The German magazine Auto Sport (I think that was the one) just did a side by side test of two Porsche Turbos, one with the standard Porsche brakes and one with the new PCCB units. Now, I don't read German, but I can tell you that the standard brakes stopped shorter consistently both hot and cold. Additionally, in racetrack laps, the standard brake car had a quicker best lap, and averaged a quicker lap time over a 10 lap test.

Couldn't read any comments about fade, but considerin the supposed higher Cf of the ceramics and reduced rotating mass, I'm kind of surprised. Something to consider if you're gonna spend big bucks on brakes.

UL

 

Wow, that's really shocking, considering it's a really pricey option too! I wonder why it works that way...

 

That is very interesting UL. Likely it was "Auto Motor and Sport" magazine. In a recent Excellence magazine, an article reported on a comparo with the exact opposite results. The ceramics totally dominated. I know that they (Porsche) have tested various compounds, time will tell what is up. In F1 testing, cast iron rotors with Performance Friction brake pads were very comparable to all out carbon/carbon brakes. In any event remember that you can't brake harder than available tire grip. But things like modulation and how fast you get to full braking power matter too.

My M3 with track pads can stop from 60 MPH in around 2.6 to 2.8 seconds. That is with street tires as measured by AP-22 datalogging performance meter. It won't go from 0-60 that quickly! This takes an average of over 1 g with peaks higher that that amount. Doing 0-60 MPH in 5.5 seconds takes an average of about 0.5 gs for the duration.

Stan

[Edited by E30M3 on 05-19-2001 at 06:22 AM]

 

I think the main advantage of carbon/carbon brakes in F1 is that they can endure very high temperatures for the duration of the race. Optimal friction doesn't help if your brakes fade after 5 laps.

 

Stan, you mean Auto Motor "und" Sport, right? :-)

Actually, I stopped by my magazine stand again and the mag was Sport Auto (they carry no fewer than 6 German language car mags, 2 French and 2 Italian!). Very interesting test indeed. I agree with your comments Stan, but what surprised me was that over a 10 lap "race" the cast iron car didn't get any slower. Perhaps a longer duration is needed to induce fade in a 911 caliber braking system, even with iron. Its also entirely possible that the better lap times for iron were attributable to inferior feel on the PCCBs.

UL

p.s. - why can't US mags test like the Germans? They run the cars at Hockenheim and the Nurburgring, put them in a wind tunnel to measure lift and do in gear testing in every gear from 20 to 150 mph.

 

I agree with you, UL, which is why I pay little attention to US car magazines.

 

>>I agree with you, UL, which is why I pay little attention to US car magazines<<

It's can be a lot of fun to actually test and tune a car using inexpensive tools such as a Vericom, AP-22, Road Dyno, Geez, g-Analyst, etc, etc. Very eye openin and you et to appreciate the huge impact of the driver practice and skill. There are lots of performance products with good reputations that don't work well or at all. Some of them advertise or sponsor cars/events. I don't know what the advertising situation is in Germany but in the US that seems to be of major concern to the editors. In many cases the authors have little if any tech experience but can write reasonably well. One of my cars was in European cars (Lotus Europa) in a three part series back in the mid 90s. I attended a photo shoot of a different car. Which had been in a bad wreck on the passenger side. It still made the magazine (must been jacked up on that side) but was simply photographed from the driver's side. They even had some 0-60s, driving impressions on it..yet the car was undriveable. Ugh. Oh UL, "and" is "und" in German!!

Stan

 

Well of course it is Stan :-)

Actually, my organization recently bought a Vericom2000, but I haven't had a chance to try it yet. I'm looking forward to it.

I agree about the specialty mags too. I once had a car appear in a McMullen Argus publication. I had to drive 75 miles to the photo shoot. When I got there, there was a thin layer of dust on the car which I prepared to remove. The photog told me not to worry, that it wouldn't show up at all. Also had a nick on the front spoiler from road debris which never showed up either. Then there was the fluid used to get smokier burnouts since regular tire smoke wasn't enough.

UL

 

Motor Trend has a recent article on the 2WD Porsche turbo and mentioned the ceramic brakes would not fade no matter how hard they tried. Maybe they don't bite as hard but also don't fade? I'd take that tradeoff on the track (consistent but lesser braking).

So when do we get the ceramic engine block that runs at absurdly high temperature?

 

I second this as well. US car magazines are far inferior to those of Europe and Japan, similar to the cars themselves . . . (for the most part - there are some good American cars).