BBMGT3

^^ + 1 on the brake issue

I would say on 1 hot lap around a typical 3 mile circuit you will 'use' your brakes more than you could in a whole day on the street...

Izzone

If u own one u have to wash it

Mine will be at Watkins glen on Monday feel free to stop by and wash it

24Chromium

She's like the hottest, most awesome girlfriend you could ever imagine. Every one, I mean EVERY ONE, stares at her and ohhs and ahhs. She is stunningly gorgeous. She's sexy as hell. She's a complete wild vixen, constantly tempting you into trying stuff you maybe shouldn't ought to do. But she makes it seem easy. Too easy. And way too fun. But... like any super model... she's high maintenance. If you run her hard and fast, like the thoroughbred she is, well then you've got to keep her in new shoes and clothes, etc., etc., etc.

I essentially am only tracking Gisele (not yet trailering, so I am putting highway miles on her driving to and from the track). And I track her damn hard. I admit - I'm hard on brakes, tires, etc. And she needs a lot of consumables. A LOT! Probably no more than any other car, but this is a Pcar and the parts are more expensive than a lot of others.

TRAKCAR

never mind Izzones post above, he was stone cold drunk and passed out 30 minutes ago.

24Chromium

Anyone know what cleaner will remove all that permanent ink from the Sharpie pen? LOL

Nordschleife

Nugget

I'm sure you are a lovely person, but you don't know diddly about the effect of thermal shock on brakes. Your argument is theoretical, reasonable argument but not supported by empirical data.

I don't want to to go on about this, but check with CJ over at the Rangers for an overview of where I am coming from.

Let me give you a couple of simple examples.

In a heavy car, braking hard from cold half a dozen times can cause physical changes to the molecular structure of the rotors, making them harder and more brittle and reducing their thermal capacity. Not so long ago I had a new set of very serious brakes on a 'bahn stormer. After 800 kilometers, the rotors were inspected, removed and remachined by the manufacturer, destroying the tool used in the process. What had I done in in the few days I had driven the car? A bit of bedding in, not as thorough as I suggested to CJ, a couple of short trips and two drives across Germany, only one of which was 'quick', but not so quick that I was 'ruffled' in any way when i arrived for dinner with my host. The same brakes in a somewhat lighter car only need their pads changing between VLN races and the rotors comfortably handle a 24 hour race.

On a circuit, brakes are usually operated at an elevated temperarure that is close to or above their designed operating temperature range. On slicks, in a cup car, excluding ceramic data, we regularly see -1.6 G retard on the straight into turn 1 at Barcelona, whilst the 'bahn stormer rarely manages more than -1.2 on street rubber, yet it is much harder on brakes in terms of the metallurgy. When travelling in company with this car, I prefer to be behind rarther than in front of Porsche exotica because I don't have to worry about being rear ended. Its a big heavy brute that is comfortable to drive at vmax and it eats brakes and gets through a tank in 50 minutes. You can see how the metal has been changed, remember that AMG put keramics on their big cars before Porsched released the PCCBs at Frankfurt in 99. Early experience indicated that the failures were even more likely amongst the MBs, 550/570, 7ers, and A8s than they were on the Turbo. There were a surprising number of cases where keramics shattered as a result of sudden use from cold. Yes, the Turbo is heavy, but not as heavy, so there were rather fewer failures. This didn't come out in testing as so much capability/capacity testing was carried out on track rather than the street.

As far as the current range of P-cars goes, I am oftendisappointed by their braking capabilities. It really isn't much fun discovering that you are approaching an impenitrable 'stau' and having to look for ways to 'extend' the braking area.

Autobahn driving presents challenges which differ from those experienced on track. Part of the problem lies in the manner in which rotors are changed when braking from cold, rather than being operated really hard as in track driving.

Based on my experience with Germany's leading manufacturers, they consistently underestimate the real braking requirements, do not test the upper bounds of the envelope in any meaningful manner and find it easy to under specify and cheesepare brakes, especially when it comes to real factors rather than box-ticking features (8 piston callipers rather than 6-piston for example, wne the 6-pistons can often out perform). The Nordschleife is not hard on brakes.

Finally, quite extensive testing shows that air ducting to brakes should be not less than 10 cm (4 inches) in diameter, to be worth installing. It is very hard to install this on a normal street car without continually having to have it maintained (think daily).

The big brakes on the GT3 offer more thermal capacity than smaller brake systems would, Autobahn driving has an extreme and deleterious effect upon them.

