MAF Screen
Screen is a substantial pressure drop at high flows.
Manifold pressure @ engine airflow = power. But the
screen also serves a purpose; it forces the air into a
more evenly distributed flow across the face, which
the hot-wire MAF depends upon for accuracy in its
reading. If your intake tract produces a biased airflow
(like for example a curve will "crowd" the air to the
outside) a descreened MAF can have distorted airflow
readings (as frequency) relative to true airflow. This
can bend the mixture lean or rich.
Since F-bodies have a relatively straight intake tract
this seems to not be much of a problem and people do
it all the time. Some folks notice things like softer A4
shifts (bad) or some mixture drift.
The right answer is to get a junker, LT1 or LS1 F-body
MAF and pop the screen off -that-. The ends are
swappable and you can go back and forth as you please.
Do not grind on them or the plastic piece. Just the screen
and maybe epoxy-fill the divot-ring in the snout if you
are an obsessive sort.
At shop-vac flow rates I found the screened MAF an
equal restriction to the stock airlid, in the pressure drop
produced. So it's worth doing if you can avoid or tolerate
any metering changes. If you have a M6 car then there
is very little likelihood of a downside. The A4s have
another thing to worry about.
Manifold pressure @ engine airflow = power. But the
screen also serves a purpose; it forces the air into a
more evenly distributed flow across the face, which
the hot-wire MAF depends upon for accuracy in its
reading. If your intake tract produces a biased airflow
(like for example a curve will "crowd" the air to the
outside) a descreened MAF can have distorted airflow
readings (as frequency) relative to true airflow. This
can bend the mixture lean or rich.
Since F-bodies have a relatively straight intake tract
this seems to not be much of a problem and people do
it all the time. Some folks notice things like softer A4
shifts (bad) or some mixture drift.
The right answer is to get a junker, LT1 or LS1 F-body
MAF and pop the screen off -that-. The ends are
swappable and you can go back and forth as you please.
Do not grind on them or the plastic piece. Just the screen
and maybe epoxy-fill the divot-ring in the snout if you
are an obsessive sort.
At shop-vac flow rates I found the screened MAF an
equal restriction to the stock airlid, in the pressure drop
produced. So it's worth doing if you can avoid or tolerate
any metering changes. If you have a M6 car then there
is very little likelihood of a downside. The A4s have
another thing to worry about.
I'm curious if their isn't more to that. Like what other factors were there. Are the guys having problems have a certain type setup like stock bellows compaired to smooth bellows. Stock air lid compaired to slp's or some other factor or combination of factors?
I did mine it's fine but I didn't do anything else but a slight internal polish I have smoth bellows and slp lid no powere adder.
I did mine it's fine but I didn't do anything else but a slight internal polish I have smoth bellows and slp lid no powere adder.
TECH Addict
Joined: Mar 2004
Posts: 2,336
Likes: 0
From: Fat Chance Hotel
I'm having a hard time believing the screen does anything to airflow. I've heard people go both ways on this but I wish the engineers who designed the piece could clear this matter up. e.g. I've seen MAF's that had no screens from the factory (ZO6) and I've seen MAF's that had screens on both ends, which tells me the screen(s) were there to protect the filament. I've owned an aftermarket EFI that had an enormous 4" MAF that had some kinda of grate or "fence" looking screen at both ends.
What gives?
What gives?
TECH Apprentice
Joined: Jan 2005
Posts: 396
Likes: 0
Like technical said you'll hear people going both ways on this one. When I bought my car it had a descreened and ported MAF and the car is an A4 and ported MAF is bad for an automatic. I bought a brand new stock MAF and left the screen in. I'd rather have a little protecting for the filament. You might pick up a few HP by removing the screen though.
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I didn't notice any change after removing mine so when someone here on the Board was selling a MAF with the screen still in place for 10 bucks I bought it and put it back on.
TECH Apprentice
Joined: Dec 2003
Posts: 342
Likes: 0
From: Houston
If you remove the screen make sure that every bolt in the air intake system is fastened with locktite and lock washers. There was an engine that was destroyed from a bolt that came loose and went down the intake. For the small gain I don't think it is worth the chance.
Alan
Alan
TECH Addict
Joined: Feb 2004
Posts: 2,826
Likes: 0
Originally Posted by 1STGEN68-2000SS
If you remove the screen make sure that every bolt in the air intake system is fastened with locktite and lock washers. There was an engine that was destroyed from a bolt that came loose and went down the intake. For the small gain I don't think it is worth the chance.
Alan
Alan
I have some ported MAF ends on my '02, but on my A/T '99, I just descreened it and I did notice a difference. I also did the EGR mod at the same time, so between the two, the butt dyno says that it picked up a couple of ponies. No ill effects on the shifting of the A/T.
TECH Addict
Joined: Feb 2004
Posts: 2,826
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Originally Posted by tump
The bolt ontop of the airfilter, you know that bolt.
Originally Posted by Another_User
Oh yah....the one you stuck on top of the filter before you put the lid back on. I knew I forgot something when I changed my air filter.
TECH Enthusiast
Joined: Sep 2004
Posts: 642
Likes: 0
From: Quad Cities, IL
Originally Posted by txhorns281
Kinda a tuning thing, but you know what AU? We should get someone to log a screened MAF and then descreen it and log afterwards... That would be veeeeeeeeery interesting... I'll put money that there's a pretty big increase in airflow. I'll throw 20% out there
Originally Posted by LSWannabe
I'm doubting it. The screen is not going to restrict airflow more than the filter. Show me proof and I'll admit I'm wrong.
<--- Descreened and lovin' it.
