Guest Anonymous Posted March 22, 2002 Share Posted March 22, 2002 Where can I find a light weight underdrive pulley for my L series motor? I checked Unorthodox Racing, they don't have one for the L motor, I also checked Nismoparts.com, but those are too expensive. Where can I find one, and will it make a difference on myt turbo motor? I am running an electric fan and no p/w or a/c. What about a cam gear?pics of my car-> http://www24.brinkster.com/jgino35 Quote Link to comment Share on other sites More sharing options...
johnc Posted March 22, 2002 Share Posted March 22, 2002 Keep your crank pulley the same as stock. Get underdrive pulleys for water pump, alternator, etc. once you determine what speed you need to turn each accessory. You should be able to search around and find the correct sized pulley for your alternator. Do some research and see what the pulley sizes are on other Nissan vehicles. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted March 22, 2002 Share Posted March 22, 2002 it's not much about size, but rather weight. The aluminum pulley weighs about 1 lb, while the stock weighs about 4 lbs. Those 3 lbs would be the same as reducing the weight of the flywheel. I only run the alternator and waterpump off my crank without the fan, so the is not much of a problem. Quote Link to comment Share on other sites More sharing options...
TimZ Posted March 28, 2002 Share Posted March 28, 2002 Originally posted by turboz: Those 3 lbs would be the same as reducing the weight of the flywheel. Well, sort of. First, rotational inertia is proportional to the square of the radius of the pulley on it's rotational axis. So, since the radius of the pulley is maybe a fourth of the radius of the flywheel, reducing weight here will only have about 1/16th the effect of reducing weight at the flywheel. Not very cost-effective.If you want to reduce rotational inertia, go to the source - the flywheel. Second, and more importantly, a good portion of the weight of the crank pulley is isolated by a rubbber strip, which makes it act as a vibration damper. With the long length of the L6 motor's crank, there are known problems with crankshaft failure above ~8000rpm, due to torsional vibration. Getting rid of the vibration damping provided by the crank pulley will only make this worse. The UR crank pulleys might work okay on L4 or V6 motors with relatively short cranks (and I think that's debateable), but they are just a bad idea for an L6, IMHO. Quote Link to comment Share on other sites More sharing options...
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