I recently got the chance to take a closer look at the Cosworth SC for the MX-5 NC.
It is no longer branded as a Cosworth SC but sold from several sources which then will put some stickers on it like FM, BBR, Goodwin and a couple more. It is rumored to be manufactured by Magnuson and originally designed by Cosworth with the hopes of becoming a factory/dealer option for the NC.
The kit was initially plagued by engine failures and poor drivability due to problems with the tune/maps in the reflash that was part of the kit. The problems including the tuner shit storm surrounding it are very well documented on forum.miata.net. The tuning issues are now fixed. I think it is safe to say that if your tune was done using Sniper or Piasini software you should keep an eye on your AFR's...
The cost of replacing and refunding engines that had been knocking them self to a certain death might be the reason Cosworth pulled out and sold the rest of the kits/design without the Cosworth brand.
This is very unfortunate as the hardware is simply the best engineered FI kit for the NC I have seen to date. The attention to detail and the way it blends in with the rest of the engine/car is second to none. It simply looks like it came this way from the factory with all oem hoses, clips, reuse of intake parts etc.
Some pics installed in the engine bay. Stealthy and compact. The SC pulley can barely be seen under the intake.
The installed kit weighs in at 35kg dry. The compressor unit comes partly assembled.
All the smaller parts are neatly ordered into sectioned plastic. No ziplock freezer bags here.
The electrical wiring and fuel line is wrapped with OEM like plastic protectors. All the aluminum parts like the new fuel rail, extended water neck thermostat housing looks like factory OEM parts.
The upper part of the intake manifold is a cast aluminum that sits on top of the compressor. It has all the right bumps and dents to fit with the stock shock tower brace and other parts. All OEM ports are preserved. Nice and gradually wider flow path into the mouth that goes down to the compressor inlet. The FM logo is just a sticker. The original cast Cosworth logo has been machined off. The left side of the manifold before the FM logo seems like a nice place for a WI nozzle.
The intake side uses the stock O-ring of the 55mm DBW throttle body. A bigger 60mm TB from the 2.5 MZR might fit with some dremel action and a conventional gasket.
The plastic parts in the kit are rotomolded and looks OEM. No polished alu or fake CF stuff here.
The MP62 unit and intake manifold is combined into one pice. The compressor can not be separated from the manifold so the discharge port might be custom for this application. The Water to Air inter cooler is sandwiched between the compressor outlet and the plenum. It comes with a new IAT sensor which replaces the stock one integrated into the MAF. The other port is for the OEM MAP sensor.
The wide plenum wraps over the SC and into the intake runners. Plenum volume and flow characteristics seems good and hopefully Cosworth has done their homework regarding flow distribution regardless of unequal runner length.
This part will be covered by the upper manifold. It might be a good idea to use some kind of heat shielding on the underside of the upper intake as well as a phenolic spacer to avoid heat soak from the compressor.
Runners looks good as expected from a cast manifold.
The SC intake mates perfectly with the upper manifold and includes the EGR port. As mentioned above, this is a good candidate for a phenolic gasket/spacer.
The water to air inter-cooler isn't optimal but adds to the compactness of the kit. Instead of routing 2.5" IC piping to the front you only need two water hoses to the heat exchanger. I'm sure it is more than capable of cooling the 8psi this kit was designed for but the MP62 tend to heat the air a lot above 12 psi. I wonder if it would be possible increase the cooling efficiency by replacing the heat exchanger with one based on the Laminova IC cores .
Some pics of the operation when the freeze plug is removed. Notice the port on the left which bypasses both the compressor and IC.
BBR says 235 hp for the same kit. I think about ~200whp would be expected with better exhaust but that 250 reliable whp would be possible with E85 and WI (given proper engine management).
Some additional data on the MP62 gen 4/5 taken from Magnuson webiste: