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Thread: MAF or SD Tuning for DD

  1. #1
    Carb and Points!
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    MAF or SD Tuning for DD

    I have been reading a lot on this site. One thing I have noticed is all tuning is for speed density or tuning the VE Tables.I have a 97 Camaro LT1 running a 94 PCM with ported heads, larger valves, cam and all supporting hardware. So I have a couple questions on tuning.For a daily driver should I tune for MAF or SD? If I tune for MAF is there a good write up on that like there is for SD?
    Last edited by 7danny; 01-25-2017 at 06:42 AM.

  2. #2
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    I have only seen a write-up for doing OBDII stuff, but it's similar to the way you do VE tuning except you just create a 2D correction table - airflow vs correction. Then, you manually go through the MAF table and find each airflow value you came up with a correction for and modify it. Then, zoom in and do a little hand smoothing on the curve so it looks nice. Ideally, you would use Hz vs BLM to get the corrections but $EE by default doesn't give a Hz value that is easy to log so you are stuck with using the airflow and BLM to determine how much the airflow number is out.

    For a simpler solution, I would try using Steve's excellent EEhack program for programming and logging. It will give you the correction table.

    http://fbodytech.com/eehack-2/

    I created a XL spreadsheet to give the correction factors but with a log file it was too big to attach.

  3. #3
    Carb and Points!
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    Thanks for that link. Going to take me some time to soak up all that. Just the xdf file adds so much.

  4. #4
    Fuel Injected! steveo's Avatar
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    i'd tune both speed density and MAF just for the hell of it. i usually run speed density myself.

    just log a lot of normal driving in varying conditions with eehack, then load all the logs at once and run the analyzer

    with default settings it'll filter most of the bad data out and use a gigantic average to try and get it 'close enough' on the first shot

    subsequent logs you analyze will fine tune it.

    eehack gives you a percentage corrections to make to your maf table, you have to input them yourself.

    then disable the maf and do some more logs, run the analyzer again, it'll give you ve table corrections

    that way if your MAF ever pukes your car will still run good

    you might find it runs better in speed density depending on what cam you run, in which case just leave the damn maf unplugged and keep tuning speed density....

  5. #5
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    Quote Originally Posted by steveo View Post
    i'd tune both speed density and MAF just for the hell of it. i usually run speed density myself.just log a lot of normal driving in varying conditions with eehack, then load all the logs at once and run the analyzerwith default settings it'll filter most of the bad data out and use a gigantic average to try and get it 'close enough' on the first shotsubsequent logs you analyze will fine tune it.eehack gives you a percentage corrections to make to your maf table, you have to input them yourself.then disable the maf and do some more logs, run the analyzer again, it'll give you ve table correctionsthat way if your MAF ever pukes your car will still run goodyou might find it runs better in speed density depending on what cam you run, in which case just leave the damn maf unplugged and keep tuning speed density....
    Thanks for the advice Steve, and great work on EEHack. Now if I can just scale it up so I can read it without having to put it into 640 X 480 mode. :)

  6. #6
    Fuel Injected! steveo's Avatar
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    here's some basic stuff on maf tuning too that solomon wrote:

    http://www.lt1pcmtuning.com/tips/

    MAF Sensor Tables

    There are four tables for the MAF, which split up its total frequency->airflow grid.

    First, find the airflow reading for your idle in your logs. Then, find the closest value(s) in the MAF sensor tables; you will sometimes have to alter two cells to affect one airflow range.

    To richen your fuel mixture (BLMs > 128), increase the value(s) you found as mentioned above.

    To lean the fuel mixture (BLMs < 128), simply decrease the appropriate MAF cells as mentioned above.

    These values are also efficiently modified using percentages (%), or multiplying the values (1.xx to richen, 0.xx to lean). Start with 1% (1.01/0.99) changes for every 2 BLMs off; so, a BLM of 118 would require a 5% decrease (128 - 118 = 10 / 2 = 5), or multiplying the MAF airflow value(s) by 0.95. Again, trial and error will be needed to see if you have overshot a BLM of 128 with your changes.

  7. #7
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    Quote Originally Posted by steveo View Post
    here's some basic stuff on maf tuning too that solomon wrote:http://www.lt1pcmtuning.com/tips/
    That seams pretty simple enough. I will tune VE first then MAF

  8. #8
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    In the OBD2 stuff I set the maximum maf frequency for failure to 0 hz then tune with the maf still plugged in. With the OBD2 stuff this puts it on the low octane timing map so it is therefore a copy of the high octane map. I tune the MAP based VE tables to get the engine running well. Then I restore the MAF and tune the MAF tables. Once that is done it is fine tweaks to the timing map. I have not had a single setup that ran better on MAP alone than the MAF/MAP hybrid. I have tuned an 0411 controlling a 383 TPI based build with a 232/240 @ .050 roller cam cut on a 110 LSA. Suprisingly it ran well enough on a stock Express van tune to fire up and drive.

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