All that acceleration takes place when the car is moving > ~80km/h, which is fast enough that the driver can accelerate as possible. Unless I'm mis-remembering, the narrator in this video explains what I was talking about - I don't have my headphones so I can't check :-\

ya tiff needell is a bit confused in that video, drivers usually don't fully understand the physics behind their vehicles. there are a lot of factors at work in a start from still like that, the main point is stop tyres from slipping too much, but nothing that can be described as "exponential" acceleration.

It is easy to be fooled by the video because you can see he is in line with the motorbike for the first meters then he looks like he is accelerating away, actually , it's the opposite, it's the bike that ran out of acceleration.

I have lots of telemetry data from cars starting from zero speed and they dont look any different from the lap posted above.

Sorry I've been derailing the thread, I'm going to continue this in pm's since I'm interested

When I buy a car, I don't really care all that much about speed; most modern cars are capable of going faster than I ever need to drive (ie over 100mph)
I care a bit about acceleration, and with current fuel prices, a lot about economy. Another thing is insurance - particularly since I live in London and my insurance premium doubled after the riot last year - a disproportionately high insurance group can be a dealbreaker. Reliability, build quality, comfort and resale value are also things to consider.
Gadgets generally won't influence what to buy, but they may encourage me to spend more.

I'm interested about engines (and possible other components, but primarily engines) and their corelation to the car's "quality". I'm interested in two ascpects:
* how it works in reality
* how it can be simplified for the purpose of a game

I guess speed and fuel efficiency are the two primary stats.

Not really. Depends on market range. On consumer, fuel efficiency seems to be on top those days. Size (where can I park) and turning radius is important for city cars.
On the enthusiast range, fuel efficiency is a more limited concern. Max speed and torque curve are considered.
I hope nobody gets upset if I hotlink this image from Tesla Motors about torque curves for gasoline and electric engines.

OK, the reality is covered. So, now, how to turn it into a formula usable in a business sim game?

The car design would have 3 parameters (only strictly technical stuff, things like aestetic, brand, etc I can invent myself):
W - total weight of the car
HP - power of the engine
EQ - engine quality, an abstract collective set of other parameters of the engine that could affect fuel effeciency for example, basicly any property of the engine that is not HP

There would be formulas needed for:
max speed = ?
acceleration = ?
fuel efficiency = ?

Take a note that the fuel efficiency is tricky, because for what speed the fuel efficiency should be calculated for? If we use max speed then better engines (max speed) will be less fuel efficient, which is not playable nor realistic (since tye client can drive at lower speed).

It would be nice if these were resembling realistic models, but it is not a priority. The gameplay is a priority. Althrough, if the formulas were both quite realistic and playable it would be great