Brake upgrade options.....

[HASNOS_82]

Heya guys (and girls)

I've owned a green GJ Sigma wagon for about 3 years or so now and i've done some research on a brake upgrade setup for the rear of the Sigma.

Basically i've found out that either the VN-VP or VR-VS HSV Commodore (sorry i cant remember which exact model) has the exact same bolt pattern, same piston diameter and same brake pads as used in the Sigma rear end. The matching rotor to use is the part number DR020 from DBA. The only trouble with this setup is that you have to get rid of the handbrake shoes (therefore, the cable and lever) as the inner hat section on the Holden rotor is 160mm (the Sigma is 174mm). After measuring the two rotors side by side, both rotors are exact same diameter (280mm) and exact same rotor height. The only differences between the two is the Holden rotor and the Sigma rotor are:

Sigma rotors are a 10mm solid rotor
Holden rotors are a 20mm ventilated rotor

SIgma's a 4-stud
Holden's a 5-stud

Also the rear brake hoses are a little different but it is easy and cheap enough to get them to be custom made to suit your application.

I'm still in the process of developing the front end....So far i've married up Toyota Lancruiser 4-piston calipers to the Sigma strut (again, same bolt pattern but offsets are much more complicated

I'll keep you posted on my findings

Ciao

[Sigmaproject]

If you dont have disc's as standard on the rear, there is nothing wrong with the Stocky Sigma Disc brake conversion.
And you use all factory parts ;) And they all bolt on without any modifications.

As you have a Wagon, you can bolt up the early Scorpion diff and disc brakes.

And on the front Starion Struts and ventilated disc's are a bolt on upgrade.

[karl_2ltgc]

I can tell you that VR/VS are a solid rotor at the rear, not ventilated.
Ive got a stuffed one on my garage floor, anyone want it?

[HoonBoy]

Stock ones are solid, HSV's (some, all, not sure??) have vented.

[Superscan811]

I agree with Sigmaproject.
For the front brakes, a bolt-on upgrade is the starion front struts.
For the rears, if you have/get a Jap diff, you can bolt up the starion rear vented discs/calipers with no modifications. Just make sure you get the handbrake cable with the diff.

Make sure it's a 10 bolt (not the 8 bolt) Jap diff if you are aiming for more power as well.

Cheers.

[HASNOS_82]

Hi guys,

Thanks for your info, but as the topic says, this is only another option. I feel there is no point in everyone doing the same modification as it gets as bland and boring as just a standard car lol.

Hopefully we see more extra alternatives in this sort of area as i'm very keen to hear what other people think

ciao.

[COBWBS]

Hi guys,

Thanks for your info, but as the topic says, this is only another option. I feel there is no point in everyone doing the same modification as it gets as bland and boring as just a standard car lol.

Hopefully we see more extra alternatives in this sort of area as i'm very keen to hear what other people think

ciao.

So if i suggest somthing to you.. Witch is easy and a straight bolt on are u goin to do it? Or am i jst wasting my time?

[karl_2ltgc]

Sigmas are quite light and realy dont need stuff all brakes in the rear.

Starion brakes are ok, but are still on the small side. 256mm rotors aint shit these days. Something more in the 280mm size are good an will still fit under 15" rims.

[Superscan811]

HASNOS_82,
how much money are you wanting to throw at the upgrade?

Most people on this forum don't have a lot of money to throw around so that is why we look for a cheap and viable solution.

The Starion upgrade may be "Old Hat" but it works very well and can be done on a very limited budget. The front and rear discs are vented, they bolt straight on and no other changes are required.

If you are wanting to go exotic (read EXPENSIVE), there are alot of options.

Choice of different multi-pot calipers.
Designing, Engineering and Fabrication of the caliper mounts and possible modification of the strut.
Larger rotors.
Modifying the existing hub or manufacturing a new one and/or modifying the new rotor to fit.
New rims (including the spare) to fit over the new, larger rotors and calipers.
New Master cylinder.
New flexible brake lines.
Getting the front/rear bias set up correctly.
Getting it engineered.
Time to complete all the tasks.
Plus quite probably 1/2 dozen things I haven't though of yet.

You can start to see why the starion conversion is appealing.

Cheers.

[HoonBoy]

Hi guys,

Thanks for your info, but as the topic says, this is only another option. I feel there is no point in everyone doing the same modification as it gets as bland and boring as just a standard car lol.

Hopefully we see more extra alternatives in this sort of area as i'm very keen to hear what other people think

ciao.

I always judge a car by the uniqueness of the rear brake conversion...

Keep it simple and make it work is a much better idea. Calipers with an integral handbrake make the rear conversion much easier, that's one of the reasons I used R31 calipers on the Lancer. If they have a drum handbrake, try modifying the backing plate to get them on and working, you can do this to put Sigma drums on to a Lancer diff for a minor upgrade in braking but better handbrake adjustment.

4WD calipers can be seriously heavy, so make sure you don't use cast iron ones, very bad idea.

[HASNOS_82]

Hang on guys, i never said that the Starion upgrade was old hat, or a bad idea, i'm all for modifying a car, i just like to see different options and ideas thrown around....that's all. I can assure you my budget is no bigger or better in any way than anyones here. Oh and COBWBS, no you wouldn't be wasting your time.....if you have an idea, why don't you share it???? isn't what this forum is all about???

[Superscan811]

HASNOS_82,
Sorry if it seemed like an attack, I was just trying to get across the point that there is ALOT
involved in doing a brake upgrade, not just slapping on a different set of calipers and/or rotors.


Personally I am looking at 300mm rotors and 4 or 6 pot wilwood calipers for the front
and for the rear, 4-pot Wilwood calipers with a seperate mechanical park brake.

These are some of the calipers I have been looking at using for the front.
Legally they need to have a rubber boot around the pistons to stop dust and grime,
so that limits me to the black calipers.

This is the front strut off a starion so you can get a bit of a size comparison.



I was looking into aftermarket silicon covers for the pistons as a way to get the other
calipers approved but I didn't chase it up. I may go down that path later on.


Cheers.

[Leethal]

if you got the bucks, hopper stoppers in victoria do an upgrade kit for siggys, using 300mm au falcon rotors, twin piston pbr calipers, all mounting hardware is supplied with the kit with the exception of the master cylinder which requires replacing with a 25mm unit, all info here supplied to me by hopper stoppers i would be happy to mail info on this kit to anyone who wants a sqizz kits price quoted to me was $1400 with slotted rotors, btw eveything in the kit is new