Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: Lesopc on 20 September 2010, 17:28:09

Title: Brake Discs to suit a V8 Omega
Post by: Lesopc on 20 September 2010, 17:28:09
Me again guys, just wondering what size brake discs i would need to stop a Miggy with a V8  (LS series) lump. I'm guessing something from a Monaro but are there any other options i could consider?

What modifications would i need to perform to get the new discs on the Miggy as i don't really want to go cutting and chopping anything if possible?

My ideas so far are:-
Discs (drilled, grooved or both???) of the same size as a Monaro
Pads to match
Braided hoses to replace rubber ones

Any other ideas might be useful.
Title: Re: Brake Discs to suit a V8 Omega
Post by: TestOmega on 20 September 2010, 17:32:47
Which brakes, front or rear?

Cheers
Title: Re: Brake Discs to suit a V8 Omega
Post by: Lesopc on 20 September 2010, 17:36:39
Quote
Which brakes, front or rear?

Cheers

Sorry, i thought that was self explanatory. It will require new anchors for both front and rear as i expect a massive BHP difference which is no good unless there is something big enough to stop it.
Title: Re: Brake Discs to suit a V8 Omega
Post by: TestOmega on 20 September 2010, 18:07:43
Using standard discs but with upgraded caliper and pads which attach to existing carriage with the two standard Catera/Omega caliper mounting bolts.

People in North America have done the following with stock 16" and 17" front wheels with Cadillac Catera (sister of Omega),

(http://i802.photobucket.com/albums/yy301/Happy2iam/Catera%20Omega%202001/GTOBrakes.jpg)

There is also an excellent thread below that may be helpful,

http://www.cadillacforums.com/forums/cadillac-catera-cimarron-forum/110285-gto-brake-swap-log-4.html

The above being GTo (V8) based adaptation seems suitable.  I believe the Monaro and GTO have much in common so you are already more knowledgeable than me.

People on the following forum also have resale kits at times for very cheap but get one with the GTO brake lines included,

http://www.ls1gto.com/forums/

Cheers and just in case it helps.
Title: Re: Brake Discs to suit a V8 Omega
Post by: Phil on 20 September 2010, 20:33:58
Theres always the option of the 330mm discs and 4 pot AP calipers from the ST200 Vectra, more likely than not the carriers will fit the Omega as this was the set up on the still born V8 factory Omega iirc

Or you could just go for Vectra VXR brakes, upgraded ones are 362mm 2 piece 6 pot AP items!!

Courtenay also do a 345mm set up for the Vectra C/ Signum that could be adapted or just go for standard 3.2 V6 Signum/ Vectra C 314mm set up
Title: Re: Brake Discs to suit a V8 Omega
Post by: whippit on 20 September 2010, 20:38:04
Lotus Carlton setup would bolt straight on
Title: Re: Brake Discs to suit a V8 Omega
Post by: DodgeyDave on 20 September 2010, 20:42:05
Depends on you budget, carbon ceramics would be the best, but could be very expensive and may not be a staright forward fit.
Title: Re: Brake Discs to suit a V8 Omega
Post by: Phil on 20 September 2010, 20:51:05
Quote
Lotus Carlton setup would bolt straight on

Which is the same 330mm 4pot front set up as found on the ST200, as suggested above  ;)
Title: Re: Brake Discs to suit a V8 Omega
Post by: feeutfo on 20 September 2010, 23:19:33
Do we need to consider that a bigger diameter disc will mean the calliper will need to be mounted further away from the centre of the wheel.? With an adapter to hub assembly perhaps? Or do the previously mentioned set ups take account for this? And still fit inside the wheel?
Title: Re: Brake Discs to suit a V8 Omega
Post by: Phil on 21 September 2010, 11:16:03
330mm discs went under 17s on the ST, but if you are going V8 than surely the wheels would be either 18 or 19's?

362mm on the VXR vectra needs 19's

Replacement carriers are generally sold as part of the upgrade kit fairly sure if you are modifying the engine bay to fit a V8 adjusting a couple of caliper carriers will be childs play!

Guess it all depends if you want more area and more pistons or same area and more pistons?

