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-   -   Unorthodox Pulley Question (https://www.zdriver.com/forums/300zx-z32-performance-technical-47/unorthodox-pulley-question-8904/)

OrangeZ32 Apr 4, 2004 08:24 PM

Unorthodox Pulley Question
 
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? :confused:

91zxtt Apr 5, 2004 03:26 PM

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.

drmx Apr 6, 2004 04:39 AM

I'm going to install mine this week, I've been told it will increase vibration slightly at idle, but other than that, no harm done.

OrangeZ32 Apr 6, 2004 06:32 PM

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

91zxtt Apr 7, 2004 11:23 AM

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

phza666 Apr 9, 2004 02:47 PM

underdrive pulley
 

Originally Posted by 91zxtt
I didn't notice any vibration increases after I installed mine.


Be careful, the only pulley that really does anything is the underdrive pulley in these cars, the others are just for show, so, unless you pop your hood alot, only buy that pulley, and it won't mess up the balance, and I didn't notice vibration either

91zxtt Apr 9, 2004 03:21 PM

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.


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