensor there that measures temperature also.

Originally Posted by MARKSKI

here is some data that I collected form my tuner.... BTW Im just repeating mostly..... some of this is a repeat in part or whole... but here is what I know about this MAF thing..
Most P car tuners use the o2 sensors as their primary feedback
sensor because they're well beyond the limits of the MAF/Pressure sensor.
So, besides those two, what's left?
So the question is : how a MAF that reads to 1400kg/hr or 51.4 lb/min
which on it's best day at 10hp/lb/min is 514hp, more typically 9.5 on 996tt,
for about 490hp will do that. Even in a larger tube, to go out to 800hp,
the thing would have to be 108mm or so vs. the stock 85mm tube, and that
still wouldn't be accurate due to the sensor only sticking out 40mm or so.
It wouldn't be in the middle of the tube.
that's what I gathered...

Originally Posted by yellowturbo

My guess would be some sort of interpolation/extrapolation assumption. Which goes back to my comment on how the ECU gets feedback on what is 'too much' (of either timing or boost). Does it keep increasing timing/increasing boost until it senses detonation or is there some sort of assumption in the program that keeps it below that threshold?
.

Originally Posted by MARKSKI

You control the boost. the car running on this kind of set up is tuned for each boost setting... so u start lets say with .8,.9,1 bar and so forth.