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Old 07-11-2008, 09:03 AM
ichbinsobose ichbinsobose is offline
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Exclamation Overblowing stock MAF, how to tune it out.

I am running 23psi from my holset on a 100% stock M50tu and I am obviously maxing out the stock MAF. I have a dyno session tomorrow morning and I am trying to get everything nailed down and a good power tune ready for then. My current tune is great for the street, but I am thinking that when my MAF maxes out at 4.9v probably at ~4k or so, I have 3k of RPMS where it is only reading the last column of timing/fueling figures... or does it ignore the MAF at WOT and read off those numbers VS the RPM's only? I am extremely rich in boost, about 11 AFR to 10psi, then it rockets off to 23psi and ~9.5 - 10 AFR for safety. If the MAF pulls 6*-10* of timing (anyone have an actual figure) when it is maxed out, I should be able to add that back to my last row relatively safely. I am sure I have another 50whp on the table here if I can figure this last issue out.

Stock m50tu, stock 3" MAF
95 525i, tuned by me on the 413 dme
Anyone have suggestions? I was going to run two wires from the ground and 5v wire on the MAF to the cabin for today, hook them to my voltmeter and watch at what load/rpm the MAF hits its max of 4.7 or 5.0 whatever, and after that add the timing and trim the fuel to the correct AFR for the rest of the rpm range.

Sorry, I usually post on bf.c but there has been a few misunderstandings and unpleasantness there recently.
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  #2  
Old 07-11-2008, 12:03 PM
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BeRzErKaS BeRzErKaS is offline
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Why not upgrade to a bigger MAF? Like the 3.5" from the 540i or a Porsche? It should give you all the headroom you need.

I run an Apexi SAFCII which displays MAF load (%), RPM, and a couple other things. It also allows you to apply a correction factor of up to +/- 50% to the MAF signal.

If you are doing your own tuning, and have independent control over timing, then something like this might work for your application.
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  #3  
Old 04-15-2014, 07:55 PM
Oxide_325i Oxide_325i is offline
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I've heard alot of good things about the 540i maf, is it a recommended maf for f/i?
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Old 04-27-2014, 08:36 AM
milKt milKt is offline
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Quote:
Originally Posted by Oxide_325i View Post
I've heard alot of good things about the 540i maf, is it a recommended maf for f/i?
Not really.

It's an optional MAF for a camshaft upgrade on some M5x/S5x based engines though.
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Old 05-08-2014, 10:07 AM
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MWatty550 MWatty550 is offline
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Quote:
Originally Posted by ichbinsobose View Post
I am running 23psi from my holset on a 100% stock M50tu and I am obviously maxing out the stock MAF. I have a dyno session tomorrow morning and I am trying to get everything nailed down and a good power tune ready for then. My current tune is great for the street, but I am thinking that when my MAF maxes out at 4.9v probably at ~4k or so, I have 3k of RPMS where it is only reading the last column of timing/fueling figures... or does it ignore the MAF at WOT and read off those numbers VS the RPM's only? I am extremely rich in boost, about 11 AFR to 10psi, then it rockets off to 23psi and ~9.5 - 10 AFR for safety. If the MAF pulls 6*-10* of timing (anyone have an actual figure) when it is maxed out, I should be able to add that back to my last row relatively safely. I am sure I have another 50whp on the table here if I can figure this last issue out.

Stock m50tu, stock 3" MAF
95 525i, tuned by me on the 413 dme
Anyone have suggestions? I was going to run two wires from the ground and 5v wire on the MAF to the cabin for today, hook them to my voltmeter and watch at what load/rpm the MAF hits its max of 4.7 or 5.0 whatever, and after that add the timing and trim the fuel to the correct AFR for the rest of the rpm range.

Sorry, I usually post on bf.c but there has been a few misunderstandings and unpleasantness there recently.
Send an email to Terry at Burger Tuning. He or one of his guys would. Also go to N54Tech.com and ask. You will get some good feedback for sure.
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  #6  
Old 12-01-2017, 06:21 PM
monkey-leader monkey-leader is offline
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I dont know about BMW but usdm cars ive tuned didnt use the MAF at WOT. So it probably will go off your tables.
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