Different Genuine GM MAF's

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VX L67 Getrag
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Re: Different Genuine GM MAF's

Post by VX L67 Getrag »

Sorry REMOVED didn't want to confuse anyone not knowledgeable!
Last edited by VX L67 Getrag on Mon Apr 22, 2013 8:27 pm, edited 1 time in total.
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antus
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Re: Different Genuine GM MAF's

Post by antus »

yeah, or just set the MAF scalers and you don't have to retune everything for the same result.
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VX L67 Getrag
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Re: Different Genuine GM MAF's

Post by VX L67 Getrag »

Sorry REMOVED didn't want to confuse anyone not knowledgeable!
Last edited by VX L67 Getrag on Mon Apr 22, 2013 8:27 pm, edited 1 time in total.
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Re: Different Genuine GM MAF's

Post by antus »

I don't know what your getting at. the MAF measures air and tells the pcm with a PWM signal. the scalars tell the pcm how many Hz is how much air. when you install a MAF that can measure more air, you update the scalars to suit and everythings fine. bigger MAF let's you meter more air and extended bins increase the code limits if you hit them.
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Jayme
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Re: Different Genuine GM MAF's

Post by Jayme »

im agreeing with antus here... you have a larger maf, great, it reads 900hz less up top. but that has zero to do with the fact that you left the MAF scalers alone and fudged the injector rate, its jsut creating more work in the long run by putting all the other tables that reference airflow out.
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The1
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Re: Different Genuine GM MAF's

Post by The1 »

all fueling should be done in injector multiplier table
MAF is simply just a air metering system for automatic injector pulse scaling, being a hotwire sensor other than basic airflow metering it also takes into account density and humidity.
Doing any mods will put the standard factory multiplier rate out hence why you need to adjust it.
Changing the MAF via increased diameter will obviously also change the airflow.
The Factory MAF tables are scaled well and i have continued even scaling in the above 10k hz in enhanced so fueling scales smoothy.
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Jayme
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Re: Different Genuine GM MAF's

Post by Jayme »

ok, so trying to understand waht you are saying.... when we put larger mafs on an engine, we should just leave the scalers alone, and just adjust fuelling to suit via injector rate?
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Re: Different Genuine GM MAF's

Post by The1 »

yes.

The main issue with playing with MAF tables/scalars is if you interrupt the spacing.

Bit like changing a MAP sensors reference, you tune via VE
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Jayme
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Re: Different Genuine GM MAF's

Post by Jayme »

ok, while I understand that idea, it still means that all your airflow variables are now lying and hold no meaning beyond lining up with table axes.... it does sound like an easy way to get the delco pcms fuel tables to work well with a new maf, but this also puts out the spark table too, as you have moved the table axis.

in an ls1 pcm, that will become a problem quick, as it uses MAP and MAF together to do fuelling, youd have to adjust injector rate, and move your whole spark table, AND redo the VE table to suit your new injector rate.

alternative is to simply adjust the MAF tables and drive away without touching any fuel or spark tables....

as for the MAP example... you put a 2 bar map sensor on which has more range, what do you do ? rescale the map sensor to 2 bar and leave the VE tables alone....
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The1
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Re: Different Genuine GM MAF's

Post by The1 »

yes moving all the tables i can understand, sorry was pointing out moving one part of the whole MAF tables/scalars, though just adjusting the base injector rate would be far simpler than doing all the tables and scalars? Any which way MAF tables are just reference hz to airflow to scale injector pulse.

Also changing MAF's will not just change the whole airflow/fueling by the same percentage, ive seen airflow increase in midrange but not top end, so moving all the maf tables in this account will not be a one fix all.

Have to look at it per application lol

Sorry EDITS :)
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