Thats UD , we were talking about the KJR

 

Damn i was going to buy one last night (KJR) and then i went through this thread???? I want some gains in terms of performance i just dont want the ability to rev faster in nutreul..LOL.

 

If I have saved just one person from a worthless mod, then my efforts have not been in vain.

 

anyway, I got the UR pulley installed in my car and i love it.....I feel the car much lighter in 1,2,3 gear.... I don't know about KJR pulley but the UR pulley rocks.....

 

Thank god someone can think for themselves...

 

Hey copper, at this point how does your KJR pulley feel? are you still second guessing this mod???

 

Now you have a role model!

This thread was about lightened crank pullies, not underdrive.

 

Performance aside, has anyone ever actually had a problem from installing a lightweight crank pulley? I thought these were fully balanced just like the oem one.

 

Forget that.... i want to know is anyone selling one? (KJR) i am totally interested in buying one.......pm me ....

 

I have a whole set of the oem size lightened and hardcoated ones on the way and am just trying to decide if I want to keep them or sell them.

 

That depends what your goals are. Are your goals to put more noticeable power to the ground? Then you're wasting your time, money, and risking possible damage by installing them. If you're goals are better looking pullies, and having pullies on your mod list, then keep them.

The irrefutable truth of the matter is that the gains are virtually nonexistent, so just factor that in to your educated decision.

 

i have my g sedan for two months and still looking for performance parts for it, thank GOD i saw this thread, save me $180. i can scratch this 2hp pulley from my list. thanks guys....

 

OK, so after reading all of this thread, I am totally lost now.
It is true that lighter mass in enertia(sp) is eaier to turn, so easier to turn means less effort to put the same amount of power, would equal quicker time to get to that speed.

There was a comment here that "The only way your car is going to accelerate faster is if it's putting out more power on the dyno. If it makes no power on the dyno, it's not making you accelerate any faster on the street. (In general)".....I am not picking a fight, but this comment is way off, maybe I am taking it out of context and sorry if I did, but lighter is faster, VQ in a G equals 298 hp........VQ in a Go Kart equals 298 hp, but acceleration is tremendous!!!
Again this may be out of context, and again sorry if that is so. But, lighter rotational mass could act on the same principal. If it takes less to move, then you will move it quicker, no gain per say, but still faster.

I don't want a pissing match with anyone, this is just a discussion and my opinion on "How things work" and yes I DO NOT have a lighter pullie, but I do have a lighter flywheel, and yes the car accelerates quicker then the stock flywheel I do NOT have any mathmatical quotations to prove or disprove anything.

 

Well munchee will not accept anything other than a proven PHD dissertation with a pre-approved hypothesis so you have no gains for you. Munch = HP ****

 

Absolutely. The question is how much of a change are we talking about. If you remove your spare change from your center console, you're also reducing the car's total mass and increasing your theoretical acceleration for the same engine power output.

I made that comment, and it is not off. When you dyno your car on an inertial dyno (which measures the rate of angular acceleration of a drum to calculate instantaneous power), any drivetrain mods that one claims increase acceleration on the street due to decreased inertia will show up (after all, the drivetrain is accelerating on such a dyno). The gains from such a mod depend completely on the acceleration rate of the drivetrain, which depends on the load (remaining vehicle mass) and power output. You should read the link I provided for a background on gains from inertia changes.

As discussed, such gains will show up on an inertial dyno. Such gains can be easily predicted based on the acceleration rate of the driveline and the change in inertia. Again, please see the link I provided that explains all of this in detail if we are still not on the same page. Here it is again (written a long time ago now): http://www.stanford.edu/~mpg/lighten...omponents.html

Lightened flywheels have over an order of magnitude greater change in inertia than that from lightened crank pullies. As such, gains in 1st gear can easily reach 10+% which is noticeable. Even so, gains decrease with the square of the gear ratios, so they quickly drop to negligible levels in the higher gears.