Stock MAS

vortec4800 · August 2, 2003

So I've been hearing mixed results about removing the screen of the MAS, hear that it straightens up the air, that the computer has to be recalibrated in order to use it, that it keeps things out, etc. But keeping things out is the job of the filter I have before the sensor anyway, and that screen has to be slowing down the air - and its a free way to gain power... I like free...

Anyhow if the Westers chip has unlimited control over the computer (because it is the computer), he should be able to recalibrate the computer to compensate for the extra air flow.

Am I correct in this statement, am I missing something, do I not understand how this all works?

asepgrad98 · August 2, 2003

i dont believe any benefit is worth the risk of descreaning, i have read about many ppl who port the MAF and their car runs lean afterwards. the screen is in there for a reason and the throttle body is more resrictive than teh MAF any how.

greyghost03 · August 2, 2003

i dont believe any benefit is worth the risk of descreaning, i have read about many ppl who port the MAF and their car runs lean afterwards. the screen is in there for a reason and the throttle body is more resrictive than teh MAF any how.

I would have to agree. The screen is there for a reason. The MAF can flow more air, even with the screen on it, than the throttle body can take in. So unless you're planning to install a larger TB, I would leave it alone. Just my .02!

Rotorwrench · August 2, 2003

A few years ago me and a friend tried this on our cars, an LS1 Corvette and an LT1 Z28. We made a few passes at the drag strip with the screens in, took them out and made a few more passes. The Vette ran close to 1/2 a second slower while the Z28 ran about the same.

When I had my Z28 I raced with several guys that tried ported air sensors and other mods to the MAS and none of them showed any gains.

Tolliverme · August 2, 2003

I talked to the service manager at the dealership where i bought my truck. He told me that the screen was to protect engine aginst dummy's that would take the air filter out and leave it out. He said that taking it out can help because the screen does reduce flow to engine.

I took mine out and had no problems at all. Seemed to get a little better low end but I never timed it.

The easiest and way to take it out is to take a jewelers screwdriver. Insert it at the very edge of the screen and colapse the edge in towards the middle just a little. continue to do this in one direction about half way around and the the screen will come out easy. be very carful that you do no not damage the fine wires that are visible from the back side of the MAS. The screen seem to be made of very light aluminum and bends very easy.

What ever you deside, Good Luck.

lrymal · August 3, 2003

I talked to the service manager at the dealership where i bought my truck. He told me that the screen was to protect engine aginst dummy's that would take the air filter out and leave it out. He said that taking it out can help because the screen does reduce flow to engine.

I think that dealer is feeding some bogus information. Check these URLs:

http://www.exicte.com/mods.html Search on that page for "MASS AIRFLOW".

http://www.greghome.com/Greg's%20Garag...AFSensorMod.htm

http://www.gmtips.com/3rd-degree/dox/tips/.../maf-screen.htm

BDBWTE · August 3, 2003

I talked to the service manager at the dealership where i bought my truck. He told me that the screen was to protect engine aginst dummy's that would take the air filter out and leave it out. He said that taking it out can help because the screen does reduce flow to engine.

I took mine out and had no problems at all. Seemed to get a little better low end but I never timed it.

The easiest and way to take it out is to take a jewelers screwdriver. Insert it at the very edge of the screen and colapse the edge in towards the middle just a little. continue to do this in one direction about half way around and the the screen will come out easy. be very carful that you do no not damage the fine wires that are visible from the back side of the MAS. The screen seem to be made of very light aluminum and bends very easy.

What ever you deside, Good Luck.

Every truck we has has the MAF screen removed. Straightening air sounds like a bunch of Internet BS. The internet is good for somethings and an abortion for others. My truck runs without the sensor even plugged in. Sure it's not good for it but it's just a motor not that much to them. Easy breath in, easy breath out good.

vortec4800 · August 3, 2003

Every truck we has has the MAF screen removed. Straightening air sounds like a bunch of Internet BS. The internet is good for somethings and an abortion for others. My truck runs without the sensor even plugged in. Sure it's not good for it but it's just a motor not that much to them. Easy breath in, easy breath out good.

Now wait a minute, how does your engine idle without the sensor pluged in? Removing the screen is one thing, but unplugging the sensor would make the computer eat itself. How does that work?

Wayne2 · August 3, 2003

I have descreened MAF on 3 so far with no problems. Run better or worse? I don't know. Didn't check before and after but my current T/A runs ~13.05 with A4 tranny and stock (save for the Super Turbo). I don't know of any other vehicle that has them. As for porting the MAF you need to check your L trim. I did this on my '98 T/A and found it needed more air. It ran better and the L trims were in range after porting it. Some engines benefit and some don't.

Rotorwrench · August 3, 2003

When the MAS is unplugged or not working the engine will run in manifold absolute pressure mode. But when the engine is running in closed loop the mixture is set by O2 sensor readings. The MAS should only effect fuel mixture in open loop. When the engine is below normal temp or at greater than 80% throttle it should be in open loop. I don't have my manuals with me, so the 80% might not be exactly right but close.

Shaners · August 3, 2003

My buddy with the 8.1L Avalanche that ordered a Westers PCM when I did, asked Lyndon about the MAS screen. Lyndon told him to "leave it alone" and that he wouldn't gain any benifits by removing it when he installs his new PCM.

I think Lyndon programs his PCM's to adjust to the stock MAS, and then he makes the PCM adjust accordingly for highest performance levels. Of course if you wanted to buy an aftermarket MAS, then I'm sure Lyndon would set you up with whatever you've got. I told Lyndon I had a "drop-in" K&N filter when I ordered and he said that it doesn't make any difference.

vortec4800 · August 3, 2003

My buddy with the 8.1L Avalanche that ordered a Westers PCM when I did, asked Lyndon about the MAS screen. Lyndon told him to "leave it alone" and that he wouldn't gain any benifits by removing it when he installs his new PCM.

Thanks, that's exactly what I needed to hear

AZ-Z71 · August 4, 2003

All I have to add to this is that when I was doing the body lift I unplugged the MAS and removed the intake. Then we decided that the truck should have been moved a little forward in the driveway. So I attempted to start the truck but it would not stay running long enough to even move it. Later when we were complete, and by the way the battery was disconnected, the truck had a mind of its own and would accelerate by itself. I could get up to 40 no problem without touching the gas. Re started the truck a few times and it fixed itself. Not too sure that the truck will run without the MAS plugged in.

Just my 0.02.