PSA : BMW 5/7-series MAF (0 280 217 814 ) is not 88mm
 

I've been meaning to post this since last year, but never got around to it, since I see more people have forked out <A href="https://forums.audiworld.com/s4/msgs/1913587.phtml">$$$</A> (me included :-( ) it's time to set the record straight

Both are ~82+ mm as inner diameter (calipers are showing BMW MAF)

<img src="http://pictureposter.audiworld.com/58573/img_1612.jpg">

Side by side (RS4 = ...067 on left , 5/7-series = ...814 on right)
<img src="http://pictureposter.audiworld.com/58573/img_1614.jpg">


Placed end to end
<img src="http://pictureposter.audiworld.com/58573/img_1616.jpg">

Note that the sensors are not the same (540i on left, RS4 sensor on right)

<img src="http://pictureposter.audiworld.com/58573/img_1618.jpg">

Anyone who still wants to buy either of these parts for their S4 let me know ... I am now experimenting with the 4" (88, 90, 95mm) FORD Mustang MAF's (which uses Hitachi sensor anyway).<ul><li><a href="https://forums.audiworld.com/s4/msgs/1742244.phtml">One of previous posting on the BMW 88mm MAF</a></li></ul>

You are correct! Here is an 88mm MAF (right) next to the RS4 MAF (centre), and S4 MAF (left).
 

<center><img src="http://pictureposter.audiworld.com/40679/july_2004_022.jpg"></center><p>
<img src="http://pictureposter.audiworld.com/40679/july_2004_021.jpg">

Looks custom made, where from ? Here's some Mustang parts
 

C&amp;L 95mm on left, Ford 90mm on right
(Using Hitachi, not Bosch sensor)

<img src="http://pictureposter.audiworld.com/58573/img_1622.jpg">

Yeah this one really is 90mm
<img src="http://pictureposter.audiworld.com/58573/img_1624.jpg">

Good eye... (edited)
 

I was told that it was 88mm by the Bimmer fella I got it from and I cursory check with a tape-measure showed it to be around 3.5". Never felt the need to break out the calipers on it. I thought it'd be more than adequate for my meager setup, and it has been :) It did require a 3 5/8 holesaw to fit in the airbox, make no mistake: This MAF will not fit in a 3.5" hole, because I tried!

Anyhow, main point: It works great, Keeping flow well within operating parameters. It's really not that different from an RS4 housing, which was an expensive rarity, at the time since it could only be purchased brand new. I got this MAF housing for well under 100 bucks.

Also, those who put these type MAF's in the stock airbox NEED to hack it up bigtime to get their flow readings right, see my post on that. If you do not you WILL get abnormally high readings.

Sorry if my post misled anyone, I don't ever recall quoting a precise measurement for that MAF, others seemed to have done that. By quoting my post it seems that I'm considered the principal perpetrator of this 5mm of deceit. For that, you get a 5mm apology: So (Sorry)

Anyhow, the main reason why I went after this MAF is because it fits in the car as perfectly as anything this size could, has the *bosch* sensor bung, and was quite affordable at the time. As I said in the past: If I had a hitachi boxed car, I *definitely* would have tried the Ford MAF route.

I experimented with both of those Maf housings - check my Picture poster and shoot me an email...
 

if you like, I will tell you what I found...