Brake conversion 284mm -> 330mm

The 305mm Brembo Gran Turismo calipers are narrower than the 305mm GTA calipers and they will fit easier within 17" wheels.
I ran these with 16" wheels and 5mm spacers - but that was a very tight fit. I have been impressed by their consistent braking but I'm sure the 330mm GTA calipers would give superior braking power.

Originally Posted by alfasud.ti

I've heard that some unusual kits have made their appearance here in Greece. They consist of the 330mm disc with the 305mm caliper

Are you sure?
Because the 330 disc is 32mm thick and the 305 caliper only takes 28mm discs...

Originally Posted by Pud237

I already have the GTA Tele's, can anyone confirm that even without the extra track width compared to a real GTA that the brake calipers will not foul on the wheels?

The extra track width of the GTA comes from the different wheels, nothing else.
So with GTA wheels on a std 156 you will have exactly the same track as a GTA.

Originally Posted by David C

The extra track width of the GTA comes from the different wheels, nothing else.
So with GTA wheels on a std 156 you will have exactly the same track as a GTA.

Well I never knew that, cheers for that Mr. C

Originally Posted by Pascs

The 305mm Brembo Gran Turismo calipers are narrower than the 305mm GTA calipers and they will fit easier within 17" wheels.
I ran these with 16" wheels and 5mm spacers - but that was a very tight fit. I have been impressed by their consistent braking but I'm sure the 330mm GTA calipers would give superior braking power.

So the Brembo GT calipers take 305mm discs, thanks for clearing that up.. For the sort of outlay they are asking I'm not sure if its worth it. More thinking required..

Originally Posted by Pud237

As good as the 330mm set up on the GTA would you say?

In terms of thermal capacity, they're not far off. Trackstar has the brembo set up on his.

Originally Posted by Pud237

As good as the 330mm set up on the GTA would you say?

I have never driven anything that had the Brembo Gran Turismo kit, however I have driven a few GTAs and a GTV Cup with the OEM 305 Brembos, and yeah the 330 setup inspires alot more confidence in braking than the OEM 305s

Originally Posted by Trailbraker

The reason I think this is that PeterK used the 2.5 V6 ABS ecu, and master cylinder with the 330mm setup, but due to the different master brake cylinder size the brake bias was significantly off (way more rear bias) and the pedal effort required was way more..
He is planning on getting the real GTA master cylinder shortly.

Alfa Romeo forum: Brakes Again - 330 ’s and rear brake bias

I've done a few track days since then and not had any problems. Mine moves about a little bit under heavy braking on the road but its never particularly worrying in fact I don't think its any worse than any other 156 I've driven.

I have upgraded to DS2500's in the front, that may have changed things I guess.

Originally Posted by David C

Are you sure?
Because the 330 disc is 32mm thick and the 305 caliper only takes 28mm discs...

No, I'm not. Just heard it as a rumour and attributed it to the fact that there is a big number of 305mm calipers that cannot be sold because it is impossible to fit them with the standard non-GTA upright.

Maybe the disc is not the stock GTA but an aftermarket non-Brembo one because Brembo did not have a 330x28mm disc with 5x98 PCD last time I checked.

Originally Posted by Chris155

Alfa Romeo forum: Brakes Again - 330 ’s and rear brake bias

I've done a few track days since then and not had any problems. Mine moves about a little bit under heavy braking on the road but its never particularly worrying in fact I don't think its any worse than any other 156 I've driven.

I have upgraded to DS2500's in the front, that may have changed things I guess.

Chris, is your set-up identical to my original proposition then? A vintage 2.5 V6, fitted with GTA 4-pot calipers and 330mm discs on the front?

Reading your thread on 156.net, I don't understand what has made the rears work harder.. Does this mean uprating the rears is necessary as well? I'm not a track driver but I do want better brakes for fast-road use. I think even if I did the conversion as above I probably wouldn't suffer from rear brake problems like you did.

Yes I have 330's on a 2.5(ish) with GTA uprights.

They're bloomin marvelous! I think the rears overheating was a one off occurance, either that of the fronts are just able to cope a lot better with a pasteing now.

I've not had ANY problems with them since.

Originally Posted by Chris155

Yes I have 330's on a 2.5(ish) with GTA uprights.

They're bloomin marvelous! I think the rears overheating was a one off occurance, either that of the fronts are just able to cope a lot better with a pasteing now.

I've not had ANY problems with them since.

You have a PM.

Originally Posted by alfasud.ti

Maybe the disc is not the stock GTA but an aftermarket non-Brembo one because Brembo did not have a 330x28mm disc with 5x98 PCD last time I checked.

i actually have a pdf somewhere that lists a 330x28 disc with a 5x98 pcd. will see if i can dig it up, but from memory it was in the track/ competition section.

Originally Posted by sj156

i actually have a pdf somewhere that lists a 330x28 disc with a 5x98 pcd. will see if i can dig it up, but from memory it was in the track/ competition section.

A Brembo one? Really? Please do try to find it. I am interested because I am using 159/Brera 3.2 V6 calipers but the discs were 330x30 ground slightly to fit into the 28mm caliper. I was thinking of having a custom aluminium bell made to fit 330x28mm rotors that are available but the cost is high.

PS: Apologies to all about the small thread hijack.

Originally Posted by alfasud.ti

A Brembo one? Really? Please do try to find it. I am interested because I am using 159/Brera 3.2 V6 calipers but the discs were 330x30 ground slightly to fit into the 28mm caliper. I was thinking of having a custom aluminium bell made to fit 330x28mm rotors that are available but the cost is high.

PS: Apologies to all about the small thread hijack.

Pics!

Before you start grinding discs, remember that the wear limit is only 1mm per face, so if you take a 32mm disc down to 30mm you are already at the wear limit before you even fit them!

Chris, I'll try and give you a ring this weekend sometime regarding the conversion. Thanks for your help so far

I just changed my both front and rear brake pads. Something interesting that the rear pads worn more than the front. Both F&R are original pads. Now it has DS2500.

Well this project had gone no-where fast

Still unable to find GTA uprights anywhere. I will be trying a main dealer tomorrow, wish me luck!

@pud237

maybe 6piston breaks and 305 discs can do the trick for y, have a look;

Brake-Systems ALFA ROMEO 147 ALL MODEL (EXCLUDING GTA) - eBay (item 300202058702 end time Mar-26-08 07:27:55 PDT)

Originally Posted by XTCgr_1981

@pud237

maybe 6piston breaks and 305 discs can do the trick for y, have a look;

Brake-Systems ALFA ROMEO 147 ALL MODEL (EXCLUDING GTA) - eBay (item 300202058702 end time Mar-26-08 07:27:55 PDT)

They are 8-piston brakes with 330x32 mm discs in 5x98 offset. Not bad at a kit price of £750 + £50 delivery.. Cheaper than the Brembo GT kit. I wonder who makes the calipers? I'm struggling to find out the manufacturer of this kit, I wonder if its really any good?