Piazza LSD diff?

Ben Wight · backyard mechanic Joined: 04 Oct 2001 Posts: 946

I never kept track of those diff posts, but now I need to know.

1. Does the piazza have a torque tube?

2. From memory, I remember the distance from hub to hub being greater, so how much does the rear wheel track increase?

3. I assume it isn't much of a hassle to cutt the spring and shock mounting paltes from the standard diff axle housings and weld them onto the piazza housing?

4. How about the disk brakes, do they need a different proportioning valve (ie. different operating pressure)than the standard drums required??

5. And anything else I am forgetting.

Thnks guys,
Ben Wight

Mooch · backyard mechanic Joined: 17 Oct 2001 Posts: 573

Don't know about the first questions but as for the brakes: yes you do. Drums are under constant pressure so you will have change the proportioning valve to a disc/disc one.

Good luck
Adam

GRMLIN · rice boy Joined: 05 Jan 2002 Posts: 37

do you know of anyone that wants to buy one.
it has a fully strengthed rear end for a race setup and is already in a gemini so it will bolt up.

cheers chris

Ben Wight · backyard mechanic Joined: 04 Oct 2001 Posts: 946

Can you tell me a bit more about the diff?

I have already found one pretty cheap, but maybe yours is better. How has it been strengthenned? What did you do about proportioning valve?

I'm curious to know how much you would want for it?
You can mail me if you want
wight@giant.net.au

Ben Wight

GasGem · backyard mechanic Joined: 05 Nov 2001 Posts: 755

Hi Ben,

I had a Piazza diff that had a torque tube, it looked exactly like a Gemini P/V diff, (Different shock mounts), I fitted it to my P/v Gem no problems just had to get a H/brake cable make, now the diff appeared to be about 1 inch wider track each side, the wheels I used were Bathurst Globes, 13x6 with 205/60/13 tires, with lipped guards they did not scrub but it was close on the outside,

Also if you are fitting it to a sedan you will need Torana rear shocks as the Gem rear shocks will not fit,

any more info let me know,

cheers

Ben Wight · backyard mechanic Joined: 04 Oct 2001 Posts: 946

Thanks, I'll keep the torana shocks in mind, but I have brand new gemmy shocks so I would like to keep them, so I will be trying to adapt the shock mounts from the gem diff.

Are you saying that the srping buckets are virtually the same, show about the trailing arm mounting locations.

Was yours drum or disk, if disk, do you do anything to the proportioning valve? Was there no way of modding the standard handbrake cable to work on the new brakes?

Cheers!
Ben Wight

GasGem · backyard mechanic Joined: 05 Nov 2001 Posts: 755

Mine is solid disks, not the latter vented rear disks, but i am told they are interchangable,

Proportioning valve, no mods done, no apparent problems yet, will be looking into that one thou, i'll let you know,

spring buckets and arm length are very close if not the same,

handbrake cable needed to be extended by about 1ft, and steel shealding extended, different fittings made, not a problem there are plenty of places that can do that,

the only shit of a problem is the ratio, mine was 3.55:1 not 3.9:1

changing the shock mounts is a bit difficult due to the different spring bucket design, don't get me wrong it is possible, but the buckets come to a point at the rear for the pin to come out for the shocks, unlike the sedan which have a flat back

either way it works fine with torana shocks and gives the engineer 1 less thing to look at,

I also have Piazza front vented disks but as yet have not had to mod the master cylinder,

cheers
Eggy

GasGem · backyard mechanic Joined: 05 Nov 2001 Posts: 755

one last thing you will need a P/Van panard rod,

cheers

Bugle · tinkerer Joined: 08 Oct 2001 Posts: 221

this is what I know about them.
There were 2 model Piazzas, first the JR130 which had a G200Z or W which had a torque tube and non vented discs. The second one was the JR120 with the 4ZC1 and it didn't have a torque tube and had vented discs. All autos had 3.5:1 and manuals had 3.9:1

Ben Wight · backyard mechanic Joined: 04 Oct 2001 Posts: 946

Are the Panel van shocks the same as a sedan?

I would prefer the ratio of 3.55:1, as the 3.9 doesn't load the turbo up much and the engine accelerates quicker than the turbo, plus the ratio isn't good for circuit racing or highway cruising, and top speed insn't enough, only about 190 flat out in 5th gear.

I'm more concerned about the LSD factor than the brakes.

Ben Wight · backyard mechanic Joined: 04 Oct 2001 Posts: 946

But are they both LSD?

Ben Wight · backyard mechanic Joined: 04 Oct 2001 Posts: 946

Hey Chris, I wish you would specify an email so I can contact you. You are selling a diff. I am buying a diff. I think we have something in common. Where are you situated?

Ben Wight

gem · tinkerer Joined: 23 Dec 2001 Posts: 152

You mentioned the JR120,was this the Aussie version ???
As I am wondering how the gemini diff could be mounted without the stupid torque tube.Thanks

Slug · tinkerer Joined: 06 Oct 2001 Posts: 196

No of course not !!! LSD was an option so NOT all piazza diffs are LSD. One more thing the spring seats are NOT in the same location, yes it goes in but it will work like shit ... Michael

Bugle · tinkerer Joined: 08 Oct 2001 Posts: 221

Yeah it was an option in Japan but all ones sold by Holden came with LSD