Anyone have a Mazdacomp alternator pulley and can measure the diameter? Trying to find out how much bigger it is than stock. I have the main and water pump and am thinking of getting the alternator. Mazda doesn't publish the size and doesn't share it when you call. Thanks.

 

I've used a stock air pump or power steering pump pulley a few times, I forget which one it is. The diameter is about the same as the alt itself. With the small main it doesn't even make 12v until about 4K rpm. It only needed a little bit turned off of it to line in up with the other pulleys and IIRC the ID is the same as the alt.

 

The diameter is the same as stock, I bought one. After I installed it, my alternator fell apart at the dyno. Now I am ordering an alternator.