Skybh escribió: How do you measure acceleration? By guess (there is no cunter in Racer). 
I did a script for the track speedest2 that measures acceleration (0-100/0-400m/0-1000m braking and eleasticity) but i don't know if it will work for your racers.
If with real torque acceleration is not realistic, the problem is elsewhere, like masses (for the 508, the car were to heavy), or gears ratios (the wheel radius also influences that) or tyres too..
If elasticity is correct but not the top speed check masses and aero
The most important is elasticity than acceleration, because there is no normalized ways to measure that (at which rpm shifting for exemple, how to start...)
Also, for torque curve, it should start and finish a 0, so the first point is a 0Nm/0rpm, the last (in the torque you've showed 0Nm/5500rpm)
And last, if with all those parameters the car is too fast (elasticity, top speed etc) check the friction (i don't know since which version this setting is aviable) but it's in differentials.diff0.friction a value like 50-100 seems correct for me (and keep maxtorque at 1).
If not aviable, lower a bit maxtorque (the old method) to something between 0.9/1.0
I am doing this in the following way :
on speedest or another map , which has a bit of a long , straight line. I put the car at the beginning of this road , I push the clutch , give gas to the max . At the top I have a table with time. Gas I'm trying to let go about a full second example . 20.30 , a minute. then jade and changing gears . When the meter is 100 km / h push pause and read the result. Of course, I make several attempts , because they do not always work out . I try to change gears low or high , depending on the sample. I choose the best result , if it occurs several times. I Uncertainty + - 0.3s . in relation to the real acceleration . Therefore, in addition analog clock in the middle , I use digital clocks on the outside , because they are more accurate.