SpeedSource Pulleys Review

The "Competetion Pulley Set" from Mazdaspeed is really THE best pulleys you can get for the RX-8. They are actually produced by SpeedSource and are widely used by pretty much any roadrace prepped RX-8. The kit is made to not use your air conditioner, allowing you to remove the system and save some weight there.

The eccentric shaft pulley is substantially smaller than stock, as well as much lighter. The alternator pulley however, though lighter, is much bigger than stock. For race cars, this is not an issue considering they're frequently up in high RPMs. For street cars, this can be a serious issue as that means the battery is not getting as charged as it needs to be. I've run into an issue once or twice where I started losing power steering and then ABS while sitting idle in grid, while using the lights, defrost, radio, and windshield wipers. The problem never came back when I kept my revs around 1,500 RPM while sitting idle however.

The power increase is definitely VERY noticeable and I've heard wind that it is supposed to be a 10HP gain..If that is true or not, I wouldn't doubt it given the fact that we're talking about SpeedSource here, but I for one don't have any comparisons. I guess for those that are looking for pulleys, this is definitely worth the price tag if you're building a race car and not a street car that you like to have fun with, given that it doesn't charge the battery unless you're frequently in higher RPMs.