987 Airbox and 74mm TB: MAF and tune issue

[The Radium King]

i have a 2000S with 987 airbox, 997 plenum, and 74 mm throttle body.

originally i ran with the stock tune. i sawed the maf holder off the original airbox and mated it to the new airbox. i used the orginal maf. it worked well.

then, i installed the 987 maf holder. note that in your case the 986 and 987 maf are the same (different part # because the 987 unit comes with the holder and the 986 unit does not; avoid earlier 986 mafs, or 987.2 mafs). the 987 maf holder is a larger diameter and requires an updated tune to work properly. i am using a tune for a 996. this works well - i monitor fuel trims and all is well within spec. it is difficult to get a 996 tune on your car; you require the dme programming code from a dealer (hard to get) as well as a piwis/pst2 diagnostic tool (or a mechanic with one) and the knowhow to use it. you have these pieces and it is a 5 minute job.

[NotthatJake]

Originally Posted by The Radium King

i have a 2000S with 987 airbox, 997 plenum, and 74 mm throttle body.

originally i ran with the stock tune. i sawed the maf holder off the original airbox and mated it to the new airbox. i used the orginal maf. it worked well.

then, i installed the 987 maf holder. note that in your case the 986 and 987 maf are the same (different part # because the 987 unit comes with the holder and the 986 unit does not; avoid earlier 986 mafs, or 987.2 mafs). the 987 maf holder is a larger diameter and requires an updated tune to work properly. i am using a tune for a 996. this works well - i monitor fuel trims and all is well within spec. it is difficult to get a 996 tune on your car; you require the dme programming code from a dealer (hard to get) as well as a piwis/pst2 diagnostic tool (or a mechanic with one) and the knowhow to use it. you have these pieces and it is a 5 minute job.

Do you have the cable 74mm throttle body?