[Sami Aaltonen]

Originally Posted by GTR LVR

To be clear on the engines, the standard road car, LM, and 1995 & 1996 GTR all share the same basic engine, although the GTR spec is officially designated S70/3, whereas the standard car and LM are S70/2. Aside from the designation, the main difference between each lies in the mapping. Both the LM and GTR have different and less restrictive exhausts than the road car (the GTR is straight thru while the LM has small cats). The GTR map must accommodate 39.4-mm air restrictors, but despite the S70/3 is still able to produce 636 bhp (9 more than the standard road car). The LM's 680 bhp results from the shedding of the restrictors and remapped accordingly. To reiterate, there is no major mechanical difference between the engine types other than exhaust - in fact a standard road car can be re-mapped to LM spec and as mentioned elsewhere, apparently has been done on a few occasions.

The 1997 GTR engine is of a smaller displacement (reduced to 6.0-ltr from 6.1 to meet FIA rules). Again, thru revised mapping, the engine is able to make up most of the lost power thru smaller displacement. There are also several mechanical modifications (sump pump location is lowered, etc.).

As for on-road performance, it would seem the best performance would come from the lowest power to weight ratio. In that, an unrestricted GTR (of any year) with an remapped engine would be the best of the bunch, as they're all lighter than a LM. As a LM is effectively an unrestricted GTR engine, by reverse deduction an unrestricted GTR probably makes ~680 bhp, and is at least 50-kilos lighter than a LM. Most GTR's also have shorter gear clusters than a LM, so although it's probably an academic performance issue, an unrestricted GTR would provide the most performance (not to mention, unique and often significant race history - something no LM or road car can claim).

Thank.You.Very.Much. for these fact informations. Really interesting and really needed information! Thanks!!!!!!