in lemans the turbo GT cars can be up to 4l, the NA cars can be up to 8l, ive no idea what the rules governing diesel NA or turbo cars are tho

There are different catagories of engines and capacity allowed.  A diesel Turbo is allowed up to 6600CC, the highest catagory iirc.  There is no restriction on the number of cylinders.

/Edit

http://www.lemans.org/accueil/ressources/pdf/2005_12_13_audi/R10_Booklet_gb.pdf

http://www.lemans.org/sport/sport/reglements/ressources/auto_2006/Regl_Particulier_2006_fr_gb.pdf

http://news.bbc.co.uk/sport1/hi/motorsport/5085664.stm

w00t.  

Job Done. :-)

http://news.bbc.co.uk/sport1/hi/motorsport/5085664.stm

"The only delay to affect their progress was a gearbox change after 11 hours, but the repairs took less than 10 minutes"

I wish I could do mine that fast !

modular

Finishing third after that sort of failure really is something, I think Audi really have done something in pushing diesel engines forwards

Audi are amazing at lemans, they won last year and the year before iirc
what position did bentley come this time?