Sunday, 8 June 2014

So what about Porsche?

My last post about the Le Mans Test day failed to mention the new Porsche 919 Hybrid. Deliberately so, for I had the feeling at the Test that Porsche was ignoring everyone else and getting on with their programme. Although it makes sense to look at their performance at the Test day in isolation, we are, after all, looking forward to a motor race; and the purpose of a race is to compare yourself with the opposition. But regardless of the objective, let's have a closer look at Porsche's Test Day.

Porsche has, arguably, the most advanced hybrid system of all: a front-axle kinetic and an exhaust gas-driven turbine feeding energy into water-cooled, lithium-ion batteries. This provides much greater energy than Audi can achieve, and delivers the power much more flexibly than Toyota. The small-capacity engine can be boosted whenever the engineers have the fuel available to them, providing the team with the ability to make the most of opportunities that might arise.

We saw at Silverstone and Spa how fast the Porsches were; they are also economical. If any car in the LMP1-H class has the ability to manage 14 laps, then it is for sure the Porsche. The fact that they did not go that far during the Test Day is surely irrelevant. Toyota may also go 14 laps come the race, but they may have to shave ultimate performance to achieve that. Porsche will be able to complete 14 laps at full power.

How fast is fast? Here are the top speeds, measured at the speed trap located just before the first chicane on the Mulsanne straight.

No. Car        Top Speed         Average top speed
1 Audi 333.9 325.5
2 Audi 332.9 326.1
3 Audi 332.9 321.8
7 Toyota 334.9 320.1
8 Toyota 336.0 318.4
12 Rebellion           326.8 322.4
13 Rebellion 331.8 323.3
14 Porsche 332.9 323.7
20 Porsche 339.1 330.3

The ‘average’ top speed is the average of the best 25 speeds recorded - removing the effect of any ‘bansai’ lappery or trickery to gain bragging rights.

The main conclusion to be drawn from this is that the two Porsches had very different programmes. I don’t think that is particularly surprising in the circumstances, but what is interesting is that the two cars finished the day separated by just a quarter of a second in terms of best lap, and the ‘ideal lap’ i.e. the one achieved by taking the sum of the best three sector times, for the no. 14 Porsche was within a hundredth of a second of that of the no. 2 Audi.

Porsche may be in only its third race, but it has spent a long time testing, and should, by now, know what it is doing. Reliability may be an issue, but then this technology is so new that Toyota must have similar concerns, and even Audi’s bullet-proof reputation puts it at risk.

The other thing to consider is going to be the time spent in the pits. Even though Michelin is providing tyres to Porsche, Audi and Toyota, it will be interesting to see if they all are able to make the tyres last the same. The more potent Toyota may find that tyre wear is more of an issue. And of course this is the area in which all the teams were concentrating at the test. And they won't tell us (at this stage) what they have learned!

I don’t expect Porsche to participate in what is undoubtedly going to be a no-holds barred battle at the front in the opening few hours, but I do expect them to get on with the job quietly and efficiently, and if they can stay out of trouble, they will certainly be a feature when the sun comes up next Sunday morning.

I’ve said it before; but it bears repetition: Toyota is the favourite for this year’s 24 hours, but if they are not perfect - on the track and in the pits - then they cannot expect to win.

Wednesday, 4 June 2014

Le Mans Test Day - more than sector times

In the ‘old’ days, when I first went to Le Mans, it was all about straight line speed. The Mulsanne straight, more than 6km long, represented very nearly half of the total lap length. Aerodynamics were important, of course, but minimising drag down that long straight was absolutely vital, even if it meant that the car was a bit lively through the Porsche Curves.

Then the chicanes were installed in 1990, and no-one was sure quite what to do. Porsche 962 entries were numerous, entered by experts like Reinhold Joest and Richard Lloyd. The factory recommended they be run in long-tail trim, but some privateers (most notably Walter Brun) ran short-tail, high downforce configuration. Those who were there will remember that short-tail proved the way to go.

These days, Toyota and Audi have had two aerodynamic configurations: one specifically for Le Mans and the other more suitable for the more typical circuits of the rest of the season. But Toyota demonstrated at the six hours of Spa that the ‘Le Mans’ configuration is really rather good at Spa as well, leaving Audi (run by Joest, coincidentally) rather scratching their heads.

Since the data from the Test Day has now been issued, I am trying to work out what it all means. Looking purely at the fast laps that were set by Marco Bonanomi in the no. 3 Audi in the morning session, the fastest lap of the session at 3m 23.799s included a sector 2 time of 1m 18.480s. Sector 2 is from the beginning to the end of the Mulsanne straight, if you are not familiar with the layout of the track, so really represents the ‘power’ element of the circuit. On that same fast lap, Marco’s time through the Porsche curves was 16.321s.

To put these two times into context, the fastest time through sector 2 in the morning session was 1m 17.667s and the best time through the Porsche Curves was 16.156s, so Bonanomi was around 1% off the best time in both the ‘power’ element and the ‘handling’ element of the circuit. So where did the time come from?

Well, fairly obviously, it came in sectors 1 and 3. But it didn't come in the ‘tight bits’ of sector 3; in both the Porsche Curves and the Ford Chicane, the Audi was not the quickest. So the advantage must have come from the Dunlop Chicane up to Tertre Rouge and from Mulsanne Corner back through Indianapolis and Arnage, to the start of the Porsche curves.

Traffic may have played a part - Bonanomi overtook five cars on that fast lap - and we cannot really know what fuel was being used, but it would certainly seem that there was more going on there than met the eye.

In the afternoon session, of course, Toyota established its position as the fastest car; a situation to which we have become accustomed this year. Right at the beginning of the session, Sebastien Buemi went out in the no. 8 car and set a series of fast laps. In two five lap stints, he set three laps under 3m 24s, with an outright best of the day of 3m 23.014s. Again, though, it is interesting to note that Buemi's best time through sector 1 on these laps were not as quick (by a margin of more than 1%) as those achieved by Davidson in the same car, later on. Down the Mulsanne though, and back through sector 3, Buemi was practically as quick as the best - to within a few tenths, at least.

Again though, the time does not seem to be coming from the Porsche Curves nor the Ford Chicane: Buemi’s time through the Porsche curves on his fastest lap was 16.034s; his time through the Ford Chicane 6.068s. Compare these times to the fastest times in those specific sectors in the afternoon session: 15.709s by Kristensen in Porsche Curves and 6.011s in the Ford Chicane (by Buemi on a slower lap earlier in his stint). So it must be the long straight(ish) bits before and after Arnage where the Toyota was making up time.

I’m aware that all this analysis doesn’t really prove anything conclusively. But it seems to me that we have moved into an era where the hybrid power units are delivering power in a different way from what we are used to; where driver techniques have changed so that time is made up differently.

Toyota, with over 100,000 hybrid road car drivers in the UK alone, seemed to have the Test Day nailed. Whether Porsche and Audi will be able to learn and adapt by the time the tricolor waves on Saturday afternoon next week, remains to be seen.