larger crank pulley on a 1990 miata?

anyone know of a crank pulley that is larger, but fits in the OEM position (spacing and bolt pattern) for the 1990 miatas? only option I have seen is the TRD over pulleys. I would like just a single pulley, not some 2 part deal.

By "single pulley, not some 2 part deal" I assume you mean a solid pulley with no damping? Bad plan.

What are you REALLY trying to do? Speed up a supercharger?

The 1990 crankshaft was only used for a year and a bit on Miatas, and there are very few parts built to fit it.

Keith I think he technically means he wants a 2 piece pulley and not a 3 piece one.

Someone needs to elaborate on how many pieces there are in a stock pulley, and which ones they are. I'm not hip to this.

Also, what's the actual goal?

Sorry...

yes, speed up the supercharger (in addition to the smaller pulley on the supercharger.. if/when I get one). and I guess.. yeah, I mean 2 piece instead of 3 piece. I just don't like the idea of adding an extra bit to it.. and would rather get something from another car. (also, I am super cheap, and 150 bucks for a pulley add-on is more than I want to pay.)

I take it you don't have room for a jackshaft?

You could always get these guys to make you a custom one. http://www.bhjdynamics.com/

If it's a 1990, I'm assuming you're looking at an M45 blower. It's almost tapped out at the normal 6 psi setting, spinning it faster ends up being more of an exercise in generating heat than power. My usual advice for those blowers is to enjoy it as-is, you're already at the point of (rapidly) diminishing returns. You've got a bit more room on a 1.6 than a 1.8, but I wouldn't go past 8 psi.

Other cars that used that crank design are the Mazda 323. Don't know what their pulley sizes are like, but there's where you want to look in the junkyard. If it were the later 1991-93 crank, we'd have a lot more options.

thing is I don't have 6 psi.... I am running at 4.5-4.7.. so I THINK I have some space left. it might have the wrong dang pulley for all I know.. or it might be on the way out and dying. (I am new to the boost world, and the car had the supercharger on it when I bought it)

First thing to do with low boost is to check for leaks and for slipping belts. I had that happen with my old 1990 with an M45, a bit of time spent aligning the idlers meant a big boost gain.