toddk911

I just came across this doing a search on our AFM and/or Bosch AFM as a guy that did some recent work for me has an 1987 Jetta that he has added a turbo to and noticed the stock AFM in my car is the same as his, jsut bigger. The cable connector was even the same so he is going to get one from a 951 and trade his smaller one out. He had mentioned that BMW 5 or 7 series also use the same unit but he thought might be bigger than ours. Anyone know if that is true??? Thought it might be a partial step up before a MAF/MAP.

So this is just some more info and pics on the varying adaptablity of these Bosch afm's:

http://www.gtv6.org/afm_mods.htm

Danno

I did this on my Supra which had the same AFM. Not much difference because the spring-tension on the flapper door was about the same. Well the net effect of restriction was about the same because the spring-tension was stronger, but there was a larger flapper-door with larger surface area. The restriction of the AFM is from the spring & flapper door, not the cross-sectional area when fully open. When I tried re-installing the AFM after I upgraded the car to MAP as a test of before & after upgrades, I removed the flapper door on a later run with only the AFM body in place. Same power as with no AFM in place.

In fact, we've got one guy with a super steathy MAP upgrade with all stock components in place including the AFM on this non-S turbo. Only difference was he removed the flapper door and used the MAP computer to send the correct air-flow signal to the stock DME. He got about the same power as us with no AFM in place, 266rwhp @ 16psi.

toddk911

Very cool!!

Is it possible to adjust the spring load of the flapper door??

Is it the opening and closing of the door that is read to control a/f ??i.e. can you run the AFM with out the door?? since that is the restriction

Also, doing more research I see that the later model BMW have the MAF now instead of flapper AFM. Would these be Bosch and/or a plug and play switch from our AFM?

eclou

BMW MAF's all use a circular plug with 4 leads. I doubt it could ever be plug 'n play. That would be just too easy to be true.

pete95zhn

I installed My Guru Map Kit just that way.I bought a malfunctioning -burned,actually- 951 AFM,gutted and glass-bean blowed it,put a used cover and electrical connection from an old BMW AFM and even used the original temp sensor.
It's a complete stealth installation with all original wiring and it is very pleasing to hear that stock inlet piping doesn't reduce power....! I'll do some dyno runs after I get my car back from complete re-spray.

kasturbo

Good thread guys. Keep the info comming. Danno, how much would the map kit be then if we used our stock afm?

Also what would be the affects if we removed the flapper door from the stock setup and using the stock dme?

toddk911

"Also what would be the affects if we removed the flapper door from the stock setup and using the stock dme?"

Yes, I am dying to know this also

westcoastprshe

"Also what would be the affects if we removed the flapper door from the stock setup and using the stock dme?"

That doesn't make any sense. You can't gut the AFM and still use it to regular the air. The point Danno made in his post was that you can keep the AFM in place to make it LOOK like its being used, so your car looks stock, even though it's not sending a signal at all.

If you remove the flapper door from a stock set up... the car won't run!

pete95zhn

Yes,this is completely true!

The reason why I used "destroyed" AFM is that I didn't want to hassle with my original,working AFM. Now I can return back to factory setup from MAP,if necessary,just switching AFMs and disconnecting AFMLink computer.

Also I can now say "Officer,of course it is completely stock..."