I Did The Intake Screen Removal... My Thoughts...
November-9th-2002, 04:08 PM
#17
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Join Date: Oct 2001
Location: Denver, CO
Posts: 337
Re: Further Information on MAF Sensor Screen Removal
Originally posted by goldstar
I strongly suggest you go to www.autospeed.com and click on Technical Features and then look for Eliminating Negative Boost. This is a five part article on improving a stock air intake system with airbox.
For purposes of this thread, I want to focus on Part 4, The Airflow Meter. The car in question is an Audi S4 2.2 liter 5 cyl. Turbo but the FI aspect can be ignored because the following information pertains only to work done on the intake system only on the atmosphere side of the turbo. The intake system is similar to the Protege with an air inlet over the radiator leading to an airbox.
The MAF is 75 mm (3") in diameter with a woven mesh wire screen on each side. Using a Dwyer Magnehelic Differential Pressure Gauge (an instrument that measures very small increments of positive or negative pressure - read about it in the article), the author was able to take a pressure differential reading before and after removal of the screens. Starting at 4000 rpm, an improvement was noticed after removal of the screens. At 6000 rpm, the maximum effect was recorded where the peak pressure DROP was reduced from 32 inches of water with the screens to 26 inches of water without them. This represents a 19% reduction. Look at the article to see % reductions at other rpm's.
The author feels that the, "Closely woven mesh causes a major flow restriction. This is not just because of the blockage factor of the wire itself, but because of turbulence which is generated as the air squeezes through the small openings." He also believes that the function of the screen on the intake side is to protect the hot wire from damage if the air filter element fails.
This article seems to provide hard evidence that removing the screen has a beneficial effect on performance. Beyond that, it is a great tutorial on improving the air intake system in general based on measured results rather than guess-work. The Dwyer gauge seems to be a really useful tool in this area.
I hope some of you will read the cited article and comment on it.
02 DX Millenium Red
MP3 Strut Tower Bar kit
AEM Short Ram intake
I strongly suggest you go to www.autospeed.com and click on Technical Features and then look for Eliminating Negative Boost. This is a five part article on improving a stock air intake system with airbox.
For purposes of this thread, I want to focus on Part 4, The Airflow Meter. The car in question is an Audi S4 2.2 liter 5 cyl. Turbo but the FI aspect can be ignored because the following information pertains only to work done on the intake system only on the atmosphere side of the turbo. The intake system is similar to the Protege with an air inlet over the radiator leading to an airbox.
The MAF is 75 mm (3") in diameter with a woven mesh wire screen on each side. Using a Dwyer Magnehelic Differential Pressure Gauge (an instrument that measures very small increments of positive or negative pressure - read about it in the article), the author was able to take a pressure differential reading before and after removal of the screens. Starting at 4000 rpm, an improvement was noticed after removal of the screens. At 6000 rpm, the maximum effect was recorded where the peak pressure DROP was reduced from 32 inches of water with the screens to 26 inches of water without them. This represents a 19% reduction. Look at the article to see % reductions at other rpm's.
The author feels that the, "Closely woven mesh causes a major flow restriction. This is not just because of the blockage factor of the wire itself, but because of turbulence which is generated as the air squeezes through the small openings." He also believes that the function of the screen on the intake side is to protect the hot wire from damage if the air filter element fails.
This article seems to provide hard evidence that removing the screen has a beneficial effect on performance. Beyond that, it is a great tutorial on improving the air intake system in general based on measured results rather than guess-work. The Dwyer gauge seems to be a really useful tool in this area.
I hope some of you will read the cited article and comment on it.
02 DX Millenium Red
MP3 Strut Tower Bar kit
AEM Short Ram intake
However, in the matter of the Protege, I don't think it is going to make that big of a difference with its removal. Mainly because Mazda does things for a reason, and they placed the mesh in there for a very good reason. A reason that I felt like leaving it in there when I put the turbo in my car...
