stillen lightweight crank pulley
 

Anybody got one yet? Is it worth the money?

RCZ and Semtex both bought them but they don't have them yet.

i almost hate to bring it up, but does the stock pulley have a harmonic damper?

conversely, does anyone make lightweight pulleys for the non-crank items (alternator, water pump, AC)?

What's that mean?

Harmonic dampers absorb vibration through the crank and prolong the life of the bottom end by reducing wear on bearings and such. They are less important the shorter your crank is. In other words it's not as important on a V-6 as it would be on a I-6.

Hehe, the myth resurfaces. Harmonic Dampers is a never ending argument, like break-in.

We'll see what happens when I get it installed...

Oh and mine comes in tomorrow, I'll get pics up when I have it.

myth, as in fictional? torsional vibrations that lead to engine failure are definitely not myth.

harmonic amplification of such vibrations would occur at very specific rpms/frequencies, so their relevance in a passenger car, whose rpms vary constantly, is probably very low, hence the assumption that they are not needed or can be eliminated.

it IS a never ending argument, especially when people say things like "it didn't happen to me, so it must not be true," which is just as misleading as "stay away from this- i had an engine failure, so this part must have done it."

anecdotal/individual experiences mean nothing except as part of controlled study. unfortunately, such study is essentially never done with aftermarket car parts. so, we are left with having to make such decisions on precious little worthwhile information.

i am just curious to know if the stock crank pulley has a harmonic damper. if it doesn't, there's not a reason in the world to avoid an underdrive pulley. if it does, people should make their decision mindful that someone thought it was a good idea.

Thanks for the info. Can't wait to see the pics, don't forget to tell us how much of a difference if any you notice

Is the stock crank internally balanced? If so, there's no harmonic damper. If you see a rubber band like ring as part of the pulley, that's the elastomer for absorbing operation noises such belt rotation sound. A harmonic dampering pulley is easy to spot such as those on domestic engines. Someone should take a picture of the pulley.

No, not as in fictional, but I'm glad it gave you a chance to explain that for the folks who didn't know what it was for.... :tup:

What I was getting at is exactly what you said later on. That everyone always talks about it and the effects of not having one, yet it becomes an argument about whether or not the car needs it. Just like whether or not the car needs a babying period during break in.

I am glad you know your stuff, but that begs the question as to why you have an R32? :p

I am kidding.

I'll let you know if my motor vibrates itself into pieces in a couple months :)

The stock pulley is not a harmonic damper, and the engine is internally balanced. There is a rubber piece for NVH reduction. This information is correct.

So back to the first question, how is it?

Didn't get a chance to install it over the weekend. Sorry, should be in this weekend though.

I'm getting impatient! Lol. Stop teasing me!

The G37 isnt seeing any gains from them

anything yet?

I've had the Stillen lightweight underdrive version on my car since Saturday, so just about a full week now, details over in my journal thread on the install and the feel afterwards, but no dyno yet:

http://www.the370z.com/members-370z-...html#post59072

In the days since I talked about it there, my impressions haven't changed. Slight horsepower bump and a more responsive (as in, to throttle inputs) engine is what I'm observing on the road.

When you say 'more responsive', do you mean it has more torque? Or just that it revs a little quicker?

I wouldn't necessarily say "more torque", but it's more than just revving quicker unloaded. It's hard to describe. The engine simply has less inertia to overcome on changes is the bottom line. It reacts to throttle changes under load (especially changes between accel + decel while staying in gear) faster. You could think of it as if the computer were inserting some very tiny electronic lag between the gas pedal and the actual throttles (or vvel, whatever), and the pulley took that away.

Butt dyno says some hps gains at the top end too, but no real dyno to confirm that yet.

Very nice Im hoping that this with the grounding kits will eliminate the slight lag when shifting my 5at

In the overall the shifts are slightly faster (the uprev/downrev period). I still have occasional very lagged 1-2 upshifts, which I'm really starting to get annoyed at. Usually they're fine, but every once in a while, it takes *forever* before it even begins to acknowledge the click for 1->2, like a full second (or more?). It's hard to tell timescales when you're expecting something so fast. When this happens, it's not that the shift itself it's slow, it's like the computer is having some kind of lag before it acknowledges the shifter input. I've learned not to click again thinking I failed to click though: it will queue them up and then quickly jump 1->2->3 when it gets its head out of its ***.