Coblt ss super

Would bigger crank pulleys be better for our cars, well any car really? I mean i was in Physics class and we are talking about torque and lever arms. I was told the larger the lever arm on a pulley is easier to turn. Would it work?

Same goes for the blower, if we are running smaller pullies does that mean the crank is working harder to turn that blower pulley since we shortened the lever arm on the blower pulley?

J.CobaltLT

wtf?!?!?


btw...im not in physics..lol

Coblt ss super

ok heres an example, if you have 2 wrenches to twist a nut off a bolt, and one wrench is 6 inchs long, and the other is 12, the further you are away from the bolt the easier it is to loosen the nut since you have more lever arm

J.CobaltLT

ah. but wouldnt the principle of "leverance" ( forgive my illiteracy ) not apply with an engine?

idk. i completely understand what you're saying, just a puzzling question. i have no definite answer </3

nich7601

I believe the engine is working harder with a smaller SC pulley, but it sure does the job

As far as the other thing, I don't have a clue.

Coblt ss super

lol idk how to explain in a motor type of view. but i was kinda wondering since one of my questions for homework was to find out the lever arm on a pulley if the tension was a certain amount on the string on it

joeworkstoohard

you're right and wrong at the same time.

the heavier pullies would also take a lot more to spin.

BigTizzle903

well in my physics class we learned about torque, not so much pullies, but from what ive been readin the net the smaller pulley makes it lighter and means it can spin faster with less friction. also the reason why upgrading your serp belt to a smaller one with smaller and lighter pulleys for things like your ac and water pump actually give your engine more hp

Red2.4SS

The larger crank pulley speeds up the belt so it takes more power to spin everything attached to it faster.

Coblt ss super

yeah i kinda figured it would work harder it has a smaller lever arm to turn and smaller lever arms require more torque to turn, so does that mean if we put bigger crank pulleys we will gain more hp and torque since we are getting the same boost but are also useing less lever arm on the crank to turn that blower?

yeah but say we made a lightweight crank pulley that was say half inch bigger, would it work?

nich7601

No idea. I'm in over my head. My phys class didn't really cover this, and powertrain and engine classes won't be for a couple years.

mufnman

smaller pulley = spins the blower faster

larger pulley = spins the blower slower

you're talking about a difference of an inch. that's not exactly a lot of work being converted to spin the blower, and the blower itself is relatively easy to turn because of the bearings. most of the resistance comes from the actual act of moving the air.

Red2.4SS

I think the M62 eats up about 30hp or so.
Not so easy to spin at several thousand RPM.

mufnman

the only benefit that a larger pulley would give is lower intake temperatures due to the air being less compressed. if someone were to find a way to make the blower more efficient at a given RPM range, then a larger pulley would be a benefit because the blower isn't having to work as hard to push the air into the engine.

Nyke

Not at all, The pulley is a circle not a lever/plank, and behind that it is a circle it has no fulcrum or pivot point to work with.

Now you have to think of a pulley system, because with a pulley system you have a source of power rotation in our case its the crank pulley, we all know why that is our souce of power for the accessories right?

Now the reason we put a smaller pulley on our supercharger is to spin it faster to create more boost.

A bigger crank pulley would spin all of our accessories faster, such as the water pump alternator power steering pump, it would however spin our supercharger faster, but being that it has to spin everything else that the belt touches faster it causes the engine to work harder thats why we only swap out the supercharger pulley.

Thats why people like to put light weight pulleys onto thier cars for more performance because thier is less rotational mass. However i do not recommend putting a lightwieght pulley onto your crank pulley because some motors are internally balanced and some are not, interally balanced motors you can swap out the pulley with no damage caused interanlly (Pistons crank connecting rods) where as a non-internally balanced pulleys use the crank pulley to balance out, these pulleys are also known as harmonic balancers, you cannot swap these pulleys out at all without causing significant damge to the engine.

Some ways to increase your power for your cobalt is to get lighter assecory pullys for the alternator, power steering pump, water pump. These gains however are minor and not worth the money most of the time, there usually for show.

Hope this answered your questions or any you may have had!

HunterKiller89

iTrader: (1)

yes and no. using a larger SC pulley would mean that for every inch in circumfrence, the larger pulley would turn with more tq, however, since it is a larger pulley, it would also turn slower. hence, a smaller pulley will spin the SC faster, but will also cause more parasitic loss because more tq is required to rotate the pulley at the same RPM. the opposite is true with the crank pulley, since the crank pulley would be providing energy (movement) to the belt, and the SC pulley would be using that energy to drive the SC screws