I've heard from a few guys that the racing pulley mess up the harmonic balancer on the engine is this true. I was kinda curious before I went throwing something like this on my car. I've heard a lot of good about these but should I just assume they're dumb and they installed it wrong?

 

If you go to unorthodoxracing.com there is a FAQ section where they answer questions like this. I was concerned about the same thing prior to installing mine. Here's the thing. The VG30DE crank is already balanced, so there is not a need for a harmonic balancer, so it doesn't have one. The TT crank shaft is manufactured within such tight specifications, that you should not run into problems associatied with a non-balanced crank, such as abnormal wear to the main bearing. The crank pulley on the Z32 is actually a harmonic dampener; which is different than a balancer (Rizz knows more of the details on the differences). You'll see harmonic balancers on older, larger displacement motors because manufacturing specs left something to be desired. I'm happy with mine underdrive pulleys.

 

I wasn't sure about it, thanks for the help

 

I didn't notice any vibration increases after I installed mine.

 

The power gains from these things are primarily due to the fact that the underdrive pulleys are so much lighter than the stock pulleys. Minimal gains are realized from underdriving the alternator, water pump, power steering and AC. The stock crank pulley weighs about 12 pounds. The UR pulley weighs under 5 lbs. That's a huge difference in rotational mass. The accessory pulleys (PS/WP/Alt) can be installed as well. I did this. These are primarily for looks. They are slightly lighter than the stock pulleys and they underdrive the items listed above slightly.