Allan McNish set an unrepresentative tenth fastest time in official trials for the 2008 Le Mans 24 Hours today (Sun 1 Jun) which was blighted with adverse weather.

1998 Le Mans winner McNish, 38, driving an Audi R10 TDI sportscar running on the next generation of biofuel for the first time, set a personal fastest time of 3mins 37.011 around the 8.47-mile circuit comprising of closed public roads with the Scotsman at the wheel. "It's the most difficult test day I have ever had at Le Mans because the weather was so inconsistent," reflected McNish.

"I don't think I did two laps where the track was in the same condition. It meant that tyre choice was tricky and it meant that any data we collected and information we learned and set-up was useless because we were just effectively going round and checking things more than any development aspect."

The Monaco-based Scotsman's co-drivers are the same as the past two years with regular Le Mans Series co-pilot Dindo Capello (I) joined by Tom Kristensen (Den).

Frank Biela (D), Emanuele Pirro (I) and Marco Werner (D), who have won the race in their similar diesel-powered Audi for the past two years, drive together once again and set the third fastest time (3:26.678) courtesy of Werner.

The third "factory" entered Audi R10 TDI handled by Lucas Luhr (D), Mike Rockenfeller (D) and Alexandre Premat (F) were fifth quickest (Premat, 3:28.359) after two, four-hour sessions staged in warm but showery conditions which caused plenty of on-track incidents. Indeed Marc Gene destroyed his Peugeot after crashing at the Esses, the Spaniard reported to have broken his toe in the impact.

Fastest time of the day went to the Peugeot of Pedro Lamy (3min 22.222secs) who exploited the brief, fully dry "window" around 1pm. Last year's pole-position time was a 3:26.344secs, 147.75mph (Stephane Sarrazin, Peugeot) with McNish claiming the fastest race lap (3:27.176, 147.16mph).

Allan added: "Hopefully the conditions are not going to be like this in a couple of weeks' time for the race because I think it will make it extremely treacherous for everybody – including the fans.

"In terms of performance when we were out on the circuit, especially in the damp and the wet, we were pretty quick. We didn't get a run on new tyres because of the numerous red flags and so when it was dry, for about 10 minutes, Dindo unfortunately was in the pit garage.

"Peugeot had a very, very fast run. There's just no question about it they have definitely laid their cards down. But with the big accident that [Marc] Gene had, that set them back but also it just tells us that they are right on the edge.  We have got to make sure that we keep pushing them to that edge."

Biomass to Liquids (BTL) has now been blended into the Shell V-Power Diesel race fuel that Audi has used to win the annual French endurance race for the past two years (2006 & '07).

The twice around the clock race on 14-15 June marks the first time a second-generation biofuel has been used in the Le Mans race. Shell V-Power Diesel also includes synthetic GTL (Gas to Liquids) Fuel made by Shell from natural gas, which provides very clean and efficient combustion.