Top Speed Driving
The science of high-velocity testing
The warm and stable climate slightly inland along Italy's southeast Mediterranean coastline near Brindisi makes the 12.6-km-long (7.8-mile) Nardo circular high-speed track the perfect spot for the motor industry to test cars year round.
The first lap on the banking is always a warming up affair. Like joggers limbering up, drivers pace themselves, building speed progressively to warm their cars' vital fluids properly, and look for any potential mechanical or stability issues. The second lap is the big one, where top speed is recorded for posterity. The third lap is cooling down time before returning to the paddock.
There are four lanes on the banking-the inner one is canted at a mere four degrees, while the top lane has 2.5 degrees of tilt that allows you to run a car hands off at 160 km/h (100 mph).
From personal experience, I can say that the faster you go, the narrower the track appears to be. Approaching 190 mph, the four lanes start to take on the appearance of a wide two-lane road, so you really don't want to be running in the fourth lane up by the Armco barrier. The best place to be on a banzai run is the line separating the third and fourth lanes.
Another phenomenon is the fact that the faster you go, the quieter things become in the cabin. I remember doing a run in a Carlsson-tuned E55 AMG a few years ago, and as the speedo needle settled just short of 320 km/h (198.8 mph), it was like sitting in a commercial jet, the engine and wind noise subsiding as the car whistled around the banking.
All the tuners provided full specifications for their cars, and one of the things we noted was how close these cars got to their claimed top speeds despite tire scrub on the banking.
On a car capable of over 300 km/h, more or less 186 mph, you can normally factor in around 10 km/h (6.2 mph) for tire scrub. The tuners had all established their top speed claims based on runs on a flat autobahn, so the fact that many of the cars came very close to their claimed top speeds on banking was all the more creditable.
In conclusion, and in the best tradition of all such events, a word from our sponsor is in order, as almost all of the cars at this event were running on ContiSport Contact Vmax tires, officially rated to 360 km/h (223.7 mph).
On relatively light cars like Porsches, such speeds are not an issue, but when you're talking about two and a half tons of TechArt Magnum, that kind of velocity puts a serious strain on any tire.
Nardo's banking is designed so that there is no lateral force up to 240 km/h, almost 150 mph. Over that speed, the onset of lateral g-forces adds to the stress on the suspension, wheels and tires.
The Magnum's 22-inch wheels were shod with a variant of the Conti Vmax in a 275/35ZR22 size called ContiCrossContact UHP, designed for heavy, high-performance SUVs like this. Conti's ultra-high-speed tires have a specially designed structure and tread pattern that delivers high levels of stability at speed while breaking up resonances.
The Continental Sport Contact Vmax holds the Guinness Book's records for the fastest rated road-legal production tire, and there are very few places left on the planet where you can explore its outer limits. Nardo is one of them.
Brabus GLK V12
Everyone expected Brabus to bring the E V12 that made its debut at Frankfurt, but as development work is ongoing, it was not to be. What nobody was prepared for was the GLK V12.
"The GLK is based on the C-Class platform, so the GLK V12 is basically a Bullit with a GLK bodyshell," says Jorn Gander, Brabus' Deputy Engineering Chief. The V12 fits straight in, and sits low in the chassis on a bespoke front subframe, while the rear subframe and differential are straight from the Bullit. Like the Bullit, the GLK V12 is rear-wheel-drive, with a 40 percent locking limited-slip differential.