Big Brake Kit for the Octavia? (Fits GTI MK5/6 and others)

[Martin]

Octavian's, lend me your eyes, feature this really bad ass big brake kit!



I was rather shocked and very impressed when I opened the box!

So why a BBK for the Octavia?

I'm a little unhappy with the brakes, they are powerful and do work fine, for a production car
I just don't like the contrast between the slow round town over powered feel (but it saves effort and is comfortable)
and needing to apply very large force when pushing hard elsewhere (but that does give good granular control of the braking)
I intend to do track days - can't stand production brake fade, happens too soon!
(Yes, put a set of DS2500 pads in and it will probably hold up for quite a few laps)
As I've taken my Octavia to Stage II, it's getting to higher speeds rather quickly,
the stock braking capability is good but now does not really match the performance of the car
Ultimately this car will become a dedicated track car, getting the necessary gear now to spread cost over time

I've been researching big brake kits for some months now:

Didn't like the R32 brake option, can be fair bit of money if you're unlucky, unlikely to yield significant improvement over the VRS brakes, very heavy, rotors not much bigger

Looked into using Porsche calipers - they are a little hard to get and could be 10 years old (sometimes expensive)
At the end of the day I found out they would foul my wheels (unless I use spacers)
Again, rotors not that much bigger, ~330mm
I know rotor diameter is not the defining factor, but if you're going to pay these $ you may as well get really big and bad ones, right?

Started looking into more serious kits with two piece rotors for decent weight savings

Looked into various other BBK's options, all were ~330mm disks, all needed wheel spacers to clear the calipers - arggg!

Then I found the HPA big brake kit which fits numerous VAG vehicles
HPA Motorsports Inc. - Big Brake Kits
355mm rotors - hur hur hur - 6 pot calipers - hur hur hur
The rotors are 32mm thick, two piece hat, slotted rotor face
But they are designed to fit under stock 18" wheels without a spacer - we have a winner!
(You have to remove the factory rotor dust shield however - I'm fine with that)
Apparently these save 14.5kg of unsprung weight

So stay tuned for installation and road test reports!!!

[Tigger]

Nice!!!!

Well done mate!

Looks like the next time we all meet up, your car will "stop" all of us in our tracks!!

[tigger73]

Did you buy these off the site or is there an agent locally? And what was the landed cost to get these to your computer chair?

[Martin]

I think they are going to be a tight fit - hope I don't have to change my wheels again
(I put a small gutter rash on one this morning - first time in 20 years - boo hoo)

You have to pay GST when you land them and a $40 clearing fee
All the good (two piece hat and 4+ pots) cost $2K+
It's a commited purchase for sure

[Tigger]

I think they are going to be a tight fit - hope I don't have to change my wheels again
(I put a small gutter rash on one this morning - first time in 20 years - boo hoo)

You have to pay GST when you land them and a $40 clearing fee
All the good (two piece hat and 4+ pots) cost $2K+
It's a commited purchase for sure

eewwww! ouch...ok...worth it I guess??

[dArK5HaD0w]

ooo......that looks very nice.
can't wait to c pics of the beast on!!

[VWindahouse]

They're going to look badass for sure!

That's a lot of unsprung weight saving. So for people that might balk at the price tag it's money you won't need to spend for the feeling of extra power. Plus you'll be picking your front teeth out of the steering wheel the first time you really have to jump on them

Winning!

[Martin]

eewwww! ouch...ok...worth it I guess??

It's like a lot of things in life, the glad and sorry
Glad you have it, sorry you had to pay for it
And quality is remembered long after the price is forgotten

When I decided to buy them, I compared them to my 60" 3D LED TV which cost $3,400
I asked which was more important and rewarding, the brakes won hands down!

I'm sure once I get them fitted I will be a very happy camper

The real question is can I get them on before the Muralan track day...

[Diesel_vert]

Motorsport is a fun hobby, but it's not cheap - those are the going rates for (proper) big brakes, so the cost shouldn't really freak anyone out.