November-18th-2002, 12:54 AM
#18
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Join Date: Aug 2002
Location: New Jersey
Posts: 349
My Turn to Remove the MAF Sensor Screen
Well I paid attention to my own research and removed the MAF screen. I used a wooden dowel as a drift and knocked the screen right out. Here are my impressions:
In an earlier post on another thread, I mentioned that I had removed the horizontal grille piece underneath the air inlet to the snorkel over the radiator providing a good flow of ambient air with a possible ram effect at the inlet. I reported a definite increase in throttle response and a seeming ability to rev more freely. In addition, there was a slight increase in intake noise probably due to the more open inlet. With removal of the screen, throttle response quickened even more with some added responsiveness during acceleration. Again, some slight further increase in intake noise but nothing obtrusive as in the case of an aftermarket intake system. I'd like to emphasize that with the exception of these two changes, this system is otherwise stock including the paper air filter.
With my AEM Short Ram installed, I noticed an increase in intake noise and perhaps a slightly faster throttle response though I'm not absolutely certain about the latter. Comparing the two systems, the modified stock one seems to have better low speed torque off the line wheras the AEM outperfoms it in the higher rpm ranges. I would have to say that the two systems are fairly equal with the modified stock one perhaps having the edge in all around, everyday driving. Unless you like a pronounced intake sound as many of you do, the modified stock system is much quieter but still more noticeable than a completely stock one.
In case any of you are wondering why I'm playing around with two systems, when I first bought my car I couldn't wait to do my first mod and naturally chose the easiest and most talked about one to perform. Afterwards I came across a number of posts about improving the stock system (particularly by jmauld and Traveler) and thought it would be interesting to try to carry out some of their ideas. If nothing else, experimenting is fun!
I hope you have found some of these obsevations interesting.
02 DX Millenium Red
MP3 Strut Tower Bar kit
AEM Short Ram intake (sometimes)
In an earlier post on another thread, I mentioned that I had removed the horizontal grille piece underneath the air inlet to the snorkel over the radiator providing a good flow of ambient air with a possible ram effect at the inlet. I reported a definite increase in throttle response and a seeming ability to rev more freely. In addition, there was a slight increase in intake noise probably due to the more open inlet. With removal of the screen, throttle response quickened even more with some added responsiveness during acceleration. Again, some slight further increase in intake noise but nothing obtrusive as in the case of an aftermarket intake system. I'd like to emphasize that with the exception of these two changes, this system is otherwise stock including the paper air filter.
With my AEM Short Ram installed, I noticed an increase in intake noise and perhaps a slightly faster throttle response though I'm not absolutely certain about the latter. Comparing the two systems, the modified stock one seems to have better low speed torque off the line wheras the AEM outperfoms it in the higher rpm ranges. I would have to say that the two systems are fairly equal with the modified stock one perhaps having the edge in all around, everyday driving. Unless you like a pronounced intake sound as many of you do, the modified stock system is much quieter but still more noticeable than a completely stock one.
In case any of you are wondering why I'm playing around with two systems, when I first bought my car I couldn't wait to do my first mod and naturally chose the easiest and most talked about one to perform. Afterwards I came across a number of posts about improving the stock system (particularly by jmauld and Traveler) and thought it would be interesting to try to carry out some of their ideas. If nothing else, experimenting is fun!
I hope you have found some of these obsevations interesting.
02 DX Millenium Red
MP3 Strut Tower Bar kit
AEM Short Ram intake (sometimes)
November-21st-2002, 11:17 AM
#20
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Join Date: Jan 2002
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Originally posted by Mach 1
the black waffle is there to "smooth" the airflow, supossedly making it less turbulent.
removing it probably will net you zero gains.
the black waffle is there to "smooth" the airflow, supossedly making it less turbulent.
removing it probably will net you zero gains.
November-21st-2002, 11:50 AM
#21
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Turbulence occurs because of velocity heterogeneities in a flowpath. This is seen in free flowing system such as a river, which has eddies and vortices, and faster flowing portions in the center of mass. By having a media (the screen) impart a uniform constriction, it is likely reducing turbulence (as Mach1 said). This is analogous to groundwater flow through a porous media (the rock or soil) where there is no turbulence, unlike a free-flowing surface stream. The screen, though, would reduce the mass of air transmitted per unit time (flux).
November-21st-2002, 01:58 PM
#22
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Originally posted by Maxx Mazda
If they wanted smooth airflow, they'd have gotten ridof the damn "elephant trunk" wavy bends in the stock intake piping. THAT causes alot of terbulence. As well, adding the screen would itself cause terbulence, not smooth out the airflow.
