Pulley Size/Fitment: Z34 vs. R35

christian370z

RPMs and the internal balancing from rotational mass, all the internals and so on are two different things. An F1 engine can do 7,000 rpm, just like a Honda Accord or Ferrari 458. They can both hit the same RPMs, but are entirely different engines.

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sloboi

I apologize if I'm a bit aggressive with my counterpoints. I deal with "factless" arguments a lot, so I get annoyed with them easily.

NOW, with that being said, I admit that my presumptions are rather baseless as well. I am going into this dampening business with two basic premises:

1) That overall, the GT-R and 370Z share a similar engine configuration
-I base this on the apparent similar fitting of the crankshaft pulley, size of shortblock (similar bore, stroke, and intake manifold fitting/size), and of course, an eyeball estimation of width to height ratio of the two engines.
2) That these similarities will mean similar crankshaft vibrations at similar RPM's.
-I base this on...well, nothing. It just makes sense to me that if 1 were true, there is no reason 2 wouldn't be.

Lastly, unless the harmonics of the engine were COMPLETELY off, I still believe that an engineered dampened pulley, at any RPM range within it's designed specifications (which is the same for the 370Z and GT-R), will out dampen the OEM 370Z pulley--which is practically undampened--save the little rubber ring. The added weight of the ATI pulley will also serve to dampen the vibrations by adding additional inertia.

I really don't mind people challenging me, or my ideas. I just don't like it when they make a comment w/o any support. It's like your grade 12 mathematics teacher always said, "show your work."

sloboi

BTW, I've already touched upon this. In reality, the only thing that should affect the harmonic characteristics of the two crankshafts would be the mass of the crankshafts themselves, but considering the breadth of variables considered (which I admit, I lack knowledge on), I've included some other engine specifications/estimations. Besides, if we're considering other variables, wouldn't you assume that a boosted VQ37VHR engine would behave more similarly to a VR38DETT? (I'm not saying the VQ will behave more like a VR than a VQ, just that a boosted VQ will behave more like VR than an NA VQ.)

The engine is already internally balanced, so there should be no "balancing" act needed for the pulley.

sloboi

I've probably been a bit of an ******* to 7419sundat, so for that, once again, I apologize. Thanks for everyone's input, though! Still no answer...tried contact AMS, and no response, as I predicted.

sloboi

That ******* was "butt-hole".

Nut_N_Much

You guys gave me a head ache but nice thread. I was curious about the Z's dampening. I've ordered an NST Pulley kit and I see your logic with a boosted engine. I had no idea the stock pulley had a rubber ring around it. Now I'm second guessing my NST. Will go SC next year, so I will keep my stock pulley around.

Subscribed, will fallow the thread to see if a supplier is found.. Thanks fellas.

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http://www.the370z.com/mazoc/99606-z...y-14-17-a.html
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