Mesh Removal From AFM = KW Increase?

Does the removal of the Mesh which is in front of the AFM and rear actually make a noticible change to response in an R32 GTS-T?

G'day Joel,

I have questioned the same thing, surely it must restrict the airflow from the air filter. Remove it and find out, and then tell me. :p
As for how much power it is robbing :confused: I imagine it could only be a kilowatt or two.

Cheers,
Doc

I am known as the FIDDLER.. So i guess i might do just that then let u know :)))

i would not touch the mesh if i were you it takes just 1 bit of crap to stuff up your hot wire and then you can pay $200 atleast for a new afm

Never, ever, remove the fine mesh from the air flow meter. It is there for a reason.

Yes, it does restrict flow. It is there to disrupt laminar flow and induce turbulence.

Think of the grate in your tap on your kitchen sink, same principle, it is there to add turbulence to the water so that the flow, no matter how small, will use the entire width of the pipe.

As the element that measures the intake air stream is small and sits in the middle of the pipe, if you didn't have the mesh there, you'd get a natural boundary layer of air sticking to the outer side of the pipe and thus all measurements would be wrong.

Mario.

damn i accidently poked a hole in the mesh when i was installing the pod filter... hope it doesnt make ne diff

damn I accidentally took mine off and threw it away ages ago.......
.......NOW you tell me........Doh!!!

*points at tinduck and laughs*

sorry :D

Mario is pretty much smack on there, the reasons he gives are dead on.

Not to go against anything Mario said. But I have 4 or 5 MAF's in the garage. Some with and some without the screens. I haven't noticed any performance loss or gain. I do believe though that it might tend to make your car run a bit rich without the screens installed. Which is never good. I can't be sure it was the MAF causing it but it could have been.

WD:devil:

Your very lucky, I'd say!

It could be just that your airfilter is right in front of the AFM, in which case, the short tract length would preserve the disruption to airflow as the air is drawn through the fine mesh of the air filter itself.

I performed testing of this many moons ago, and found that the AFR would significantly be changed due to incorrect measurments from the AFM - in some cases so much so that the test engine would run very lean (over 13:1)...

Mario.

I would have to agree with both points about the mesh. If it came with the mesh you can bet that sensor was calibrated as such. I have also seen sensors come without mesh but to support Mario the actual sensor was on the sidwall.

mario, my air flow meter was buggered so i got another one to replace it, and everything was good. The one i replaced it was 2nd hand, and it already had the mesh removed, but my car runs fine.
I understand what you said about having the mesh, but howcome mine still runs fine??

Teh effect of the missing mesh might be very minimal, they could also cause you to run rich/lean. Finding a replacement of sorts might be a good idea if you properly secure it.

My Filters are always mounted directly in front of the MAF.

WD:devil:

Is there any powergains by slapping on a bigger AFM from another car to an RB20DET.. Say if my dies.. Mind you I know i would have to have it tuned to suit..

Help please dude.....

.....I removed my AFM inlet mesh a while ago to fit the neck of my vector cone filter( the one the RS500 Cossies used) just inside it. I have done this to save having to make up a square-to-round fitting flange, as the O/D of the filter neck is the same as the I/D of the AFM.....
....This was done a while ago now, and the car seems to run fine.....(ECU reset)....
.....Am I asking for trouble and need to replace the mesh and fabricate a flange, or will the close proximity of the vector filter be enough to disrupt the air flow , in your opinion????

....any help much appreciated, as this will kinda affect the final tweaks on my cold air partition......

Thanks,

Jon.

Maybe not the opinion you were looking for but here goes. You should be O.K. without the mesh. I've done the same thing before and had no ill effects. But if you feel confident in fabing a screen or come across a cheap AFM it certainly won't hurt. Hope I've helped.

Thanks NIF....you have....:)

Jon.

Relax Duckman, I've been running low 13's for 6 months now with no screens.

WD

.....cheers WD....I appreciate the help.....I know that we don't always agree, but how do problems get solved without a little debating? :D

...I've been racking my brains for remnants of fluid dynamics lectures for the last 2 days now, with respect to Mario's comments.......and from what I remember, if the flow is not disrupted, (i.e: no mesh), then the column of air in the middle of a tube will flow faster than the air sticking to the sides, so by definition, the air at the centre is flowing FASTER THAN AVERAGE......Which means that the air flow sensor (in the MIDDLE of the AFM) is sensing a greater than actual airflow......and therefore telling the ECU that there is MORE air than there actually is.........so the ECU will fuel according to the amount of air that it THINKS it is getting......and the car will run RICHER if anything, and NOT weaker...........
.....This presents me with a dilemma: I know that Mario knows more about this stuff than I will ever know......but he says that the car will run dangerously LEAN with the mesh removed.........yet after a sleepless night I cannot find fault with my argument........

FLUID DYNAMICS EXPERTS NEEDED URGENTLY!!!!!

Help please Mario??

Jon.

You are absolutely right about air flowing faster in the middle. But think about the fact that there bends in an intake system. If there were to be a bend just before a sensor then the flow in the middle of the sensor wouldn't be the fastest.

Stock...The MAF is mounted directly behind the air box. No bends.

Aftermarket Filter...99% of all the filters we use are installed with MAF directly behind the filter. No bends.

Think of the screen in the MAF in relation to your kitchen sink. Remove the screen and the water spews out all over the place. Install the screen and you get one solid flow in one direction. With the screens installed the air consumed into the engine is concentrated to allow the MAF to to recieve the proper signal. With it removed the air will tumble past the sensor. Only allowing it to recieve a partial signal.

The MAF has a sensor in the middle which will constantly try to stay at the same temperature. The amount of electricity sent to the sensor to keep it at that temperature is measured. This signal is then calculated and fed to the ECU for use with the other sensors to determine the best fuel map.

So if the MAF only reads a fraction of the air intake it could send the ECU the improper readings causing your car to lean out. Obviously since your car is actually ingesting more 02 then your ECU thinks it is.

With the car at WOT the ECU uses a predetermined fuel map no matter what the sensors say. So as to provide maximum fuel and air. This is why our cars run rich under power. This is also why we can safely raise the boost to 14 or so PSI without running to lean.

Sorry for the story...just got caught up with things.

WD:devil:

Just luv the stories ............. they make me understand it better.....keep em coming.......

thanks ..............:) :) :)

You are right about no bends before the AFM. Mine is the same way, just presenting a hypothetical situation (food for thought). Also think about this, air has to "bend" around a filter as it is sucked through. It would be interesting to see direction of the air path. :sun: