The fast life & times of Andy Wallace

The main issue is directional instability. Beyond 450km/h the car moves around a lot...

ASH WESTERMAN

THIS IS THE second time Iíve broken a speed record. The first was the McLaren F1 record of 386.6km/h in 1998. I was young [aged 37] and naive when I signed on for the McLaren record. When you are young you either donít really know or donít care, but as you get older, you do think about things more, and youíre more aware of possible consequences.

If I thought about it logically when we talked about this Chiron attempt, I may have said, ďNah, itís okay, you guys go ahead [without me]Ē, but in the end, I said, ďAll right.Ē

I walked away after saying Iíd do it and I thought, ďYou must be barking mad.Ē But I donít have a death wish; over the years Iíve driven quick cars, and at the end of the day, Iím a car enthusiast.

And I have been going fast for a long time. I was offered a Le Mans drive by TWR in 1988. They set up a test at Paul Ricard, which I knew from driving a 500kg F3000 car that stayed glued to the road. Now I was in this great big Jaguar XJR-9, running the low-drag Le Mans set-up, and at 330km/h it was swerving all over the place, using the whole width of the track. You really had to manhandle it: no power steering then, of course. It was a shock to the system.

There was no Le Mans test weekend back then, but I studied the gear charts before practice, and I knew 6000rpm was 320km/h. On my first lap I ran it up to 6000rpm on the Mulsanne straight and I said to myself, ďThis is as fast as I want to go.Ē Youíre in the grooves worn in the RN138 by heavy trucks, you catch a slower car and need to go around it, you put on a bit of lock but the camber pushes you back, you put on a bit more, the back of the slower car is rushing up to you, you climb up the camber and lurch down the other side, and you almost steer into the opposite barrier. There I am thinking, ďThis is jolly fastĒ, and another XJR-9 comes past like Iím tied to a post.

So the next lap I held the throttle down, my toes curling up in my shoe, got to the kink which everybody said was flat, but I lifted. But on my third lap I managed the kink without lifting, and then it was all right. We were doing 397km/h that year.

Dunlop were very unhappy with the safety margin of the radials, which were only good for 400km/h and we were just about on that, so they insisted we went to cross-plies. Suddenly, even with the same rolling diameter, the gearing was all wrong. Thatís because cross-plies grow at maximum speed. So instead of gearing for 397km/h, we geared for 370km/h, and that, with the tyre growth, got us back to 397. But it felt like at least 480. You tell yourself, ďIf a tyre goes bang now Iíll hit the barriers so hard I wonít know anything about it.Ē


People ask, ďDo you feel safe? Is there fear?Ē

There are risks; you canít pretend thereís not. But everyone in the Bugatti team is so good at their job Ė the engineers, all the team Ė that you eliminate the risk as much as possible. I was aware we are doing something special when we set the record in August.

But itís still a huge jump in speed. If you drive at 300km/h then itís a real shock, even to take the Chiron to its [electronically limited] max of 420km/h; you have to get used to it. You have to work up to these things gently to try and acclimatise. But itís still a complete shock to be up at mid and high 400s.

In terms of preparation, itís all very methodical, as youíd expect. During the week at the track, first we validate all the data Ė wind tunnel, etc. We do that at 250km/h, nice and easy, then we know how accurate the data modelling is relative to the real world at Ehra. Then we go up in 50km/h increments.

The main issue is directional instability. Beyond 450km/h the car moves around a lot...

On the day of the record, first we waited for the cross-wind to be not so strong, then did a full lap at 200km/h, to make sure temps and pressures were stable. Then we attempt a few serious runs, adding a bit of speed, then you know what you need to do: into the banking at 250km/h, down some gears, see the exit, then bang, pedal flat. You just flick the switch in your head and do it.

While youíre doing the run, youíre not just sitting in the car driving, youíre monitoring various things, checking off a list in your mind; itís busy. In terms of the feeling, itís really amazing to come off the banking at the end of Ehra-Lessien and hit the flat section, and pin a Chiron Super Sport for 57 seconds. It just accelerates and accelerates, really strong, and itís not until you pass 450km/h that you realise the rate of acceleration is decreasing, but youíre still accelerating Ė itís almost unbelievable to think about the number.

The main issue is directional instability. See, getting up to 450 is quite manageable, but after that the car moves around a lot and you have the feeling that youíre not controlling the car as much as youíd like. Itís nice to have full control, and after about 450 you realise thatís not true anymore. Itís nothing to do with the tyres, nor the aerodynamics, itís just physics. Itís not as if there are any vibrations Ė itís super smooth Ė itís just that the front wheels are spinning so quickly itís the inertia, the gyroscopic effect Ö you make a steering input and the car just wants to keep turning. If thereís a cross-wind and you get pushed to one side of the track and you turn slightly to get back, it just wants to keep turning, so you are continuously turning, left and right, just to go straight.

If you watch the video itís hard to see, it looks like Iím just sitting there and it doesnít look too difficult. But if you look at the white line and you look at the side of the car, you notice the distance from the white line is changing ... youíre doing 132 metres per second, and itís moving around.

At 447km/h thereís a surface change on the track; when you hit it at that speed, it feels like a jump, like all four wheels are coming off the ground. You brace yourself for the íjumpí, but you donít lift Ė that would make it much worse Ė so you keep it flat and thereís this whump where it feels like itís lifted and landed back down, four square.

Itís intense, but Iíve been doing crazy things in cars for a long time. Itís just another day, in that sense.



McLARENíS TOP-EXIT EXHAUST

600LTíS WASTE GASES TAKE A FAST-TRACK TO THE TOP

McLAREN IS NOT a company known for fickle design follies, and even though the top-exit exhausts that pierce the engine cover of the companyís 600LT look like the stuff of concept fantasy, they make as much engineering sense as they do street theatre.

In the case of the Longtailís sibling, the 570S, dumping waste gases at road level requires a complex exhaust system that hurdles the rear axle, involving restrictive angles all the way, but the 600LT gases take a short cut and that has numerous advantages.

Not only does the shorter system reduce back pressure, allowing the 3.8-litre turbo V8 to find even more power and noise, a significant chunk of weight is left on the parts shelf. Eight kilos is saved in tubing and a further 4.6kg spared in heat shields and the cooling fans that would be required to vent heat from the engine bay.

McLarenís trademark aerodynamics are also improved. Without conventional low-exit pipes, the wall-to-wall rear diffuser is an aerodynamicistís dream, allowing greater air management at the rear of the car. The result? Boosted downforce and improved stability.

Thereís little aerodynamic upset where the exhausts spit hot gas centrally over the large rear spoiler, with a majority of the hard work performed at the outside edges of the wing. A coating of matte black Ceracoat prevents heat damage to the carbonfibre surface and structure.

DANIEL GARDNER

1 PIPE DREAM

Donít expect to see the next Kia Cerato blowing exhaust through its top. Despite the advantages, top-exit exhausts generally only work for cars which have the engine located behind the driver, and which have high horsepower expectations.

2 JUST HOT AIR

No, thereís no happy by-product such as extra downforce, with only a few grams of thrust generated by even the most hardcore turbo-car exhaust, but you might be able to toast a marshmallow. Sweet.

3 NOT AN EXHAUSTED IDEA

Before McLaren, Porsche brought the race-car-derived feature to the road on the back of its V8-powered 918 Spyder hyper hybrid, and you can bet the 600LT wonít be the only car to follow the high-performance Germanís lead.