Under drive crank pulley

[67dartgtgo]

Anyone ever tried this March under drive crank pulley?
Just changed my harmonic damper and found my stock pulley was rotted through one of the grooves. An accident waiting to happen.
Need to replace it but thought I might try this March pulley.
Will The under drive spin my water pump faster or slower?
http://ep.yimg.com/ay/chucker54/march-performance-billet-2-groove-crank-pulley-3.gif
http://chucker54.stores.yahoo.net/mapebi2grcrp.html

...Brian

 

[qkcuda]

Underdrive crank pulleys are smaller and spin your water pump slower. They save horsepower by using less to drive the pump. If your cooling system is marginal, you will probably overheat, especially at low speeds. I was running one and had to go back to a 1:1 pulley to control overheating in traffic.

 

[nerd racing]

I wouldn't unless you run electric fans. You could see the same gains by using stock pulleys and running a properly designed performance crankshaft damper. Dyno proven power gains over OE rubber dampers, on multiple ranges of engines through work.

 

[67dartgtgo]

Thanks guys...sticking with what works.