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[stealthiskey]

The AFM on my 944 turbo is starting to show it's age.  It's one of those restrictive "barn door" style air flow sensors, which has some pretty obvious disadvantages over a MAF sensor.

Seems pretty common for folks to shell out $800-1200 for the MAF conversion kit from certain aftermarket companies, but I don't think it would be so challenging to fit a Ford or other sensor in there and reprogram the ECU to accept it.

Plan would be to calibrate the AFM to determine voltage output vs airflow, then do the same to the MAF assembly and find the equation that would relate them.   This would probably involve a variable speed leafblower, duct tape, and some independent air flow sensor.  Taking a look at the .bin in tunerpro, it seems like that's all I'd need, and then set all the IAT corrections to 1x.

What I need is a decent MAF sensor to work with.  I was figuring Ford truck type sensor, and I'd rig up a way to place it into some 2.5 or 3" aluminum pipe.  Any of you nogs know of a good (cheap) sensor to support around 300 hp?  I was thinking maybe out of a 97-20xx ford truck.  If anyone is headed to their local yard and wants to snag one for me that'd be cool.

I'll do a writeup on how-to calibration and tuning the thing.

[92CXyD]

Have you talked to JD and Robb?

They may be able to give ya insight or pointers on making this project easy.

Looking forward to this. 

[DasPoop]

use a bosch sensor at least. Also the air flow curves are similar but not exact. The vane meters top out at 5v MAX no matter how much air its just 5v the hotwire on the other hand will continue to produce small voltages higher than 5v.

http://splitsec.com/products/mafkits/MAFkits2.htm

read the documentation associated with the kits to get an idea.most motronic computers wont like 5+v coming in on the maf signal side.

[92CXyD]

So a volt clamp would be used?

[DasPoop]

http://14point7.com/UAFC.php

this would be a better option because you can manually just alter the maf signal. It would not alter the signal enough to fuck with timing. They are very close.





Dyno graph of an e30m3 with the vane swapped over to a hot wire. really frees up the intake. I wouldnt be surprised if your turbo spooled much sooner as well.

[stealthiskey]

Yea I figure the biggest improvement would be turbo lag/throttle response rather than gross hp.  Once that flap is open, it's not much of a restriction, but it currently sure takes a while to get there.

[turbohf]

http://www.maftpro.com/

maybe that will help you out? im going to be running one of those in the VR4. swap the shit for flow old ass Mitsu MAF for a shitty ass GM one lol.

[PhilStubbs]

in to see how this goes. i have a friend with a miata that needs to ditch his AFM

[stealthiskey]

Hit up the junkyard and got a few MAF sensors.





From left to right:
1 Plastic one from a 97+ F-150 4.2L V6
2 Metal one from a similar gen Ford Explorer 4.0L V6
3 From a early 2000s Hyundai Sonata V6

Grabbed the first two because I know the fords used them and I figure I need two to calibrate one MAF to the AFM, using the second MAF as a control.  Then happened upon the Hyundai part, which might actually be the best.  It is same diameter, but takes up less space, and has provisions for couplers/hose clamps on both ends, rather than a flange.  It is a 3 wire rather than 4, which I suppose means it doesn't have a built in air temp sensor, but depending on how this goes I may not even need one.

Looked up prices for these sensors new.  They are all about $100 on rock auto, the aluminum one was the most expensive at ~$120