Was speaking with my engine builder today about engine balance and brought up the subject on lightened flywheels and underdrive pulleys.
I think everyone who currently has an underdrive pulley fitted must notice the more agressive engine note beyond 3000rpm.
The is because the at certain RPM's, the crankshaft will resonate violently and this usually overcome by the stock front pulley with harmonic balancer. The outer part of the stock pulley is supported by a flexible rubber bond which dampens the tortional vibration of the crank.
An underdrive pulley does not have a tortional dampener built into it and therefore cannot dampen the vibration resulting in rod and main bearing problems.
A lightweight flywheel does not have the same negative effect because it is not designed as a dampener and there is no need to have dampeners at both end of the crank.
Therefore, I'm removing my ASP front pulley and going for a JUN lightweight flywheel instead.
Steve
P.S I'm still upgrading until someone buys my Z
[This message has been edited by Steve E (edited 28-09-2001).]
Was speaking with my engine builder today about engine balance and brought up the subject on lightened flywheels and underdrive pulleys.
I think everyone who currently has an underdrive pulley fitted must notice the more agressive engine note beyond 3000rpm.
The is because the at certain RPM's, the crankshaft will resonate violently and this usually overcome by the stock front pulley with harmonic balancer. The outer part of the stock pulley is supported by a flexible rubber bond which dampens the tortional vibration of the crank.
An underdrive pulley does not have a tortional dampener built into it and therefore cannot dampen the vibration resulting in rod and main bearing problems.
A lightweight flywheel does not have the same negative effect because it is not designed as a dampener and there is no need to have dampeners at both end of the crank.
Therefore, I'm removing my ASP front pulley and going for a JUN lightweight flywheel instead.
Steve
P.S I'm still upgrading until someone buys my Z
[This message has been edited by Steve E (edited 28-09-2001).]