Ghetto dampener pulley????? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

DDSR240 · 08-27-2008, 02:15 PM

I was searching for any homeade harmonic dampener but i couldnt find any. My question is this do you think it would help to use a layer of dynomat on the inside lip of a aluminum crank pulley..and before I get flamed I do know it is much better for someone to fork out the 450 dollars and get a real one but if dynomat dampens all vibrations wouldnt it be a good idea to use it,insted of no type of dampening what so ever?? And one more thing how would you make shure the pulley was still balanced with the dynomat?, Is there even a way to do that?

Def · 08-27-2008, 02:49 PM

Say it after me... damp, damper, damping. Nothing is getting wet here.

To answer your question - no, Dynomat will do nothing to reduce the torsional vibrations in the crank. This is a torsional vibration, not a simple bending mode like your trunk vibrating from too much "phat bass." You need a mass rotating out of sync with the crank at its natural frequency, and the stock crank pulley has a rubber strip that allows this(and everything is tuned to give the system the desired response).

the head · 08-27-2008, 03:16 PM

wow...right up there with running sand through your engine to hone out the intake and exhaust...pure stupid

DDSR240 · 08-27-2008, 03:21 PM

Sorry man it was just one of those "crack-pot'' ideas I tend to have but I understand they are torsional vibrations but they are started by harmonic vibrations thats why I thought it could help, btw we don't have hooked on phonics in south carolina yet LOL

Def · 08-27-2008, 09:37 PM

Quote:

Originally Posted by DDSR240

Sorry man it was just one of those "crack-pot'' ideas I tend to have but I understand they are torsional vibrations but they are started by harmonic vibrations thats why I thought it could help, btw we don't have hooked on phonics in south carolina yet LOL

Harmonic vibrations just refer to vibrations due to the response of a system to an input, which is pretty much what all vibrations are when you get down to it.

Torsional vibrations refer to the system(crank in this case) involve the crank twisting back and forth. You need something twisting back and forth in the opposite way to counteract this at the right time.

*burnsauto* · 08-27-2008, 05:44 PM

dynomat would just throw off the balance of crank anyways.

do it right, call ATI. fork over your money for all the R&D they put in, and enjoy.

08-27-2008, 02:15 PM	#1
DDSR240 Zilvia Member Join Date: Dec 2006 Location: South Carolina Age: 34 Posts: 259 Trader Rating: (0) Feedback Score: 0 reviews	Ghetto dampener pulley????? I was searching for any homeade harmonic dampener but i couldnt find any. My question is this do you think it would help to use a layer of dynomat on the inside lip of a aluminum crank pulley..and before I get flamed I do know it is much better for someone to fork out the 450 dollars and get a real one but if dynomat dampens all vibrations wouldnt it be a good idea to use it,insted of no type of dampening what so ever?? And one more thing how would you make shure the pulley was still balanced with the dynomat?, Is there even a way to do that? __________________

08-27-2008, 03:16 PM	#3
the head Nissanaholic! Join Date: Jul 2002 Location: in a dark room mastering the art of typing with one hand Posts: 2,164 Trader Rating: (3) Feedback Score: 3 reviews	wow...right up there with running sand through your engine to hone out the intake and exhaust...pure stupid __________________ I never knew you could do that with an eggplant

08-27-2008, 03:21 PM	#4
DDSR240 Zilvia Member Join Date: Dec 2006 Location: South Carolina Age: 34 Posts: 259 Trader Rating: (0) Feedback Score: 0 reviews	Sorry man it was just one of those "crack-pot'' ideas I tend to have but I understand they are torsional vibrations but they are started by harmonic vibrations thats why I thought it could help, btw we don't have hooked on phonics in south carolina yet LOL __________________

08-27-2008, 05:44 PM	#6
burnsauto Premium Member Join Date: Dec 2006 Location: 717, PA Age: 35 Posts: 3,153 Trader Rating: (5) Rides Gallery: burnsauto Feedback Score: 5 reviews	dynomat would just throw off the balance of crank anyways. do it right, call ATI. fork over your money for all the R&D they put in, and enjoy. __________________

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08-27-2008, 02:49 PM	#2
Def Post Whore! Join Date: Apr 2004 Location: Houston, TX Posts: 2,701 Trader Rating: (16) Feedback Score: 16 reviews	Say it after me... damp, damper, damping. Nothing is getting wet here. To answer your question - no, Dynomat will do nothing to reduce the torsional vibrations in the crank. This is a torsional vibration, not a simple bending mode like your trunk vibrating from too much "phat bass." You need a mass rotating out of sync with the crank at its natural frequency, and the stock crank pulley has a rubber strip that allows this(and everything is tuned to give the system the desired response).