Tuesday 31 March 2015

The Prologue - FIA WEC test days at Paul Ricard

Although I wasn’t at Le Castellet for the FIA WEC’s “Prologue”, I did try to track the lap times – and thanks to the ever-helpful David Escribano at Al Kamel Systems, I do have a lot of data about what went on.

I must admit my primary concern was to follow the progress in the LMP1 class – and progress is certainly the operative word: some of the lap times, particularly from the Porsche 919 Hybrids, were quite astonishing. Of course Porsche set the fastest time at the Prologue last year as well, but Brendon Hartley’s time from last year was 4.069s slower than this year’s best time, set by Neel Jani – coincidentally in the equivalent session on the Friday evening. That’s an improvement of more than 4% - which would mean knocking around eight seconds off the lap time around Le Mans.

Surprising perhaps, but nothing new: John Surtees qualified his Ferrari eight seconds quicker in 1964 than Pedro Rodriguez’s pole position time (also in a Ferrari) the year before. And Phil Hill then went a further eight seconds quicker in his Ford Mark II twelve months later. More recently, Peugeot managed to find an eight second improvement between 2007 and 2008: Stéphane Sarrazin setting the lap times in both cases.

So, even if some eyebrows were raised, the improvement is not so staggering as it may appear at first sight; development in motor racing never stands still.

Don’t forget that Porsche is also now running in the 8MJ hybrid class – a 33% increase on the 6MJ that it ran last year. Similarly, Audi has stepped up to the 4MJ class from running with 2MJ in 2014 (according to some, less than it had in 2013). And the Joest Racing team must have also been pleased with a 3% improvement in their lap times compared to last year’s Prologue.

By contrast, Toyota has remained in the same 6MJ category as it ran last year, yet still was able to show a 2.407s improvement on last year’s best time.

However, I worry about reading too much into any of these lap times, because to the best of my knowledge, there was no control over the amount of fuel being used throughout the test. I have been told on good authority that there was no control during last year’s Prologue either, so at least we are comparing ‘like-with-like’.

Readers are probably aware that the regulations limit the fuel consumed by LMP1 cars in two ways: firstly an instantaneous kg/h rate, and secondly based on the MJ content of the fuel used during a lap. The 2MJ, 4MJ, 6MJ and 8MJ categories refer to the amount of energy that may be released from the hybrid systems per lap of Le Mans. For other circuits, the limit is a percentage, based on the circuit length, but multiplied by a factor of 1.55. This means that you can deploy more energy per kilometre (provided you can harvest that much) at other circuits.

Similarly, the amount of fuel allowed per lap is also limited, but with a multiplication factor for circuits other than Le Mans of 1.11. For Paul Ricard, this means that Porsche must be able to manage a minimum of 31 laps on a tank of fuel and that Toyota and Audi each must be able to do 30 laps.

Let’s look at the long stints then:
No. Car Driver Laps When Lap time
7 Audi Tréluyer 30 Friday afternoon 1m 40.849s
17 Porsche Bernhard 31 Friday afternoon 1m 41.621s
18 Porsche Lieb 30 Saturday morning 1m 41.731s
1 Toyota Nakajima 29 Saturday afternoon 1m 42.724s
7 Audi Fässler 30 Saturday afternoon 1m 41.364s
8 Audi Di Grassi 30 Saturday afternoon 1m 41.188s
17 Porsche Hartley 31 Saturday afternoon 1m 41.548s

The average lap times shown are calculated as the ‘sanitised’ average: in other words, ignoring the out lap, the in lap and in the case of Nakajima and Fässler, laps under yellow flag conditions. Note also that both Lieb and Nakajima are one lap short of their minimum - but I include them as I believe these stints were intended to be race pace simulations.

If - and it is a big ‘if’ - the Porsches were over-using their fuel on their fast laps and if the times shown above are true reflections of race pace, then it is possible that the Audis might be quicker than the Porsches over a whole stint when we get into serious racing starting at Silverstone in two weeks’ time. But they would have one less lap per stint - at least at the shorter circuits like Paul Ricard and Silverstone. And according to my calculations, at Le Mans, the Audis will be stuck on 13 laps (as they were last year), whereas both Toyota and Porsche should be able to manage 14.

