I currently have the `purple' MAF fitted to my 1997 Turbo 2000 but have just fitted an STI RA engine with VF22 turbo and also have a newage TMIC to fit over the easter break. Car will be mapped soon using an Apexi PFC.

Is it worth changing the MAF before the mapping? If so, which one should I go for?

Any help would be much appreciated.

 

Do you already have the PFC? Do you have its Commnder too? If so, then does the PFC have its base map still on it (or another map by a previous owner, etc.).

If so, then you could temp hook it up, and on the Commander you can see if the MAF is outputting the correct voltages under 'Monitor' > 'Air-F' (to be monitored under any of the '1-channel'; '2-channel'; '4 channel'; '8-channel' views).

I don't know what the MY97/98 purple MAF's voltage range is though - ask JGM Simon.

(FTR, the MY93-96 green MAF's voltage is 1V at idle... to 5V at WOT/max load - it could be the same(?) )

Alternatively, do the same test - but using your OEM ECU already in there - with a voltmeter across the MAF, and running inside the car, for a passenger to observe whilst you take it for a spin. Actually, this is prob the better option, as you wouldn't know how unsuitable the map on the PFC is fro your car... don't want to be blowing up the motor for the sake of, ironically, checking the MAF.

Also, the pre-99/00 MAFs are generally reliable, anyhow..

 

Thanks for that, and no, I don`t have the power FC yet.

So if the voltages are as they should be, don`t bother changing it ?

 

That's right.

As I say, find out from JGM Simon what the voltage range of the purple MAF is, then you'll know what to look for when testing it. If it rises and falls correctly with the revs/load on the engine (based on that voltage range), then you know it's working okay.