In Reply to: Underdrive Pullys or Lightweight Flywheel.HELP PLS posted by Willy on April 30, 2000 at 16:46:32:
I installed the 002 Evo u/d pulley about 2 weekends ago and I love it. There is a noticeable power increase and I recommend it, however you have to ask yourself what you are looking for. The pulley swap will boost HP and torque a little bit, about 6-8 and 10-12 respectively. It is a simple (I think) job, and costs between $350-500 for the hardware. Probably cheaper for you since I have a 95 and pulleys are cheaper for 96+.
A new flywheel will not add any power, however it will do wonders for acceleration since you are halving the rotating mass. So, the engine can spool up a whole lot quicker. From what I understand there are some issues with lightweight flywheels, namely they tend to die (stall) easily when the car is at idle -- however a simple bump of the idle speed up a couple hundred RPM by modifying the chip is supposed to cure that. Also, from what I have heard, driving around town is not quite as smooth -- because the engine can spool up so fast, it can also drop revs a lot quicker so it might be harder to match revs when shifting to avoid jerkiness.
Usually the flywheel is far more difficult to install since you have to take the transmission apart, but since you are replacing the clutch anyway I guess that is a moot point. Flywheels are approximately twice as expensive as pulleys.
As you know, you can't do both because of harmonic issues (I have heard it is possible to do if you get both professionally balanced). I think though that in the end the flywheel will yield more dramatic results. I went the route of the pulley because it was cheaper, easier, and I am a HP freak trying to eek out all I can.
Hope I didn't confuse the issue any.
002 Evo u/d pulley
Jim C Euro HFM chip
UUC clutch stop
other goodies in the works...