Strange Vibration

[hellix2484]

I am getting a strange vibration when my RPM's reach 5000.

I have two ideas that i might be. One is it is my side exaust vibrating on the rocker pannel and two it might be my Under drive crank pulley.

What do you guys think. It only happens when I get into high RPMs.

[slowion2]

if I had to guess without seeing it I would say the pulley. you can try swapping the stock one back on and see if it still makes the vibration. sounds very similar to what Nathan got with the sohc pulley on his dohc

[hellix2484]

hmm I wonder if I will have to change my belt to check that out.

I also have the alternator under drive pulley.

[dream36realms]

I agree with Vinnie. After reading many conversations here and there, the most consistent outcome, was not to use lightened crank pully, because it will do what you are saying is happening. If that is not the problem I'd be happy to hear it since I would like to do that mod(if it works)

[slowion2]

you're not picking up that much hp with pulleys to begin with. it will rev slightly quicker, but a belt to bypass p/s and a/c will do the same thing

I'd rather have the stock pulley with a damper than a lightened one that I've seen crack and fail before

[hellix2484]

OK I will swap it out this evening and see what happens.

I have also been thinking about changing my exhaust any ways so I may do that too.

Dual LT1 tips out the back. :twisted:

[hellix2484]

Wellz I pulled off the pullies and there is no more vibration noise. [img]{SMILIES_PATH}/sad.gif[/img] I did notice a slight drop in performance but I am hoping to make that back when I remove my A/C.

[S.Bretz]

NOOOOOOOOO. A/C is a must in Fl...get naaawzzz.

[hellix2484]

luckly for me I don't live in FL [img]{SMILIES_PATH}/smile.gif[/img]


Although I have noticed that the my A/C has stoped making that noise. ???