JKDman, thanx for the great pictures. Point of interest - looking at them, especially the first one, it looks like this is a two piece hub or is it just the shadows? It just looks like the outer inertia ring in the front part of the hub is separate from the inner hub? By the way, you keeping the hub in your desk or just a very nice garage?

 

yup. Thanks for posting the pics JKD. JCV, it looks like it's all 1 piece to me. The rubber looks like it's in a little slot. I just stuck a little knife point in there and it went in about 1/8" before it stopped on something solid.

 

The first pic is a short of the rear
The second pic is pretty self explanatory
The third pic is of the front. (What you'd see from the front of the engine)

It shows a piece of hard rubber in between the inner and outer but the thrd pic shows that the rubber doesn't go all the way through.

I keep the hub in my room. Wish my garage was that nice.

 

i'm gonna say whatever jkdman said cuz i'm so damn lazy to type this out.

 

As an outsider to this thread......

I'm LOST!

 

You don't want to know. If you participate, tread litely... Like every other pully thread it ends up in a war between the reds and the blues.

 

I came for the "final word" as this was on my wish list, not since reading this thread, I crossed it off 5 times and writan in down 4!

 

WRAH, with all the snow in Columbus you won't need any performance parts for a long time. Since you haven't followed this endless thread, the pulley test is still to come!

Hydrazine, UDR makes pulleys in red and blue- kinda non denominational.

 

Regardless, the pulley adds HP to the wheels. Freeing it up is adding it. If the car is faster, then more power is going to the ground. If the car accelerates faster thru any rpm then it's making more power.

A lightened flywheel causes no crankshaft problems and is not a damper therefore I believe what they say when it comes to road course racing with a lightened flywheel. Lightened flywheels are far lighter than UDPs and since more of the weight is further from the crank axis, the rotational inertia is much more severe. A lightened flywheel is great for a car that spends a lot of time racing in the upper rpm range and also offers better rev matching. In a drag race, the lightened flywheel offers no benefit. If anything, it hampers 1/4 mile performance because the motor is far more prone to bogging on launch because of the lack of inertia. Lots of Maxima owners run Fidanza flywheels that are about 10lbs less than stock. These guys are no quicker or faster with the lightened flywheel many guys actually went slower because when they launched the car bogged down.

 

I just did the crank pulley mod and I'm loving it. Acceleration is improved and low end responsiveness is noticeably better. Most impressed with it so far.

 

1. You can't balance harmonics. There's no such thing

2. In picture #1 of the backside of the pulley, you see the rubber ring. The central part of the pulley south of the ring is it's own pulley (call it pulley #1). This pulley is heavy cast iron and has slides over the crank. The upper part of the pulley north of the ring is it's own pulley. Mounted to this pulley (call it pulley #2) is the ribbed surfaces that drive the belts. Pulley #1 fits inside pulley #2 and the rubber ring is what joins them together.

Probably not.

Haha. You don't care that you UDP probably didn't make you any quicker? Why did you get it then? Have you ever been to the track to test before and after?

You guys asked me to provide pics of a failed pulley and now you're gonna bust my chops about a failure of something I can't control? Are you serious, Fruitcake The failures of these pulleys are completely rare and isolated and typically seem to happen to older cars with high mileage in salty climates. Look at the pics again and take note at how rusted that thing is. My 96 Maxima's 112K pulley looks brandnew compared to that one.

That wasn't a sidetrack. I was simply agreeing with JCV and it seems to be something most G35 owners don't understand. The reduced rotational weight of my tire combo will result in a quicker car, much like what you believe the UDP is doing. However the lighter rim/tire combo is far more effiective than an UDP because:

1) More rotational weight is removed (10lbs vs 2.2lbs)
2) The tire/rim combo requires a lot more energy to move because it isn't mounted directly to the engine therefore reducing rotational weight is more benefical to the overall performance.
3) The tire/rim combo keeps more of the weight closer to hub compared to the stock 17s therefore less energy is wasted accelerating the rims.

Side benefits:

1) Grip
2) 10% improvement in gearing


I guess I'll just have to agree to disagree on the UDP issue. Years ago when the UDP was introduced to the Maxima community it was the mod to get, just as what we're seeing with the G35 community. Everyone that got the pulley swore it made a difference, the engine revved faster, and the car was a lot faster. Then us track racers started putting these things to the test under the timing lights and under the rollers of Dynojet 248s. The truth became known and now no one on Maxima.org buys these anymore except for the newbies that don't know any better.

 

Actually and for the final time, the rubber ring does not go through the pulley. If you look at pic 3, there is no gap of rubber. It is nothing but solid metal connecting pulley 1 to pulley 2 as you state it. Why you still claim that it goes all the way through baffles me.

Again, I ask you to put your $ where you mouth is. Your information is incorrect. The stock pulley is not ~4 lbs. It is closer to 7. Please don't make this assertion again without some back-up or, again, put your $ where your mouth is. You're spreading incorrect information by either ignorance or on purpose. Either way, it's wrong.

 

You're failing to grasp what I'm saying here. Pulley #1 fit inside of the Pulley #2. Portions of the Pulley #2 cover the ring so that you can't see it from outside. A lip of metal is covering ring.

Since you think you're looking at one single pulley and you believe that UR UDP is flawless and that the stock pulley will fail, I dare you to cut out that rubber ring (torch it, cut it, etc) and see what happens. $100 says you'll have two pulleys.

 

DaveB throws down the gauntlet! $100

I have to agree with DaveB here. Its probably two pullies with one floating in a layer of captured rubber. I won't bet money on it but a two part pully would make sense simply because the damping effect would be much more efficient for a given size and mass.

I have a band saw for sectioning...

---------
You see what I mean WRAH? These pully threads get nasty.

 

Isn't that the truth.