I've been thinking about getting new pulleys. Can someone educate me about the advantages of chaging my pulleys? In fact which ones need to be changed? What brand should I buy? How much should I expect to pay for it, and installation?

Thanks!

 

alternator,power steering, and A/C get it from AEM cost @180 for 3
you can also change the underdrive pulley get it from unorthodox @180
installation not included

 

Don't bother, just loose a few #'s and you'll gain the kind of HP they're boasting.

Or, save your $ and get a NOS kit, then you'll have way more power then any underdrive pulley'd give ya.

BTW, some people have been known to blow blocks with the crank pulley, it throws the balance of the crank off.

 

Yeah, that unorthodox crank pulley sucks because it doesnt have a harmonic damper in it like the stock one. All thise vibrations are BAD for ur bottom end.

 

I was under the impression that Honda cranks were internally balanced (my SR20 crank is). I've had UR pulleys on my SE-R for about 6 months now with no problems at all. And I've done 3 track schools and 6 autocrosses since install.

I think it feels like a lightened flywheel. Which if you think about it, you're removing weight that the crank turns (just like lightening a flywheel, but on the other end). On SE-Rs the dyno shows about a 5 whp increase nearly thoughout the entire rpm range. 5 hp doesn't sound like a lot, but being over whole rpm range really increases the area under the torque curve, which is what determines acceleration. Pulleys might give you as much increase in area as, say a header, which pretty much gets all it's power at high rpms.

My $.02, pulleys are a good bang for buck mod.

 

someone posted this on another board....

Courtesy http://www.unorthodoxracing.com:

"A harmonic damper is a unit bolted to the crankshaft snout that is completely separate from the belt drive system. An engine that uses a harmonic damper has the accessory drive crank pulley bolted to it, they are separate pieces that are attached to each other. Balance shafts, which are used by several manufacturers, are specifically designed to eliminate harmonic vibrations. None of the vehicles we manufacture pulleys for have harmonic dampers in the traditional sense."

Preludes use balance shafts. Civics use neither.

Then there's the argument on the little rubber ring inside the factory crank pulley. It serves a purpose called "torsional dampening." Proper aftermarket underdrive crank pulleyes don't have a rubber ring for dampening. Here's why:

"Torsional damping is necessary due to the excessive diameter and weight of the factory crank pulleys. The design of our underdrive crank pulleys eliminates the need for any torsional damping for two reasons. One, the diameter of our crank pulleys is smaller than the original designs, in almost all cases smaller even than the rubber torsional ring, therefore effectively reducing the force the accessories have on the crankshaft. Second and most importantly is that our pulleys are significantly lighter than their OEM counterparts (anywhere from 3 to 11 lbs.). This weight loss dramatically reduces the stress exerted upon the rotating assembly by the excessively heavy factory crank pulley."

This isn't marketing. This is physics. Also, Godspeed Motorsports has been using underdrive pulleys on all their cars with aboslutely zero problems for years.
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what about just replacing the crank pulley? would that be the best solution?

 

interesting, thanx for the 411