Guest Column – Henri Pescarolo

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Diesel dismay

Le Mans legend Pescarolo says that the current regulations for the 24 Hours mean that petrol-powered entrants can’t race on equal terms

The beauty of the Le Mans 24 Hours has always been that different kinds of car can compete for victory: open-cockpit cars and coupés, normally-aspirated cars and turbos, V8s and V12s, and now diesels as well as petrol-powered machinery. The most important thing is that they should all have the chance to win, and right now that is not the case. 

My team’s Pescarolo-Judd 01 was two seconds off the pace of the new Peugeot 908 HDi at Monza for the opening round of the Le Mans Series in April. That will mean we will be five seconds behind around the long Le Mans lap, or the same gap as we had to the Audi R10 TDIs in the 24 Hours last June. I believe the difference comes only from engine power. 

Emmanuel Collard was following one of the Peugeots in practice at Monza for three laps and really had a chance to compare the performance of our petrol-powered car with that of a turbodiesel. He reckoned that the 908 was not so good in terms of handling: in medium and high-speed corners, he felt he was a bit quicker, and under braking they were losing a little bit of time compared to us.

Emmanuel said that the big difference was out of the corners at the beginning of each of the straights. The diesel cars really gain from 180-200kph up to 260-270kph, and that can only be down to engine power and torque. The top speeds are actually very similar, partly because the diesels have more drag because of the extra cooling they require.

I believe the maximum power of the turbodiesel V12s on the test bench is around 735-740bhp. I am not sure they are able to use all that power in the race, though maybe they can in qualifying. However, I’m sure that Audi and Peugeot can race with 700bhp, whereas we have a maximum of 640bhp with the new 5.5-litre version of the V10 Judd engine. 

The rules that give the diesels an extra 60 or more horsepower are bad for the future of Le Mans and the series that takes its name around the world. I have a good contact with a manufacturer looking to do the 24 Hours with a petrol-engined car, but they will not make a decision before there is parity with the diesels. Why would they sign up to do Le Mans and spend a lot of money if they are going to be five seconds off the pace? 

We know that Porsche has said that it would not move up to the LMP1 class as long as diesels are so blatantly favoured. And what about Honda? It says it wants to come but hasn’t told us when. The rules are threatening to kill the competition.

Some people say that if a manufacturer came with a big budget and a new petrol-powered LMP1 car it would be much closer to the Audis and the Peugeots than us. I’m not so sure. Perhaps they would not be five seconds behind, but definitely four or three and a half seconds. That means at the end of the race the gap would be a minimum of three laps. 

Look at what Porsche has done for this season. It has spent hundreds of hours in the windtunnel coming up with a heavily-revised version of its LMP2 RS Spyder, but it is only one second a lap faster than the old car. The aerodynamic rules have been very well written, which means that there are no big gains to be made. No one is going to find the five seconds to the turbodiesels in the wind-tunnel. 

I am not criticising the decision to allow diesels to race at Le Mans. On the contrary, I believe the Automobile Club de l’Ouest is absolutely right to encourage diesels, hybrids, bio-fuel cars and other new technologies. I have always said that. But the important thing is to get the equivalency between the cars right. If you favour one type of engine everyone will have to go in that direction. Right now, you have to have a diesel engine if you want to win. I’d love to run a diesel, but unfortunately there isn’t one available to me.

I believe it would be bad for Le Mans if everyone was forced to run diesels, particularly for the public who come to watch the race. Sometimes when I’m on the pitwall and I happen to be looking down at the timing screen when an Audi or a Peugeot goes past, I hardly notice it because it is so quiet. The noise of the cars is an essential element in the excitement of motorsport. I think the spectators would miss the noise of the cars.  

We should not forget that the ACO has changed the rules for this year by reducing the fuel capacity of the diesel cars from 90 to 81 litres. But this only represents a reduction in performance of 0.7 seconds a lap over the 24 hours, which is far from sufficient.

I think it is time all the prototype teams joined me and petitioned the ACO to do something about these iniquities in the rules. At the moment I feel like a lone voice.