Spec Miata Style adapter?
 

http://wardsweb.org/cars/miata/spinduction400.jpg

I'm wondering if someone makes something similar for an S4 airflow meter... It just seems totally wrong to use an adapter that's only about 1" thick...

How are you going to cram that under the hood?

My dad's a TV repairman; he's got an awesome set of tools. I can make it fit.

Where and to what end?

He had better be a welder.
He'd have to knock a hole in front of the car so that thing can stick out of it.

Have you looked at the space that you are working with yet??Take a look in the engine bay.

Oh come on Styxie, you can do better than that.
You assume the location of the AFM is a given but it doesn't have to be.
Shorten the tube between the throttle body and the AFM and viola!, room for the Miata piece.

Still don't see the point though.

I wanna see the headlights pop up as 7 inch DVD monitors!

yes, even HKS made one as i have a few lying around.

http://www.ebay.com/itm/MAF-Mass-Air-Flow-Sensor-Intake-Adapter-for-Mazda-86-89-RX7-RX-7-13B-87-88-/281239463582?pt=Motors_Car_Truck_Parts_Accessories&fits=Model%3ARX-7&hash=item417b2da69e&vxp=mtr
it needs to be extremely short to fit behind the headlight but the one linked should work as a universal unit. why would a short adapter be bad? the shorter the pipe is the better the airflow should be. on turbo engines the length of the suction tube can cause dramatic results, on non turbo engines the results would be much less dramatic but the principle is still there.

a longer induction tube translates to better low end throttle response at the cost of upper end breathe, shorter lengths should result in the opposite taking more advantage of the engine design assuming the auxiliary ports are functioning.

The point was to give a nice gradual change from a round filter to the rectangular input of the afm. I wasn't expecting it to be that long, I just used that as an example. It's a n/a car, and the plan was to use 4" piping necking down to the 2 X 2.5 rectangle just do that as much of the air entering was laminar as possible. I know in header design, 7 degrees is about optimal for any diameter change without inducing turbulence.
I have since decided I'll probably go with a large diameter k&n cone filter (on the order of a 6" inlet) and devise a "velocity stack" type radius leading in.

don't overthink the ability for air to move where it needs to. moving to a bellmouth isn't going to make a big difference but only cause you headaches in trying to fit everything in there.

the airflow meter itself is already the major factor to airflow disruption.

What about smoothing the airflow pre-afm so that more will actually pass through it? I know it's fully open by 3500rpm or so, so why not find a way to make it LESS of a restriction? Had one of Collin Chapman's guys NOT "overthought" airflow, would we have the knowledge of "ground effects" aero we do today? I don't expect 25% hp gain, but just something that is a little better.

what other mods do you already have out of curiousity?

Yeah I use the short one and my filter already rests up against the car ,any longer and it simply wouldnt fit.

Atm, just the Atkins sleeves. Have a Bonez high flow cat coming and a cat-back exhaust. Eventually, I'd like to have one of Rotary Shack's headers on it with the aux ports opening via rpm sensor. I have an E-Manage Ultimate in the wings and a second motor to play with the porting on. I learned my porting from Craig Nagler, only actually ported a couple motors as of yet. I may build a MegaSquirt for it. This is going to be a test-bed for my RX-2.

Is he gonna shit or is he gonna kill us? :lol:

two things.

1st the HKS adaptor is a nice piece, its tapered internally, and not a pipe welded to a plate like the Ebay ones.

second, its been proven that the real restriction is the hose between the engine and afm, sure its 4" on the outside, but measure the inside...

plus the airflow meter is square, it disrupts the airflow more than the opening to it does, then the convoluted tubing to the engine... so you see you are looking in the wrong place.

get a standalone and remove the AFM, make a straight pipe to the throttle body and then choose a performance filter that works.

worrying about the pipe going to the AFM is just wasting your energy. if you want to see a difference with just that then you would be better served to create a ram air induction system to the nose of the car for cooler, denser air. most people fail in this because creating an efficient duct system to the front of the car can be a complicated task. there's no issue in working with airflow dynamics but you have to be sure everything downstream can handle the changes, otherwise the gains will be negligible.

the intake manifold is already a restriction in the 7300rpm range as well. no amount of upstream mods you do will fix that.

freeing up the exhaust then going standalone would be your largest gains