Oh! And no codes either. :thumbs:

 

Removed my screen & now I have a window leak, my radio does not work, my blinkers are out & my A4 clutch is smelling now. :banghead: :jester :leaving:

 

Any gains from removed screens are short term and will be learned out by the PCM and trying to program for un-metered air is a waste of time and in no way accurate.

If you ever want to tune your car or accurately read the trims, don't remove the screen. Period.

 

whats a carpe dm? out on the edge of the world we fish for dm carpe! aka alabama salmon............ha ha just kiddin. can you put the screens back in if it don't work? i have ported maf ends, and the halltech trap, now i need the manifold, wonder if i should do it all at once. didn't want to get ls1 edit until i got the gears, and converter.....and headers. :)

 

Quote: "If you ever want to tune your car or accurately read the trims, don't remove the screen. Period"

Why is that the Vette Doctors removed my 2001's screen at dyno tune time and the car runs great, better than stock?

Why do stock 2002 up Z06's have no screen and they run great?

 

:iagree:

 

A) Because the stock air box has directional vanes
B) The electronics and PCM, as a system, are calibrated

I've tuned every imaginable combo (SC,Turbo and NA) and I am willing to hand you the benefit of that experience....don't mess with the screen unless you are prepared to live with the results or tune around them. Period.

 

Charlie knows what he is talking about. :yesnod:
JB

 

I had a 97 auto that I removed the screens on......and had a surging problem with no noticable HP improvement. The 96 collectors edition and WS6 Firebird had no problems and on the dyno the WS6 gained 3hp. This mod is definately a roll of the dice the question you need to ask yourself is: do you feel lucky? :confused:

 

This mod is definately a roll of the dice the question you need to ask yourself is: do you feel lucky? :confused: [/QUOTE]

So, this is a matter of luck? I don't think I'll try it. That is wierd though. It works for some and not others? :confused: :skep:

 

WTF? Where do you think of this stuff IMQUIK :lolg: :lolg: :lolg:

 

I removed mine and it runs great- Those who are against it- does't an aftermarket air filter do the same thing...YES. Did you tune after that??

 

I punched out the screen in my 02 and it ran great, no problems at all and 0n my 04 I put in an after market and it ran like crap and after 50 or 60 miles I took it out and punched out the screen in the stock one and it still ran like crap for about 50 miles and before I got around to changing it, It started running great so I feel that even with a relearn process it will still take at least 50 miles before you will be satisfied....Just my OP. Got to have a little patience. :seeya

 

:iagree: :iagree:

Thats what I don't understand. Doesn't any intake mod do the same thing? It brings in a little more air. So does removing the screen on the maf. Doesn't that remove the restriction and allow just a little more air to pass through? How could that mess things up but an aftermarket intake system make things better? I think the people with problems aren't giving the computer enough time to get used to it or messed up the contacts on the maf. But thats just my opinion and I could be completely wrong. Can someone who knows what their talking about step in and correct me please. :D

 

It's NOT about air volume. It's about air VELOCITY. The faster the air moves over the metering resistors of the MAF, the cooler they become, and the PCM puts in more fuel and timimg. By taking the screen out, you have changed the velocity calibration of the MAF to a lower level. Also, this allows UNMETERED air to pass through the MAF. At WOT the PCM relies almost exclusively on the MAF for A/F mixture. The result is a leaner A/F mixture at WOT with less timing. An extreme case could even start to tickle the knock sensors, if you start to ping, which would further reduce power due to knock retard. To do this with the assumption that you will get a few extra ponies at WOT is not worth it, IMHO. :smash:

 

Think about this; how could air, just by passing through a quarter inch honeycomb increase velocity to the point that it would not decrease almost instantly?? By the time it hits the meters it is already slowed to the point in which it came in. Could you please explain your UNMETERED air hypothises?? There is no passages for the air to escape by removing the screen so how do we end up with unmetered air?? Also how do you figure that the MAF read temp?? MAF stand for Mass Air FLow. It reads the amout of air that passes through the sensor.
This is what GM has to say:
Mass Air Flow Sensor
The Mass Air Flow (MAF) sensor measures the amount of air which passes through it. The PCM uses this information to determine the operating condition of the engine, to control fuel delivery. A large quantity of air indicates acceleration. A small quantity of air indicates deceleration or idle.

So I say do it, a few horsepower is worth the 5 minutes :smash: :smash: :smash:

 

Ok, I'll try.
1: The air pressure builds up on the inflow side of the screen where there is metal. This causes the air that is flowing through the holes to get squirted through. It's called venturi effect. The same amount of air flowing through a smaller passage creates more velocity.
2: No, by the time it hits the meters it is going as fast as it was when it left the screen. Remember, the engine is sucking air like crazy, creating a low pressure area behind the screen, and air pressure changes at the speed of sound.
3: With the screen off, there will be more air flowing through the metering area that will not affect the metering resistors.
4: A breif description of how a MAF works. There are Nichrome wires suspended in the air path and are heated to a know temperature with a calibrated current. Nichrome changes it's resistance with temperature. As more air flows past the wires, they cool off because the warming current is constant. This causes the resistance of the nichrome to change to a lower value and the current is greater on the other side of the wire. The output of the wire is connected to a voltage to frequency convertor. It's actually a voltage controlled oscillator. as the current goes down, the frequency goes up and the PCM can read this as a comparison value to the MAF tables. It is these values that the PCM uses to change things like fuel injector pulsewidth, for air/fuel ratio, and spark advance, retard.
5: That is why you probably won't get the hp you desire in the long run. There are a lot of tuners on this forum that play with the MAF, but they won't do it unless they have intimate knowledge of the air/fuel mixture and the ability to tune to the new values the PCM will be receiveing. :smash:

 

I wonder if anyone has actually dynoed before and after maf screen removal to put this to rest. Everyone has a different opinion on it. I wish I had a dyno near by, because I would try it to see if theres a difference. I would really like to know now. :crazy:

 

Well, there are tuners that have done that and they found that it actually deteriorates performace in the long run. They have found that you CAN improve the airflow to the engine this way, but you have to recalibrate the PCM tables to account for it. And yes, if the PCM is recalibrated you can pick up some hp. A couple of well respected tuners on this forum have measured the pressure drop (vacuum) inside the manifold on an engine running at it's peak. They then observed that if the pressure drops below that level engine performance suffers. The reason that the vacuum increases is because the engine is trying to suck more air than the intake can provide. They have found that a modified airbox (VaraRam, Blackwing, etc.), stock MAF, stock airbridge, and stock coupler can support up to 500hp, I think. The pressure doesn't start to drop until the engine is sucking enough air volume for that much power. So a lot of these aftermarket intake gizmo's don't do a lot. The cold-air intakes work well because they accelerate the air. :crazy: No such thing as cheap hp. :(

 

"No such thing as cheap HP" ... :iagree: you want some real #'s... gotta have some real $$$ but hey if you want to try out all the free mods :cheers: