Gm Maf Blow Through,screen Or No Screen Which Is Better

[sickandtwisted]

I AM INSTALLING A GM MAF BLOWTHOUGH PIPE ON MY CAR FROM DEJON TOOL.I HAVE THE GM MAF,IS IT BETTER TO RUN THE BLOWTHOUGH WITH THE SCREEN,OR WITHOUT THE SCREEN.I AM GOING TO BE RUNNING ABOUT 25 PSI FROM MY T4.WILL THE SCREEN BE RESTRICTIVE,OR WITHOUT THE SCREEN WITH THAT MUCH BOOST DESTROY THE HOTWIRE OF THE MAF.I KNOW OIL AN DIRT WILL MESS UP THE MAF SO I RUN MY CRANKCASE VENT INTO A CATCH CAN WITH A BREATHER. IF YOU ARE RUNNING A BLOW THROUGH LET ME KNOW HOW ITS WORKING FOR YOU,AND IF YOU RAN INTO ANY PROBLEMS.THANKS

 

[Devicex]

WELL, I HAVE my maf in blowthrough with the screen in place, no problems. To keep it or not is up to you, I doubt it will be restrictive unless you're making serious power. There seems to be some issues with taking it out as well... but I'll let you read up on that by subscribing to the DSM Translator yahoo group and searching the archives.

 

[THEDUKE]

I ran mine with the screen but it is a pull threw, but one day I had a backfire & it blew the screen out. Could not tell any differance after that.
I believe I will always take them out from now on just so that the screen cant get in something if it was to break it loose.

 

[kpt4321]

For God's sake, don't type in all caps.

The screen helps you get a more accurate reading, so I won't remove it unless I start pulling a lot of air.

 

[Libila]

what screen are you guys talking about? I just bought a mas and translator but I have no screen. Can you help me out? Mine will be blow through.

 

[AgntorangeDSM]

old thread but, on the gm maf's there is a screen on the front side of the sensor to help direct air flow. I'd leave it.

 

[Boosted98gsx]

the honeycombs help evenly distribute airflow (since it acts like a liquid when pressurized) across the heated element to more accurately gauge the amount of airflow passing through it.

 

[92AWDHX40]

Yes i have mine on also, it keeps the elements from getting damaged at least in my
case so im leaving mine there.

 

[SBR Joe]

the honeycombs help evenly distribute airflow (since it acts like a liquid when pressurized) across the heated element to more accurately gauge the amount of airflow passing through it.

^^^^^ What he said.



Joe

 

[dsmfa9nutter]

I took mine out. Mainly because my puppy thought my maf was a chew toy and the honeycomb was crushed. :/

 

[viprez586]

What the...WTF Why?

Do you know how a hot-wire mass air flow sensor works?
Let me educate you.
First off the mass air flow sensor does exactly that- measures mass air flow drawn through the intake tract.
How? Well for hot-wire MAFs they have this heated grid (aka honeycomb) in the sensor housing which is maintained at a certain temperature. As air flows over the sensor, the air cools the heated great while the ECU controls current flow through resistors to maintain its specified temperature. The sensor then sends a frequency/voltage based on the current required to maintain temperature to the ECU and calculates how much air is coming through in Hertz/Voltage.

Its okay though, you probably got this idea typing into Ebay and saw the "Performance" MAFs with no grid or wire in them.

Not only does this grid/wire monitor the temperatue of grid/wire itself but as previously stated it helps direct airflow.
Also some have a grid that its plastic to direct airflow while there is just a small wire being heated.

Now ask yourself if you think its a good idea to remove it.

 

[1992awdlaser]

I would take it out. I have seen cases where it came apart because of the pressure from boost when set up in blow through. I have mine out and have no problems tuning the car or anything. Also I know many others that have theirs out without any trouble. Directing airflow isn't as important with boosted cars as it is with the camaro's and such. Why? Because we are pushing the air into the engine most of the time not drawing it in.

 

[viprez586]

Directing airflow isn't as important with boosted cars as it is with the camaro's and such. Why? Because we are pushing the air into the engine most of the time not drawing it in.

I agree with this statement for hot wire, however with karman vortex MAFs the grid is extremely important in directing airflow.

