mk5 brake upgrades

[Preen59]

Ok sure thing mate..

BMW, Mercedes, Porsche, Brembo, Wilwood.. They all know nothing too... Right?

I'm not even going to bother replying.

Apart from this.. F1 use carbon fibre brake discs which are completely different, and its horses for courses. It depends on the setup.

[PhilMart]

Some good theories and ideas here .. thanks for this, although I was not the one who requested it. I read in another post that rotors seem to wear almost as fast as pads on the MKV and as such was very intertested in the comments should I need to get new rotors at any time. Why not go for better and it might even save me some money from some prices I have seen.

I certainly can't justify a brembo setup so why not these options.

Thanks

[Blitzen]

I'm just running outside with a cordless drill to make my rotors look better...I don't know what Ferrari, Porsche, Maserati, Mercedes, BMW, (insert high end manufacturers name here that have a clue about cars and brake set ups).
The truth is that the slots in rotors dissipate less gas than cross drilled rotors. As stated earlier, the slot creates a 'wiping' effect accross the face of the pad, clearing debris, and having a more effective braking surface. Much of the heat is dissipated by the vanes in the brake rotors themselves.

[Maverick]

Ok sure thing mate..

BMW, Mercedes, Porsche, Brembo, Wilwood.. They all know nothing too... Right?

Actually they do know something, how to market the cars/products to cashed up fools who think that drilled discs on the car somehow make it perform better. Also Brembo and Wilwood make what their customers want but recommend slotted and mainly sell slotted or smooth rotors.

I'm not even going to bother replying.

Apart from this.. F1 use carbon fibre brake discs which are completely different, and its horses for courses. It depends on the setup.

F1 before carbon used slotted rotors.

That's right, they used slotted rotors. No drilled, not drilled and slotted but just slotted rotors. How much money goes into F1 technology each year?

CART, IRL, NASCAR, ALMS, WRC, TransAm, Formula Atlantic, F3000 and so on ALL use slotted rotors. They must know something? Right???

I'll now back up my claims with proof if you need more then what I have provided (the part about reducing the amount of metal, reducing the surface area and so forth).

Darrick Dong; Director of Motorsports at Performance Friction.

"Slots - a radial groove cut into the surface of the disc - serve a couple of purposes. One of these is to help remove debris from the disc surface; the other is to help expel gases created during braking.

In the days of asbestos brake pads, there was a gas boundary layer that appeared at the interface area of the pad and rotor. Although that gas boundary still occurs, it is much less of a problem with modern friction materials. Slots are more than adequate to carry that gas away.

Years ago, that gas boundary, along with reducing weight, led to the popularity of drilled rotors. However, in the intervening period, the myth has persisted that cooling is the main reason for drilling rotors. Anyone that tells you that drilling makes the disc run cooler is smoking crack. Although there is a belief among some that drilling can have a slight effect on cooling by drawing additional air into the venting vanes, even those that subscribe to that theory say drilled rotors are more of a liability than a benefit."

In case you're wondering who Performance Friction are check their website out http://www.performancefriction.com/profile.htm (they supply NASCAR, over 40,000 police cars, heaps of emergency vehicles and so forth with brake pads and discs.

Here are some more quotes

Power Slot: "At one time the conventional wisdom in racing circles was to cross-drill brake rotors to aid cooling and eliminate the gas emitted by brake pads. However, today’s elite teams in open wheel, Indy and Trans Am racing are moving away from crack prone, cross-drilled brake rotors in favor of rotors modified with a fatigue resistant slotting process."

Stop Tech: "StopTech provides rotors slotted, drilled or plain. For most performance applications slotted is the preferred choice. Slotting helps wipe away debris from between the pad and rotor as well as increasing the "bite" characteristics of the pad. A drilled rotor provides the same type of benefit, but is more susceptible to cracking under severe usage. Many customers prefer the look of a drilled rotor and for street and occasional light duty track use they will work fine. For more severe applications, we recommend slotted rotors." (Note that even though Stop Tech sells both drilled and slotted rotors they do not recommend drilled rotors for severe applications.)

Wilwood: "Q: Why are some rotors drilled or slotted?
A: Rotors are drilled to reduce rotating weight, an issue near and dear to racers searching for ways to minimize unsprung weight. Drilling diminishes a rotor's durability and cooling capacity."

From Waren Gilliand: (Warren Gilliland is a well-known brake engineer in the racing industry and has more than 32 years experience in custom designing brake systems ...he became the main source for improving the brake systems on a variety of different race vehicles from midgets to Nascar Winston Cup cars.) "If you cross drill one of these vented rotors, you are creating a stress riser that will encourage the rotor to crack right through the hole. Many of the rotors available in the aftermarket are nothing more than inexpensive offshore manufactured stock replacement rotors, cross drilled to appeal to the performance market. They are not performance rotors and will have a corresponding high failure rate"

From Baer: "What are the benefits to Crossdrilling, Slotting, and Zinc-Washing my rotors?
In years past, crossdrilling and/or Slotting the rotor for racing purposes was beneficial by providing a way to expel the gasses created when the bonding agents employed to manufacture the pads...However, with today’s race pad technology, ‘outgassing’ is no longer much of a concern...Slotted surfaces are what Baer recommends for track only use. Slotted only rotors are offered as an option for any of Baer’s offerings."

