Red Dawg

iTrader: (1)

Has anyone besides Harlan used a twin maf setup, or is Harlan the only one that has used one? I would like to use a twin maf setup instead of HP Tuners 3 bar setup.... seems like it would be better for a daily driver. So if Harlan or anyone else who has used such a setup could post some info on it that would be awsome. Thanks

Oh... thought I would post in here since most of the people that would use such a setup are FI, and this forum get more action than the PCM forum anyways.

69firebird

iTrader: (14)

Harlan is the nly person that I know of that has ever run a dual maf setup; he mad his, and said he isnt making it for anyone else.

alot of people wanted to run it, im not sure if he is still running it. Harlan used it but had to runa different year ECU and alot of changing he said.

red90cobra

iTrader: (36)

he used it with the gm pcm too. he know his stuff up and down. he's the only one using it that I know of too.

Srun

John_D.

iTrader: (2)

I'm planning to use a mini-afc that I got from zzperformance back when I had the v6 in the car to scale down the frequencies 10%. It intercepts the maf signal, much like a maft, but with finer levels of adjustment.

At first I thought that would give me only 10% more airflow, but after analyzing it further, it's from 27% on the low end to 38% on the high end. 38% more airflow within the stock maf frequency range should be enough coverage for a little while (5-7 psi). Since I haven't maxed it out yet with the head/cam setup. If I need more, I can always bump the percentage on the mini-afc a few points (and rebuild the maf table).

I remapped a screened z06 maf table (that I'm already running with my z06 screened maf...). First I ran a 10% reduction in frequencies reported for each of the cells in the maf table, just to see what the new frequency would be for each of those points in the air flow range. Then I interpolated those new frequencies back to the 125 hz
increments used in the table. This will be the new table I'll load up to correspond to the mini-afc output.

Next I compared the new airflow to the old airflow at the same hz ratings, and found the percentage differences, cell by cell.

Here is an example you can directly lookup without having to do the interpolation:
The flow in the stock table for 3750 hz is 13.60
3750 minus 10% is 3375
So now the pcm will see 3375 hz when the flow is 13.60
The old value in the stock table for 3375 is 10.38
10.38 * 1.3102 = 13.60
Old airflow times some percent = new airflow

I just got a little better than a 31% increase in airflow that I can map in that same frequency range, for a 10% bump down in the frequency being reported.

Once you get up to 5500hz, it holds at 37% and 38% all the rest of the way up.

I think this will be a lot easier than twin maf plumbing.

I had a hunch the airflow change % would be different than the frequency shift %, but I didn't realize how much, until I ran the numbers.

2FAST4U

Harlan had it on a CUSTOM one of protype PCM that read two mafs. As I heard it? not someing worth doing or researching IMO.

sb427f-car

Just curious, why not run the 3 Bar MAP? I seriously doubt you'll have any tuning or driveability issues on that set up. Same basic way of controlling the engine, just two different ways of getting there.

2FAST4U

this is what DFI,FAST,ect... all do it works but those are full computer replacements or piggyback systems.