3.2 Air Flow Meter Port, Polish, Barn door adjust

[Fixer]

I adjusted the barn door tension then ported and smoothed out my '86 Carrera's AFM for a very noticeable power gain.

I couldn't document my 3.2 Carrera AFM port-polish / adjustment (no digitals then) but did the same P&P for my 928 "RS" project with very nice gains as well. The 1983 928S has the same AFM as a 3.2 Carrera (with same part number)

This AFM was also used on E30 BMWs (among other cars), it's an "off the shelf" part to say the least. It seems they are set for fuel economy from the factory.

I searched to see if you guys are doing this to your 3.2's AFMs (I'm sure some have) but wanted to share this anyway. There are very noticeable gains and no drive-ability
issues Thread is at bottom:
http://forums.pelicanparts.com/porsche-928-technical-forum/750209-us-4-7l-air-flow-not.html?highlight=AFM

[sugarwood]

I can imagine adjusting the flap tension having an effect on responsiveness,
but how can smoothing out the sides increase performance or air flow?
Does it create THAT much air resistance? Are you sure there is no placebo effect?

[sugarwood]

In many other models of care, the MAF/AFM is often replaced as a wear item at 100k miles or whatever.
How come I never hear barely a mention of ever replacing the 3.2 AFM ?

[DaveMcKenz]

I think most of the wear is on the sliding contact from the moving barn door. Many people do indeed rebuild or tune up their AFM's because of this wear. I am not sure if new AFM's are available, but I bet they would be over $600.
I had mine rebuilt by Bavarian Restoration and it smoothed out the low RPM bucking I was noticing.
Dave

[Fixer]

Originally Posted by sugarwood

I can imagine adjusting the flap tension having an effect on responsiveness,
but how can smoothing out the sides increase performance or air flow?
Does it create THAT much air resistance? Are you sure there is no placebo effect?

No placebo effect. Definitely a noticeable gain and more than my chip gave imo.

Adjustment alone of the spring tension allows more air and fuel to be delivered throughout the rpm range. The porting and polishing/smoothing was a WIT thing to max gains..

Read the entire thread, this AFM is such a crude item inside.

It took me about 3-4 hours milling and smoothing carefully iirc, For example, even the barn door stop's size can be reduced to a 1/3 of it's original size.. This is directly in the air flow.

Clean the contacts WIT also, I used a light coating of dielectric grease when done cleaning iirc.

Hi Dave McKenzie ! (Great Guy)

[DaveMcKenz]

Hey, Matt.