The brakes are original, not sure if been rebuilt but we pulled the pistons out and had a look, looked alright. The master cylinder is probably original also, the line from the master cylinder has been replaces since we broke it, rests are stock and theres braided lines from the chassis to the callipers. fluid.. i wouldn't have a slight clue.

i wanted to go 993tt fronts but they won't sit under the 16" rim will they? and grinding the wheel down will weaken it.

 

Well it sounds like it might be time to spend a little bit of money and go over some of those parts.
As for fitting them under a 16" wheel...I'm not sure. My instincts say no, but Tony G has just fitted 350mm rotors and Cup Callipers under his 17" wheel. So the Big Reds and smaller rotor just might fit? I'm sure there'd be some info re that in here.

 

Patrick - now that I'm running a supercharger on my S2, I expect my terminal speeds to be around 200km/h on most tracks and probably 240+ on Conrod Straight at Bathurst. I'm running stock brembo brakes at present with PFC97 pads. This all works quite well, although I do get a fair bit of cracking in the (smooth/plain) rotors. I can brake on the limit of adhesion (pre supercharger at least), so not sure what benefit bigger brakes may give.

Do the larger big blacks/reds make a difference or just prevent the rotors overheating/cracking and provide longer life?

PS - never had an issue with a soft pedal.

 

Eric, juts fyi those are the same speeds as my car hits. eg: I pull 236-240km/h through the kink at Bathurst. The car is running stock (albeit superbly maintained, always near new discs etc) M030 brakes with no issues. I found the pagid Blue or Black pads great at those speeds. Hope that helps as input.

 

The M030 brakes are a little bigger than the standard brembo. The PFC97 pads are awesome - no issues there. My query was more around what are the benefits of bigger brakes - how can they stop you quicker if I can already brake at the limit? Perhaps an issue if durability, or perhaps the 5 lap sprints we do at club events isn't that taxing on the brakes anyway?

 

You get the advantage of moving up to a larger rotor, plus the pad for the Big Red/Blacks is a lot larger than that of the 'Medium Blacks'. However, you do go up in unsprung weight and extra rotational inertia that can count against you. Bit of a choice but one that has been paved by many guys before me.
Also I didn't really have success with the X drilled rotors as many others would agree. I think it was something the factory did way back in the 917 days when lightness was everything and of course with a race program, they just replace expendables. I guess if you guys have ABS then it's possible you're not realising if you're getting to the extent of your brakes capabilities? I never noticed the stock system cutting in on the track. Only ever during Motokhanas when coming into the 'garage'. On the black car without ABS, I was flat spotting tyres during the last season. NOT fun at all!! Expensive and really inconvenient.
Hope we can all catch up one of these years at Bathurst. Reckon I'll hit 300kmh down Conrod!!

 

Ultimate braking performance is limited by tire grip so if you have enough retarding power to lock your tire from the point of brake application and you have enough retarding power (and control) to hold the tire at the limit of it's braking performance down to the speeds required, and you can do it consistently, over and over without brake fade then you have enough brake.

In that case bigger brakes that potentially offer more retarding power and heat absorbtion won't stop you quicker, and may even stop you slower.

But... if you increase your tire grip by changing to bigger or stickier tires, or you increase power and are now braking form higher speeds and you now can't reach the tires grip limit straight away in braking, or if your brakes still work fine but now fade after multiple applications then you need something more matched to the tire you are using.

Everyone assumes you need the biggest brakes you can possibly fit to get the maximum stopping power, but it's not true. You need 'enough' brake for the tires, the performance level of your car and type and length of event you are driving in. Any more is potentially just extra weight.

Of course big brakes do look sexy...

 

All good advice^^

Steve, what pads are you using by the way??

 

Though it is not very popular on this forum, unassisted, a properly engineered braking system - pedal, connecting rod, master cylinders etc can give you immediate feed back with brake action from the moment you touch the pedal. There is a lot of slack in the stock system and pedal feel is a bit vague. I happen to have a Koklen dual master setup if anyone is interested. We could not fit it into my car, we had to use a Wilwood/Tilton setup.

 

I have a dual-master in my car as well. I did not like it at first, but after a bit of tuning with master cylinder sizes I am starting to realize the benefits of the system.

 

These days I am using Hawk DTC-70s. I used PFC-01's for a long time, good pad but had some problems with the pad blocks cracking and crumbling so gave them up. The DTC-70s have been excellent. The Stoptech ST-60 is a big pad, so they last very well.


I know what you guys mean. I have raced a few open wheelers and agree there is nothing like a direct mechanical pedal for feedback and control. I miss that feel and have thought about doing a dual master setup on my car a few times, but I always wonder just how much of an improvement it would really offer for the trouble, considering the brakes on my car have been excellent the way they are anyway?

I also worry that the 944 is just so big and heavy and I can’t be bothered with the physical effort anymore. I have got lazy in my old age and like my ABS, power brakes and power steering

Still, would be curious to drive a 944 with a properly setup dual master system and see what it felt like.

 

The first and biggest mistake with dual MC's is getting the Piston area calcs off, front-to-rear. Most people stick on Turbo calipers to the rear and this throws the whole set-up out of proportion where it is hard to tune with the factory pedal ratio, no matter what MC combo you try.

 

[QUOTE=333pg333;5765230]
If you have excessive pedal movement and a soft pedal, you have:

1) air in the system still
2) swelling lines, yes even if they are SS lines!
3) a leak! check calipers, line fittings, hose joints and master cylinder
4) internal leak in master cylinder... pressure is blowing past seals
internally so you do not get press. to calipers AND you get a long pedal
5) cracked firewall and master moves when brake pressed."

QUOTE]

Cracked firewall?!?! Is it someone happened?

 

Yes it's quite common problem on 944/968 models. Have seen it many times.

 

WOW!
How is it possible? Which is the solution?