Another thing that will need checking is bore size on the replacement discs as i would assume FWD front hubs have a different bore??
Title: Re: Brake Discs to suit a V8 Omega
Post by: matty on 21 September 2010, 13:47:25
i fitted fiat coupe brembos to my old vectra
Title: Re: Brake Discs to suit a V8 Omega
Post by: Kevin Wood on 21 September 2010, 14:30:37
Adding pistons to the caliper doesn't help the brakes dissipate heat, which is a function of the size of the disk.

A larger pad area might help the pad take a little more abuse before throwing in the towel but a larger disk would be a better upgrade.

.. and then you have to consider the brake balance. Change the piston area or disk diameter and this will shift.

That said, how much more weight are you going to be stopping, and from how much faster?

Kevin
Title: Re: Brake Discs to suit a V8 Omega
Post by: Lesopc on 21 September 2010, 17:04:20
Quote
Adding pistons to the caliper doesn't help the brakes dissipate heat, which is a function of the size of the disk.

A larger pad area might help the pad take a little more abuse before throwing in the towel but a larger disk would be a better upgrade.

.. and then you have to consider the brake balance. Change the piston area or disk diameter and this will shift.

That said, how much more weight are you going to be stopping, and from how much faster?

Kevin
Well i reckon that a V8 LS lump will take the car to a max of around 170mph (not that this will be seen much if ever) and the engine itself will account for most of any weight difference...a fair few kg maybe???
Title: Re: Brake Discs to suit a V8 Omega
Post by: Lesopc on 21 September 2010, 17:06:27
Quote
330mm discs went under 17s on the ST, but if you are going V8 than surely the wheels would be either 18 or 19's?

362mm on the VXR vectra needs 19's

Replacement carriers are generally sold as part of the upgrade kit fairly sure if you are modifying the engine bay to fit a V8 adjusting a couple of caliper carriers will be childs play!

Guess it all depends if you want more area and more pistons or same area and more pistons?

Another thing that will need checking is bore size on the replacement discs as i would assume FWD front hubs have a different bore??
I am looking to go to 18" Ronals so anything that will go inside those is good. I think that for purpose the discs need to go bigger with more pistons in the caliper too????
Title: Re: Brake Discs to suit a V8 Omega
Post by: TestOmega on 21 September 2010, 17:58:57
Quote
Quote
330mm discs went under 17s on the ST, but if you are going V8 than surely the wheels would be either 18 or 19's?

362mm on the VXR vectra needs 19's

Replacement carriers are generally sold as part of the upgrade kit fairly sure if you are modifying the engine bay to fit a V8 adjusting a couple of caliper carriers will be childs play!

Guess it all depends if you want more area and more pistons or same area and more pistons?

Another thing that will need checking is bore size on the replacement discs as i would assume FWD front hubs have a different bore??
I am looking to go to 18" Ronals so anything that will go inside those is good. I think that for purpose the discs need to go bigger with more pistons in the caliper too????
Couldn't the wheel size change mess up your speedo and odometer!

http://www.miata.net/garage/tirecalcold.html

Just thinking :-? [smiley=engel017.gif] [smiley=engel017.gif] [smiley=engel017.gif] [smiley=engel017.gif] [smiley=engel017.gif]
Title: Re: Brake Discs to suit a V8 Omega
Post by: Lesopc on 21 September 2010, 20:48:01
Quote
Quote
Quote
330mm discs went under 17s on the ST, but if you are going V8 than surely the wheels would be either 18 or 19's?

362mm on the VXR vectra needs 19's

Replacement carriers are generally sold as part of the upgrade kit fairly sure if you are modifying the engine bay to fit a V8 adjusting a couple of caliper carriers will be childs play!

Guess it all depends if you want more area and more pistons or same area and more pistons?

