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Heys guys I installed the Driftmotion Light Weight Pulley kit so I figured I would share my impressions. So a few weeks ago I had my car up on the lift just to have a look around and found that my crankshaft pulley was cracking pretty badly and I had heard some horror stories about when the pulley decides to come apart so I knew it needed to be replaced. Even with my discount I didn't want to for one from the dealership....while looking for a cheaper option I came across the Driftmotion Pulley kit. I did some research and the reviews were mixed. I wasn't sure then I called Aaron at Driftmotion. We spoke for awhile and I felt comfortable making the purchase. $150 and a few days later viola....
The pulleys look great!!
While doing research some people were saying that the pulleys would not be the rights size so I took measurements. Some people were also saying I would have charging problems with an underdrive pulley so I requested the stock size pulley.
Measurements
I was kind of skeptical of the weight savings until I held the pulleys at the same time.
1. The absolute weight difference shown on the scale is nearly meaningless.
2. The reduced diameter of the crank pulley, and (most important) reduced weight at the rim of all pulleys is far more important. The inertial saving is far more than the weight difference.
3. The speed of the accessory drive will be reduced in direction proportion to the ratio between the old damper OD and the replacement; your alternator, power steering and whatever is driven off that belt will run slower and consume less power.
4. If the alternator is in that belt your charging rate will go down; if it's really slow it won't charge at idle when the lights are on.
5. You no longer have a harmonic damper; no engines have been built without one for about 60 years. They didn't build this in to the replacement because it costs lots of money, not because you don't need it. What does it do? It prevents (at least reduces) destructive torsional vibration from wrecking your crankshaft. How to deal with this: it may show up as extra vibration, "buzziness" in the steering wheel, shift lever, pedals etc. at certain RPM regardless of gear ratio or throttle opening - keep away from those. Drive through them, but not in them continuously. Raising your speed by only a few mph makes you safe.
Thanks for the information. Fortunately while driving over the last couple of days I haven't felt vibrations it actually seems to be smoother but that could be because my old pulley was in such bad shape. To avoid poor charging issues I decided to go with the stock diamter pulley so I shouldn't have to deal with those issues. I am enjoying the increase in throttle response and the actual changes with small throttle inputs.
I would never use that crank pulley. It is pretty much known to cause issues I can't believe Aaron told you it was safe. Everything else is fine except for that crank pulley.
Wow great posts from Kitabel and TrackMKIII. Thanks for the input guys. Kitabel actually answered all my questions because I immediately wondered if balancing the rotating assembly would eliminate that harmonic vibration.
TrackMKIII or anyone else considering the under-drive pulley, one idea for the charging at idle is you could change out many of your bulbs to LED so they draw less power. Its amazing how many little bulbs you can find that draw a lot of power.
Light Weight Pulley Kit