Grassroots Motorsports: "Crossdrilling your rotors might look neat, but what is it really doing for you? Well, unless your car is using brake pads from the '40s and 50s, not a whole lot. Rotors were first drilled because early brake pad materials gave off gasses when heated to racing temperatures, a process known as "gassing out." ...It was an effective solution, but today's friction materials do not exhibit the some gassing out phenomenon as the early pads. Contrary to popular belief, they don't lower temperatures. (In fact, by removing weight from the rotor, they can actually cause temperatures to increase a little.) These holes create stress risers that allow the rotor to crack sooner, and make a mess of brake pads--sort of like a cheese grater rubbing against them at every stop. Want more evidence? Look at NASCAR or F1. You would think that if drilling holes in the rotor was the hot ticket, these teams would be doing it...Slotting rotors, on the other hand, might be a consideration if your sanctioning body allows for it. Cutting thin slots across the face of the rotor can actually help to clean the face of the brake pads over time, helping to reduce the glazing often found during high-speed use which can lower the coefficient of friction. While there may still be a small concern over creating stress risers in the face of the rotor, if the slots are shallow and cut properly, the trade-off appears to be worth the risk. (Have you looked at a NASCAR rotor lately?)

AP Racing: "Grooves improve 'cleaning' of the pad surfaces and result in a more consistent brake performance. Grooved discs have a longer life than cross-drilled discs." and "Cross drilled...can compromise disc life. Radiused drilled...mainly used for aesthetic reasons on road applications."

[Blitzen]

I didn't know Pump Duse changed his name...

Man, with a name like 'Darrick Dong', how can you take him seriously!!!

CART, IRL, NASCAR, ALMS, TransAm, Formula Atlantic,and so on ALL use slotted rotors. They must know something? Right???...Wrong!!! These are all American racing formulas, and hence, boring as poo. Therefore, the yanks know nothing, and this info can be disregarded...

[Preen59]

I didn't know Pump Duse changed his name...

Man, with a name like 'Darrick Dong', how can you take him seriously!!!

Hahaha. Sounds to me like someone who has read too many books.

[Mischa]

what the hell is this crap? get out of my thread that was supposed to be useful.

maverick do you have any idea about physics?

[Maverick]

what the hell is this crap? get out of my thread that was supposed to be useful.

The information is useful.

maverick do you have any idea about physics?

???? Why do you ask that?

[brad]

What diameter are the MKV discs?

If they are 288mm then the Skoda upgrade is to retain the original caliper but fit 312mm discs with the appropriate caliper cradle.

What part of the braking system are you trying to improve? Where are the brakes letting you down?

At another forum I use, we have a resident brake engineer. His general recomendation is "Ferodo DS2500 pads & decent brake fluid" (Ferodo 5.1 or Motul 600 IIRC) but it depends on what outcome you are after.

[dangerous_daveo]

I don't know if I would call a DS2500 a street pad... You really need to be aware they are on your car and get a little heat in to them first. I mean they are good after that. I'm no brake engineer, but I know I've had a number of different set ups on my previous car, and if you start going higher end pads, you really need to be aware that if a kid runs out in front of you going down your street, you might not be able to stop in time. As long as everyone realises these things when making choices.


Anyway, on a side note, how do all these upgrades affect how the ABS and ESP etc??? I would have thought they would have been designed to work within a set range that only stock gear would work with? I don't know, hence asking.

[Maverick]

Anyway, on a side note, how do all these upgrades affect how the ABS and ESP etc??? I would have thought they would have been designed to work within a set range that only stock gear would work with? I don't know, hence asking.

Within reason they don't affect the systems. The systems are adaptive to different circumstances as they rely on input on things like wheel speed, they don't nor do they need to know if you're stopping faster because it's dry or because of new discs.

There is electronic brake force distribution to adjust pressure to all the wheels so even if you had massive brakes on the front and tiny ones on the rear the system will still work.

ABS doesn't care what size brakes you have as it works off wheel speed.

And ESP doesn't care as it relies on sensors like wheel speed, car speed, steering wheel angle and so forth.

[DUB 20V]

Within reason they don't affect the systems. The systems are adaptive to different circumstances as they rely on input on things like wheel speed, they don't nor do they need to know if you're stopping faster because it's dry or because of new discs.

There is electronic brake force distribution to adjust pressure to all the wheels so even if you had massive brakes on the front and tiny ones on the rear the system will still work.

ABS doesn't care what size brakes you have as it works off wheel speed.