I can drive on tracks anywhere in the world, apart from Germany, there are very few places in the world where you can drive at over 180 mph on a daily basis, legally comfortably and safely. Practical experience followed up by some proper data (not extrapolated) has convinced me and a handful of brake system engineers (you would be surprised how few guys there are in this field), that the Autobahn is really hard on brakes.

R+C

BBMGT3

^ @ Nordchleife...

From a mettalurgy standpoint, your point is well taken and you are right, that cruising along at 180mph+ for long enough that your brakes are almost at ambient temperature, then stomping the pedal would result in the "damage" you are referring to.

So, sure the German autobahn is tougher on brakes from that standpoint, but the context that I think was being referred is "normal" wear and stopping power requirements.

Case and point is looking at a lot of supercars out there - M6's, SLR's and so on, and they last all of 2 laps before the brakes give up. A C2S will go for 3x longer, let alone a gt3.

Anyway, the whole "braking on cold brakes" applies to racing brakes as well, so I'm not sure what your point is.

Finally, even if you are on the autobahn, threshold braking from 180mph - 0mph as you indicated on ice cold brakes does not seem very wise by any standard, so unless its an emergency situation, I can't see why you would regularly do that just from a safety standpoint. If it IS an emergency situation, then warped rotors are a very fair exchange IMO

sin911

May I suggest a regular .1 GT3 to you? It is clear that you want a GT car, so I won't try to change your mind.

I have a .1 GT3 that I use for track and weekend drives. It is an amazing car! On the street you can't even get 60% of it's capabilities. Just a blast to drive! I can't even begin to describe the intoxicating sound getting the needle towards the red line... While the laws and traffic limits the car's performance why spend $50k extra for a mkII RS?

rodsky

I don't understand why you would have to be going from 180 to 0 on the autobahn? Seems like that would be very unusual. On the track, you are hard on it all the time. You're comparing two wildly different situations. Of course if you had to do 10 stops from 180 on cold brakes, may be tougher than tracking but c'mon when you gonna do that.

As to the OP, get a 997.2 GT3. a bit more livable for the street and not giving up too much on the RS.

Nordschleife

You have to live in Germany and own a big fast heavy car to understand what is going on. What I am talking about IS normal, you are regarding it as ABnormal.

'Supercars' often perform badly on the track because they are badly driven and underbraked (thanks to the accountants). Even after demonstrating that the most successful Le Mans driver in history couldn't stay ahead of a bunch of amateurs with proper brakes over a few laps at Hockenheim in otherwise identical cars, it took years to result in changes of policy and then only in a half hearted manner (yes to keramics, no to proper callipers).

If you have to brake at 180 mph, you HAVE to brake, no question as to whether it is wise to brake hard. People who worry about that usually end up buried in the car in front of them. If this sort of thing worries you, then the Autobahnen are best avoided. From time to time I find myself travelling with folk in the Auto Industry in the States, its always the high speed braking that impresses them most. I have learned to give tham a practice halt first, so they are not alarmed. When coaching these techniques I emphasise the importance of getting as much retardation as possible as soon as possible, as this gives you more leeway in the event of the unexpected.

The relevance of what I am talking about is that Germany and German driving conditions are the heimat of the GT3 (in all its variants), roads tend to be good and fast, the nation appreciates quality engineering, driver education is regularly covered in all branches of the media and women can explain the 4-stroke cycle. I know a good many folk who do not like driving in the US, and avoid it like the plague. Personally, I find driving in the TriState area unspeakably awful and try to avoid it.

Whilst high speed driving on public roads might be abnormal and even abhorrent to you, it is normal to others and the GT3 WAS and IS designed for these conditions. The day the car is optimised for US conditions, it loses its edge.

Incidentally, the rotors are not warped, rather just heat cured. They just aren't very good at the stopping business. I dare say the warping might come later, especially in a car with a slush box.

R+C

Nordschleife

Rodsky

The phenomenon of the stau is well researched and covered in academic journals extensively. Most of the better papers are wrttien from an OR perspective, so the Journal of Operational Research is a good place to start.

To cut to the chase 'wave reactions' in traffic cause unpredictable tailbacks to occur. You cannot predict where they may occur, however a girl flashing her knickers may reasonably be expected to cause a stau to develop ahead of the flask, as it were. So the polizei discourage such behaviour.

If you re-read my post you will see that remarkably few sudden stops can destroy a set of otherwise pristine brakes.

R+C

Nugget

Those autobahn drivers must get tired of replacing their brake pads every week. I mean, I only get five or six track days out of a set of pads (way less than 1,000 miles, for sure) and if the autobahn is even harder on brakes then it must require new pads even more frequently than that.

Nordschleife

What happens to the pads is that they become tempered/glased and lose their effectiveness, rather than worn. Machining fixes them too.

