will i benefit from a 90mm LMAF?

Discussion in '1994 - 1995 Specific Tech' started by Blackened302, Sep 5, 2007.

  1. i have a 90mm LMAF i scored from a friend and i'm wondering if using it will benefit me.

    i have the curve for it and know i can just try it, but will i really benefit from using it?
  2. What do you have now? The Ford Mass Air meters are very nice and very accurate.
  3. If you're not pegging your current meter and your AFR is where it should be, I'd leave well enough alone. :)

    What does your transfer look like for it? I used the 03 Cobra RYAK curve from EECAnalyzer and that one was the closest for me. Clint sent me the one he uses on his meter but it was two full points rich up top and the idle was not close. The RYAK is about half a point rich stock and idle was much better.

  4. i'm running the stock GT/Cobra maf right now, and also running the j4j1 maf transfer.

    heh, how would i know if i'm pegging my current maf? unfortunately, i won't be able to find out if my AFR is where it should be anytime soon.
  5. Check those datalogs to see if you are close to 5 volts at WOT.

  6. Looking at your combo, I would say you are not pegging. The datalogs will know for sure.
  7. i haven't gotten a chance to look at all 5 datalogs completely, but so far i see where i'm getting to 3.5volts, and that wasn't on the WOT run. gonna look at that one when i get home today.

    i did notice that sometimes the voltage would read at crazy #'s like 279.xx volts--that's gotta be wrong.
  8. You must be datalogging with CalCon to get crazy numbers like that. :)

    Did you have your logs posted somewhere with a WOT run? I'll take a look at them if you do.

    If you haven't already, get a WOT run in and see where you stand. In my experience, it takes a full trickflow kit with exhaust to peg a stock MAF.

  9. Found your logs - the highest I see is at 4.8v around 5900rpm. Looks like you're ok to me.

    Be sure to put the max voltage on the MAF up as far as it will go (4.99).

  10. thanks Wes, i appreciate you taking a look at them.

    do you think 4.8v is cutting a little too close, especially if the max is 4.99v? i usually shift around 6200, so i'm wondering if the extra rpm's will be enough to peg.

    is there a scalar to set the max voltage of the MAF?

    thanks for the help, man!
  11. I think you are fine at 4.8-4.9v, man.

    You are getting the full potential of your meter. If you step up to a different meter, you are going to be vastly under-utilizing the new one and may also be giving up some accuracy/resolution as well. Even if it does just BARELY peg (like by .05v or so, I don't see it being a problem at all -- running the stock tune, you are already probably rich up top - a wideband would let you know this for sure.

    The real problems with pegging the meter show up when you've still got a lot of RPMs left to go - then as you get further and further away from the point at which you pegged, you will start to run lean. Big problem with a blower as you can imagine... the EEC only puts in enough fuel for the maximum the meter can read - even if more air is flowing through it.

    If, down the road, you are encountering a problem there is a way to increase the fuel up top based on RPM that can be used to deal with a slightly pegged meter or you can choose then to upgrade to a new meter and piping to match it all up. Again, this would be where a wideband shines so you can see exactly what is going on. I'd check the voltage again once the weather gets cooler to see if you are any closer to pegging than you are now.

    Continue to figure out the tuning stuff and run it as-is. What you learn by working with a GOOD MAF curve and values will help you tune in the new MAF if/when you do upgrade.

    "MAF Voltage Maximum" is the scalar you want to edit. I set it to 4.999.

  12. Hey ... About getting close to pegging that meter :)

    Allow me to put out this thought to everybody here :D

    Suppose Paul gets a WB and finds he is fat :eek:
    through the upper range of the t curve

    Does anybody think that would make a difference :scratch:
    after the t curve has been made optimum

    If so :shrug:

    How ;)

  13. thanks, Wes--great response! i appreciate you taking the time to explain--it's a lot clearer to me now.

    Grady--good question. from what i know so far, i wouldn't think it would really make a difference, except for maybe a little less mpg... that's as far as my brain goes for coming up w/ an answer, hehe.

    thanks, gents!
  14. What about this :shrug:

    If you were too fat for the upper end of the t curve ...

    You'd be reporting air flow values that were inflated ... Correct

    How would it change things when you leaned the curve

    Is it possible ... after the optimization ...........
    you might report air flow values that only represents 4.8 volts :shrug:

  15. No matter if he leaned or richened the MAF transfer, he's gonna be at 4.8v. The voltage that is being output from the sensor is not affected by what numbers are put into the computer.

    Colder air, on the other hand will be denser than this summer air and might put him a bit higher.

    The way the MAF's are curved, the higher up in flow you go, the more airflow is crammed per volt. So 0.2v up high in the curve represents a lot more air than 0.2v at idle in the curve.

    Check out the (simplified) transfer of my Lightning meter to see how this plays out...

    0-1v: 0 to 30kg/hr (difference of 30)
    1-2v: 30 to 150kg/hr (difference of 120)
    2-3v: 150 to 430kg/hr (difference of 280)
    3-4v: 430 to 912kg/hr (difference of 482)
    4-5v: 912 to 1675kg/hr (difference of 763)

  16. There you have it :D

  17. so we ruled out the 90mm MAF, but what about a 75mm? Pro-M's "bullet" style 75mm?

    even though it's calibrated for 30's, i can still load the curve in my tune and it should work, correct?

    thanks, guys.
  18. Paul :D

    I know you get tired of hearing this
    Without datalogging

    You just don't have any way to verify the things you are trying to do :(

    You could go to a different meter and inj's
    After you load in the t curve and inj's size

    How ever it runs ... is ... how ever it runs :shrug:

    If it needs a bit of tweecing with inj values or t curve ....

    You can only guess which way to go with fine tuning :scratch:
    I'd have to say ... it would quickly get very :bang:

    I skimmed over this thread again and I gotta agree with Wes :nice:

    I'd say you you'll be fine with that OEM meter

    I'd go with that known over an unknown with other meters :Word:
    You have the ability to see the big pic ;)

    Well my friend :D

    Did I answer your Q :)
    Just tell you what you did not wanna hear :)

  19. hehe, thanks Grady--that about still answers the question. i was hoping that since it wasn't as big as the 90mm it would yield good results--again, not being able to datalog is biting me in the #$!.

    reading over Wes' response again puts things into perspective. i forgot about what he said, which makes perfect sense.

    one of the pluses for being able to run this 75mm bullet meter would be that i could attach the air filter to it directly (as opposed to using my home-brew adapter for the stock unit w/ the squared end--falls off once in a while... guess i should be looking for a solution to that instead, huh..).

    thanks, though. my buddy'll let me have it at a good price, so i may get it now while i can and hope to use it later on, at least.
  20. You certainly could :nice:
    load up that bullet meter curve and see what happens :shrug:

    I would like to point out .........

    Since you are pushing 4.8 volts on the OEM meter ...

    I would get around to a meter with a bit more room :)
    After you can make things ... just like your combo needs :D

    IMHO Paul ... You've come a long way in a short amount of time
    with your basic understanding of how things work in the pcm ;)
    by the things you've posted here and other sites

    Hope you don't mind me offering you a word of encouragement :)
    I really do like to see the light turn on for other folk :banana: