Author Topic: Mass Flow Meter Change (Read 3092 times)

quinn11m20 · « **on:** August 23, 2009, 02:46:12 PM »

Hey Guys and Girls,
Just yesterday I wired in the ARM 1 and ARC 2 system from Split Second. It replaces the AFM that is highly restrictive. Did some fine tuning and noticed a little peppier engine. Before I started, I swapped out my chip's. I went back to the stock chip and hopefully this week I will have time to swap back to my performance one. All in all it took me about 2 1/2 hrs. Now, I have had the parts for about three weeks. I did a test fit of the sensor and filter, and I had to buy another set from the local GM performance shop. I will take some pics of what I have done and try to post them with your help. I have always had an issue posting pics on this website. I will also let you know of the performance gains that I get when I swap to my performance chip. Quinn Out!:rolleyes:

bmwman91 · « **Reply #1 on:** August 24, 2009, 04:40:20 PM »

Are you going to be dynoing it for before/after comparisons? I did a custom MAF conversion & dyno'ed it and got 0 gain in power. Throttle response improved, as did idle stability, but power was not gained.

The M42's AFM is actually not restrictive at all. I know that having a flapper door in there intuitively seems like a choke, but it actually does almost nothing to create backpressure (it takes about 0.25lbs to push it fully open / 2.5in^2 = 0.1psi drop across the flap). The M20 suffers from restriction with its AFM, but only because the flow area is too small, not so much the flapper door. In the M42's case, the flow area is perfectly sufficient for an internally stock motor. If anything, MAF's have trouble with the M42 since it has no overlap in its intake strokes & unless proper signal filtering is applied, the ECU will have serious aliasing issues since its sampling rate is somewhat low.

See here for details on my project.
http://bmw.e30tuner.com/articles_mafcon.php

(BTW I am in no trying to discourage you or anyone else, I am just sharing my experience)

quinn11m20 · « **Reply #2 on:** August 24, 2009, 06:28:36 PM »

I have not dyno the car yet. I just put back the performance chip. I have not noticed much of a difference either. Sounds different though. I plan to do a complete engine rebuild when I get back from Fort Drum in November. I have over 260k and whe needs a serious rebuild. I did the MAF change not looking for serious power but some extra tuning advantages. For example, If I install a turbo or when I put on my 10 lbs fly. Overall just a more responsive engine. It can be done. Thanks for the info, by the way. I will try to post some pics of the swap and get some dyno results. OUT.

bmwman91 · « **Reply #3 on:** August 25, 2009, 11:30:33 AM »

Cool, thanks. I have never seen the SS kit up close. The improved throttle response was worth it to me, and if you plan to do some heavy mods to the motor then a MAF is a good route to go.