Then there’s the tyres. Never has so much energy been put through the tyres of LMP1 cars, so more frequent tyre changes must be likely. But part of Audi’s strategy in 2014, choosing the lower hybrid class, was to reduce tyre wear. Even though Audi has gone up a class, its cars are still likely to be less hard on their tyres than those from Toyota and Porsche. Not to mention Nissan. With less rubber in total on the road, tyre wear is surely going to be an issue for the front wheel drive car. As it will not make its debut until Le Mans, I think it can probably be discounted from this year’s 24 hour race. Next year, though - who knows?

So what conclusions to draw from The Prologue? How much do the lap times over 17 hours of testing tell us? Is there more speed to come before Silverstone? Or are some of the lap times flattering, only to deceive? And where does Toyota fit into all this - were they not pushing as hard at the test? If not, why not? Or has Toyota under-estimated the progress made by Audi and Porsche?

Many of these questions will be answered at Silverstone. Without doubt, speeds have increased. With the revised qualifying procedure, expect pole position to be a low 1m 39s. If the weather is good and there are no caution periods, 1200kms could be completed in six hours. We might also get an indication of whether the boardrooms of Stuttgart, Ingolstadt and Tokyo think that the World Endurance Championship is more important to win than Le Mans, or not!

As always, your thoughts, comments, criticisms are welcome below.

Friday 27 March 2015

Sebring 12 hours - the anatomy of victory

The 63rd Annual Mobil 1 Twelve Hours of Sebring Fueled by “Fresh from Florida” provided a perfect opportunity for the Action Express Racing Team Coyote Corvette DP to demonstrate its superiority over the rest of the 43 car field in the classic race around the runways and service roads of the historic airfield circuit last weekend. It must have been a particularly satisfying win for Bob Johnson and his team, following their failure to capitalise on a similar performance advantage at the opening round of the Tudor United SportsCar Championship at Daytona at the end of January, when Chip Ganassi used a well-timed full course caution period to snatch victory for his more economical turbo Ford-powered Riley from the GM-branded car.

The second of the traditional Floridian enduros ran with just 28 laps behind the Safety Car - out of a total of 340 completed - which left more than ten hours for some proper racing, including one green flag period of 3h 47m 59s. And it was this long green period that enabled the Action Express car, ably piloted by João Barbosa, Sébastien Bourdais and Christian Fittipaldi, to establish a lap’s advantage on the rest of the field and allowed the team to run the final two hours to the flag without any real concerns.

No race of this length is ever easy, but once the fragility of the LMP2 challengers proved their undoing, there never seemed much doubt that the Mustang Sampling sponsored car would come out on top of the Corvette DPs. If the relatively smooth surface of Daytona was too much for the Le Mans-rules cars, what hope did they have over the bumps of Sebring?

So how was it done?

Well, in the first place, it was a fault-free run. The car completed the race with just fourteen pit stops, the longest of which was 1m 14.684s - and the Safety Car was out then in any case, nullifying any time lost in the pit lane: Fittipaldi resumed and simply latched on to the tail of the queue of cars. Every other stop for the car was less than 1m 04s. The length of the stints was dictated, to some extent, by the timing of the Full Course Yellow (FCY)periods, but during green periods, the car could run for 23 laps between refuelling stops.

The full list of pit stops looks like this:

Stop no. Activity Time in pit lane
1 Barbosa stays 1m 01.557s
2 Barbosa to Bourdais (FCY) 1m 01.295s
3 Bourdais stays (FCY) 0m 58.029s
4 Bourdais to Fittipaldi (FCY) 1m 14.684s
5 Fittipaldi stays 1m 03.265s
6 Fittipaldi to Barbosa 1m 01.899s
7 Barbosa stays (FCY) 0m 49.623s
8 Barbosa stays 1m 01.695s
9 Barbosa to Bourdais 1m 02.148s
10 Bourdais stays 1m 00.833s
11 Bourdais to Fittipaldi 1m 01.039s
12 Fittipaldi stays 1m 03.303s
13 Fittipaldi to Barbosa 1m 03.969s
14 Barbosa stays 1m 02.977s
Total 14m 26.316s

As usual, the time spent includes the time spent driving down the pit lane itself. Needless to say, the time spent in the pits by the Action Express car was less than any other prototype that finished the race. And of course, the actual time spent stationary is considerably less than the time spent in the pit lane.