And ESP doesn't care as it relies on sensors like wheel speed, car speed, steering wheel angle and so forth.

good write up

[brad]

I don't know if I would call a DS2500 a street pad... You really need to be aware they are on your car and get a little heat in to them first. I mean they are good after that. I'm no brake engineer, but I know I've had a number of different set ups on my previous car, and if you start going higher end pads, you really need to be aware that if a kid runs out in front of you going down your street, you might not be able to stop in time. As long as everyone realises these things when making choices.

The DS2500 is not a pad that I would have chosen as I consider it a track pad, but on the other forum I run, we have a lot of guys using them (maybe 9 users) on Subarus and they all sing their praises no matter what their driving style. Given they are using them & in this case I'm the armchair expert (never tried them) I take their word that they are good. MAybe Subaru pads are crap but all of them report better cold bite.

Anyway, on a side note, how do all these upgrades affect how the ABS and ESP etc??? I would have thought they would have been designed to work within a set range that only stock gear would work with? I don't know, hence asking.

On most cars, the ABS software is written with a fair amount of gimme, so different pads don't upset the applecart and in many cases will improve braking without detriment to the ABS system.
BUT!
On the latest HSVs, the ABS software has been written specifically for the OEM brakepad (which is a derivative of DS2500) and in theory, any variation from OEM may cause a deterioration in braking performance...... or so I'm told.

This guy explains it better:

Now all HSV's come with 2500's regardless. Bit of a story behind that though, it's to do with the new Bosch ABS system in them. The old systemwas verrrry basic and worked very differently to the new one. You could put any compound of pad in there and all would be well. The new system is calibrated to a specific deceleration v grip rate. If you throw a different set of pads in there the system has big problems and tends to increase your breaking distances.

cracks me up that a guy that works with brakes all week cant spell braking.

This is not like it's a new or uncommon thing. The E60 BMW's are the same. The last 4 years of AMG Mercedes are the same. All F series Ferrari's are the same. It's just that HSV have finally caught up with 10 year old technology.
The story behind it is that we were approached 2 years ago by HSV and Herrod's (No, not Harrop) to come up with a formulation for the new models. Well instead of ****ing about with that we decided to try various formulations already in circulation. During our testing process we found that the braking distances actually increased. We were at a bit of a loss to start with until we discovered that HSV had purchased the "new" Bosch ABS units which work completely differently to the older ones.
Basically;
The older ABS units worked by waiting until a wheel actually locks before releasing brake force to that caliper. The new one is a predictive system. It uses vehicle speed, steering angle, individual wheel speeds and individual wheel rates of deceleration and "predicts" when a wheel is going to lock. So the never actually locks, it simply slows down to the slowest possible speed without locking. Very good, very safe. However, it has to have a reference point of calibration, this is the grip co-efficient of the materials used to stop the wheel spinning. If you put a pad/rotor in that is much higher you then put the calibration out. The ABS thinks the wheel is going to lock sooner than it actually will so it backs the brakes off more, thus increasing your braking distance

Sorry to Hijack your thread Mischa - thought you might be interested.

[Mischa]

What diameter are the MKV discs?

If they are 288mm then the Skoda upgrade is to retain the original caliper but fit 312mm discs with the appropriate caliper cradle.

What part of the braking system are you trying to improve? Where are the brakes letting you down?

At another forum I use, we have a resident brake engineer. His general recomendation is "Ferodo DS2500 pads & decent brake fluid" (Ferodo 5.1 or Motul 600 IIRC) but it depends on what outcome you are after.

standard mkv are 288, gt and gti are 312(or something) and r32 is 345

yeah i guess i should start with pads and fluid and possibly slotted rotors to curb brake fade

[Maverick]

On most cars, the ABS software is written with a fair amount of gimme, so different pads don't upset the applecart and in many cases will improve braking without detriment to the ABS system.
BUT!
On the latest HSVs, the ABS software has been written specifically for the OEM brakepad (which is a derivative of DS2500) and in theory, any variation from OEM may cause a deterioration in braking performance...... or so I'm told.

That sounds like BS to me.

This would mean a change in tyres would affect the system, as the tyres wear the car would end up locking up the wheels all the time as it would expect a certain amount of grip.

As the pads wear the same would occur.

And how does it determine the road surface type and condition without taking the wheels to the point of lockup? You can brake harder on warm tarmac then you can on wet tarmac for example.

What happens when you have two wheels on a gravel shoulder and two wheels on the tarmac? The system would lock the wheels on the gravel side.

There's no way a manufacturer would modify an ABS system to only work with one type of brake pad and under some conditions.

ABS system work by watching the speed sensors on each wheel, there is a point immediately before a wheel locks up where is experiences rapid deceleration. The ABS system knows the point at which at rapid deceleration is not possible so it reduces the pressure until the wheel accelerates again and then increases pressure again until it senses this deceleration again.

On the Golf you also have ESP which gives two additional sensors (the HSV I assume has this as well) which is a steering wheel angle sensor and a gyroscope and these are used to assist in braking on corners.

As such the ABS system is designed to be able to handle a wide variety of conditions both from wheels and tyres to road surfaces and conditions.