lighten crank pulley (alloy)

[EddieYee]

imho, i dun have much prob with a smaller lcp as i am using one now for >5years. the only thing tht matters me is tht it does makan ur belt slightly faster(below 30k km?) and the rotating sound produced from it while idling(still baearable). advantage, i dunno bout the hp but u definitely feel the torque gain + lighter rpm. so pros n cons. my 2cents.

 

[JonXen]

Not all LCPs are undersized. I personally don't recommend undersized either unless your car's a race car and is always high revving the crap outta the engine.

I'm using the which is slightly (3% to 5%) undersized... and the difference is the acceleration. That's it. Top speed, torque, HP, all not affected.

However there's a risk when using LCP, the rubber dampener on stock CP is called a "harmonic dampener". It absorbs minor or any sort of vibration caused by imbalanced crank or generally the whole assembly. Without the rubber you run the risk of wearing out your crank oil seal or the crank pulley much faster. No catastrophic damage or whatever scary stuff.

My crank assembly and my original pully was balanced when the engine was rebuilt. When it spoilt (the pulley) I changed to 2 original pulleys and each one got damaged one way or another. Imbalanced pulley la, damn loud squeeling noise la, then finally I swapped to the LCP. Now I change my crank oil seal about every 5 to 6 months because of leaking problems.

So not only do I have to worry about harmonic vibration, I have a problem with balancing too but at least the CP is no longer breaking down like the earlier 3 OEM ones.

I thought Mythelogy LCP did have harmonic dampener.

I keep wondering, if using lightened pulley, does it affect your car cruising because of the inertia?

Are you sure the top speed won't be affected after change to lighter pulley? How about to maintain the top speed? Like when we release the pedal, the speed wouldn't reduced very fast for the OEM one I think.