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maf

This is a discussion on maf within the External Engine forums, part of the LSx Technical Help Section category; how can you tell if your maf is bad im getting slight misses seems like around 1800-2300 rpms plugs awires ...

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    Member cobra12345's Avatar
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    maf

    how can you tell if your maf is bad im getting slight misses seems like around 1800-2300 rpms plugs awires all new the screen was removed from maf by the previous owner its clean no oil or anything on it car idles correct

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    Moderator 35th-ANV-SS's Avatar
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    Quick Test # 1 with the engine running, tap on the MAF sensor. If the engine stumbles it is a sign of a bad MAF.

    Quick Test #2 Disconnect the MAF with the engine running. If the engine condition improves, MAF is likely bad.

    Just because it "looks" clean doesn't necessarily mean it is clean. I would get some CRC MAF cleaner and clean it anyways.

    Removing the screen by the previous owner was a bad idea.

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    Member ls1wallen's Avatar
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    When I talked to Frost on the phone. He told me that taking the screen out will not hurt anything if done properly.

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    Moderator 98TransAmWs-6's Avatar
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    Quote Originally Posted by 35th-ANV-SS View Post
    Quick Test # 1 with the engine running, tap on the MAF sensor. If the engine stumbles it is a sign of a bad MAF.

    Quick Test #2 Disconnect the MAF with the engine running. If the engine condition improves, MAF is likely bad.

    Just because it "looks" clean doesn't necessarily mean it is clean. I would get some CRC MAF cleaner and clean it anyways.

    Removing the screen by the previous owner was a bad idea.
    That is actually not true, if done right. Think about it, 02' and up corvettes don't have a MAF screen. The only reason for the screen is to smooth out airflow and is only useful on vehicles that don't have straight intakes.

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    Moderator 35th-ANV-SS's Avatar
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    Why do you think changing "air flow" would not have an effect on how the PCM sees and monitors it?

    Just curious...

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    Moderator 98TransAmWs-6's Avatar
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    You are not exactly changing the airflow more of removing something that would be straigthening the airflow if you didn't have a straight intake but you do so it is not really needed. I am sure it would have an effect on how the PCM sees it but not enough where you have to get a tune to correct it right away or be harmful.

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    Moderator 35th-ANV-SS's Avatar
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    If the screen is not needed, why is it there to begin with? I'm pretty sure, the screen smooths out the air flow, not the other way around like you mention. I could be wrong though.

    Why does everyone on this site 95+% of the people say "Do not touch your MAF"?

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    Moderator 98TransAmWs-6's Avatar
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    Quote Originally Posted by 35th-ANV-SS View Post
    If the screen is not needed, why is it there to begin with? I'm pretty sure, the screen smooths out the air flow, not the other way around like you mention. I could be wrong though.

    Why does everyone on this site 95+% of the people say "Do not touch your MAF"?
    Didn't I say it was intended to smooth out airflow but that it wasn't necessarily needed on straight intake cars because the airflow doesn't need to be straightened out? I don't know what they all say that, but if it was needed why would GM not put it in the 02' and up corvettes? I don't have the screen in my MAF and the car runs absolutely fine. But like with anything if you don't do it correctly it could mess things up.

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    Moderator 35th-ANV-SS's Avatar
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    What gain did you get from removing it?

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    Moderator 98TransAmWs-6's Avatar
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    Quote Originally Posted by 35th-ANV-SS View Post
    What gain did you get from removing it?
    Maybe 5 hp but I didn't do any dynos before an after so I couldn't really say. May be more noticable once you are hitting closer to 500 hp. I am going to get a SD tune anyways and run a 4" tube from my lid to the TB.

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    Moderator Firebirdjones's Avatar
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    Quote Originally Posted by 35th-ANV-SS View Post
    Why does everyone on this site 95+% of the people say "Do not touch your MAF"?
    My feeling is that someone had a bad experience and it's been passed around on the internet as a bad idea, so everyone follows suit.

    The real truth of the matter is that the screen isn't a necessary item. It takes up space in the air track and slows down airflow. Most good tuners will tell you before getting a tune to remove the screen and pick up a few more ponies as a result, including Frost.

    Most High HP applications won't even use an MAF at all and go SD tune. I went SD tune on my wifes car which is actually very mild, but what a difference it made.

