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LSD option for an 8 bolt diff?

djr4917

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Hey, I have a stock VK calais with an EFI 3.3 and I'm pretty sure an 8 bolt diff (It's got 10 bolts on the cover but I was told you don't go by that). Anyway is there a good LSD option for for the 8 bolt Salisbury? I would like to only have to change the centre but If not what's the best option? My research hasn't turned up much.

Also on a side note does anyone know someone who is wrecking a VK calais near Melton, Vic? I need a front bumper and a rear right side bumper. Thanks.
 

Darren_L

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the 10 bolt diff is easily identified by the oval shaped cover on the back of the diff
as for the 8 bolt, I don't believe there is an easy LSD option for these diffs. I could be wrong, but I'm fairly sure LSD option was only on the 10 bolt. Probably cheaper and easier just to buy a complete 10 bolt LSD diff. Only real difference will be the size of the uni-joint at the diff, so might need a tailshaft to suit as well. But otherwise it should be a straight swap
 

SL/ENUT

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There was an option of LSD with the 8 bolt diff.
 

djr4917

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I take it they are hard to find? I have been looking for a short while and haven't found anything.
Would I be better off just fitting a 10 bolt or Borg Warner or something?
 

SL/ENUT

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Sure are rare. They aren't strong etc.
 

djr4917

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Yeah I thought you were going to say something like that. I'll just stick with the Borg Warner idea I think.
If I fit one out of a VL Turbo it should go straight in yeah but still have to change the tailshaft?
I would like to fit a single piece shaft anyway.
 

Darren_L

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VL LSD Borg Warners aren't cheap...
Yes they are fairly much a straight fit apart from the tailshaft
Just be aware they are a bit wider than the VH diff, so if you have wide tyres they may scrub

And do your homework before fitting a one piece shaft to a Commodore, personally I would avoid it. Common problems are floor pan clearance, vibration from uni-joint angles. 2 piece shafts are a better design, providing the CV joint is kept in good order and you set your driveline angles up correctly. Most vehicles these days use 2 piece shafts, including heavy vehicles & V8 Supercars
 

djr4917

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I might know someone wrecking a couple of VL's where I could get one.
Fair enough with the tailshaft, you can lower the car provided you set the angles up on the tailshaft yeah,
would you have to take it to a specialist?
 

Darren_L

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yeah you could take it to a specialist but a bit of trial and error can also work well. There are specs in the workshop manual, but you need some sort of inclinometer to measure them If by any chance you don't have one.... and you have a smartphone, you can download an app and use your phone as an inclinometer. Might not be as accurate as the actual Kent Moore instrument, but it's not that crucial - it still comes down to a bit of trial and error sometimes. But factory settings are a good starting point.

Angle 'C' (the angle between the CV joint and the diff) is usually the only angle you need to change when the car is lowered. Usual symptoms are vibration under acceleration. When you lower a car, the diff goes up in relation to the CV which is fixed to the floor. So you need to lift the CV/centre support mount in order to maintain the original angle. There's usually some shims between the centre support mount and the floor pan. Remove the shims and fit them between the centre support hoop and bracket (which effectively lifts the CV). From there it's a bit of trail and error, if the problem is reduced but still present, add a bit more shim. If you go too far from memory you get a vibration on overrun.

I can scan a diagram of the driveline angles if you need them
 
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