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Originally Posted by MulsanneMike
Can't really say that these days. The RS Spyder has a 2900 mm (114+") wheelbase but is doing just fine in ALMS...Wheelbase now has a lot to do with the overhang regulations and has become a method by which the rear wing can be moved away from the airflow disruptions of the roll over/cockpit area. Though it also allows a maximising of the underfloor area because at a 2900 mm WB, adding the 1000 mm max from and 750 mm max rear gives you the max car length. It's my understanding that the RS is using the maximum front and rear overhangs.
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Not to go off topic, but there goes the theory that the Audi R10's wheelbase is causing its cornering problems against LMP2 car(thus, it's mostly weight). F1 cars back in the 80's had wheelbases of 107-110 inches-which is what most prototypes had until the last couple of years. On F1 cars, when active suspension and traction control was banned, wheelbase lengths massively increased. When active suspension/TC was banned at the end of the 1993 F1 season, most F1 cars had 110-113 in. wheelbases The 1994 Williams FW16 had a short wheelbase, and was almost uncontrolable in some circumstances until a long wheelbase version came out early-mid season.
But it does go to reason why the long wheelbases from an aero stand point. Under the old LMP rules you could run a long tail car, with the slight disadvantage of more polar weight(slightly more rearward weight bias due to the extra bodywork weight), but with the advantages of reduced drag, and more downforce(especially with the old rear wing endplates). Take the Audi R8 for example. It had an overall length of 4640mm, a front overhang(front edge of the front diffuser to front wheel centerline) of 900mm, and a rear overhang of 1010mm. And it had a wheelbase of 2740mm/107.9inches, the same as an Aston Martin DB9/DBR9. The Bentley Speed 8 took that concept further, with a shorter front overhang, and longer rear overhang, but almost the same wheelbase as the R8.
The Audi R10 probably has the maximum rear overhang of 750mm, and has about an 920mm front overhang(slightly longer than the R8), and thus the long wheelbase. And that also might through out the window the fact that the size and weight of the engine of the R10 is the main reason for the long wheelbase. When one considers that the R10's engine is believed to be about as long and heavy as the Ford 351 Windsor SVO based Panoz Elan 6L8 OHV V8 engine, but the 6L8 was used in normal wheebase(107-110in) mid-engined LMP cars in the past, it seems that Audi found something in the wind tunnel, and Porsche found the same with the RS Spyder, as did Dome.
This also seems to explain the size of the Peugeot 908, which is about as big as the R10.