NB to NA SC compatibility
 

Evening, all. I do hope that this is not a "dumb" question.

You see, I am looking to purchase a BPM MP62 supercharger from an NB. The donor car has the original motor, plus AC and PS. I am looking to install it on my 1990 1.6 chassis which has had a 95 1.8 swapped in, a FM depowered steering rack, and full AC delete. As you can see, there are a lot of variables between the two cars, so Google isn't too helpful or else I wouldn't be asking the shark tank.

I know the SC can be installed and will run. I'm not worried about that. What I am curious about, however, is - what kind of parts am I looking to replace or swap? Belts, brackets, etc.

Attached is the SC sitting in the donor car.

Thank you all in advance.

https://www.miataturbo.net/attachmen...ine=1452826234

That looks like the BRP kit and it has a 6 rib auto tensioner. That means it does not use any of the steering or AC belts. If you are getting the full kit including the three extended exhaust studs and underbrace you should be good to go.

You may need to change the intake hose to fit whatever MAF you are using.

Mechanically, everything should bolt up. Crank overlay pulleys are interchangeable between 1.8 NA and NB in this regard, and the hotside of the motor is pretty similar, so same brackets.

No idea what electronics are included with that package, but I wouldn't count on any of them being compatible with your 1.6 chassis.

Thank you guys. That helps.

The PO estimated 200-210 HP on the powercard. Don't know how accurate that is, but I'm expecting over 200 HP on my engine and MS setup. Should be an absolute blast regardless of HP.

Odd question: that bulge on the crossover tube is some sort of intercooler, isn't it? Or am I mistaken? Obviously it doesn't look like a traditional IC, but I thought I read somewhere that this is what it is.

PO is very optimistic.

It's an intercooler which uses water instead of air on the "ambient" side. These systems involve the use of an external radiator placed up front where a traditional intercooler would be.

Some of these systems use an electric coolant pump and a separate coolant tank. I've also seen some which leech engine coolant from the overflow bottle. Then, at the extreme cheapest end, are those which take hot coolant under pressure from the engine's water pump and use it to pre-heat the intercooler, thus defeating the purpose of having it.


And, yeah. Unless there's a dyno sheet showing otherwise, 200 HP on a powercard is kind of iffy. The MP62 can do it, but it needs more fuel and better cooling.

I figured the PO was being optimistic. I'm still happy with my purchase though. If you were to estimate HP, what do you think I'd be making on my setup?


As far as the intercooler, would it be best to delete the provided IC and run a normal crossover tube, or keep it? It has the BRP stamp on it, if that lends anything to quality.

Ballpark with powercard... 180?
You could push it over 200 with some good injectors and megasquirt.
Water to air coolers are rarely effective enough to warrant their use.
Sell it and run a decent air to air cooler.
Do a little searching for the ebay cooler that many of us use and rig up the piping yourself.
Few people run the exact same piping scheme, but any of the good build threads will have a setup that works.

Thanks. I'll be selling the IC and the powercards. Total long shot asking on this forum, but if anyone wants them, PM me.


I'm weary about the air to air IC. SCs have that whole idle droop issue. I know it can be countered, but I'd like to see how it does without.

I was gonna say 160, which is what FFS rates their base system for on the NA 1.8.

Even Pat's gigante whipple uses an air to air IC.
This location is questionable though.
https://www.miataturbo.net/attachmen...ine=1452876252

Yeah, that's probably more accurate now that I think about it.
Reports of 180 on an MP62 are usually from a MR member's wet dream.

FM doesn't even claim 180 at the wheels on their intercooled Voodoo-II 1.8 NA turbo system, and that's without the parasitic loss from turning the blower.


180 on an MP62 can be done easily, but not on the stock injectors. IAT also starts to get iffy if you're not running good intercooling or blasting huge amounts of liquid into the plenum.

Guys, I'm not sure the OP (or the PO) are referring to WHP here.

Even still, 200 BHP =/= 160 WHP. And I doubt seriously that they took the engine out and ran it on a brake dyno.

I would keep the W/A intercooler for that setup. It's will keep AITs ok and not add any throttled volume really.

I would not run without an intercooler unless you're running E85. Even then, I'd still intercool it.

Agreed. The OP said the PO "estimated".

Thanks everybody. Seems like everything points to a green light. Eager to see how everything works out. I'll report back once everything gets going.

We weren't talking about what the OP said about what the PO claimed. We were asked for an estimate, and everything I said after that was in response to Monk, who guessed 180. That's why I quoted him, instead of the OP, in my response.

:eggplant:

I just want the OP to understand the responses he gets to his question, and how they compare to the PO's overly optimistic estimate.