Let's get right down to it.



The kit is installed and ready to go (though the vacuum hose for the bypass valve is messy-looking and I'll be ordering a catch can as having a filter on the end of the valve cover line is hideous). But there were some hardships with the Bofi Racing Supercharge Kit. Altogether, the kit wasn't terrible to put on, but there are grievances and problems that will always need to be solved along the way.

Problems With the Kit and/or Description of Needed Parts:

• To make more PSI, you need to purchase the Overlay Pulley, unfortunately what they don't say is that we, as 1.6 US owners, must also change the crank pulley to the BP's. The Overlay Pulley does not fit the 1.6 crank pulley.
• They do not disclose that you will need a Power Steering Pump Bracket if you had from the factory a manual rack (and therefore a non-power steering bracket for the idler). If you attempt to bolt up their idler bracket, it will, but you won't have the adjustment needed for the supercharger and the belt will be nearly half off most of the pulleys. Picture 1 and Picture 3
• The kit will not clear the A/C compressor or lines, so if you want to retain your A/C, this kit isn't for you.
• If the fuel rail bolts aren't tightened with Hulk strength and then Medium Loctite applied, they may back out. The spacers they supply with the knock-off 640cc EV14 replicas don't appear to be the best quality in terms of engineering. They supply extras. After pressurizing the fuel system, #4 injector was leaking at the o-ring due to the connector pushing slightly against the head. Bofi recommends that the connectors be as vertical as possible to produce the best spray pattern. This is not going to happen as all the connectors come in contact with the head and therefore leak. However, turning them slightly to ~90* seems to work just fine, though I expect the fuel to not be adequately burnt.

Parts You Will Need to Purchase in Addition to the Kit:

• ECU. Either MegaSquirt, Speeduino, SpeedyEFI, ME442, ME221, Haltech, whatever.
• WBO2 Sensor of your choice, with a gauge.
• Boost Gauge
• Power Steering Pump Bracket if you have a manual rack
• Mazda GTX323 PCV
• 1.8 Crank Pulley if you have a 1.6
• Alternator and Water Pump pulleys that are ribbed, not V Belt, if the Overlay Pulley is purchased Picture 4

Parts Recommended to Purchase:

• Cooling System Re-Route
• Vacuum Hose
• 3" Worm Screw Clamp for the Air Filter (The supplied clamp is absolute garbage)
• T-Bolt Clamps for all other Intercooler Piping, By-Pass Hose, and BOV Hose
• 2 M10 Flat Washers to shim idler pully so the belt rides evenly on the surface Picture 2
• 1 M10 1.25x40MM and 1 M10 1.25 bolt, and nut along with 1 M10 lock washer for the idler pulley to fasten to the power steering pump bracket

1: Prior to the installation of the power steering pump bracket, this is how the belt sat on the pulleys.


2: After installation of the power steering pump bracket, the belt now rides properly on the pulleys. The "furthest" pulley was shimmed with two M10 washers to allow the belt to ride in the middle of the pulley. Pictured is the pulley PRIOR to shimming.


3: The power steering pump bracket that is need, along with a "This will work for now" bolt and spacer setup.


4: R Theory alternator ribbed pulley.

R Theory Aluminum Water Pump and Alternator Pulleys:

This was a miscommunication error, however it worked out. I have a 1.6 alternator which needed a 1.8 alternator pulley. In my case, the 1.8 ribbed pulley does fit my 1.6 alternator, however, if the spacer is removed from the alternator, the pulley comes in contact. If the spacer is left it, the pulley sits too far forward on the alternator shaft. If the pulley is flipped, it cannot be tightened down and makes contact with the alternator's body. The solution to this unique problem is to make a shim out of a washer approximately 2 MM in width, drill out the center of the washer and grind it down so it will fit onto the alternator at the proper height.

Or you can use a 5 rib pulley from a Chevrolet 2.5 Iron Duke. It fits quite nicely, but it is not good looking.

 

Vendor Review

Bofi Racing:

Wonderful vendor. I purchase the kit in early December of 2021 and it was received in March of 2022. The total cost, including shipping, for the kit and the overlay pulley was $3,551.79. Which isn't a terrible price whatsoever. There were bits here and there that needed to be purchase; R Theory Motorsports pulleys, a power steering pump bracket from Miata Source, and a Dorman crank pulley. Although the kit needed some massaging and there were some problems with their description, their customer service has been nothing but stellar. Given the time zone difference, they've been quick to respond over Facebook Messenger (and would likely be fast to respond via email as well). I'd definitely be giving them money in the future if I hadn't spent it all at once on everything I needed.

R Theory Motorsports:

We had some miscommunication, but the owner was communicative and offered a solution (I didn't take it as the cost to ship mine back and the new one to me would be near the price of the pulley I needed). I didn't take them up on the solution, but will be purchasing the correct pulley separately. That being said, their customer service was great as well, but, like Bofi, their descriptions could be more succinct and accurate.

