Engine crank pulley

crank pulley

http://cgi.ebay.com/ebaymotors/OBX-...ewItemQQcategoryZ38656QQitemZ7999456992QQrdZ1

i know nothing of crank pulleys, are the 5-10 hp gains legit?

nobody likes obx on here! lol

Depends alot on applications - but power gains can be significant with lightweight, underdrive (smaller diameter crank pulley or larger accessory pulleys) pulleys. Some cars - like your V8 Camaros and Mustangs show 10-15WHP gains on dynos with just pulleys. Imports are generally around the same ballpark or little less.

Lightweight to help reduce rotational inertia and sized up or down to cut down of parasitic drag from accessories (water pump, A/C compressor, smog pump, alternator, oil pump, etc.). The more accessories you have - the higher the probability of freeing up some extra power.

Sounds good on paper and looks good on some dyno runs - but they never really talk about long term effects or possible problems that you might run into. Since the accessories are driven at a lower speed - if your engien was already had a marginal cooling, oiling, or charging system - then you would worsen the situation with a underdrive system. Most require removing the OEM harmonic balancer (usually built as part of the crank) - doesn't sound like a big deal, but rebuild a few engines with an without them installed and you will see a trend. Most will tend to have more significant main bearing wear and sometimes crank damage from excessive vibration. Also depends on motor design and how it was run (forced induction on better parts, stock with forced induction, abused N/A, etc.)

For some - pulleys are the perfect solution - cheap horsepower gains for little investment. Plus extra power and longer life are generally not found to be inclusive with each other. But for those that use the car for a daily driver and prefer not to do any engine rebuilds too soon - then these pulleys are not a good thing to have.

you don't want to mess with crank pulleys dude, about the gains I dk if it's legit, probably not and well since it comes from OBX then even better for me answering a quick NO lol OBX=TRASH!

im getting the unotrthodox ones for my 03 rolla s from wha ti here they work i wouldnt trust obx they dont know shit from rice ive called them on many occasions to ask them stuff and they gave me answers that we i called my buddy at the dealership and they were all wrong but as far as i know the newer rollas harmonic damper is inside the crank not actually on the pulley its self so just ask around some more later man and good luck