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Brake Upgrade, Seriously Considering It, Here's the System, Will Need Others

A8 / S8 (D2 Platform) Discussion Discussion forum for the D2 Audi A8 and S8 produced from 1994-2002

Brake Upgrade, Seriously Considering It, Here's the System, Will Need Others

 
Old 10-19-2002, 05:10 AM
  #21  
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Default and a question ...

.
Do the Audi and Porsche caliper accept the same banjo bolt?

If thread, pitch, or length is different, you'll need new brake lines. This isn't necessarily a bad thing, you'll have an excuse to upgrade to braided SS lines.
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Old 10-19-2002, 05:17 AM
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Default Ok, just what I have heard..

there are both 288mm and 312mm rotors for the A8. I have the 312mm rotors. What I heard is that the US market had the 288mm. Could you check this with your car?

Anyway, would it make any difference for the upgrade? Could brackets and calipers still be the same?
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Old 10-19-2002, 06:52 AM
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I don't know, but I think I might upgrade to the SS lines anyways.
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Old 10-19-2002, 06:54 AM
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Default I have a brand new rotor in my closet

I actually bought it about a year ago from some guy who used it for BIRA engineering. Probably for the A6 upgrade.

I'll have to take it out of the box and measure. But leaving for WI right now, I'll do it Sunday night.

pw
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Old 10-19-2002, 07:07 PM
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Default You really should look at 332X32mm rotors...a lot better heat sink

<center><img src="http://pictureposter.audiworld.com/1510/mvc-267s.jpg"></center><p>The pads on the Porsche monoblock are a lot smaller than what the Big Reds or the Stop Techs use. The anulus on the 332 versus the 321 will be much better. The 332 rotor will put the pad farther out on the leading edge...which is where you want your bite. The extra 2MM on the width means a lot for the heat sink.

StopTech, as well as probably Brembo and Performance Friction have bolt on rotors with aluminum hats that are perfect fopr the 17" wheel. The price is not too bad.

Don Istook<ul><li><a href="http://pictureposter.audiworld.com/1510/mvc-268s.jpg">http://pictureposter.audiworld.com/1510/mvc-268s.jpg</a</li></ul>
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Old 10-21-2002, 01:58 PM
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Default Laptimes vs. Weight

The A8 and S8 are great grand touring cars, as are their counterparts from other (mostly German) makers.

If you want to have fun on the track, however, think light.

In teaching new instructors, I often use the "traction circle" concept. You can accelerate, brake, and turn only within the circle defined by your vehicle. A well balanced track car will have a "round" circle. An A8 has an elliptical shape, long on accel, short on decel, and narrow on turning.

Yes, you can make a GT (like the A8) car into a fast track car, given big enough brakes, tires, and springs. It still won't be much fun to drive (eg, Corvettes), and it will be a MISERABLE street car.

Better, find a cheap 944 turbo. Put slicks and race pads on it, plus spec belts, etc, and have a ball. And, if you bend it, no big deal.
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Old 10-21-2002, 03:10 PM
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Default Re: Friction Circle

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I agree that the concept is valid; but I'm not sure what you mean by the elliptical shape. On the track, it seems to me that the S8 is weak only in acceleration.

Since you never see 1st gear on the track, acceleration g's range from about 0.5-0.1 depending on speed in gear.

Lateral acceleration and braking are probably both about 1.1 g max with the stock suspension and max performance street tires.

Even with a stock suspension, the A8 is probably not much different with the same tires. From 50-110 mph, typical track speeds, better gearing actually results in acceleration g's slightly higher than the S8. Braking would be about the same. Lateral acceleration would be only slightly lower with the stock suspension.

My conclusion is that our cars are only "weak" because they're low powered for their weight, but they certainly are fun at the envelope of their flat-topped friction circle. Fun would increase with less weight, would decrease dramatically if you did bend the car, but obviously racing slicks won't help acceleration.

Note from the link to the World Challenge Mid-Ohio qualifying times that even the S4 is quicker than all -- including the Porsche 911 Cup, the Acura NSX, BMW M3, and Corvette.<ul><li><a href="http://www.world-challenge.com/2002/moh/gt-qual.html">Mid-Ohio World Challenge qualifying</a></li></ul>
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Old 10-30-2002, 03:26 PM
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You wouldn't happen to be selling any carrier brackets that can accomodate the mounting on an S4?
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