mk5 brake upgrades

[brad]

That sounds like BS to me.

I can only tell you what I was told by a mate (an internet person that I've actually met) who has the best job in the world. He spends half his week on a racetrack & has driven (with serious intent) cars that most normal people wouldn't even be allowed to sit in at the MotorShow.

He gets paid very nicely and when not stuffing about with high performance cars, he designs braking systems for trains, trucks & anything else that you might think of.

I've considered myself a brake specialist for 26 years but if this guy starts talking about brakes then I stop, listen and follow his advice.

I added 2 quotes from him (from another forum) as edits. Did you notice them? He explains it better than me.

[Maverick]

1

I can only tell you what I was told by a mate (an internet person that I've actually met) who has the best job in the world. He spends half his week on a racetrack & has driven (with serious intent) cars that most normal people wouldn't even be allowed to sit in at the MotorShow.

He gets paid very nicely and when not stuffing about with high performance cars, he designs braking systems for trains, trucks & anything else that you might think of.

I've considered myself a brake specialist for 26 years but if this guy starts talking about brakes then I stop, listen and follow his advice.

I added 2 quotes from him (from another forum) as edits. Did you notice them? He explains it better than me.

I saw those but it isn't quite right. As he said in there the old systems would essentially lock the wheel and then release and the new systems are as he explained and I explained but there is no way that the systems can be designed for a type of brake pad and there is no way for the system to operate as per the explanation given about HSV etc.

The sort of smarts the system has is that at 100kph the car knows that it takes ~5 seconds to stop, if the wheel is getting to the point of deceleration that the car will stop in ~1 second it knows that the wheel is locking and backs off.

An upgrade to the brake system of say genormous 6 piston calipers at the front, 4 piston calipers at the rear, slotted discs, warmed up metallic race pads, ultra sticky tyres, braided lines and new brake fluid may stop the car in ~4 seconds at 100kph.

This is far away from the ~1 second point that the ABS controller has as the point for backing off the brakes and there is no way that any brake upgrade could get to anywhere near the ~1 second point. The same applies throughout the range, the point at which the ABS controller has set as the point at which the system backs off is unreachable by any brake upgrade by a huge margin.

[brad]

I saw those but it isn't quite right. As he said in there the old systems would essentially lock the wheel and then release and the new systems are as he explained and I explained but there is no way that the systems can be designed for a type of brake pad and there is no way for the system to operate as per the explanation given about HSV etc.

/snip considered argument.

Mate, If I knew anything more about the subject I'd discuss, but I'm lost now.

[Preen59]

Hmm good to see this thread stayed on topic!

[Mrk_Mickey]

Hmm good to see this thread stayed on topic!

AND it's in the mk5 section...we learn heaps very good.

[Bug_racer]

That sounds like BS to me.

Same here

ABS works off individual wheel speed sensors and an acceleration/deacceleration meter under the steering wheel column area .

If you look at it its saying that under only 1 type of condition the ABS will work .This will be detrimental to the whole system . What if you went on ice with slicks , shock condition , brake disc/pad condition , even extra weight in the car , you would prematurely lock up or brake less efficiently than a car without ABS !

[tinto]

Hmm good to see this thread stayed on topic!

It's a cloud of useful (IMO) information around brakes and the systems at use in a MKV, why is that off topic?

Barney's post answered where you can buy all the stuff you'd need.
I was about to post the ecs link for the R32 upgrade, until I saw he'd covered it.
Best bang for your buck after same size rotors/pads that I can see.

The ECS site says you'd need to go to 18" wheels - I think this depends on the wheels you have, as DanGSR (also linked by Barney) is running 17".

How big were the brakes on the TT that your wheels came from, Misha?
...and what sort of driving are you doing to want to upgrade the brakes on a GT?

[Mrk_Mickey]

...and what sort of driving are you doing to want to upgrade the brakes on a GT?

Yeah I wanna know that too....considering your car stopped us pretty well on that rd near my place

[BarneyBoy]

It's a cloud of useful (IMO) information around brakes and the systems at use in a MKV, why is that off topic?

Barney's post answered where you can buy all the stuff you'd need.
I was about to post the ecs link for the R32 upgrade, until I saw he'd covered it.
Best bang for your buck after same size rotors/pads that I can see.

The ECS site says you'd need to go to 18" wheels - I think this depends on the wheels you have, as DanGSR (also linked by Barney) is running 17".

How big were the brakes on the TT that your wheels came from, Misha?
...and what sort of driving are you doing to want to upgrade the brakes on a GT?

I'm glad I wasn't the only one who thought that...
Thanks, by the way!

Here's some FAQs from the Brembo page at Buybrakes.
I think it covers much of what has been discussed above.