If they wanted smooth airflow, they'd have gotten ridof the damn "elephant trunk" wavy bends in the stock intake piping. THAT causes alot of terbulence. As well, adding the screen would itself cause terbulence, not smooth out the airflow.
November-21st-2002, 02:04 PM
#23
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Originally posted by Mach 1
You might want to do some more research before you make such false statements. Dont want to mislead people...
You might want to do some more research before you make such false statements. Dont want to mislead people...
I've been looking at it more carefully and comparing it to other systems that are proven to smooth airflow, and this screen is about 1/5 of the length of the other systems. The holes are also about 3x times as large. I am more willing to say that this is for making it quieter then smoothing out the airflow. "IF" it is doing any smoothing of the airflow it can only be doing VERY little.
November-21st-2002, 02:32 PM
#24
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i think fossil boy provided the logic backing my remark.'
as far as making it quieter, the strange shaped intake box is designed for that. Thats why the strange shape.
Just about every car on the road has a screen in front of the factory MAF meter, and I have read and been told by well informed people its purpose is to smooth airflow. Combined with fossil boys statement, it makes sense to me.
Wheres your proof of your remarks?
as far as making it quieter, the strange shaped intake box is designed for that. Thats why the strange shape.
Just about every car on the road has a screen in front of the factory MAF meter, and I have read and been told by well informed people its purpose is to smooth airflow. Combined with fossil boys statement, it makes sense to me.
Wheres your proof of your remarks?
November-21st-2002, 03:05 PM
#25
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as far as making it quieter, the strange shaped intake box is designed for that. Thats why the strange shape.
Wheres your proof of your remarks? [/B]
Here's a few more.
IMO, the screen will straighten out the air. IMO, it will make the intake quieter. IMO, it will restrict airflow. IMO, it will protect the sensor if the air filter fails. Several of my engineering classes have given me the knowledge to have those opinions.
Neither you, nor I, know for which of the above reasons that Mazda put it in there. (Maybe all of them) They could've put it in there simply because it "made sense" to put it in there.
Last edited by jmauld; November-21st-2002 at 03:47 PM.
November-21st-2002, 05:11 PM
#26
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So your entitled to an opinion which doesnt need proof, yet my opinion needs proof?
Uh...ok....I think I wasted enough time on this subject and with you and your brand of logic.
later
oh wait, I would like to hear your theory on the shape of the factory intake setup...I need a good laugh.
Uh...ok....I think I wasted enough time on this subject and with you and your brand of logic.
later
oh wait, I would like to hear your theory on the shape of the factory intake setup...I need a good laugh.
Last edited by Mach 1; November-21st-2002 at 05:14 PM.
November-21st-2002, 06:41 PM
#27
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Originally posted by Mach 1
...(snip)
as far as making it quieter, the strange shaped intake box is designed for that. Thats why the strange shape.
(snip)...
...(snip)
as far as making it quieter, the strange shaped intake box is designed for that. Thats why the strange shape.
(snip)...
Its not that shape itself that makes the intake quieter, rather the size is what does the trick. If I remember correctly it is supposed to be 1.5 times larger than one cylinder's volume.
Then again I might just be on crack.
November-21st-2002, 10:33 PM
#28
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Originally posted by StuttersC
I believe the "strange shaped" box you are reffering to is that wierd piece of palstic that is located at the entrance to the box with the filter in it?? Right??
Its not that shape itself that makes the intake quieter, rather the size is what does the trick. If I remember correctly it is supposed to be 1.5 times larger than one cylinder's volume.
Then again I might just be on crack.
I believe the "strange shaped" box you are reffering to is that wierd piece of palstic that is located at the entrance to the box with the filter in it?? Right??
Its not that shape itself that makes the intake quieter, rather the size is what does the trick. If I remember correctly it is supposed to be 1.5 times larger than one cylinder's volume.
Then again I might just be on crack.
On my car (2000 protege ES) the intake plastic thing is the most unusally shaped thing I have seen on any car. It has the inlet under the hood line to try to get cold air, then it has a huge empty box near the top, then after it truns down toward the filter box, it has another very strangly shaped box like thing that hangs way down, almost to the bottom of the radiator. I would love to hear from a Mazda engineer the reason behind it. In my experience, some cars do have some strange shape boxes in front of the filter (that are used to quiet the incoming air) but the mazda box is really strangley shaped and really large...