Mikey97Z

So the screen is a restriction once you go over 750 cfm? How much air does a stockish LT1 pull in at WOT? If it doesn't exceed 750cfm, that would explain why there's no performance gain. Maybe the throttle body and blades are a bigger restriction than the screen.

Mikey97Z

Maybe the calibration has changed. You'll never know.

anaik

According to "Injuneers" Scanmaster readings; 240 gps at 5800 rpm, for a stock engine.

97WRAITH

Yes! no problems here.

ponyackn

!MAF screen works well for me. Maybe we shoulda made this thread an actual poll so we could see the results easier.

Dan K

I say don't touch it. Although Brent does have proof that you can flow more air through it.

I read something somewhere that explained why. Maybe something from Pro-M...they make MAF sensors for mustangs...maybe more by now.
But anyways. I'll try to explain this the best I can.

The screens are to keep crap away from the heated element that is in the sensor and to help straighten out the airflow coming into the sensor so that said heated element can more accurately measure how much air is coming in. If that element gets dirty or a piece of something gets on it due to the screens being gone it will not measure the airflow coming through the MAF correctly.

In a nutshell, when you remove these screens or port the ends...all you are doing is allowing more air into the engine that the maf is not seeing or measuring.
The computer knows how much air should be coming in based on the frequency that heated element is reading. When you descreen and port, you are increasing the area inside the MAF housing and allowing more air into the motor which the computer does not see. Therefore you are slightly leaning the mixture out. In essence, more parts of air per the same parts of fuel. That's is why some people do gain a slight bit of power. That's fine. You're just tricking the computer.

But what happens more times than not, is you can really screw the MAF and computer up with your descreen and port mods. Then you will start to have some of the problems that others have already listed in previous replies. Only "cure" for this is to modify the MAF tables by scaling them up. Doing this increases the amount of air that the computer thinks is coming in based on the frequency that the heated element is sensing. Therefore you just wasted a whole bunch of time ruining a perfectly good MAF sensor by trying to trick the computer to gain a couple of horsepower and fixing it by changing the maf tables in the computer.

Only reason I can think that aftermarket MAF sensors don't come with screens is because that slight bit of leaning the motor out is where the claimed "10-12 horsepower" comes.

I would think the only reason to do any sort of modifications to the MAF sensor is because you think you can flow more air through it than it can probably measure.
Then it's time for a bigger MAF sensor...not a port job on your stocker.

Turbo Regal guys love the 3 1/2" LT1 and LS1 maf sensors because we can flow more air through them than the 3" stocker. I think Ramchargers is working on a 4" maf sensor for those who are already reaching the limits of the 3 1/2" models. I think the Z06 maf is 4", isn't it?

Leave it alone...it isn't worth it.

Mikey97Z

Even this slight hope of power is all in vein, since the mixture is being monitored by the O2 sensors in the exhaust, and as soon as they see the mixture get leaner, the PCM will compensate within seconds. The PCM will always maintain the target A/F ratio.

Dan K

But at wot...that slight gain might be realized.

hairbear21

I must post again, becuase there are some very valid arguements made here. Like I said before, I have ported and polished mine, but I did leave the screen in. The reason for this is because I was looking at it, and while I can see a reason for the screen-to straighten airflow for accurate readings, I could not find a reason for the vanes. They will not significantly straighten any air, and they are more or less a hinderance. When I did mine, I CAREFULLY took apart the MAF, LEFT IN the black plastic piece (how much more can it really flow without it), and left the screen in. Since then, I have had absolutely NO problems with idle, it actually smoothed out, and performance has not gone down. If anything, it probably went up a tad, and I emphasize a tad. I did it hoping that even with the PCM's recalibration, that it would still lean out a little at the top end, simply because these cars run as rich as pigs.
So, as far as a vote, if you have a few hours to kill (you will need hours to do it right), and the right tools, dremel, hacksaw, snadpaper, etc..., then by all means do it

mc63

At first, I removed the screen... encountered a rough idle after a couple days.
Pulled it and ported it.... same rough idle and also gas milage dropped about 2 or 3 mpg, BUT, It did rev quicker and have more top end pull. So I re-installed the screen just to see...
Gas milage came back up, rough idle went away and it still had the quick rev and harder top-end pull!!!
So in my experience, porting helped as long as I keep the screen.
Of course everyone else may experience something different,
Porting does allow more air to flow, so with the screen in it also allows the sensor to measure the added flow.

Michael

Perry93TransAm

Debris hitting the wires of the sensor? You do run an airfilter right? The wholes of the screen are not very small, if something can get through there it can get on the wire anyway. And if you have crap thats large enough for that screen to stop then your filter is not installed right!!!

cmillard

The majority is wrong if they say pull the screen.

Removing the screen is a mistake unless you have a perfectly straight itake tract (which most f-bodies don't)

The screen is there to create laminar flow across the sensor wires so one side of the MAF doesn't get more flow and mis-meter the incoming air.

Pulling the screen and getting different readings is understandable- you've thrown the calibration off.

It's not worth it, just another thing to throw off the correct fueling, and that's what really matters.

Hope this helps,
-Christian

Perry93TransAm

Catch dust?? the screen?? thats kinda hoping isnt it?the air moving is pressureized and unless the screen was oiled down or soemthing dust would just keep moving on through.

cmillard

The MAF can be cleaned with standard electrical cleaner.

If anyone's curious how GM arrived an using a MAF I put an SAE paper up here:

http://www.carprogrammer.com/Z28/PCM...00-01-0546.pdf

very good reading, not too deep.

Hope this helps,
-Christian

RedWolf

(i wrote this in another thread(Do Not Remove Your Maf Screen!) but here ya go again.) T.P.I.S.(www.tpis.com), did a write up in thier LT-1 Hint book which says:
Flow restriction for the 1994 Camaro with LT-1.

CFM

test 1 all stock.......................409

test 2 TPIS air filter................428

test 3 remove first air entry
(that little vent behind the
dr head light)..........................447

test 4 drill 7 holes
in the filter cover......................475

test 5 hi flow elbow between
MAF and filter assembly............535

test 6 remove MAF screen........559

test 7 52mm with air foil...........605

test 8 remove air filter lid..........618

test 9 remove air filer base.......726

so as you can see.. removing the screen DOES increase your air flow, according to them.
just thought id share with you all.