Gernby

Basically, it's just one of those mods with a very low "bang for the buck". A light weight battery, light weight flywheel, light weight exhaust, etc. will give more gains per dollar.

ans2k

Lol and how is that different from what I have said?

RedLineS2k10

Wow.........................Why did i know when i saw three pages for a simple pulley question i would end up in a physics/math/science class.....Why am i paying UOP so much again?? lol

Im glad this was brought up because i was always wondering about doing this to my f24c...With the OEM stroker kit, the rotational mass has been reduced quite a bit, with the lightweight flywheel, i was thinking putting lighter pulleys would just add to the mix of a pretty free flowing motor.

I have read on k series motor (primarily being the k20z3) which is basically an s2000 motor with i-vtec, that certain off brand companies C.Pulley are not properly balanced and can cause massive internal problems. I can see the water pump pulley creating a problem considering how shitty its designed to begin with, but alternator, power steering (yes i have power steering on an s2000 motor),i can see making a difference, but ive always been very cautious when buying crank shaft pulleys due to improper balancing, etc.

Thanks for the great info guys...

Where did the poor guy go who started this topic?

The Internet

Sorry for mixing your inputs up, that's my fault. But I do disagree that an object with less mass would not reduce friction, that goes against the laws of physics. If you ran out of gas, what would you rather push, a CRX or a Ridgeline? This is exaggerated, of course, but it's to make you think about the difference in mass and friction. It may be nominal here, but the rotational speed is greatly increased as well, increasing the friction applied (Newton's First Law). This is why an object's rotational mass is considered to be greater than it's static mass, because the coefficient of friction is directly correlated to the object's mass.
The only reason that they would show no gain at a constant point is because there is 0 acceleration, which I explained earlier, this equates to 0 net force.

And just for the record, we're not just using formulas, we're showing how you would prove a gain from them, since it was said repeatedly that there is no way of conclusively proving so. And then you go and say you can't measure it, after we literally just provided the means of doing so. I guess you're right about it being a waste of time if you're too hard-headed to apply the formulas...
Not to mention the fact that you have no experience with these pulleys, yet you speak on them as if you're an expert.
What about the dry carbon canards that appear to do nothing? They don't seem to add much form or function, yet they have shaved a full second off a time attack run. I have a lightened flywheel, and there is definitely a better transfer of power over my stock flywheel. I bet my car would have dyno'd more than it did had I done a before/after as well, which brings me to another point that you guys haven't mentioned.
You say the gains aren't even measurable, yet the thing is, as you combine mods, more power is obtained. Adding an exhaust to a stock S2000 will not see the same increase that a heavily modded S would see from the same exhaust. Case in point; a friend of mine added an exhaust to his stock S197 Mustang GT and gained 12whp. Another friend added the same exhaust to his S/C'd S197 Mustang GT and gained 44whp.

Gernby

Kid, you're screwing up your high school physiics if you think changing the weight of a metal pulley will cause the rolling resistance of the belt to change. After all, it is the rolling resistance of the tires on the road that makes it hard to push a car. Rolling resistance of a tire goes up with vehicle weight, but rolling resistance of a belt on a pulley is totally independent of the pulley's weight, unless you want to start talking about the gravitational pull between the pulley and the belt! If you were to roll a car on bare metal rims on train rales, it would be really easy to push.

You also seem to be confusing me with someone else again when you say I said you can't prove gains from light pulleys. You could definitely calculate the theoretical gains if you were to put a LOT of effort into weighting ALL of the rotating parts in the drivetrain. What I've been saying all through this is that you wouldn't be able to MEASURE a gain from something as small as this. Modern dynos can't reliably measure less than a 1% change.

The Internet

You must be getting old then, "pops." Seem to have forgotten already that you said this:
So you're saying that you didn't say I couldn't measure it, but I can still prove it... how does that make any sense?

And for the record, I'm not screwing up anything, you seem to forget what the pulley attaches to... which would be the crank, which means it would give the crank less resistance to spin it. Which in turn, would mean that the engine is fighting it less to spin the belt. The belt isn't the driving force here, it's simply being acted upon, but the medium in which that power is transferred to the belt has been improved (by being lightened) therefore resulting in quicker response.
And I don't know what a "rale" is, but I do know that isn't exactly the case either. How? Because I've had to do it. So once again, you speak as an expert about something you know nothing about. Congratulations, and thanks for trying to guess my age because I'm keeping things simple in hopes that you'll understand it. Unfortunately, it still appears to be over your head.

I'm going to stop responding to your thoughtless posts, because I do agree that the gains from this are small, but I still contest that it can be measured. Reliably? No, you're probably right, because all dynos seem to be fairly unreliable, but it can be done, tons of effort or not, but you guys didn't specify that it had to be easy for a lazy bastard to do.

pastoli

FYI- I found this set on ebay. I offered the guy $145. I am sure you could get it for less! So if you would like to try this mod or what not, it can be done without breaking the bank. If it is for appearance or what not its not a bad price.

http://cgi.ebay.com/ebaymotors/ws/eBayISAP...RK%3AMEWNX%3AIT

Gernby

I guess you'd have to be an engineer (like me) to understand that there are lots of things that can be proven, but are too insignificant to measure with common equipment.

BTW, I'm not guessing at your age, since your profile shows your birthday to be 5 February 1987.