It may have been somewhat premature to read too much into the pre-Le Mans test day earlier this week, but there was clarity in the struggles endued by the Japanese LMP1 contingent.

Whilst Toyota were hot favourites coming into last year's race, this year they appear to be bit-part players as the TS040 Hybrid struggles to make the huge strides comparable with the Porsche and Audi entries.

However, at least Toyota is just about in the hunt... Nissan's much anticipated public debut of the GT-R LM NISMO, by contrast, seemed to prompt more questions than answers.

A series of minor - but time sapping - reliability issues meant that none of the three cars completed a lot of laps and many of those that they did complete were done in the wet, leaving it not only 20secs off the ultimate pace, but adrift of most of the LMP2 contenders. Nissan may have said it wasn't courting headlines, but it was always going to be keenly watched.

Ironically, however, Nissan did produce one rather striking headline, particularly set against the context of its lap times - the car is seriously quick in a straight line!

At a circuit where top speed is usually king, the Nissan was crossing the speed traps at a remarkable 336kph officially, though many believe it was exceeding 340kph at its peak. Granted, the car that set the time did it very early on and clearly was not optimised at all, but I have been told that a much higher top speed is expected in qualifying when a different aerodynamic configuration is to be used.

Exciting stuff... but then how does this translate to a slow lap time? In short, the Nissan can corner, just not as quickly as the other LMP1 cars, or it seems the nimble LMP2s.

Indeed in the Ford Chicane the cars were about the slowest things out there in the first session, slower in fact than most of the GTE Am field, but that was improved a lot in the second session. Overall the GT-R LM corners like a LMP2 it seems. If the team find a way to improve that cornering performance then the GT-R LM could be pretty potent.

One big problem with the GT-R LM is its hybrid system, built by SIlverstone based company Torotrak. The 2MJ twin flywheel hybrid system is not what was originally intended to go into the car. A bigger 8MJ system has been envisaged but there were too many issues with it to get it working correctly, so a smaller design was adopted. There are many rumours of the system being taken out of the cars for the test at Le Mans, but I have seen some of the data and the flywheels were definitely in operation on the data I saw (which was from one of the few dry laps run in the morning session).

The reliability issues the car has suffered come as no shock to me at all. I look at the space under the front of the car and it is just so full of complicated things. The engine, the turbos, the front crash box, coolers, there is barely any space for the suspension and I cannot even see the gearbox. This looks to me to be the worst car I have ever seen in terms of serviceability, so I feel very sorry for the mechanics. There are just pipes and wires running everywhere.

This complexity is certainly going to hurt the Nissan team in a 24 hour race, where making quick fixes is crucial, but I think it probably hurt them really badly in the test too - they spent many hours fixing tiny things, because the car is too difficult to work on.

One fix that was a surprise was to the rear view mirrors on the car, they are mounted in neat little pods just on the insides of the fenders, and while the drivers have not been very happy with them the car also has rear view cameras. However, halfway through the test session at Le Mans the officials forced Nissan to change the design of the mirrors on all three cars before they could go back out on the track. The cars had been at the track for a week I do not understand why the French decided to make this demand in the middle of the test. It was very strange. The mirrors were moved about 5cm outwards, but it still took time to move them all properly.

In the end the Nissan's completed very few laps overall, and set a best lap time over 20 seconds off the LMP1 pace, but with the weather and the reliability problems this is not very indicative of performance overall.

I think Ben Bowlby will make a lot of improvements for the 2016 version of the car but the race at Le Mans this year will prove very difficult I think.

Max Yamabiko

Max Yamabiko will bring you a closer look at the technical side of F1 and motorsport in 2015, from the latest developments and solutions employed to keep you ahead of the game