310 replies to this topic

[ls2lxhatch]

The main weak point of the BW78 is the welding of the upper control arm brackets. If they are done properly then 400-450 rwhp should not be a problem on a street car. You would need slicks and a drag strip to push the BW78 to its limit.

 

FWIW drive trains are rated by torque not horsepower. In theory you could break any diff with 100 hp if you used a low enough gear ratio to increase the torque past the limit of the diff.

 

The Truetrac is available for the BW78 plus a few locker style centres.

 

In my opinion the best centre for the BW is a KAAZ. The KAAZ LSD is a cross between a clutch pack LSD and a locker. In a straight line the torque is used to increase the clamping pressure on the LSD clutches which makes the KAAZ a locking LSD.

 

The Detroit Truetrac never locks. The Detroit Truetrac uses worm gears to transfer %75 of the torque to the wheel with the most grip. In a straight line you get %75 to one wheel and %25 to the other. If you jack one wheel off the ground the other wheel will not turn. 

[76lxhatch]

The Tru-trac is great around corners (with some traction), you can get the hammer down early and it will get great drive out where locking diffs just make the back end step out

[ls2lxhatch]

The beauty of the KAAZ design is that around corners it is just a normal clutch pack LSD with a light clutch preload. However once both wheels are turning at the same speed the clutch load is increased to the point where the diff is effectively locked.

Edited by ls2lxhatch, 06 June 2016 - 05:32 PM.

[Heath]

Can someone enlighten me regarding how necessary moving the shock mount is? Is it to fit big tyres or just to clear certain brake assemblies?

 

What brakes assemblies are a drama? I don't have any brakes, wheels or tyres so I can't see where anything belongs right now haha. I'm gonna go 1" shorter in diff length only, but with a full floater end and unknown brakes... no idea what clearance issues I'm going to find.

[dattoman]

Shortening the diff will cause issues with the brakes

Calipers foul on the shock

You will need to locate the caliper to the front or move the shock

[76lxhatch]

The R31 calipers don't foul on the shock (standard diff width) but you have to remove the caliper to get the shock on and off which is a pain in the neck. It also looks to me that the shock is more upright and fits the upper mount straighter after moving it in a little.

 

The big advantage though is that moving the lower mount up means you run HQ length shocks, more options (e.g. easy to find Bilstein etc).

[Heath]

I consider that to be an advantage, but I consider the fact that I've gone out and bought McDonald Bros mounts that have an integral shock mount a disadvantage.

 

Hmmm...

[torana_nick]

Mcdonald Bros cut my shock mount and relocated it using there bracketry.

[ls2lxhatch]

There are a few pictures earlier on in this thread starting with this post.

Rorym


Youngy11 The upper control arm mounts look to be a good design as they avoid welding to the cast centre.


76lxhatch


[url=http://www.markswork....au/Pages/daves project lead page.htm]Marks Workshop[/url A9XII


2wild4u

[Heath]

If you're willing to make a different style of swaybar mount on the chassis, or get a different shape of swaybar made up (spring shops can do this, you just need to give them a template) then there's no reason the tidy R31 swaybar mounts couldn't be used, I feel.

[76lxhatch]

You can see in the photo that ls2lxhatch posted above of mine that I used the sway bar mounts on the diff housing, and the end links go through the upper arm mounts just in front of the arm pivot

 

Its just a Commodore bar with the ends straightened out, can get various sizes up to 18mm from factory cars for next to nothing.

[ls2lxhatch]

The mounts look like they might be in the right spot for the UC style swaybar available from K-MAX and Whiteline.

This is the K-MAC UC style on my hatch.

 

[Heath]

This is what the UC's have, but LH/LX don't have any mounts on the body (the swaybars just connect L and R lower trailing arms to one another lol)

[76lxhatch]

All I had to do was make a hole in the upper arm mount

 

(please ignore the mess, I've just fixed a leak through the diff pinion spline)

[Heath]

So you have to pull the upper arm off before installing the link pin? I guess that isn't the end of the world.

 

What's the swaybar off? Aftermarket or standard UC (IF that's standard R31, you beauty!)

Edited by Heath, 09 June 2016 - 11:07 AM.

[ls2lxhatch]

Whiteline BHR37 swaybar

 

K-MAC TRC1

 

More pictures here

http://ls2lxhatch.com/suspension.htm

[76lxhatch]

So you have to pull the upper arm off before installing the link pin? I guess that isn't the end of the world.

 

What's the swaybar off? Aftermarket or standard UC (IF that's standard R31, you beauty!)

Not quite as easy to get at it with the arm installed but can be done - if you look at the photo above of the Whiteline bar you can get your fingers and/or a spanner in there.

 

As above, its a live axle VB-VS Commodore bar with the ends straightened out a bit in the press. The R31 bar I had was a spindly little thing and would have been narrower more like the UC one so you would need to fabricate brackets.

[Heath]

Both nice solutions, but I'm particularly a fan of just running in straight into the floor of the upper mount after a bit of bending on the original bar.

 

Nice work.

[76lxhatch]

I guess you could just spread the arms out a little wider to make the R31 bar work, you'd want a bigger one that what I had but I suppose they must be available