Le Mans Test Day Reflections: Part Three, GTE

The GTE class continues to attract a large and varied entry for les vingt quatre heures, despite an increasing proliferation of other endurance races and the overlap between GT3 and GTE regulations. The stated aim of the FIA is to bring together the regulations for GT3 and GTE, along with whatever the USCR ends up with for a GT class, and although there is little sign of it happening yet, it must surely come, and the class will then be better still for it.

The distinction between GTE and GT3 is becoming more blurred as the FIA Endurance Committee seems to be falling into the trap of continually tweaking of Balance of Performance regulations for GTE, which results in some noses being put out of joint as the playing field is tilted in favour of others.

The FIA Endurance Committee is allowed, under article 18bis of the Sporting Regulations, to balance the performance of cars in the GTE-Pro and GTE-Am classes and to that end has made a number of “decisions” since March this year.

There are various ways in which these adjustments can be made:

· Weight
· Restrictors
· Rear wing gurney
· Rear wing height
· Fuel tank capacity

The thing that I find difficult in these regulations is that changes are made from one race to the next – and indeed further changes have been made this week, between the Test Day and the race itself.

For example, at the beginning of the year, the Aston Martin Vantages were allowed to run at a weight of 1205kg, which they did at Silverstone and Spa. For the Test Day, they were given a 10kg penalty, and now a further 10kg has been added, so that the Astons will have to race at Le Mans at 1225kg.

The Chevrolet Corvettes, which don’t race in the WEC, were allowed to run at the Test Day at 1250kg, but will be penalised for the race at Le Mans by an additional 10kg. Olaf Manthey’s Porsches, on the other hand, which had to run at Silverstone and Spa with two 29.3mm restrictors, will have 29.6mm restrictors at Le Mans. Having run with these at the Test Day, no further alteration has been made (yet).

However, SRT Motorsports, which run the Vipers, have, since Test Day, had their 10kg weight adjustment removed, and also get an increase of 5 litres in fuel capacity.

And even those rules that have not changed from race to race, give us the anomaly that the Ferrari 458 Italias are restricted by an 85-litre fuel tank, while everybody else can have a 90-litre tank – except for the Aston Martins (and now the Vipers) which have 95 litres.

This constant shifting of the parameters by which you go racing risks undermining the class and its credibility. It also means that teams spend resources lobbying and campaigning that could usefully be otherwise employed.

Having said all that though, it is good to see a strong entry in both GTE-Pro and GTE-Am; peppered with top quality drivers. Out of a possible total of 50 Gold / Platinum graded drivers in the two classes, there are 34 Platinum and 11 Gold. Even if BMW isn’t at Le Mans this year, their absence is compensated by the presence of Corvette, Ferrari, Aston Martin, Porsche and the SRT Vipers. There is depth here that is lacking in the Prototype classes.

Enough of the politics and the background, though, what was there to be learnt from the Test Day? It’s difficult to say, really, as you never really know how hard people are trying. Especially because, as we have seen, the Endurance Committee was watching carefully, to see if any further performance balancing was necessary.

Looking at the average of the best 5 laps of each car from each session (thus including an element of wet-weather running), gives us:

[sws_divider_small_padding]Perhaps this explains the decision to further penalise the Aston Martins, although the Endurance Committee must have seen something in the telemetry data to make them penalise the Corvettes, as these figures don’t particularly suggest it was warranted.

Were the Porsches perhaps sandbagging less than the AF Corse Ferraris?

How much will the additional weight slow down the Astons? Will they also be able to use their larger fuel tank to their advantage? At the Test, the Aston Martin and the Viper both did a 12-lap stint during the day. The longest stint that any of the Ferraris managed was 10 laps, and the Corvette and the Porsche did a maximum of 7 and 6 laps respectively.

The big question of course, is how far they’ll be able to go in the race. The problem is that even though the fuel tank sizes are different, for it to make a significant difference, then you need to be able to get a full lap on the additional fuel. My calculations suggest that the Ferrari will be using around 6 litres per lap, which means that 14 laps is its maximum range. The rest will use more fuel per lap, but while the Corvettes should be able to get 14 laps per tank, I reckon that the Porsches might only be able to go for 13 laps.

Despite the additional 10kg, the Aston is still lighter, and crucially has been granted aerodynamic advantages by the regulations as well, so I think that 15 laps might be achievable. However, if they can lap more quickly than their competition, they will be better off short-fuelling the car at each stop, reducing its average weight during the race as well as reducing the tyre wear, and pitting at 14 lap intervals. At least, that would be my strategy.

In GTE-Am, driver quality will play more of a part than in any other class, in my opinion, and now that the ACO has reviewed the driver gradings, there are fewer anomalies than there were this time last year. The regulations require that each crew may have at most one Platinum / Gold driver in it, and there are only three crews that have a Platinum joined by two Silver drivers. These are the two IMSA Performance Matmut Porsches and the 8 Star Ferrari 458.

The best laps achieved by each during the Test were:

[sws_divider_small_padding]As always, we don’t know exactly what programme these teams were working through, so we don’t know how reliable the conclusions that might be drawn are. But experience counts for a lot at Le Mans, and the IMSA Performance Matmut team have more experience than most.

Paul Truswell