I've just done a wee experiment with Gran Turismo 6, the talk of weight got me thinking. I'm very consistent with this game, been playing the GT series religiously since it started, I picked a new 'performance' hatchback and drove on a track I know like the back of my ****. I set a benchmark with it completely standard, then changed one variable at a time; Weight, power, suspension and tyres. I know that this is in no way a real-world test, but it's a very good simulation and pretty interesting to me all the same.
Car is a 2010 VW Golf VI R, brand new and a car I have never driven in this game. Track is Laguna Seca. All times are averaged over first four laps of each set up.
Standard car
1.49.5
-306 kg
1.46.5
+154 bhp
1.46.2
Racing suspension
1.46.7
Sports soft tyres
1.38.5
The standard car was a bit of a pig to drive, exactly why I chose it to be honest, it didn't disappoint. The weight reduction was a significant improvement in every aspect. I had to fully tune the engine, intake and exhaust to 406bhp to match the lightweight time, and the car became utterly hateful to drive. The racing suspension was tuned to what I though was 'about right' for a fwd car of that weight and power, it handled significantly better than either previous set ups. I was blown away at how much difference the good tyres made (roughly comparable to AD08R or similar), car still handled like a people carrier though.
The race suspension was by far the easiest to drive quickly, the soft tyres were highly comical on OEM suspension and the high power was horrendous. Overall, the weight was the biggest improvement.