Intake Installation

Last updated: March 16, 1999

I installed the MM intake last weekend, and it was a pain in the @ss. There is a right way to install it, and at least 3 wrong ways that I discovered. The right way should be fairly simple.


Additional Parts



  1. Remove the stock air box, being careful of the hoses. Remove the three gold-colored brackets that used to hold the airbox in place.

    (Note: the third one that has the bracket supporting the radiator hose was removed by MM when they did the install for Jim King. I was going to leave it there to support the hose, but since MM took it off, I will do so as well. Also, with it there, the hose was slightly squashed between the airbox and the bracket, so removing it should help eliminate this issue.)

  2. Remove the foam rubber that used to seal the radiator to the frame. This is about one inch wide by six inches long. I used a utility knife to cut it.

  3. Insert the new airbox in place, but do not bolt it down yet.

  4. Attach the big turbo air hoses to the new airbox. This is best accomplished with the box not yet bolted down so you can move it up and down to find the best angle to get the hoses on. This is where the new hose clamps come in handy, as the stock spring-type ones are impossible to get on. (And they flew off of the channel locks I was using and knocked my glasses off! on one occassion, and shot across the garage on others (I was using a good pair of channel locks too).)

    Note: this is where I installed it, removed it, installed it, removed it, ... many times. I did manage to finally get the old clamps on by removing the hoses from the turbos, attaching them to the new air box, and then putting the hoses back on the turbos. For some reason those hose clamps had more room to get them back on than the ones that went to the airbox itself.

  5. Attach the other hoses to the airbox. If you are not using the airpump, be sure to block off the hole for it, or the airbox will suck in unfiltered air and possibly chunks of stuff (note technical terminology :-). (I think you might be able to order the airbox w/o the fitting for the airpump - ask MM when ordering.)

  6. Bolt the airbox down using two of the bolts that held the gold-colored brackets in place.

  7. Install the K&N filters. (I originally tried to put them on first, but there is not enough room around them to get the bolts in place).

  8. Attach the airbox top plate.

  9. Enjoy.

Date: Tue, 25 May 1999 12:47:22 -0500
From: "Westbrook, Chuck E." (

Last Friday I received my M2 cold air intake system, and installed it Saturday. The design is very good with great welding.

It didn't come with instructions, but the installation is not difficult:

(1) remove the old system completely except for the #1 turbo inlet hose, leave it attached to the #1 inlet

(2) remove the rubber connector end pieces from both turbo inlet hoses that connected them to the old air filter box, the new aluminum tubes are smaller in OD so these aren't needed

(3) remove the three brackets that attached the old air box to the frame

(4) remove the foam rubber between the side of the radiator and chassis on the right side

(5) if you are running an 86 cooling system overflow cap unit and also have the AST removed as I do, then you might have to remove then reroute the overflow hose during this installation

(6) take the top off the M2 unit and remove the two filters

(7) slide the new box down into the side between the radiator and frame, this requires a little finesse, during this maneuver, you will have to slip the end of the #1 inlet hose onto the bottom aluminum tube on the box, you also have to align the middle tab of flat aluminum side sheet into the side slot of the fan, when all is aligned and connected, push down slowly while you guide the box in

(8) secure the box to the frame with two of the 10mm bolts taken from step 3

(9) attached the #2 turbo inlet hose and the other four small hoses, use screw clamps for all of these, not the spring clamps

(10) the two air filters have connectors that are slightly angled, install the bottom filter so it angles down and is center in the box, then do the same for the top filter

(11) attach the box cover

From: Kenneth Stone
Date: June 28, 1999

This thing is truly amazing. All aluminum and beautifully welded, it can now be ordered powder coated black for only an extra $12 - trust me, its worth it! The side resting near (on) the radiator hose is insulated, and it now comes with two screw-type hose clamps for the two large hoses going to the turbos. The only downside? It was a bitch-and-a-half to install. If this post helps just one person, I'll be happy. They really should include instructions. I spoke with Brian and he told me the correct way only after I installed it about five times. So here it is:

  1. Remove the duct from that goes from the intercooler ducting to the airbox.

  2. Remove the stock air box.

  3. Remove the three gold colored/brass brackets that supported the airbox.

  4. Take a razor, utility knife, or any other sharp instrument and cut & remove the foam strip (it's about 1.5"x9" long) between the radiator and frame of the car. There are probably some leaves stuck in it.

  5. Ok, the next part was definitely not obvious to me. There is a small rubber hose that runs from the radiator fill tank behind the right, front headlight assembly, across to frame, under the intercooler, and up to the overflow tank where your radiator cap is. Now locate the small bracket next to the fill tank. Unbolt it and move the line to the other side of it (behind it) and bolt the bracket back on. This frees up a little slack and prevents a kink later on.

  6. After step 5, my hose still did not have enough slack for the box. Brian said this varies from car to car. If this happens to you, remove the hose at the overflow tank and remove it from its clip on the rail at the base of the battery. Now carefully, so as not spill any radiator fluid, re-route the hose to the other side of the left bracket supporting the intercooler (essentially, it's between the brackets). It doesn't come close to touching any of the pulleys or belts, and it shouldn't rest against the intercooler. All the same, move the plastic insulator down (it slides) a little to protect the line from the intercooler.

  7. Remove the large air hose that sits on top, and if it makes things easier, the hose next to it (not to the blow off valve). Put the air box in about a quarter of the way.

  8. Remove the boot around the end of the bottom large hose, or it will be too tight. Now install the lower large hose and clamp it on good. I used the stock clamps. I know they're a pain but I've gotten used to them (all you need is a big pair of vice grips).

  9. Push the box into place. Watch to make sure that bottom hose stays on square. It likes to try to pull off on the bottom half. Watch the insulation on the box so that it doesn't scrape against the radiator fans frame (I tore a chunk off!). Guide the small hose from 5&6 behind the box.

  10. Screw the box into place. I used the long screws that held the stock airbox in place instead of the short brass ones. Remove the boot of the top large hose on the end that connects to the airbox. Attach all hoses and clamps.

  11. BUY A NEW HOSE FOR THE AIR PUMP!!!! HA HA HA! I cannot tell you how much this pissed me off. The stock hose is short by about an inch. Just go buy a radiator hose with a 90 degree bend in it and about 4-5" on each side of the bend. The hose I bought was thicker so I needed new clamps too. Install.

  12. Now the last part gave me a lot of trouble - installing the filters. Don't laugh. I played with their positioning quite a bit so that they both fit with the lid on but didn't rub against eachother and were secured far enough on the collars. Make sure they're on tight! Install lid.

  13. Install plastic piece, supplied by MM, over intercooler ducting with rivets or epoxy.

Date: Thu, 6 Apr 2000 14:44:11 -0500
From: "Steve Obrien" (
Subject: Re: (rx7) (3) Oil in my airbox

Oil is getting into your air box from 2 different hoses that lead back to the air box;

  1. Air bypass valve (lower blow off ) vents air/oil mist, vents when vaccum is sensed in extension manifold
  2. Charge control valve (upper "blow off") vents air/oil mist, vents during 3000rpms to 4500 rpms

As for the "mysterious hose" that leads to nowwhere, that hose is a vented hose from the air baffle on the stock air box. Its not suppose to be connected to anything. a little bit of oil in your air box is normal.

[Mail me] [To Lightning home] [To my home page] [Copyright Notice]