996 MAF Housing Diameter - 986 Forum - The Community for Porsche Boxster & Cayman Owners

insite · 09-08-2010, 05:22 AM

i am looking to verify the INNER diameter of the stock 996 MAF housing (1999). The number I have is 84mm. Can anyone verify this is correct? Thanks.

JAAY · 09-08-2010, 07:16 AM

I don't remember the exacts, but if you are looking to get one. You can buy a cayman S houseing. The only pain about that is that it comes with the sensor so there damn expensive, The alternative is to get a BMW mass air houseing, same part. I don't remember what model or years but they come with out the sensor and are cheap and correct. I believe that a 2000 540i is one of the models that the housing is a direct fit for us. Just some stuff to think about.

J

Cloudsurfer · 09-08-2010, 09:02 AM

Quote:

Originally Posted by JAAY

I don't remember the exacts, but if you are looking to get one. You can buy a cayman S houseing. The only pain about that is that it comes with the sensor so there damn expensive, The alternative is to get a BMW mass air houseing, same part. I don't remember what model or years but they come with out the sensor and are cheap and correct. I believe that a 2000 540i is one of the models that the housing is a direct fit for us. Just some stuff to think about.

J

Spell check not working so well?

insite · 09-10-2010, 01:56 AM

JAAY -

good call; the E39 540i housing is a match. i picked one up from a guy on bimmerforums.com for $40. thanks for the advice!

Quote:

Originally Posted by JAAY

I don't remember the exacts, but if you are looking to get one. You can buy a cayman S houseing. The only pain about that is that it comes with the sensor so there damn expensive, The alternative is to get a BMW mass air houseing, same part. I don't remember what model or years but they come with out the sensor and are cheap and correct. I believe that a 2000 540i is one of the models that the housing is a direct fit for us. Just some stuff to think about.

chaudanova · 09-10-2010, 09:49 PM

what was the inner diameter of the 996 and 540i Maf housing? Can you tell me the OD also?

Would there be any advantage to using a 996/540i larger housing with the regular 986 maf sensor if connected to a cone filter on one end, and, for my current setup to a larger 3" through hose/pipe with 75mm TB and IPD plenum?

Cloudsurfer · 09-10-2010, 11:04 PM

Quote:

Originally Posted by chaudanova

what was the inner diameter of the 996 and 540i Maf housing? Can you tell me the OD also?

Would there be any advantage to using a 996/540i larger housing with the regular 986 maf sensor if connected to a cone filter on one end, and, for my current setup to a larger 3" through hose/pipe with 75mm TB and IPD plenum?

Absolutely not. The OP needs a 996 sized MAF because he will be running a 996 map on his 3.4. A 996 sized MAF on a 986 map would give horribly inaccurate air mass readings, and the car would run poorly.

If you didn't know, the actual MAF sensor is the same, it's only the housing that is a different diameter.

While I realize you may have a larger TB and aftermarket plenum, the DME still needs accurate measurements of air mass, and that depends largely on the size of the MAF housing matching what the DME was calibrated to expect. The DME's used in the cars are very good at adaptive learning, so if there were to be any gains to be had from your setup, after a few miles your car will have learned to compensate for the added flow (if any).

insite · 09-11-2010, 02:46 AM

Quote:

Originally Posted by chaudanova

what was the inner diameter of the 996 and 540i Maf housing? Can you tell me the OD also?

Would there be any advantage to using a 996/540i larger housing with the regular 986 maf sensor if connected to a cone filter on one end, and, for my current setup to a larger 3" through hose/pipe with 75mm TB and IPD plenum?

cloudsurfer is right; your air fuel ratio will be miscalculated if you run the incorrect MAF housing diameter.

if you are just looking for a flanged MAF housing with which to make a cold air setup, the MAF from the E39 BMW 535i (the V6) has the same inner diameter as the boxsters.

JAAY · 09-11-2010, 07:49 AM

One piece of advice you should take. Get a wide band O2 put in when you are done. I thought my car was running great. Turns out I was running a bit rich. I have since dialed it in and the car gets great mpg and makes a ton of power.

jaykay · 06-21-2012, 11:48 AM

Quote:

Originally Posted by insite

cloudsurfer is right; your air fuel ratio will be miscalculated if you run the incorrect MAF housing diameter.

if you are just looking for a flanged MAF housing with which to make a cold air setup, the MAF from the E39 BMW 535i (the V6) has the same inner diameter as the boxsters.

Is this still valid information for a 3.2L 2000 S? What is the exact id of the stock MAF housing?