Obviously a total waste of money if buying just for appearance or road driving, but for modified cars and heavy track work, they're worth every penny.

EDIT - engineering components to be strong is cheap and easy, but to make them lightweight without sacrificing performance is expensive and difficult, and is often reflected in the price. Wheels are a good example - there is a reason why eBay wheels are cheap...

[Weekend-Warrior]

Do you know what size pistons they have?

You might find you end up with a longer brake pedal. It could also change the bias.

Will be interested to hear the results.

[Martin]

Each caliper has three pistons on each side of the rotor disc
2 * 28mm & 2 * 31mm & 2 * 35mm (approximately)
In total this will be a lot more surface area than stock for sure
Normally with bigger pistons you would get a longer peddle, better feel and need to use less force
I'm guessing the smaller pistons are trying to reduce this effect - they should kick in fairly quickly

[Martin]

I found this very useful post regarding piston size on a UK forum:

In a single piston sliding caliper, you need to work out the area of the single piston, then double it, because on a sliding caliper, the opposite fixed pad in the caliper applies an equal and opposite force to counter the force from the single piston, this is why the disc isn't 'pushed' over to one side by the single pot.

If you DO decide to look at other calipers, just to the maths on the piston sizes and you can get an idea of how it'll effect the pedal feel.

So, the S3 has a 54mm piston as standard, which has an area of 2290mm², which doubled, gives 4580mm². This is what you need to match to retain an OEM pedal feel.

On a fixed 4 pot caliper, you consider each piston just once, as they work in opposite pairs.

The porsche 996 front calipers, and LCR Brembos, both have 36 and 40mm pistons. each 36mm piston has an area of 1018mm², and each 40mm piston has an area of 1256mm².

2 of each gives you a total of 4549mm², surprisingly similar to the 4580 of the standard setup. it's only 0.7% different infact, so a very good match indeed. This is why the pedal feel still remains good. You also get much less flex with the 4 pot calipers compared to a nasty sliding iron caliper.

[Weekend-Warrior]

In total this will be a lot more surface area than stock for sure

More than double.

I'm guessing the smaller pistons are trying to reduce this effect - they should kick in fairly quickly

To my knowlegde the reason for the dissimilar piston sizes is for even wear across the pad.

You may find that the rears actually come on faster and under hard braking may even trigger the ABS on the rear.

If you have high temp pads you may find it a bit interesting when they are cold pulling up at the first set of lights.

IMO a BBK is great on a track hack if set up correctly with the right master cylinder and bias valve. Not so great simply bolted onto your road car.

[Martin]

The kit comes with ceramic pads intended for (heavy) street usage but can handle (limited lap) track work
They are Corvette pads - huge area on them
Should be fine even when cold...

[Martin]

I've been measuring these HPA brakes and my wheels to see if the installation is likely to be successful
I'm only concerned about calliper clearance to the wheel spokes - all other mechanical aspects are fine

I can see why these will fit under stock wheels - it's because of the large rotor diameter - that pushes the calliper further away from the hub and wheel centre - there is more clearance to the wheels spokes out there

I also discovered that my Audi RS4 wheels have much more clearance than the Skoda Neptunes (which are sold) and the Golf R wheels - they are my backup plan if things to get too tight (need 3mm clearance)

I also placed a rotor inside a bare 18" wheel to see what it looks like - our 18" wheels do tend to dwarf our stock 312mm brakes, but it's completely different with these 355mm rotors which fill 80% of the interior wheel diameter

Our VRS rotors are 25~26mm thick - these HPA rotors are 32mm thick
Now on paper that does not sound like much - although mathematically it's 23% thicker
However, holding these big HPA rotors is quite intimidating - they are a massive lump of very thick steel

I may have to see if I can weight stuff - the stock brake parts and the HPA components
The HPA callipers are clearly very light, despite being physically massive they are not at all heavy
The rotors weight a ton, I would expect tears if I dropped one on my foot

I'm very tempted to throw some DS2500 pads in the rear
(can't find the Ferodo DS2500 part number for the 1Z4)

Any suggestions as to what brake fluid to use?