Are there any other ways of increasing the FPS on an old system (PII or old PIII say), possibly by disabling the drawing of extraneous parts of the track, such as buildings, trees and other stuff which you don't strictly speaking need to race ?
Drastic I know, but what does it matter if you just want to race and need a little visual fluidity ?

On such a system, changing all the in-game settings to their minimum and turning off the cockpit draw barely gets me into double digit FPS figures a lot of the time.

Dev's ? Anything drastic I can do ?

PS I have a GForce2 GTS in this machine along with 640Meg of RAM. The CPU is the real limiting factor.

The game burns CPU to run the engine, it is also your bottle neck. You'd need to pretty much remove everything that makes LFS a sim to get it to work.

I got LFS S2 to work reasonably well on a 1GHz Athlon. Turned all the LOD sliders to minimum and drove with no other cars and no AI players. Even doing these steps, I seriously doubt you'll get playable framerates from anything much slower. You might have a chance if you play with an old S1 build.