Benefits and downfalls of an underdrive pulley?

[jdpolzin]

What are the ups and downs with using an underdrive pulley on the crankshaft? I have a new one and am wondering if I should ude it or my alunimum stock size one. Any suggestions would be great! thanks -----Jeremy

 

[johnplogii]

I had to take mine off because it would only put out 11 volts at idle & my battery would get weak. I don't think it does the cooling system any favors either.

 

[Gary Wells]

What are the ups and downs with using an underdrive pulley on the crankshaft? I have a new one and am wondering if I should ude it or my alunimum stock size one. Any suggestions would be great! thanks -----Jeremy

------------------------------
These work better on Fords than they do on turbo Buicks, at least on street turbo Buicks. Aluminum stock size one won't leave you stranded. Just my .02 worth, before taxes, too.

 

[Grumpy]

I have run them since 1990 ish ... lemme go check my battery

 

[jdpolzin]

I think I'll stick to my aluminum one!