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Discussion Starter · #1 ·
Heard a couple people talking about maxing out their MAF at 11.5k or so running high end seteups, w/ rpms still to go, so my question is, what exactly does the computer do w/ fueling once the MAF # stops increasing, does it just continue delivering fuel like its constantly flowing @ 11.5k, or does it try to increase fuel delivery somehow?
 

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Discussion Starter · #2 ·
Maybe I put this in the wrong forum, wasn't sure if it should've gone under the electronics b/c the MAF or fuel b/c of the resulant fuel changes?
 

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Discussion Starter · #4 ·
So you have to run extra rich in the top end so it doesn't lean out as RPMs increase then?
 

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The solution is to get a replacement MAF that you won't outflow, the correct tables in the PCM and a fuel pump and injectors that can keep up.

You can try to richen up the top end enough to compensate, but that isn't a real solution and it's not accurate at all.
 

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I agree with the Pope 100%. Try very hard not to overrun your table, and get a bigger MAF if you think you might. It would be bad enough if the relationship between measured airflow airflow and MAF frequency output were linear but it's much worse than that. The relationship between the two is actually exponential. Where a change of 125 Hz may correspond to a change of .05 - .06 g/sec of air down low in the MAF table, a 125 Hz change will also correspond to a change of 1.4 g/sec of air up near the high end of the MAF table. In other words, runing out of even a small amount of frequency can translate to a large shortage of fuel. I hope that makes sense without charts, lines, arrows and circles. :)

John
 

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johnt said:
I agree with the Pope 100%. Try very hard not to overrun your table, and get a bigger MAF if you think you might. It would be bad enough if the relationship between measured airflow airflow and MAF frequency output were linear but it's much worse than that. The relationship between the two is actually exponential. Where a change of 125 Hz may correspond to a change of .05 - .06 g/sec of air down low in the MAF table, a 125 Hz change will also correspond to a change of 1.4 g/sec of air up near the high end of the MAF table. In other words, runing out of even a small amount of frequency can translate to a large shortage of fuel. I hope that makes sense without charts, lines, arrows and circles. :)
I think 3800s will need to start to go MAFless...too much ppl are dependent on MAF table which is already starting to work outside its inherent design...
 

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After the 11500Khz, the PCm goes to Speed Density mode and looks at the VE tables. If you tune your car to run on the VE table alone, if and when you happen to overrun the MAFF table do to weather or whatever, the engine will still run pretty good an safe to boot. It helped mine during the colder high barometer nights here in the midwest. The best way is add the LS6 maff or go to the new HPTuners 2bar or 3bar speed density set-up ;)
 

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Discussion Starter · #9 ·
If our cars can run on speed-density stock, then why do we have a MAF sensor at all? I honestly never knew it switched to speed-density mode.
 
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