 

[dsm-onster]

I would take it out. I have seen cases where it came apart because of the pressure from boost when set up in blow through. I have mine out and have no problems tuning the car or anything. Also I know many others that have theirs out without any trouble. Directing airflow isn't as important with boosted cars as it is with the camaro's and such. Why? Because we are pushing the air into the engine most of the time not drawing it in.

No. N/A cars run at 14.67 psi a sea level. All cars run boosted because all cars run in the earth atmosphere. Boosting changes the atmosphere in which the engine works. There still is no flow unless the piston goes down, drawing the air in. This is why good turbo sheetmetal intake manifolds have velocity stacks. If the air were pushed in, the velocity stacks would greatly inhibit flow as they are completely in the way of flow. So boost or not, airflow demotrates similar basic characteristics of all compressable fluids.

The Karmen vortex effect (how stock dsm mafsmeter air) still applies to different atmospheres, though the hertz results differ for the same volume flow in different atmospheres. This is a basic chracteristic of compressable fluids. Understanding that the Karmen vortecies are eddy currents that can be used to measure airflow also shows us that massflow whips bacwards at high speed and one mass unit can cool the hot wire twice. Even boosted. If this is frequent/severe enough, your hotwire meter will not read consistantly nor accurately.

That being said, a maf that is located relatively far away from the turbo does not "see" as much turbulance from the compressor. A long as the transitions to the hot wire maf are VERY straight, and VERY smooth. A silicon hose and clamp does not help this. The maf will still be relatively consistant without the screen. in such a case. Also, if you calibrate, or tune your maf, it dials out the difference of having the screen in or out. So you can do away with it and retune if there is a difference noticed in your particular setup.

Not only does this grid monitor airflow but as previously stated it helps direct airflow.

Edumacate a little less please . A maf honeycomb/screen/grid does NOT monitor/measure/meter airflow. It DOES guide it to the maf meter better, as you mentioned.

 

[sickandtwisted]

Wow I just got a email saying this was replied to. My god is this a old topic. I have been though this a haltech E6K and a AEM EMS since then. I did leave the screen in when I used it but using a stand alone with a map sensor is 100 times easier and better for the hp my car is now making.

 

[babyviper]

Summitracing sells a gm maf that is designed to work without the screen so if you really want to run without the screen you could buy there product but I wouldn't otherwise. Summit wouldn't make a product designed for screen removal if all you had to do is remove the screen.

 

[Calan]

Summit wouldn't make a product designed for screen removal if all you had to do is remove the screen.

Of course they would (will)... if there are people willing to pay for it.

 

[90laserRSfwd]

It's all about the $$$, like it or not..

 

[tstkl]

I agree with this statement for hot wire, however with karman vortex MAFs the grid is extremely important in directing airflow.

does the fact that you can't run a karman vortex maf in blow through have anything to do with that? You HAVE to draw the air in a karman maf since it can't handle the positive boosts accurately.

 

[dsm-onster]

Well, if you new the curve the hertz response would be while on boost you could do it. The 3g guys do it . The vortecies still show the same VOLUME flow before or after the turbo. The REAL problem running a Karmen vortex maf sensor in blowthrough is the issue with the barometric sensor. It can't read boost. It flatlines at a certain pressure. Then the volume flow input cannot be acurated corrected. The intake temp sensor is likely lazy (or slow to respond to aircharge temp change), too.

Even on boost, air is sucked in by the cylinders. A karman vortex maf sees atmospheric "boost". We all run in boost. Just some of us see more vacuum than others .

 

[viprez586]

Edumacate a little less please . A maf honeycomb/screen/grid does NOT monitor/measure/meter airflow. It DOES guide it to the maf meter better, as you mentioned.

Yeah I was getting ahead of myself in my sentence there. All fixed.

Summitracing sells a gm maf that is designed to work without the screen so if you really want to run without the screen you could buy there product but I wouldn't otherwise. Summit wouldn't make a product designed for screen removal if all you had to do is remove the screen.

Auto part retailers will sell you a lot of dumb stuff. Take "injector cleaner" for example - Really you think your injectors need cleaning but you pour it into your gas tank just to clean the tank and lines leading to your fuel filter to clog that up or even sneak tiny particles past it to your injectors. Don't even get me started on radiator stop leak too.

Anyway I think the general consensus here is not to remove the grid.