: Screen in the intake system



Purplewgn2000
09-29-03, 06:56 PM
Hey all, just curious to know what the screen in my intake system is for. There is a screen at the point where the filter hose meets the intake/TB system. What the heck is this screen for?

El Dobro
09-30-03, 02:02 AM
It's a mass airflow sensor.

Purplewgn2000
09-30-03, 02:28 AM
I know what the MAF is and what it does, but I was wondering what the screen did. I dont see a screen on any aftermarker MAF's and was wondering its ultimate purpose. Is it to silence the intake sound, "straighten" the airflow like a K&N claims to do, or just something for me to ask about? See what Im saying? The honeycomb design is much like a catalytic convertors. I know cats arent very flow efficient so the screen in the MAF wouldnt be much better.

El Dobro
09-30-03, 09:41 AM
It straightens out the turbulence of the airflow so the sensor operates efficiently.

Purplewgn2000
09-30-03, 03:32 PM
Well, Ive heard many, many times that people remove this screen in the attempt to gain some horsepower. What is your opinion on doing so? Since it actually serves a purpose I dont think I will be removing it, but if you have had different experience I would love to hear it. Thanks for replying.

elwesso
09-30-03, 05:42 PM
It doesnt straigten out airflow..... but rather it prevents big chunks of debris from hitting the MAF and damaging it..... From people not changing their air filter enough...... Or the filter not doing its job......!

Descreening will provide you with maybe .0035 extra HP and you risk damaging your very expensive MAF...!!!

Purplewgn2000
09-30-03, 06:55 PM
Well, that pretty much kills it. Thanks for the info. I think I will choose safety over power. I will miss that xtra .0035 horsepower though (hehe). It may have taken me from a 14.8 to a 14.79999999999 in the quarter. :>)

elwesso
09-30-03, 08:31 PM
Whenever you want to start changing things, you must try and figure out why the MFG put it there...... They dont put things on the cars just for shits and giggles......

El Dobro
10-01-03, 11:46 AM
If you do a net search for Honeywell Mass Airflow Sensors, you'll see articles on them and why there is a honeycomb. According to the article, airflow turbulance is cut down to going as straight as possible across the sensor by the honeycomb so it can read the flow more accurately. They also go into different types of material for honeycomb use. In a nutshell, the screen is there so the air isn't blasting the sensor from all angles.

buickman69
10-05-03, 01:06 AM
With the turbo Buicks, there is 2 screens and we remove 1. However, in the Northstars, there is only 1 screen and it's "in there". The Buicks simply pop in and out but not the Caddys.

ShadowLvr400
10-05-03, 10:29 AM
I've pulled my screen, and it might have added a horse, and a bit of noise on the intake. But both gains were marginal. With the K&N filter though, I've not been worried about chunks of debris.

airbalancer
10-05-03, 11:22 AM
If the sccreen is for straighting airflow then it should stay in as the senor may get a false reading
In the hvac industry turning vanes are used all the time to reduce trubance in the duct work and the less trubance the great the airflow
If then screen is clean it should not reduce airflow and the engine is design for the screen so you are chaning the specs if you take it out

freakzoid
10-18-03, 09:21 PM
If the sccreen is for straighting airflow then it should stay in as the senor may get a false reading
In the hvac industry turning vanes are used all the time to reduce trubance in the duct work and the less trubance the great the airflow
If then screen is clean it should not reduce airflow and the engine is design for the screen so you are chaning the specs if you take it out

The honey comb is infront of the MAF because the Mass airflow is mostlikely measured by a hot wire aninometer. The need to measure air speed through the device, since they know the diamter of the device that gives you flow rate of the air and using the average density of air at that temperature (what the IAT is for) they know the mass of the air comming in.
Measuring the speed of the air is done easily when the air flow in closest to the laminar flow region, which is where the flow through the pipe looks like concentric pipes and there is no turbulence. the honey comb is meant to straiten the air flow out so it can be measured because turbulent flow is a problem, in reality it can only get the air to the transition region which is a mix of laminar and turbulent flow.
The animometer works by heating an element which heats the air with a known amount of energy and they measure the temperature a fixed distance away. Knowing the composition of air they know how much it heats up and they can calculate velocity from that.
I hope that was way too much information.
Lenny
Chemical Engineering Student