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    Moderator 98TransAmWs-6's Avatar
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    Quote Originally Posted by Firebirdjones View Post
    My feeling is that someone had a bad experience and it's been passed around on the internet as a bad idea, so everyone follows suit.

    The real truth of the matter is that the screen isn't a necessary item. It takes up space in the air track and slows down airflow. Most good tuners will tell you before getting a tune to remove the screen and pick up a few more ponies as a result, including Frost.

    Most High HP applications won't even use an MAF at all and go SD tune. I went SD tune on my wifes car which is actually very mild, but what a difference it made.
    Is there any real difference in how the car drives with the SD tune? I am thinking of going down to Frost's shop and getting the tune.

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    Moderator Firebirdjones's Avatar
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    Yes a big difference in how it runs and drives. I have a much more stable idle now that doesn't hunt at all (has small cam). The idle is now rock steady.

    I also have much better throttle response, very snappy. It now mimics a well tuned carburator, like an on/off switch for lack of a better description. Unlike the lazy feeling throttle it once had, even after dialing in the MAF tables.

    In my opinion, it's one of the best things I've done to the car. It's only mildly modded with a small cam and valvetrain, headers, and intake. Not something that even came close to maxing the MAF's capabilities, but the drivability improvement is what sold me on the SD tune.

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    Moderator 98TransAmWs-6's Avatar
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    Quote Originally Posted by Firebirdjones View Post
    Yes a big difference in how it runs and drives. I have a much more stable idle now that doesn't hunt at all (has small cam). The idle is now rock steady.

    I also have much better throttle response, very snappy. It now mimics a well tuned carburator, like an on/off switch for lack of a better description. Unlike the lazy feeling throttle it once had, even after dialing in the MAF tables.

    In my opinion, it's one of the best things I've done to the car. It's only mildly modded with a small cam and valvetrain, headers, and intake. Not something that even came close to maxing the MAF's capabilities, but the drivability improvement is what sold me on the SD tune.
    Well I'm sold on it now. I just need to find time to drive 2 hours down to Frost.

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    Senior Member INMY01TA's Avatar
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    I'm from the "don't mess with the maf" camp. Back in the beginning I bought the Granitelli maf (screenless). Car ran great for a month or so then I started getting misfires. Went back to the stocker and sold the Gmaf. Problem solved.

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    Moderator 98TransAmWs-6's Avatar
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    Quote Originally Posted by INMY01TA View Post
    I'm from the "don't mess with the maf" camp. Back in the beginning I bought the Granitelli maf (screenless). Car ran great for a month or so then I started getting misfires. Went back to the stocker and sold the Gmaf. Problem solved.
    Did you have it tuned for the aftermatket Maf? Also was it bigger than the stocker? Because if you didn't have it tuned and or it was bigger than the stocker that would be why. If it's tuned correctly for a aftermarket maf you shouldn't have any troubles but the real debate was if removing the screen, not having a aftermarket maf vs the stocker. Removing the screen on the stocker will not have any bad side effects if done right since you are not increasing airflow, you are removing a part that was intended to straighten out airflow but is useless in straight intakes.

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    Veteran 0rion's Avatar
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    aftermarket MAF's are worse than de-screening your stock MAF but IMO you shouldn't touch your MAF if you're not going to tune for it and I'm sure that's what Frost was eluding to also. Unless you're getting a tune don't mess with the MAF period.

  18. #18
    TunedbyFrost.com Tuner Frost's Avatar
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    I commonly remove MAF screens during tuning, but I am calibrating for the change while making it.

    The good news is, at WOT, it's typically only 0.1-0.2 of a point AFR change by doing this. It's repeatedly been worth 3-5rwhp on a bolt ons car and 5-9rwhp on the cam only cars. This is the only MAF mod that I line up behind.

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    Senior Member JayTA98's Avatar
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    Quote Originally Posted by Frost View Post
    I commonly remove MAF screens during tuning, but I am calibrating for the change while making it.

    The good news is, at WOT, it's typically only 0.1-0.2 of a point AFR change by doing this. It's repeatedly been worth 3-5rwhp on a bolt ons car and 5-9rwhp on the cam only cars. This is the only MAF mod that I line up behind.
    Frost, do you calibrate all your mail order tunes for a descreened MAF? or only if the costumer tells you about it?

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