How to improve frame rate
There are a few things you can do to improve the frame rate without sacrificing the details. First, look at the estimate frame rate the game make and set the actual 
frame rate about 2 or 3 fps slower. This will ensure that the processor occupancy will be below 100% at most of the tracks. If this doesn't improve things much, 
I am afraid you have to turn some details off. 

In my own experience, the best details to turn off are the hill and bank in the mirror first. Then in the foreground. This should improve things a fair bit. Any more decrease in 
details and you may as well run the game in VGA with full details. Oh, by the way, NEVER have the sky texture on anywhere. This will only make your P166 runs like a 386. 

Now use the trackside detail switch to adjust the CPU occupancy. The idea here is to keep the CPU occupancy below 100% most of the time when you are on the track. I have mine in low detail most of the time as I bought the game for racing cars not looking at nice scenery:) 

Well, that's it really.

Y. F. Hung