Mesh Removal From AFM = KW Increase?

[-Joel-]

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..

[TINDUCK RACING]

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.

[NIF]

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.

[TINDUCK RACING]

Thanks NIF....you have....

Jon.

[WDRacing]

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

WD

[TINDUCK RACING]

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

...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.

[NIF]

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.

[WDRacing]

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

[swampy]

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

thanks ..............

[NIF]

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: