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8 Second 6spd
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does anyone know the supra MKIV's MAF voltage output/range to the ecu? searched to no avail.

thanks!!!!
 

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Lbs / min of airflow = -0.0484(V^4) + 1.0634(V^3) - 2.8255(V^2) + 3.7958(V) - 1.6926

5 volts is ~49 lbs/min on the OBD2 logger. The scale may not be 100% correct on this formula, but the curve is.

From what Ash Powers told me (I don't know if you have heard of him, he does some ECU reprogramming for the Z32s) your stock turbo MAF flows better and meters just as much as our stock MAF. I did see a spot in the software he was using where you could re-define the lookup-table used to generate the load value.
 

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8 Second 6spd
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Discussion Starter #4
yeah

yes, i know ash very well.... he tuned my car @ batlground. i am switching over to a vpc setup to elimate the MAF's
this is my main reason for asking the question, to see if the supra MAF and 300zx MAF have the same voltage range....

i am looking going to buy wolf's vpc which has a supra chip in it. i am trying to determine if the chip will work in my car, since it is running pretty damn close to the same injector size as my car. (a 300zx w/ 850cc border inj.) wolf's chip is 720cc, but i can accomidate the fuel maps using the zemulator. i am just wondering if using the supra chip will cause any unforeseen problems.

-joel
 

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Discussion Starter #5

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Do the mkiv's use a hotwire maf meter? If so, I don't think you'll really be able to find that information unless someone had logged it on their own,and that would not be accurate either. If it uses a hotwire MAF, it bases the voltage output of the sensor on the amount of current needed to maintain a constant temp to the hot wire, don't know exactly how to explain it, but basicly has a wire kept at a certain temp, the more air that passes it,the more it cools and thus the more current it needs to maintain the required temp, the sensors output signal is determined by the current flow required to do that, not by the auctual volume of air passing through. Assuming you're talking about a turbo model. I don't have a mkiv, but I'm fairly certain they use a hotwire maf, if not sorry.
 

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toypro said:
Do the mkiv's use a hotwire maf meter? If so, I don't think you'll really be able to find that information unless someone had logged it on their own,and that would not be accurate either. If it uses a hotwire MAF, it bases the voltage output of the sensor on the amount of current needed to maintain a constant temp to the hot wire, don't know exactly how to explain it, but basicly has a wire kept at a certain temp, the more air that passes it,the more it cools and thus the more current it needs to maintain the required temp, the sensors output signal is determined by the current flow required to do that, not by the auctual volume of air passing through. Assuming you're talking about a turbo model. I don't have a mkiv, but I'm fairly certain they use a hotwire maf, if not sorry.
Yes, both the Z32 and MKIV turbos use hot-wire mass air sensors. The formula I posted was taken from readings from a voltmeter and corisponding readings from a OBD2 datalogger. I am 100% sure the curve is correct, although the overall scalling might be a little off. If you look at the equation you see it is far from linear.

Note that GM mass air sensors have a frequency output, but are still hot-wire type. Supposedly GM did this for better noise resistance.

Hot-wire mass air sensors indirectly measure the MASS of air, as Toypro said. This is why they can be used in blow-thru setups. Thus my units are in pounds per minute. If by "volumetric quotient" you mean a chart of volume versus voltage, then those are the wrong units (although its obviously convertable).
 

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Grant said:
Note that GM mass air sensors have a frequency output, but are still hot-wire type. Supposedly GM did this for better noise resistance.
grant,

do you have any more details on the outputs (and inputs if any) of the mkiv maf and the GM mafs. a buddy of mine with a DSM says he can get a box that converts the output of the GM maf's to something the DSM ecu can use. it'd be nice if we could do the same. vpc's and aem's cost too much.

dan
 
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