Juha Kivekas' Post Card from Le Mans 2001

Text and images copyright Juha Kivekas
It certainly was wet. One really felt sorry for the Hawaiian Tropic girls and would have wanted to shelter them. Saturday evening was really a rainstorm - the pace cars leading the pack for long periods. It made you wonder whether it really is in the spirit of endurance racing – pace cars that is. Shouldn't these cars really be able to travel with designed pace in all conditions?

Audi was the pre-race favorite. Bentley was considered a dark horse with some well-proven Audi technology. Chrysler has a chassis that many regard as benchmark, but with a clear handicap with the engine. The Dome was known to be quick over a small number of laps - reliability compromised by the F1-type engine. The Sodemo-Peugeot engines of the Pescarolo-Courages had some more power than last year. Nobody expected much of the Panozs and the Caddies. The rumor told that after Le Mans Panoz will swap back to the old chassis. Then there was the Ascari that looked a bit outdated and messy by its construction.

In 675-class the MG was the one to be watched. It certainly turned fast, but in the end it was the ROC-VW that took the honors. A lot was also expected from the Barbour Racing Reynard, but it turned out to be a bit of a disappointment.

In the GTS-class: The Saleen fastest over one lap and the Vettes over 24 hours. Seems that the all-conquering Viper is at the end of its development. Can't wait to see the new version that Oreca is supposed to work on for the coming years.

Finally we also saw some competition on GT-class as the Callaway raced with its very civilized engine tone against the awful, awful, awful ear tearing tone of the GT-Porsches – the work horses of sports car racing.

Of course during the race we did not yet know about the direct injection of the factory Audis. The only hint was that Martin Brundle told with a quiet voice that the factory engines had about 5% advantage in consumption. I took it as the usual racers excuses. Sorry Martin, but I guess sometimes drivers can be trusted. Thinking afterwards, the Audi engine note revealed very little if anything. Maybe, had I known it I would now write that my professional ear detected something hard in the sound. Honestly, I did not. The news came as complete surprise – even if the gains of direct injection has been speculated among the “enlightened” ones.

The Audis had the new side outlets as had been reported by the tech press. Also they had more ventilation on top of the front fenders than last year. The privateer Audis were still in the ‘00-spec as far as visual aerodynamics was considered. On the track all the Audis look so smooth, like going on rails, marginal understeer everywhere. (Look for more Audi details on Mike's great R8-pages)

The Bentley was fairly conservative and carefully engineered. The underbody solutions looked very modest. The side outlets of the front diffuser were smallish to say the least. The width of the rear diffuser was only about 70 cms.  From their press pack figures one could calculate interesting and conflicting figures:  "The amount of downforce generated at 150 mph is sufficient theoretically to drive the EXP Speed 8 upside down".   Based upon that quote: 
> Downforce @ 150 mph 1000 kgf (2200 lbf) .... CL = -2.0
> Downforce @ 200 mph 1777 kgf (3911 lbf)
> Top speed quoted at over 215 mph .... CD = 0.43  (600 hp, transmission & tire efficiency 0.95)

The data above conflicts with this additional press release quote:  "To maximize its potential advantage, the EXP Speed 8 has been tested in a Formula One specification wind tunnel at Emmen in Switzerland for over a year and in over a thousand configurations resulting in more than 2.5 tons of downforce being generated at 200 mph".
>Downforce @ 150 mph, 1406 kgf (3094 lbf)
>Downforce @ 200 mph, 2500 kgf (5500 lbf)..... CL= -2.8

This data really probably just indicates the downforce range available to the Bentley with the first numbers closer to Le Mans trim and the second set indicative of an ALMS type circuit.  Though none of the numbers are "scientific" as they are based off what the manufacturer has let us know

The Bentley also had one of the tire jack holes right in the middle of the diffuser. In some of the TV-shots taken during the rain storms, one could see a stream of water coming from the engine compartment out the tire jack hole in the diffuser.  This stream was presumably sucked by the low wake pressure in the diffuser. During the rain the closed cockpit seemed to be a bit vulnerable. I would not be surprised if they had next year a heated windscreen and enhanced ventilation.

