I've installed a couple of superchargers, the M45 version, on Miatas and always enjoyed the increase in power.  Several years ago, Moss Motors released the larger MP62 blower for the 94+ Miatas and this is my first experience installing and driving a car equipped with this setup.

Prior to receiving the blower (takes up to three weeks to build and ship), I decided to do some of the basic preparation work.  This included extending the TPS harness with soldered joints and shrink wraping - DO NOT use the butt connectors provided in the kit.  One loose joint will have you searching madly trying to track it down.  Some 1/4 wire loom also gives it a factory look.

Because my car is equipped with a Jackson Racing header, I wanted to cut down on the amount of heat cooking the bottom of the supercharger.  I've been warned away from header wrap and so elected to use the header blanket sold by Track Dog Racing.  It's easy to install and will deflect a fair amount of heat away, providing a minimally cooler intake charger but every little bit helps.  I also put a heat wrap on the radiator hose closes to the header to extend its life.

Speaking of hoses, I changed out all the hoses and the radiator, belts and the timing belt, preferring to have a known quantity when it comes to critical elements like cooling.  Probably overkill on a 30K mile car and so use your best judgement if considering a forced induction application.

Part of the attraction of the Moss Motors system is that it comes with a Powercard-Pro for fuel management and a timing card for (obviously) timing control.  That's the good news.  The bad news is that these have to wired into the harness that brings all the wiring to the ECU.  To do so, you have to use vampire clamps, only one step above butt connectors in my opinion.

So, to make life a little easier, and to also make it easier to someday return the car to stock wiring, I elected to purchase an ECU extension harness from Boomslang.  To me, it's $99 well spent and helps insure you don't have loose connections in a very critical area.  This is the extension harness labeled with the appropriate tags for the various wires that will need to be cut and soldered once the actual power and timing cards arrive.  The writing you see is mine, trying to keep myself straight as to which end is the harness connection and which one plugs into the ECU because some of the card wiring has to be wired in one direction or the other to interrupt the timing signals.

When the unit finally arrived, first task was to get the electronics wired in to the boomslang harness.  As it would eventually take three separate Powercards (ECU piggyback) to get it correct, I'm glad I used a harness extension or I would have butchered my stock wiring pretty badly.  You can see the boomslang harness going into the ECU in this picture plus the timing and Powercard hooked into everything with properly soldered joints.

Because of the prep time already spent, final install time was only about three hours.  The finished product looks pretty factory, the only cosmetic issue is the large 3/4" hose that carries air over to the idle air control valve.  Because of the location of the fitting on the plumbing, it has to take off towards the front of the car and lays on the valve cover.  I'm going to look for a 45 degree fitting that will bring it off the plumbing back towards the rear of the car and then run it along the firewall and down the intake side, out of sight.  I'll then use a 90 degree fitting to bring it back over to the IAC valve.  I think it will make for a cleaner installation.

My first impression:  Wow!  It's a very noticeable difference in power with no discernible change in driveability.  The idle circuit is very stable with no droop whatsoever and tip in to boost is seamless.  I've decided to install a boost gauge and an air/fuel meter so that I can better tune the car.  Once those are installed, it will be off to the dyno for fine tuning and some verified results of the install.

Of course, seat of the pants means nothing without verification of the power output, coupled with tuning on a Dyno.  I also installed an Innovate LM-2 wideband O2 system to get exact readings on the airfuel ratios.  To finish it off, I put in an autometer boost gauge to make sure the blower was providing the advertised PSI.  It is, at 7.0psi initial boost and 8.0 at redline.

We finally got it tuned to 171HP and 147TQ, a 65HP gain over stock and an additional 48lbs ft of torque - better than a 50% improvement in HP.  Estimate crankshaft horsepower is now 195 and there is enough room left in the timing to probably get it to the magic 200 cranshaft horsepower.

One additional change that was needed was to the fuel injectors.  Unfortunately, the stock 270cc injectors were running out of headroom at around 155HP and the engine was going lean at around 6500rpms and causing detonation.  Thanks to some really intelligent and competent people at miata.net and miataturbo.net, I was steered towards swapping out the stock injectors for 305cc units from a Toyota Supra.  They were 100% plug n play and created no driveability issues out of boost and provided sufficient fueling to balance the AFR curve to 12.0:1 across boost.