Katshot
10-19-03, 10:25 AM
Dear Lenny,
Let me explain the MAF to you. Your explaination, while entertaining, is not even close.
The "hot-wire" MAF does NOT measure air "speed" and the wire does NOT heat the air.
The MAF works like this:
The PCM is programmed to maintain a specific temperature at the wire (sorry, I can't remember the exact temp) and it calculates the airflow across the wire by tracking how much current it must supply to maintain the set temp. The honeycomb screen is there to maintain smooth, even airflow across the wire to minimize the possibility of a sampling error at the wire. Removing the screen will do little if anything for performance. I have read several reports from people that have removed their screen and later found that their idle was left a little rough afterwards. I removed mine and could detect no difference in the idle quality of performance.
You have to understand that much of what is done inside your engine is controlled by outputs from the PCM based on calculations it makes via inputs from several sensors. The MAF is just one of those sensors and it is not even a required sensor to run the car. If you don't believe me, go ahead and unplug it, the car still runs just fine. The OEM backed up the MAF calculations with a version of the previous system. It's called "Speed & Density". It's just a slightly more crude way of calculating airflow but still effective.

Suntan superman
10-21-03, 11:31 PM
So with all that said after I've already pulled my screen out, Where do I get a new one?

foo
10-24-03, 02:00 PM
THE SCREEN THE SCREEN...
This is my take on it... The screen protects and it also smooths airflow so the sensor is more accurate.. So that being said, IF YOU ARE INSTALLING A K&N FILTER or a new INTAKE system , knock the screen out! It does restrict some airflow. The K&N filter is DESIGNED to smooth the air flow so the screen wouldn't be necessary any more, and as for protecting it as long as your filter is on tight with no leaks and you keep it clean and oiled you will have no problems. The thing about K&N filters is that if you DON'T OIL IT it WILL NOT filter dirt very well at all. I tend to reoil every 30k miles or when i change tranny fluid unless you live in a really dusty area then u have to do it more often. Just my 2.5 cents :>

El Dobro
10-25-03, 09:51 AM
The screen isn't offered separate for the Caddy MAF sensor. Pick one up at the junkyard or just live with it 'cause it's a $200 part.

Katshot
10-26-03, 08:09 AM
".....THE SCREEN THE SCREEN...
This is my take on it... The screen protects and it also smooths airflow so the sensor is more accurate.. So that being said, IF YOU ARE INSTALLING A K&N FILTER or a new INTAKE system , knock the screen out! It does restrict some airflow. The K&N filter is DESIGNED to smooth the air flow so the screen wouldn't be necessary any more,......"

Just wanted to point out that the MAF installs AHEAD of the K&N ducting so it would recieve no direct benefit from the K&N's airflow characteristics. The K&N's smoothing effect will mainly benefit airflow through the throttle body.The screen is directly ahead of the MAF so it DOES have a direct effect on the aitflow across the sensor. The question is, does it REALLY matter?

foo
10-26-03, 10:17 AM
".....THE SCREEN THE SCREEN...
This is my take on it... The screen protects and it also smooths airflow so the sensor is more accurate.. So that being said, IF YOU ARE INSTALLING A K&N FILTER or a new INTAKE system , knock the screen out! It does restrict some airflow. The K&N filter is DESIGNED to smooth the air flow so the screen wouldn't be necessary any more,......"

Just wanted to point out that the MAF installs AHEAD of the K&N ducting so it would recieve no direct benefit from the K&N's airflow characteristics. The K&N's smoothing effect will mainly benefit airflow through the throttle body.The screen is directly ahead of the MAF so it DOES have a direct effect on the aitflow across the sensor. The question is, does it REALLY matter?


Ummm...... AHEAD?? The K&N is the first thing the air hits.. I don't know what you are looking at :) the air goes into the K&N then into the little 45 degree angle pipe (if u made your own or bought a kit) and then that hooks up to the MAF and then that hooks to the TB..as long as everything is smooth inside i don't see why you would need the screen.. also none of the aftermarket MAF's have the screen

Katshot
10-26-03, 10:35 AM
Obviously, we're talking about two different systems. On most of the CAI systems (including the K&N on my car) I've seen, the MAF is directly after the filter. I guess on your car it's different. Like I originally said though, I took mine out and noticed no difference anyway. There is sound technical information to suggest that its use DOES provide a benefit but in the end I'd say "to each his own".