Another thing that will need checking is bore size on the replacement discs as i would assume FWD front hubs have a different bore??
I am looking to go to 18" Ronals so anything that will go inside those is good. I think that for purpose the discs need to go bigger with more pistons in the caliper too????
Couldn't the wheel size change mess up your speedo and odometer!

http://www.miata.net/garage/tirecalcold.html

Just thinking :-? [smiley=engel017.gif] [smiley=engel017.gif] [smiley=engel017.gif] [smiley=engel017.gif] [smiley=engel017.gif]
Not according to some who have replied to a previous post. Just as long as the overall wheel diameter  stays the same, which means lower profile rubber????
Title: Re: Brake Discs to suit a V8 Omega
Post by: TestOmega on 21 September 2010, 20:54:29
You are right I did not recognize that, sorry :-[
Title: Re: Brake Discs to suit a V8 Omega
Post by: Squidy on 22 September 2010, 07:13:48
if your buying new disks i would get grooved, i've heard that drilled disks can crack and are only ideal for race track
Title: Re: Brake Discs to suit a V8 Omega
Post by: DodgeyDave on 22 September 2010, 10:51:29
I'm no expert but I'd be very surprised if drilled discs were prone to cracking, most high powered cars like Porches come with drilled discs as standard these days :)
Title: Re: Brake Discs to suit a V8 Omega
Post by: Squidy on 22 September 2010, 17:55:08
Quote
I'm no expert but I'd be very surprised if drilled discs were prone to cracking, most high powered cars like Porches come with drilled discs as standard these days :)
im not 100% sure its just what ive heard that it can be a concern, plus i think that grooved look better
Title: Re: Brake Discs to suit a V8 Omega
Post by: aaronjb on 22 September 2010, 17:58:05
I've heard the same - as I understand it, it all depends how the discs are manufactured.. aftermarket 'drilled' discs were often just that - plain blanks drilled through - and could crack where the drilled holes produced stress risers, whereas Porsche (etc) drilled brakes were manufactured that way (I'm guessing that drilling prior to stress relieving the metal stops the problem, but I'm no metallurgist)

EBC 'drilled' discs are dimpled, though, to stop that problem.
Title: Re: Brake Discs to suit a V8 Omega
Post by: Lesopc on 22 September 2010, 18:41:10
Quote
I've heard the same - as I understand it, it all depends how the discs are manufactured.. aftermarket 'drilled' discs were often just that - plain blanks drilled through - and could crack where the drilled holes produced stress risers, whereas Porsche (etc) drilled brakes were manufactured that way (I'm guessing that drilling prior to stress relieving the metal stops the problem, but I'm no metallurgist)

EBC 'drilled' discs are dimpled, though, to stop that problem.
Dimpled seems a new way of doing it these days, as the drilling does not go full travel through the disc????
Title: Re: Brake Discs to suit a V8 Omega
Post by: Kevin Wood on 22 September 2010, 20:38:21
Drilled or grooved disks are purely cosmetic unless we're talking about motorsport use, though. The holes in drilled disks can act as stress raisers and promote cracking. Not a problem in motorsport use where the disk won't get many thermal cycles before being binned, but on a road car where you might expect the disk to last 60k miles, a couple of years or so I wouldn't bother.

Kevin
Title: Re: Brake Discs to suit a V8 Omega
Post by: Marks DTM Calib on 22 September 2010, 21:17:42
One could argue that you dont need to upgrade the brakes unless your planning to drive more agressively

The weight has not seriously increased and its not like you brake against the engine power.
Title: Re: Brake Discs to suit a V8 Omega
Post by: 2woody on 22 September 2010, 23:34:21
there's lots of stuff to bear in mind here.

weight. My Holden actually weight less that my MV6

tyres. DO NOT UNDER ANY CIRCUMSTANCES do anything which increases the hub height of the the tyre/wheel package. So, if you go for 18" wheels, then lower-profile tyres are a necessary. Actually, you're going along the right lines - decide on the size of brakes you need for the performance you have and then fit the wheels you need to clear the brake package.

I'd suggest that around 330 to 350mm discs are appropriate. But I might be wrong - I only have 20 years of brake designing experience.

I have three Omegas that may be of interest to you :-

Holden Commodore with 300mm discs ( eek ! ) twin-pot GM calipers - hopeless for the performance.

Opel Lotus Omega with 330mm discs ( really good brakes, but unreliable ) 4-pot AP calipers - think £2500 for a complete car's worth.

Opel Omega EVO 500, with a 350mm brake package that I've come up with (18" wheels required) reverse-engineered for about £250

whatever you decide to fit, then you need to have the package developed by a professional braking company, and by that I mean Bosch, Conti-teves or AP racing, and not a second-division outfit like EBC, or indeed anyone who would sell you a grooved or drilled disc.

Unfortunately, I don't carry the third-party insurance that would let me divulge the 350mm kit contents.