Want less intake restriction? - A 929 AFM works!
 

I thought I'd start a new thread on this.

It is plug & play, except that fuel goes 40% rich.
It takes something like an S-AFC to adjust for the flow difference.
I had to dial back all my set points by 40%.

Oh yea - it is bigger...

The inlets:
http://208.62.166.66:82/guest/pics/91TII/TID/AFM-in.jpg

The outlets:
http://208.62.166.66:82/guest/pics/9...ID/AFM-out.jpg

Installed:
http://208.62.166.66:82/guest/pics/91TII/TID/AFM.jpg

I got this one on e-bay for $31.
I think it's the same one the Cosmo used.

this is a cone-type AFM? Does that work on an s4?

Hmmm the pluger is also much bigger...

any dyno test or 0-60 tests before and after???

sweet, is it plug and play? noticable gain? what year 929 afm did you use? how much did it run you? -alex

The big plunger takes less force to move because if its larger area.

The venturi opens way wider as the plunger depresses, so the ID/OD difference is more.

The plunger has a longer stroke.

AND - THE BIGGIE - The ECU & the S-AFC can handle it.

I hope to play with the G-tech this weekend.

these can in fact work on the s4 correct?

The S4 plug is different, but you could rewire it.

I think someone said the S4 AFM actually flows better than the S5.

hmm...i would need then a S5 plug and the 929 afm. so i think ill wait til i get some results from you.

It's the S5's AFM that's the main intake bottleneck.

This looks like the wide mouth bottle I've been looking for.

and im tried of th bulk that is the S4 flapper

Two of the 929 AFM's I saw on e-bay were rectangular hole input, round output, flap type S4 style, and were also this big.

I can only guess at S4 plug compatability.

very interesting ... keep us updated on this please ..

what year did you use?

Mine runs lean enough, dont think my AFM's working right. Anywho the car runs and idles fine so im not messing with it in that department.

Many people say it but that's absolutely false. They base this assumption on a guess. Some people have the logic that because the cone is in the way that it is a restriction whereas the flapper moves aside and is not. Untrue. The cone may be in the way but it is very nicely shaped which is good for airflow. The flapper door style is always in the way. In other words the edge of it always causes alot of turbulence which decreases airflow. Airflow through the S4 afm is far less than it would be through a hole shaped the same size with smooth inlets and outlets and no edges to pass. I have flowbench tested each one in the past but sadly didn't save the numbers. I can tell you that the S5 does flow better though.

well let us know what the part number is of the afm that you are using. i am going to buy one up if i can find it.

Brian

I wonder if using some sort of resister or adjustment to the pot would let this work with a stock ECU. I would love to see someone flow both of these and compare resistance from one to the other at several diferent flow rates.

SureShot, always the thinker! :icon_tup:

Stop making assumptions you cannot prove objectively.

Airflow has to also travel with more delfection from the larger center plunger...

I'd like to see hard proof that it does flow more - flowbench anyone?

Else, I don't see any performance advantage since you're still trying to match airflow with fuel delivery.
So you're changing the meter size, but you still need to jack the signal down to match the airflow being delivered?


-Ted

i dont think this 929 AFM is going to do anything.

you do know hes going to use an afc to alter the signals right? jesus christ let the man tlk. yall alwase say it won work till someone goes and prioves your little theoretical assumtions wrong. its bigger and less restrictive. point blank.

Glad I am not the only one thinking this

But you have this huge vortex now in the middle of you air flow...which based on aero dynamics says that the larger AFM would actually hinder air flow and slow intake velocity.

So until this can actually be proved to do anything I am (and probably Ted as well) more than skeptical.

This is basic Fluid Dynamics 101.
Also, it breaks Newton's first law - the shortest route between two points is a straight line.
Think about it.


-Ted

I hope Icemark sticks around a while, this thread has huge ugly potential.

This is only partially true. And only one factor of many that would affect losses (resistance to flow).

My degree is in mechanical engineering, fluid flow was one of my main areas of study (gas turbine engines etc).

Air can only flow until it is sonic and at that point is direclty limited by cross sectional area. Is flow anywhere near sonic in this thing? No but it is almost certainly turbulent.

If the 929 flow meter truly has less resistance to opening, and a lager "bore" it may indeed flow with less losses, depending on how much are you are actually trying to stuff through it.

It all depends on what the reynolds number is (likely turbulent) and if turbulent it basically only depends on CFM and minnimum cross sectional area. As the differences between the two in shape are incosiquential when they are that minimal and we are talking turbulent flow.

it wont do anything.