For photographers the biggest curse was the Bentley color. The British racing green is  so muted that even a Fuji-brand film and polarizing filter is not enough. No wonder there is so many B & W shots of this car.  Still, the speed was there. Look out for this car next year. The will and spirit of the team seemed really genuine and sincere.

Aerodynamically the most interesting cars were the Chrysler and the MG. Both had the Lola type front fender solutions (Allard is the probably the one that should be merited. Then again already in the 30s cars had separate fenders). But, I still dare to doubt the benefit of letting front diffuser underside flow into the cooling channel. If my eyes were correct the MG boasted knife type joints at least in its lower front wishbones (yes, according to their technical material they have metal flexures mounting the front suspension--Ed). Dernie & Co. has brought some F1-tech to sportscar racing. Rumor says that a customer MG would cost some $750 000 – was that the idea of the 675-class?  Ridiculous!

The LM-Sarthe track requires a lot of top speed therefore downforce is compromised. The Chrysler had covered part of the rear diffuser with blocks. During a pit stop they took off the rear bodywork and I had a chance to see some dirt water trails on the surface. I was really surprised to see the flow being attached all the way around the rear fenders. I still cannot quite grasp it, no, not even with the rear wing. Similarly I got a shot of a Pesca-Courage from above. Flow separation on the rear top deck before the trailing edge was made visible by dirt.

Brundle had told in the press conference that there is weird bump in the middle of the Tertre Rouge -corner that can upset the car quite severely. So there I went to make some observations. First I noticed that the Panozs had a clear problem. They had huge momentary oversteer during turn in. Looked wild and marvelous though.

The Bentley was clearly understeering with quite a lot of lock. It occurred that they might have had a spool.  But the worst car there was the Ascari. It could be down to over driving or a wrong line choice but the car was everywhere at Tertre Rouge and not just sideways. The two most beautiful cars in this corner were – you guessed it – Audi and Chrysler – like on rails with modest lock, the cars forgiving a lot.

The teams that should be credited are Joest-, ROC- and the Vette-teams. Joest for being perfect, making it look so easy. They changed the rear ends of the cars in about 6 minutes! The question again; is it really along the spirit  – changing something really major in a car during an endurance test. ROC must be credited for winning from an underdog status and Vette for really understanding what this race is all about. The only criticism of the Vettes go to a small style error. Because of cruising in safe mode for the last parts of the race a couple of slower GT-Porsches went by. Still, at any rate the guys did a good job.

Talking about the Vettes one must also comment the Saleen cars. They look really great – visually and on the track. But honestly and objectively, they are not in the right class. They are closer to protos than GTS-cars.

The prize of visual aesthetics goes to Gulf-Johansson Audi. It was really retro and almost brought tears in the eyes of the most fanatic LM-fans. The sound prize goes to all the American cross crank V8s and somewhat surprisingly to Callaway: big power and yet so civilized.

It was a year of appalling conditions. Jacky Ickx said he had never seen such bad conditions at the Sarthe track. It is really a pity as the race is more than just a futile car race. It is an outdoor festival and requires a good weather to make one. Still this is the ultimate race of men and machines. THE race – at least on this side of the pond.
 
 
 
 

Juha Kivekas (Dipl.Ing) is the managing director of Apextrem Ltd. which is a small Finnish R&D company specializing in vehicle dynamics and aerodynamics.  He has  also worked as a professional race engineer in lower categories and is the aerodynamacist for the Finnish Ski Jumping team.  He has participated in some 160 aerodynamics R&D projects varying from bridges and race cars to subwaterlevel craft and space devices.

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ęCopyright 2001, Michael J. Fuller