Here's a quick write up I did on the homemade intake setup I came up with a while back.

:edit: I forgot to mention, installing the intake in this manner required removal of the metal bracket that hold the hood prop in place for clearance. I removed my entire hood prop since I plan on installing the dual hood lift kit anyways.
http://www.rspeed.net/RSpeed_Mazda_M...nab050115x.htm

Required Materials:
(2) Spectre 3-2.5 reducers
http://spectreperformance.com/#CATALOG.8751

(2) Spectre 3in 90degree bends
http://spectreperformance.com/#CATALOG.8698

(1) 3in tube 6inches long
http://spectreperformance.com/#CATALOG.8718

(2) 3in silicone couplers
http://spectreperformance.com/#CATALOG.8771

(1) Standard cone filter
http://spectreperformance.com/#CATALOG.8131

(1) Vacuum adapter kit (includes hole saw and fittings to tap ISRC and valve cover vent
http://spectreperformance.com/#CATALOG.8711

(1) ½ inch (maybe 5/8 check hose from ISC/IAC) 90degree vacuum elbow

Air meter to 3in adapter
http://spectreperformance.com/#CATALOG.81413

Wire

Wire strippers

Solder

Soldering iron

Heat shrink

Electrical tape

3/8in wire loom

Zip ties

I was able to find all these parts at my local oreilly’s, check with your local parts store or order online to save some money if you’re not in a rush.
First I disconnected my battery. Always a good idea when doing electrical work

Next I went back to the engine bay and cut the AFM plug harness about 8 inches back from the plug and then soldering in about 5 feet of additional wire. If you chose to do this be careful because on mine (1992) two of the wires are color coded the same (black w/ green strip) Just cut these wires one at a time to avoid mixing them up. The rest are all different, just match them color for color.

After tinning and soldering the extension in, I ohm checked the wires from the plug to just the other side of the cut. They all checked less than .4 ohms so I heat shrank each wire (be sure to slide heat shrink on before soldering), electrical taped the bundle about ever 3-4 inches then stuffed it all in some 3/8 wire loom.

I ran the loom along the firewall, zip tieing it in place as I went until I reached the opposite side of the engine bay. From there it was just simple plugging it back in the AFM.

I run the afm and filter to the passenger/intake side of the engine I removed the factory intake and all its parts. Then I separated the AFM from the airbox and installed the 3in adapter I had purchased. After doing that I set aside the AFM for the time being.

I installed the first 3-2.5in reduced to the throttle body. From there I cut and inch off of each of my 90degree elbows to tighten the radius. Connect the two 90’s with a 3in coupler and insert on end into the 3-2.5in reducer on the throttle body. On the other end of your other 90 slide the 2nd 3in coupler on and insert the 3x6in tube.

On the AFM attach the second 3-2.5in reduced to the exit side and your cone filter to the intake side. Attach the AFM to the 3in coupler on your 3x6in tube and tighter all hose clamps (don’t over torque)

In order to tap for the ISC/IAC and vent tube I took a grease pen and marked the locations of my vent tube hose and ISC/IAC hose.

Remove the whole assemble by loosening the clamp on the throttle body reducer. Take your vacuum adapter kit and drill one small hole for your vent tube and one large hole for your ISC/IAC hose. The kit includes a fittiner for the vent but you’ll need to use the 90degree vacuum elbow for the ISC/IAC. The supplied grommets in the kit work for both.

Now simple reinstall everything, connect your hoses and tighten all clamps. Plug the extend harness and plug back into the AFM and reconnect your battery.

Start the car and check for leaks, if none are found go for a drive and enjoy! I found that this setup responds very similar to the stock box but give you’re a nice throaty sound from the engine, and since I’ve had the crossover tube out I’ve notice slightly cooler engine temps accord to the OEM gauge.

 

 

This is how I pumbed the hose for the re-circ valve below the throttle body

 

 

Don't think the pictures work unless you're logged into miata.net.

Needs more turbo.

 

FN nice

 

I'll change the links later once i have access to a computer instead of just my phone

 

Thanks

 

Nice job. Soooo many people would have just hacked something like this together.

I ditched my stock hood prop location when I boxed in my air filter but found that it hides nicely in the cowl area. The plastic clip from the passenger side of the car, where it used to be secured, fits into a factory hole in the firewall about 2-3" from the driver's side. Pop the rubber coated end of the hood prop in the clip, and direct the other end towards the wiper linkage. It'll lay flat, not bounce around, and be close at hand when you need it.