I ordered the correct pulley for the 1.6 alternator and it fits wonderfully. While the 1.8 pulley fit with some modification, the belt was not seated properly on the crank pulley and was wearing prematurely. Now that the correct alternator pulley is on, the belt is aligned properly. A 1.8 alternator pulley will get you by if you happen to have one, but be prepared to replace the alternator belt sooner than later.

Miata Source:

Zach is nothing but great. Shipped the bracket quickly, definitely fair pricing, though the description said hardware would be included, no hardware was provided. Not a big deal, as the non-power steering bracket utilized the same hardware. Zach is a used parts and new parts vendor and I've used him several times.

 

Update

While breaking in the clutch on day 2, not getting a block from home, I hit 1 PSI and the intercooler piping off of the supercharger's outlet blew off. The provided worm screw clamp failed causing the silicone piping to blow off into the belt, shredding some of the interior of the hose. Luckily, the part of the intercooler hose that was damaged was close to the end and doesn't appear to harm its ability to hold more boost than 1 PSI.

I have doubled up on worm screw clamps at the outlet (using better clamps) and have ordered T-Bolt clamps for the rest of the piping.

The original review will be updated and I'll get in contact with Bofi to see if there's anything they can do about the problem I've encountered. I don't hold out hope they'll replace the hose, but if they offer a discount on the hose or free shipping to the States that'd be wonderful. They're a smaller company, so there's only so much that they can reasonably do.

 

Midsommar update?

 

The kit has been wonderful after the tune. Very responsive and reliable. I took it on a 2.5 hour roadtrip in 80+ degree weather the following weekend to iron out any bugs and everything did well. I have no complaints this far.
While the engine and kit did very well over the course of the last couple of months, there are some things that will need to be purchased to make the kit "finished" in my eyes:

• The DarkAdditive intake will be purchased to ensure good intake temps and a cleaner engine bay. Since the supplied air filter was too large for LHD, of bad design, and would not stay on the supercharger's intake plenum, I had to use a
  Spectre
  Spectre
  air duct hose and a cone filter I had laying around. While it works and does what it's supposed to do, the filter had to be crushed somewhat to fit in the pocket next to the booster and the routing of the pipe is long and has to wrap around the strut tower.
• FlowForce 640 CC injectors will be purchased so I know that they will be good quality and have low variability in flow rate. I'll get the other injectors tested and sell them to help cover cost.
• The supercharger's "hot side" intercooler hose I'll have to purchase during the winter from BOFI and have them ship it over. When it came into contact with the belt, it did rub quite a bit off and although it still holds boost (due to the double worm clamps) I'd rather replace it. While I'm sure I won't have any problems in the future with the original, I'd prefer to have a non-fucked up hose.

Those are the only "complaints" that I have about the kit and the update for a couple of months on of consistent driving. If it comes down to it that the supercharger needs a rebuild, I have to get another intercooler, or replace the injectors, most of it can be sourced locally or within the US for faster shipping.
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Hi, I have a 1992 Miata na 1.6 with a self built supercharger kit. I would like to mount the Bofi Racing overpulley, but I don't understand if I can mount it on my original pulley and why I should also change the water pump and alternator pulley.
Bofi racing told me that it fits on the 1.6 even without changing the other pulleys. I would like your opinion and experience before buying one. Thank you.

 

If your water pump and alternator use a v-belt then you will need to change the alternator and water pump pulleys to a serpentine style and change the crank pulley to a full serpentine style pulley. There are, from what I can gather, two different types of crank pulleys for the 1.6, Bofi is assuming that you have the style of crank pulley which they're overlay pulley will work. Mine, however, wasn't that style so I was forced to upgrade the crank pulley, alternator, and water pump pulleys. The crank pulley I used I believe is a BP pulley.

Is it worth changing to a complete serpentine setup? Meh. It's not going to hurt anything staying stock, but if you change all the pulleys you know that the overlay will work.

 

it’s because BOFI sells a one-size-only pulley. 1.6 and 1.8 differ. Trackdog Racing sells a similar 150mm overlay, but they make variations, depending on the VIN.

https://trackdogracing.com/crankoverlaypulley.aspx

while the overlay pulley is more expensive, it will probably be cheaper and less hassle than buying the other pulleys to adjust.

 

A little over a year into the supercharger build and it has been a fantastic kit. I have had some problems with it that were noted in the write-up, and only one other problem that I've since figured out.

The spacers that are required for the supercharger to fit well on the bracket and head, the pulley made contact with the hood causing a grinding sound that I couldn't diagnose until the pulley wore through some of the paint and metal of the skeleton structure. This may either be due to the height of the supercharger or the clearance of the hood as I installed hood struts rather than the hood prop. It's hard to say which is which.

That has been the only complaint I've had in the last year and it isn't a terribly big deal for me, though I can see how it would be for someone with a clearly mint Miata that wants a supercharger.