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I got them all installed today, and they fit great and went on smooth. They are in perfect balance and everything is running great. I will take it for a drive tomorrow and see if I can tell any improvements.
I'm very interested.....thanks for your time!
Waiting on more results.....
BTW did you happen to weigh the difference between stock?
no, i didnt weigh them, but the stock was MUCH heavier...you will be amazed with the size and weight difference between stock and these or any type of UR lightweight pulley for that matter.
I had the UR underdrive pulleys installed a while ago and didn't notice any difference, except the AC wasn't as cold as it used to be. The shop that installed them did a before and after dyno run but they didn't produce any gains.
There is a oil seal that you have to be careful with I believe. Anyone back me up on that? The crank oil seal..
I can. I wouldn't get them. First, one has to understand how/what adding bolt on do. That's the reason my car has so few. A crank pulley, when bolted on, becomes part of the crank/rotation. It may unbalance the engine. That can cause the oil seal to warp/leak. An unbalanced lower end, can cause more damage & of course hurt performance. If one really wants to get pulley(s), its best to get the best & newest available.
Last edited by andre12031948; 11-14-2010 at 12:58 PM.
IIRC, aren't the cranks in new engines internally balanced? There has been much debate on pulleys and the safety/reliability and I believe one came to the conlclusion that since the motor is internally balanced, pulleys won't have an effect on the longevity/reliability of the motor. That is, assuming they are installed correctly with the correct sized belts. Just my
I had the UR underdrive pulleys installed a while ago and didn't notice any difference, except the AC wasn't as cold as it used to be. The shop that installed them did a before and after dyno run but they didn't produce any gains.
As far as a pulley unbalancing the crank, every consider what you guys do to the OTHER side of the crank? ie.. aftermarket clutches, flywheels etc....
This has been my reasoning for a long time. Many of the people who say negative things about balance and aftermarket pulleys won't think twice to go with a lighter flywheel.
I will say that my experience with underdrive pulleys isn't all that great. On my last car, I had a UDP and after installing, it seemed like the car had a little more power and smoother revs. BUT after having it for some time, I had trouble with the AC (the pulley isn't turning as much as stock), and the battery wouldn't hold a charge if I didn't drive the car a lot. (Alternator pulley isn't getting turned as much either) So with that, you also have to consider that your water pump pulley is underdriven as well.
I just purchased a Stillen oem sized crank pulley b/c I think the weight saving may help but I don't think I will ever go with another underdrive crank pulley unless I can overdrive the accessory pulleys so that they have oem operation. I know on the last car I had (99 eclipse NT), they actually offered overdrive pulleys for the accessories to compensate for an underdriven crank pulley. I just never bought them before selling the car.