Why use drilled or slotted discs?
Drilling or slotting discs aids the disc in several ways:
The edges of the slots or holes continuously clean and refresh the pad surface as well as providing increased brake "bite". Additionally, they prevent gasses from collecting between the pad and disc interface.
The disc is lightened, thereby decreasing its rotational inertia.
Improved ventilation increases the disc's ability to shed heat, resulting in cooler operating temperatures

What are the advantages of drilled and slotted discs?
The main advantages of drilled and slotted discs are the same: increased brake "bite", and a continuous refreshing of the brake pad surface. Drilled discs have the additional advantage of being lighter and running cooler. However, there are certain pad materials that should not be used with a drilled disc.

Why are there so many holes in a cross-drilled disc?
The number of holes in a cross-drilled disc is part of the engineered system. Brembo has done extensive testing with regards to the number of holes, their size, their location and their chamfering. This attention to detail is what truly sets Brembo apart in the world of braking. The same attention to detail that is delivered to the Ferrari Formula One effort is a component of the high performance program. The number of holes in a disc is in part a function of the size of the disc and the internal venting (if it is a vented disc).

Are discs with cast-in-place holes better than cross-drilled discs?
Brembo has extensively studied and tested cross-drilling versus casting the holes in place and found no significant effect on performance or durability.

Hope this helps 'condense' some of the above discussion.

BTW I don't believe that drilled brakes are purely fashion driven. Far too many car makers use them at the very top end of their range in no-compromise models for it to be all wank. And F1 brakes are an entirely different animal, made from different materials and operated in entirely different conditions. Correctly designed, cross drilling aids in not just weight reduction, but degassing and cleaning. And they look good.
In fact, after a quick poll of performance marques, the only one that doesn't offer cross-drilled brakes is HSV on the 427 - theses are slotted only. Make of this what you will.

[Mischa]

It's a cloud of useful (IMO) information around brakes and the systems at use in a MKV, why is that off topic?

Barney's post answered where you can buy all the stuff you'd need.
I was about to post the ecs link for the R32 upgrade, until I saw he'd covered it.
Best bang for your buck after same size rotors/pads that I can see.

The ECS site says you'd need to go to 18" wheels - I think this depends on the wheels you have, as DanGSR (also linked by Barney) is running 17".

How big were the brakes on the TT that your wheels came from, Misha?
...and what sort of driving are you doing to want to upgrade the brakes on a GT?

i honestly dont know what size brakes are on a base model TT, possibly it has the same brakes as a gti? R32 brakes will indeed fit under certain 17" wheels but i think its a matter of a few mil so theres no real way of knowing for sure.

driving wise nothing serious really, just lots of weekend drives and even then i can feel the brakes starting to fade after not long.

[BarneyBoy]

I seem to remember the TT coming out initially with 16" wheels (those flat, wide, 6 spoke VAG alloys) was it around 2004? Could have been earlier, but a local guy had one and I remember the 16s on it.

Being VAG, and seeing as the TT is really a Golf , I can't see why Audi would do too much that wasn't available off the shelf. Other than Audi branded callipers on the S models, why wouldn't they use Golf parts? I guess we need an Audi guru here?

[Maverick]

I'm glad I wasn't the only one who thought that...
Thanks, by the way!

Here's some FAQs from the Brembo page at Buybrakes.
I think it covers much of what has been discussed above.

<snip>

Hope this helps 'condense' some of the above discussion.

Not at all, buybrakes is a retailer of brakes, the faq was written by them and flys in the face of all of the evidence that I posted above that shows drilling to be purely for the tossers. Many people believe that drilling is cool but it's not and you're only perpetuating the myth.

BTW I don't believe that drilled brakes are purely fashion driven. Far too many car makers use them at the very top end of their range in no-compromise models for it to be all wank.

Road going cars often purchased by posers who never drive them at anywhere near close to the limit.

The Ferrari 360 has drilled rotors but you are warned not to track the car with the rotors, the 360 challenge and GT have slotted rotors. (proof enough yet?)

Ferrari Enzo has cross drilled but again you're warned not to race, the Maserati MC12 uses slotted and it's the race version of the Enzo.

Cars in the Le Mans use..... wait for it..... slotted!

Rally cars use... wait for it.... slotted!

And F1 brakes are an entirely different animal, made from different materials and operated in entirely different conditions. Correctly designed, cross drilling aids in not just weight reduction, but degassing and cleaning. And they look good.

Current F1 brakes as I pointed out are made of carbon fibre, previous brakes were made of metal and they ONLY used slotted. Every single F1 team ONLY used slotted. Did you also see all of the major motorsports where EVERY single competitor only use slotted.

