Here's some pics of my stock pulley.

The first picture shows where the rubber ring is. I don't know how far it extends, but it is not exposed on the other side of the pulley.

The second pic is the pulley on a bathroom scale. Not the most accurate, but it gives you a rough idea. It's about 7 lbs.

For the original poster, I don't think you're going to find the "final word" on the pulley debate. We can argue about the theories until we're blue in the face, but only experience will tell us if the pulleys do in fact cause engine damage. No one has 100K miles with the lightened pulley on their g35.

An analogy I can think of off the top of my head is Vioxx. In theory it should work great, but it was only after it was on the market for a few years that we saw serious side effects from it. So you'll have to wait a few years to get "the final word."

 

Alright, some brave, desperate, or drunk soul needs to cut or press apart their pulley in the name of science.

Al, since we have a good, endless argumentative thread from hell going: what's better for a NA G or Z, large diameter, short tube exhaust headers and short collector or smaller diameter long tube, long collector headers.Heh, heh. This will be good for starting the famous backpressure argument on this forum. Any takers?

I am also working on a light weight plastic or cardboard pulley for my CISMO prodcut line.

 

This is how I see it. Correct me if Im wrong. Basically the Unorthodox pullies are lighter, ie. less mass. The horsepower the engine creates does not increase by changing the pulley. The engine is not getting more air or creating a more powerful explosion (combustion) to create more power. I think that the power the engine is making is just more efficiently being transfered to the ground because the lighter pulley requires less energy to turn than the stock one, which in turn equates to allowing more energy to make its way to the ground, which is what you feel with this addition.

 

The pulley has less inertia but the real deal is you underdrive accessories like the alternator and power steering which do take horsepower. A simple underdrive pulley, not lightened, would provide horsepower without the other issues all are fighting about. this is where it all started many years ago.......

 

I drove my car for 26,000 miles WITHOUT a pulley and just put it on last week. I've started and stopped the project more than once waiting for the debates to conclude. Guess what? The debates won't end!

I will say from experience there is a noticeable improvement in around town driving performance at low RPM after install. The car seems to go by itself off the line. Sure it's just the lower inertia but more power is available. The difference is real, not imagined.

Additionally, my examination of the stock pulley leads me to conclude the rubber ring does not go all the way through. You cannot see or feel any rubber on one side. My guess is it is only the width of the outer pulley. And no you can't have my stock pulley. I need to toss it back on the pile of engine rubble after my VQ explodes.

Thanks Hydrazine and JCV for your explanation on the physics of it all. I finally understand the purpose of the dampener (didn't need the scary links but they're appreciated). The bottom line FOR ME is the crank pulley adds noticeable kick and is statistically unlikely to harm my engine during the time I own the car (if ever). That and no documented evidence of failure linked to the crank pulley on any site makes me say enjoy it!

 

Now my next question is about the lightened flywheels and clutch. By going with a Tilton Clutch and Flywheel you cut out about 60 lbs of spinning bull sh*t.

If you think the pully makes a difference check this out. It's freakin awesome.

http://www.350zmotoring.com/forums/s...ghlight=tilton
http://www.350zmotoring.com/forums/s...threadid=18641

You've got to see the video!

I really want one of these bad boys. These make pullys look like mothers milk. Is it trashing the engine??? Probably, but either way it sure looks like major fun.

 

[QUOTE=E_K]No one has 100K miles with the lightened pulley on their g35.
QUOTE]
You're right, e_k. However, the 3.5 vq came out at least a couple years (IIRC) before the G in the max and some of those owners are either close to or probably over 100K by now.

No reports of engine failure.

There are too many vq owners with and underdrive pulley with significantly more miles than me. If/when there is a report, that's when I'll reconsider. Until then, it's regular blackstone oil tests for me, which have been exemplary.

 

uhh, yes, i was not expecting any money for my extra pulley. i bought it off ebay for 15 bucks to send in for R&D. if anyone wants to cover shipping, i will send it to em to hack and dice and rip all they want.

but, is this going to answer the question once and for all?

 

Absolutely not. That will only settle a pissing war between al and dave.

Weather on not the rubber goes completly through the pully is tangent. The fact is that the OEM pully is a damped pully and the UR pullies are not. That's the bottom line.

And what once appeared like good supporting evidence in favor of UR pullies is now somewhat diminished. The initial assumption was that the VQ in the Maxima and the G35 were identical and hence the pully/harmonic systems were identical. But as the recent pissing match has shown, the damped pullies on the Maxima and G35 are completely different in mass and size. Pullies that are completely different in mass and size tends to suggest they will have different damping frequencies, rates and charecteristics.

In fact, if the G35 pully is substantially heavier, a higher damping mass (generally) tends to suggest the heavier pully has a lower frequency potential and higher damping factor. Thus putting a light weight, undamped UR pully on the G35 may be more detrimental because the different pully tends to suggest there may (possibly) be less internal damping built within the G35 VQ.

To me, the risk has not been mitigated.

Speculation. Conjecture. But its deductive reasoning.

 

Hydrazine, screw the Tilton, get the EVO 3.91 gear set for even more fun. If you also change tire diameter to around 25", you have a final ratio near 4.10. that's about a 15% increase in effective torque. That will launch your butt and accelerate the car like a cat on habenero sauce. And then add a light weight pulley.....

 

How is the extent/depth of the rubber that goes through the pulley tangent to whether it's damped or not? The articles I've read on this that have shown what a damped pulley looks like show the rubber going all the way through it or through a majority of it. The fact is, we don't know how far that rubber goes through the pulley. If it's just on the surface (1/8"), one could epoxy a rubber band on the UR pulley and get the same results (slight exaggeration but you get the point.) If the depth is more substantial, then I will agree wholeheartedly that the stock pulley is dampened.

That pulley in the pic was from an older model 3.0 vq (1995-1999) and not the 3.5 vq in our G/Z's.

 

Let me know how much and where to paypal.

 

Al,
Are you asserting it isn't a damping pully?... ...

 

Sorry if I haven't been able to express myself clearly enough. Here's my point:

All other things being equal, I would think that the dampening ability of a particular part would be dictated by 2 things:
1. how much of the part is comprised of the dampening material, be it rubber, asphalt, etc and,
2. how the aforesaid dampening material is integrated into the part. Put another way, the rubber would be more effective if it were pressed between the metal versus just being on the surface of the part.

For our purposes, we've been debating how far the rubber actually goes through the pulley. My position is that it is slightly recessed into the pulley while others have argued that it goes almost completely through the pulley.

Now that we have someone graciously willing to part with a pulley, and someone willing to pay for shipping and a 6-pack (non-company business) for a shop guy to cut it for me, we'll know the answer soon enough.

If the rubber is just slightly recessed on the surface, it can't do that much damping. If it goes almost through the entire pulley, then obviously, it would have much greater dampening ability.

I hope I've cleared up my position.

 

The rubber cannot be going more than halfway through. If you examine the pulley, you'll see that the second half is basically just the metal pulley. Pushing down with a small screwdriver between the rubber and metal, I can only go about 3 mm.