Allan McNish and Oliver Jarvis prepare for what the British duo and their Audi team hope will be a successful Le Mans 24 Hours by participating in a one-day test on Sunday (9 Jun).Sixty-one cars have been invited to take part in the 2013 Le Mans 24 Hours test day, an important dress rehearsal for the race itself as it gives the entrants the only opportunity to run on the Le Mans circuit before the race on 22-23 June.Three optimised hybrid-diesel Audi R18 sportscars contest the test and this years race with Dumfries-born McNish sharing his car with Tom Kristensen (DK) and Loc Duval (F) while Jarvis, from Burwell near Newmarket, shares his car with Marc Gen (SP) and Lucas di Grassi (BR).McNish said: The Le Mans circuit is long and unique with changes of tarmac due to the fact that the majority is made up of public roads so the test day is critically important. We test our cars in a variety of conditions and try and simulate elements.Of course we test on other tracks but until we get to Le Mans with its long straights, the high and low speed nature of its various corners, there are questions to be answered although Audi has a lot of experience and understands what Le Mans is about.So we arrive with the data bank full but there is no substitute for taking our Audi onto the track, to get a feel and understanding of it prior to heading back there 10 days or so later."Each of the three Audi R18 e-tron quattro cars start the test day with a pre-determined plan involving aerodynamics, so we understand the feel of the car, and a tyre programme so that we get information for Michelin.The length of the Le Mans track doesnt make it an easy task either. To learn a track you need around 12 laps and that equates to an hour at Le Mans, so for three drivers per car thats three hours meaning thats the morning session done just for driver acclimatisation.So in effect there is only the afternoon to undertake the specified task set for our car meaning its a difficult and busy day. It is a heavy day for all cars, but it is a day that is absolutely necessary for us to be best prepared prior to going into the actual race.Weve seen from the opening two FIA World Endurance Championship races that our Audi is competitive but we will also be watching Toyota closely during the test day.Jarvis commented: The test day is extremely important. It will give me the opportunity to re-familiarise myself with the track since last June. In the case of Lucas [Di Grassi], who Im sharing the car with along with Marc [Gen], it will give him the chance to learn the circuit for the very first time.Throughout the day we will work closely with our engineers trying to gather as much data as possible ahead of the race. This information will prove extremely important, as there is very little practice time before official qualifying when we return for race week.Setting the fastest lap time on the test day is not vitally important. The two other Audi Sport Team Joest R18 sportscars and every other team will be focussed on working through a set programme on what they need to achieve to save time when we go back there for race week.Quite often outright lap times are not the key focus but the day should give us a good opportunity to directly compare our performance with our main rival Toyota.The remaining factory Audi sportscar is driven by 2011 & 12 Le Mans winners, Marcel Fssler (CH)/Andr Lotterer (D)/Benot Trluyer.