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can i scale the MAF tables?

Bio248

Bio248

DUI BABY
basic background: locals on facebook are having the typical timing vs. boost debate, it turns into running out of MAF headroom and they all jump in and say that you need an AFC to scale back the MAF tables so you can get your head room back.

now, knowing what an AFC does, and why it should and should not be used, can you use tuning software (HPT, DHP, TT) to scale the MAF tables themselves, essentially making the AFC a useless object unless you are old school and want to keep it simple? i only assumed this was possible because it only makes sense to be able to do it.

nitty gritty details on how you'd accomplish this to help refute or deny my case would be preferred.
 


You can use a tuner to change the maf table to add or subtract fuel from the frequency range, but that doesn't change that the maf will run out of frequency range based on airflow ceiling. The AFC makes the PCM think that the maf isn't getting as much air through it by scaling it back so you can run more air with a higher ceiling or more flow. If that makes sense.
 
Does the AFC affect the entire frequency range of the MAF or designed to affect a certain upper frequency range?
 
Entire range. So say you have the AFC set for -12%, just take your maf table and subtract 12% from it and upload the tune.
 
that's the cheap AFC 1.0, OH4. the 2.2 does it by 1000 hz increments, i had one. i tuned old school style with it to keep my fueling in check in my 3.2 meth setup.

so you're saying you physically can't scale the MAF tables themselves so that the PCM reads a scaled back value?
 
Correct Bio, and yea I should have clarified that I was talking about the fixed AFC. Even with tuning you're gonna have a flow ceiling that the maf can only read so much.
 


That's correct Rico, but for some reason I thought that the tuning softwares out there would allow something as useful as this.
 
To properly scale the maf you need to be able to adjust what the pcm sees as cylinder displacement.

otherwise you have to use an afc.

It might just be a limitation of our pcms since they used it for only one size engine unlike the gm v8 pcms.

This only applies when you reach the max value the pcm can interpret from the maf frequency.

seems a gm maf can read up to 15 khz but the pcms dont have values past 11-12 khz.

In other platforms they typically go sd, its just as accurate in terms of air modelling without a restrictive maf in the system.
 
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There are other ways around this without an AFC.... lol.... It does involve JB weld, some balls, and some knowledge of how to setup custom maf sensors.
 


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