Under IMSA rules, the time spent stationary consists mainly of getting fuel into the car, so the length of time in the pits depends largely on how much fuel is required, which is in turn dependent on the length of the previous stint. As the table above shows, Barbosa got the most time behind the wheel, as he managed to get three shifts to the two each for Bourdais and Fittipaldi. Here's the full breakdown of the driving periods:

Stint no. Driver Laps Time
1 Barbosa 22 42m 19.467s
2 Barbosa 27 1h 04m 21.575s
3 Bourdais 22 54m 00.786s
4 Bourdais 28 1h 02m 44.283s
5 Fittipaldi 25 52m 12.941s
6 Fittipaldi 22 42m 27.064s
7 Barbosa 12 25m 53.412s
8 Barbosa 25 53m 04.216s
9 Barbosa 22 42m 04.219s
10 Bourdais 23 43m 56.789s
11 Bourdais 22 42m 03.538s
12 Fittipaldi 23 44m 42.196s
13 Fittipaldi 26 58m 23.241s
14 Barbosa 18 34m 43.108s
15 Barbosa 23 44m 16.664s

The totals for each driver were:
Driver Total Laps Green Laps Time
Barbosa 149 137 5h 06m42.651s
Bourdais 117 84 3h 22m 45.396s
Fittipaldi 118 90 3h 17m 45.442s

Endurance is always a team effort, and it is important that the drivers work well together; but I am always interested in comparing the lap times of the drivers of a car, to see if there is any evidence of a weak (or sometimes a particularly strong) member of the team: after all, many of the driver's excuses can be ignored if one is able to drive the same car more quickly in the same conditions than the others...

Having said that, team managers may give specific instructions to their driver: setting a target lap time, for example, to which some drivers may be more obedient than others. The tables above give you practically all the information you need to work out average lap times for each stint, for each driver, for yourselves, but to save you the trouble of that, I’ve laid it out on a stint by stint basis in the table below.

Stint no. Driver Stint Average Lap Green Lap Average
1 Barbosa 1m 55.430s 1m 55.246s
2 Barbosa 2m 23.021s 1m 54.803s
3 Bourdais 2m 27.308s 1m 54.852s
4 Bourdais 2m 14.439s 1m 54.951s
5 Fittipaldi 2m 05.318s 1m 55.699s
6 Fittipaldi 1m 55.776s 1m 55.810s
7 Barbosa 2m 09.451s 1m 55.128s
8 Barbosa 2m 07.369s 1m 55.505s
9 Barbosa 1m 54.737s 1m 54.634s
10 Bourdais 1m 54.643s 1m 54.560s
11 Bourdais 1m 54.706s 1m 54.751s
12 Fittipaldi 1m 56.617s 1m 56.528s
13 Fittipaldi 2m 14.740s 1m 55.848s
14 Barbosa 1m 55.728s 1m 55.471s
15 Barbosa 1m 55.507s 1m 55.396s

The column showing the Green Average lap is the average lap time for the green laps in the stint: ignoring laps into and out of the pits.

Consider this: Fittipaldi drove 90 green flag laps. On average, as can be seen above, his laps were a second slower than those of his team-mates. In that case, the car could have been a further minute and a half ahead: nearly a lap!

Perhaps that is speculation a little too far. But how did engineer Iain Watt and Crew Chief Bill Kueller get their car to be so much quicker?

The answer, if one looks at the sector times (Sebring is split into 10 sectors by the IMSA timekeeping team), lies in the fact that in only two of Sebring’s sectors was the #5 car quickest. It was not fastest through either of the two speed traps. And yet, of the three Corvette DPs around at the end of the race, it had easily the fastest average lap time. It may not have been as fleet of foot as the Ligiers, but nevertheless it strikes me that the team was quickest by virtue of the optimum compromise. And if that meant that the car wasn’t quite to Fittipaldi’s taste, it was certainly better than anything else at Sebring.