View Full Version : 3" VR6 (Big MAF) mod ** workable?

10-01-2010, 06:56 AM
For those of you B5 guys running without a MAP sensor in your cars (AEB/AJL engine codes), has anyone successfully tried a "Big MAF mod"? The idea goes like this: place your OEM sensor in a large, 3" MAF housing. The car will now be ingesting a quantity of un-metered air, which requires compensation in the fueling. The solution to that is a size increase directly in proportion to the airflow increase. In the case of an AEB with 210cc injectors (with a 4bar FPR) would be 317cc injectors (still at 4bar).

I know this mod (okay, it's really more of a hack) has gotten done. In fact here is a forum thread which more or less covers it (http://www.audi-sport.net/vb/a4-s4-forum-b5-chassis/82912-scroll-outlaw-hybrid-turbo-build-thread-quattro-3.html#post910254). But does anyone else have experience with it?

10-01-2010, 07:59 AM
When I first went BT I experimented with 630's and a 4" maf on a UNI 440 file. It ran OK I was going to fine tune it with a split second psc-1. I ended up switch back to the recommended injectors and maf housing for the file. I wasn't planning on building the internals so I didn't need all the fueling.

10-01-2010, 11:43 AM
I have a custom aluminum "vr6" maf housing for sale if you interested. PM me