Alfa Pages

Ken McCarthy · Posted: Tue Oct 24, 2006 7:23 am Post subject: Bigger Front Brakes

I finally have 284mm diameter front discs up and running on the Sprint. Hardest part was getting this particular disc in Australia as it is a size that fits cars not sold here. In the end, I got them by accident when Brembo sent two 4-wheel-bolt-hole discs in a box meant to contain 5-wheel-bolt-hole discs. All this after I had gone to the trouble of looking up the part numbers while I was in the UK recently with a view to importing the discs.

Anyway, I have used the original calipers (33 Series 3 for ventilated 239mm discs) set out on simple brackets but the hub carriers required machining as the brackets mount on the other side of the caliper mounting lugs. Pads are EBC black kevlar. Braking performance is certainly improved although how much is attributable to the larger discs I am not sure as the old discs were worn out and pads were different.

One downside is a slightly worse ride from the front caused by the increase in unsprung weight of nearly 2kg per disc. I may try removing the anti-roll bar as I already have stiff springs. Light weight two part discs might be a future suggestion for Santa.

The conversion will only work with 15 inch (or larger) wheels and even then they should be checked for clearance before proceeding.

If anyone is interested I will provide drawings and photos. I have still not worked out how to post them on this discussion page.
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Ken McCarthy - 16V Sprint

tvatavuk · Posted: Tue Oct 24, 2006 8:07 am Post subject:

Ken,
have you tried looking for vauxhal "some model" calipers?

I'm sure intrested in seeing how you done it. You can't put pictures here on site, but you can put link to it. So you need first to upload it somewhere on web (photobucket.com,imagehost,imagevenue...there are a few web sites that offer space for uploading pictures) and then link it in your post.

cheers
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Tino Vatavuk
Little black dress which replaced Alfa Romeo 33 S 16v Permanent 4 GMo

Scott Sander · Posted: Tue Oct 24, 2006 10:36 am Post subject:

Ken,

How to have images within posts can be found on the FAQ page.

http://www.alfa-pages.co.uk/faq.php#24

Certainly would be interested to see what you did for the brakes.

I fitted some slotted rotors to my 16V and use Ferodo DS2500 pads. Apart from a bit of time needed to warm up, they do the job quite well.
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Scott Sander
'91 Alfa 33 Boxer 16V Monza - Awesome
http://www.sanderfamily.com

gritsop · Posted: Tue Oct 24, 2006 12:30 pm Post subject:

Hi,

Ken it would be interesting to see this brake project photo documented.

Perhaps a short manual for Bobbber's restoration site? Wink

Best regards
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Thanassis Gritsopoulos
1991 Alfa 33 1.4 IE
2001 Alfa 147 1.6 Distinctive

http://www.alfa-restoration.co.uk
Parts Shop: www.alfa-restoration.co.uk/shop

Ken McCarthy · Posted: Wed Oct 25, 2006 1:26 am Post subject: Bigger Front Brakes

OK, we will see if this works. Please note, no guarantee is given that the details given will work or that they will meet local government approval requirements. You will have to do that yourself.

The disc is a standard Alfa (Fiat and Lancia) part fitted to some 145 and 146 cars plus others. Alfa part number in the UK is 46427947.

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Ken McCarthy - 16V Sprint

Ken McCarthy · Posted: Wed Oct 25, 2006 1:27 am Post subject: Bigger Front Brakes

Seems to have worked but the images are in reverse order so please start at the bottom and work up.

Regards
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Ken McCarthy - 16V Sprint

Ken McCarthy · Posted: Wed Oct 25, 2006 1:38 am Post subject: Bigger Front Brakes

This is what it looks like on the car.

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Ken McCarthy - 16V Sprint

tvatavuk · Posted: Wed Oct 25, 2006 9:52 am Post subject: Re: Bigger Front Brakes

Ken McCarthy · Posted: Wed Oct 25, 2006 11:42 pm Post subject:

Thanks Tino

By the way, the little picture of the wheel and disc on the car is a thumbnail so will enlarge if you click on it.

I think I am getting the hang of posting pictures now.

Regards
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Ken McCarthy - 16V Sprint

BigAl · P4 Joined: 06 May 2003 Posts: 2990 Location: U.K Surrey

Just a couple of questions, Im guessing that by making the disk bigger and putting the pads on the outer of the disk, improves braking performance.
If there is more force can the original mounts handel this?
Can the calipers from the 145 / 146 be fitted?? If so as there is much more pad surface area, therefore more braking forec, will the brackets / original fitting be able to handle it??
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x2 33 16v
pictures http://www.alfa-pages.co.uk/viewtopic.php?t=5203

tvatavuk · Posted: Wed Mar 21, 2007 10:16 pm Post subject:

You can see more info in racing forum.
search for Leve 3 and 4 brake upgrades.

You can use 145/6 calpers but not their mounts for 256mm disc upgrade or you can use
- Alfa 155 Q4 - 284/22/44 discs
- Opel Calibra 2.0 turbo calipers mounts (for 284 discs)
- Opel Calibra 2.0 turbo pads or if you want to have wear indicators ALfa 145/6/7 pads (from 1.8 and 2.0 TS engines)
Everything fits bolt on.

Only thing you must make is brake hose adapter or new brake hoses to fit from AR hoses to Opel calipers.

Calipers from Alfa 145/6 TS (1,4) could be fitted bolt on to Opel Astra GSI/Opel calibra 2.0 caliper mounts (for 257mm discs), so if you find AR calipers that fit on Opel calibra 2,0 turbo mounts there is high chance you can use same original AR brake hoses.
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Tino Vatavuk
Little black dress which replaced Alfa Romeo 33 S 16v Permanent 4 GMo

Ken McCarthy · Posted: Thu Mar 22, 2007 12:20 am Post subject:

BigAl

In theory, the two main factors affecting braking are the leverage (distance from the axle centreline to the point of application of the pads) and the force applied to the pads. The friction between the pad and the disc is mostly a function of force between the pad and disc but the pad and disc material do have an effect. The area of the pad has more to do with wear and "life" of the pad.

I don't know if the 145/6 calipers fit as they are not available here to try. Most of the increased pad area of these units is on the inside (closest to the axle centreline) so has less effect. I have mounted the 33 calipers so the outer part of the 284 disc is used giving about 20% more leverage than the 239 disc. This is a lightweight car, and for road use, this would seem to be enough.

No engineering analysis has been done on the strength of the caliper mounts but these things are usually overdesigned by manufacturers and bracketing out for larger discs is fairly common. I have used common practice with materials and metal thickness and good engineering practice with the bracket design.

I note Tino's and other posts and there now seems to be a fair bit of information about on this subject and some options. I didn't want to do anything that couldn't be returned to original. Also, we don't have access to many of the makes/models that are available in Europe.

Regards
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Ken McCarthy - 16V Sprint