Tiger03447

Would an AFM off of a later car, such as a 968 or 951 or perhaps a 928 be able to give better airflow than the original 944 ones? I know that to go with a later AFM one has to change the DME out also...seems that a 3.0 L would have a different/better AFM than one from a 2.5. Lord only knows what a 928 AFM would require to operate on our engines, if at all.

V2Rocket

968 had a hot-wire MAF sensor so that's a no-go.
All the 8-valve NA 944s used the same "size" AFM, but of course there was different electronics/voltage early vs late. AFM inlet is approximately 50mm x 50mm

The 16-valve (S and S2) used the same "size" AFM as the 951. Inlet size approx. 50mm x 60mm. Don't know if the actual electronics are the same or not though.

The 951/S/S2 AFM will not bolt onto the NA airbox.

But even the larger AFM will not compare to the benefits of a MAF or MAP conversion.

odonnell

BMW guys swap them around, and they use the same bolt pattern, so maybe one from a 535i would physically mount to the airbox. But then you'd be stuck with figuring out how to make the signal usable to the DME, otherwise it would completely throw off internal calculations.

konakat

I think that would actually be worse rather than better. An n/a would probably never flow enough air to completely open the vane, so you would have more restriction at the top-end.

asmperformance

Actually, all the vafs are completely open after about 80% load. The larger vaf from the S2 works on the 2.5 and works well once the transfer functions are changed in the tune.
The comment about the benefits of going with a map is correct.

odonnell

Yeah. Trying to optimize the AFM is putting lipstick on a pig. MAP or MAF, plus a real tune that incorporates those gains is ideal.