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Big Vibrations Issues!

abr33
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  • 3 weeks later...
abr33 Proficient

abr33

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Have you tried turning the shaft 180 degrees yet to compare if vib's better or worse

Tried everything really, even phasing 90 degrees, im running stock shaft till the manager of spicer comes out and looks at it

urtwhistle Proficient

urtwhistle

Posted
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funny you say spicer. I rebuilt my stock 2 peice with spicer uni's and the first pop of the clutch it shattered 2 of them. So I went a big single shaft which give the car a slight vibration about 110-120kph. I have come to the conclusion that it must be something to do with the harmonic's of the shaft at that rpm.

nobby Collaborator

nobby

Posted
Posted

Don't take any of this the wrong way.

Nissan put a 2 pce drive shaft in for a reason.

I also admit, standard seems heavy at that.

But why make a super car and handy-cap it with this sort of construction?.

Id like to know all about the spicer and their uni's, more info please.

I'd suggest rear sub frame, diff , and gearbox miss-align enough to cause or at least contribute to the vib problem.

Or I'm simply wrong.

Recon someone who builds race cars professionally should knows what the "usual causes" of the vib given what your trying to do.

you may simply have to pay for a fix.

Good luck I'm keeping a close eye on this may have to do mine sooner or later.

Cheers

urtwhistle Proficient

urtwhistle

Posted
Posted

hhahaha yeah you should have seen the guy who built the shafts face when I walked in on Monday after picking it up on the friday. We then freighted the shafts from Perth to Brissy I think it was as Spicer wanted to see it before they would warrant any of it. They claimed that I must have had the wheels locked up or something. Then claimed it was impossible to smash both the front uni and the rear at the same time. But yeah they refused to warranty it so I gave them the finger and the guy that made the shaft met me half way on making a single. Drive shaft balancing service's in Malaga. They are a good bunch of guys too.

The funny part was the yoke's didn't break even after machining them to suit the spicer uni's but the centre's crumbled. PS it was 3500rpm launch in a 350hp R34 gtt. on crappy 235's

  • 4 weeks later...
abr33 Proficient

abr33

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So the problems almost gone now, turns out the spigot on diff was .3mm undersize, and bolt holes being super neat, when loosened off I wiggle plates and no play... The manager/engineer came and inspected the setup, and detected this, took it back, made new spigot perfect size, re-balance again and sent back and I fitted it, and now it runs great to 110 km/h but 110-120 it has the same vibration however nowhere near as severe as before, its just annoying now. Everything setup and balanced perfect we are at a loss as to what the issue now is. The only thing suggested was the unis, as they are a solid centre type, have fibre thrust washers on ends to stop play, and inturn offer resistance, the possibility is they are just tight enough to begin vibrations at that speed. IF this is the case, it'll pan out in the next few hundred kms.. I hope so. Input?

  • 2 months later...
abr33 Proficient

abr33

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Posted

Definately shaft. Stock has zero vibes. Havent done anything for a couple of months but its coming back this week hopefully with results. We have gone to a slightly lighter tube, kept the 1350 uni at box, and middle and diff are 1310's i think. Will post results. I hope lol.

  • 2 weeks later...
abr33 Proficient

abr33

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Finally sorted! Running slightly lighter 3 inch tube and 21r uni's, we have a good result so far. So many combos and different things and this is where we got to. Still rated well over 600hp and not alot heavier than stock, cant say enough good things about the level of service from Hardy Spicer in Newcastle and the persistance to get this right.

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