Most of my car friends in Germany have replaced their stock brakes. Good brakes are very expensive, but worth it for peace of mind. One of my close neighbours has his engine rebuilt every year and switches to his 4wd for the winter, surprisingly the Gallardo is excellent at getting up to the skifield.

Germans do spend a lot on their cars and differentiate between track and road driving., frequently buying into a proper race car as that avoids many compromises, so you may find yourself sharing a pit break with Herman Tilke or Ulrich Betz.

R+C

BBMGT3

While I haven't lived in Germany, I have driven in Germany, on the autobahn, many times, at the speeds we are discussing. Mostly in RS6 (V10) and M5s. So I know what a big heavy fast car is (weird to be saying this on a gt3 forum, but whatever). I have no 'objection' to the Autobahn. I wish more nations would adopt it.

Furthermore, here in the UAE, prior to 2008 (before enforced speed limits), 270kph+ was a familiar sight in my C2S. 285kph was the most I achieved in my gt3 before having to slow for a curve. This is all on public roads. So, I like high speed driving on ANY roads, provided safety and legal risks are managed or mitigated. I also am in a position to say that I have had the occasion to "have to brake at 180mph", and your statement does not hold much water. You can spot a 'hazard' 500m away and lift. You can lightly brake. You can be progressive with the brake. And, of course, you can hard brake. But, the phenomenon you are describing applies to racing brakes as well - hard application at high speed on cold brakes = unwise. Actually braking on a cold racing brake @ 180mph = accident.

Your example about the Lemans driver @ Hockenheim is interesting, but does not support your point; now you are referring to a track situation where brakes overheat, fade, etc.

You're right about the road infrastructure in the US - for the most part not very friendly to high performance, low ground clearance cars. I drove a Ford500 when I lived in Texas. With CVT. It was awful.

Back to the Autobahn. What you are describing is a snake of cars, all doing >170mph, following closely, and hitting a tailback. Autobahn or no autobahn, that just isn't very wise. At that speed, unless you are in a racing car with a reasonable expectation as to where the guy ahead of you is going to brake (normal braking point for a corner), why on earth would you follow that closely???

Now, average highway speeds are clearly much higher in Germany than, say, in the US. And the cars are designed with regular trips north of 100mph in mind. Thats why we love German cars - they're great cars, because they are engineered to work at higher speeds. So, if your point was that brakes on road cars in Germany on the autobahn get a harder life than brakes on road cars anywhere else on earth, I doubt anyone would argue with you.

But you are comparing apples (road work) to oranges (track work).

Nordschleife

Bmardini
I have no quibble with most of what you say, however, if you don't get as much speed off as possible as soon as possible, your options as you approach the cars in front are severely limited. all too often, dynamic groups of cars travelling at 120 mph or so can turn into an impenetrable mass at 50 mph, you don't want to arrive on their rear bumpers doing 100 mph thinking you only have to redeuce speed a little more, when you really have to get off another 50 mph.

Your argument about braking hard on racing brakes holds no water (bit like the desert), racing brakes are almost never cold, whilst brakes on the Autobahn are often chilly if not exactly cold. My point about the lads hooning round Hockenheim was to illustrate how hopeless even leading manufacturers can be about brakes. (If I talk to German engineers in English about brakes, they don't listen, if I say the same thing in German, they listen)

You don't have to be travelling in a high speed convoy to need to worry about the cars behind, cars which you passed some time ago catch up real fast in these situations, most people hit their hazard lights immediately they begin to stop, and turn them off as soon as the following car(s) turn on their's (to show you have noticed their actions).

I am making two points -

1. In the first place the GT3 is made for the domestic German environment and developed for other markets, so the concern about high speed braking is entirely relevant to the car's makeup.
   
2. The kind of braking that occurs at high speeds on the Autobahn causes severe wear and even transformational change to the rotors (and pad surfaces). This is not as obvious (although the colour change is remarkable) as the damage done by continuous and repetitive braking on a race track, but it often has an even more deleterious effect on braking performance.

BTW, covering 500m in 6 seconds (300 kph), means, in my book, that you don't have much time to consider you options, and that getting 'quite a lot of speed off "real soon now"', provides you with more leisure to choose what to do. Some of the time an infinitessimal adjustment of speed as early as possible allows us to arrive, at speed, at the rear of the obstructing vehicle just as it pulls over, but quite often, circumstances change and your options are limited.

i didn't realise that UAE had got liimits, at leat the roads will be better that the States and UK, where many country lanes are not scheduled for full resurfacing for over 150 years.

R+C