Weight reduction is bad as this means more heat into less mass. Don't you see the issue! There are no problems with gassing any more since asbestos went away, a slotted rotor can more then handle any minor gassing issues and the cleaning. And as you said the "tosser" factor.

http://www.dba.com.au/2006/QnA/DBA_QnA_14.asp

For the record, the four disc rotors on a typical big sedan have a total swept area of 351.5cm2. The cross-drilling on a DBA Gold rotor removes 22.9cm2, while the slots take away another 5.4cm2. That’s a total of 28.3cm2, or 8.1 per cent of the surface area.

Removing surface area is BAD as there is less contact between pad and disc. This slows down the braking process. Notice how slotting takes away a fraction whereas drilling takes away a lot more. Removing material from a rotor increases the chances of it warping because there is a point at which the heat distribution is affected by the (mainly drilled not so much slotted) changes to the rotor which lowers the point at which a rotor will warp.

In fact, after a quick poll of performance marques, the only one that doesn't offer cross-drilled brakes is HSV on the 427 - theses are slotted only. Make of this what you will.

The tosser factor, people believe they are more sporty.

The physics of braking further dispels the drilled myth.

http://www.stoptech.com/tech_info/The%20Physics%20of%20Braking%20Systems.pdf

http://www.stoptech.com/tech_info/wp_brakesystems_upgradeselections.shtml

DRILLED VS SLOTTED ROTORS

"For many years most racing rotors were drilled. There were two reasons - the holes gave the "fireband" boundary layer of gasses and particulate matter someplace to go and the edges of the holes gave the pad a better "bite".

Unfortunately the drilled holes also reduced the thermal capacity of the discs and served as very effective "stress raisers" significantly decreasing disc life. Improvements in friction materials have pretty much made the drilled rotor a thing of the past in racing. Most racing rotors currently feature a series of tangential slots or channels that serve the same purpose without the attendant disadvantages."

But then what would StopTech know

http://www.stoptech.com/proven_technology/test_wins.shtml

If that's not conclusive enough proof that drilling is for tossers then I have no idea what is, it's a myth that drilled discs give any performance improvement and it seems to be perpetuated by people that either thing they look cool or trying to justify their purchase. Especially on a car like the Golf all you are doing is DECREASING your braking ability compared to a slotted rotor.

But by all means if drilled rotors turn you on and you're not interested in performance but in looks then go for it but don't try and claim that they offer any benefits because they clearly DO NOT.

[brad]

BTW I don't believe that drilled brakes are purely fashion driven. Far too many car makers use them at the very top end of their range in no-compromise models for it to be all wank. And F1 brakes are an entirely different animal, made from different materials and operated in entirely different conditions. Correctly designed, cross drilling aids in not just weight reduction, but degassing and cleaning. And they look good.
In fact, after a quick poll of performance marques, the only one that doesn't offer cross-drilled brakes is HSV on the 427 - theses are slotted only. Make of this what you will.

I think the difference is that the top line cars have cross-ventilated brakes. IIRC the holes aren't drilled, they are cast or forged in to the disc so that the grain structure follows the contours of the metal rather than being cut off by a drilled hole. Because drilling shears through the grain structure of the metal, this causes a stress point & cracks eminate from that point - which is weird because if you have a travelling crack in metal, the fix is to stop-drill a hole at the end of the crack.

[brad]

driving wise nothing serious really, just lots of weekend drives and even then i can feel the brakes starting to fade after not long.

brake pads, fluid, rotors - in that order if money is tight.

[BarneyBoy]

Not at all, buybrakes is a retailer of brakes, the faq was written by them and flys in the face of all of the evidence that I posted above that shows drilling to be purely for the tossers. Many people believe that drilling is cool but it's not and you're only perpetuating the myth.

Oh FFS, it was reproduced by buybrakes from info from the Brembo site - buybrakes are an authorised Brembo dealer.

Road going cars often purchased by posers who never drive them at anywhere near close to the limit.

No ***** - however Mischa wants bang for buck and not a car to run every weekend in the Australian Production Car Championship. That's why IMO I suggested R32 discs and callipers (undrilled and unslotted BTW!)

...it's a myth that drilled discs give any performance improvement and it seems to be perpetuated by people that either thing they look cool or trying to justify their purchase.

Attached: pic of brakes used by Tossers to stop a 2 tonne car from 400kph as inefficiently as possible. Braking described by Gordon Murray (an initial critic of the Veyron) as "phenomenal".

Unhappily it goes to show that there is no one definitive answer here. It depends on what you need the brakes for. For racing, perhaps slots are the way to go. But racing brakes are a poor choice for the road.

Mischa: go for the R32 discs