More tests, another post, sorry. :P
http://www.youtube.com/watch?v=ETzi0XO6pu4
Quoted from youtube description: I've decided to compare 2 sims, LFS and iRacing, directly with a real life equivelent. While both sims each have their own different physics flaws, this test is focused on how to me, iRacing feels unrealistically out of control the minute the cars start to fishtail, especially in the formula Mazda.
The RL video is the best I could find, showing Alonso in 2006 throwing his car around at high speed (120+ mph I'd guess) in celebration upon winning in Japan.
The LFS footage is of me driving with a formula V8, running a setup with intake restriction to bring the power down to 260hp, similar to iRacing's formula Mazda's 240, with similar wing and suspension settings, and an open differential.
The iRacing video shows 2 replays, the first running with the advanced Laguna set, and the second with the basic Laguna set.
I tried to carry out the tests on areas where the track had no bumps or sudden elevations to influence the outcome.
You'll notice in the RL clip that Alonso is not worried about losing control of the car, and seems very comfortable throwing the car around violently. The car does not spear off the road into the gravel trap.
In the LFS replay, things look very similar. I'm able to throw the car around quite violently, and, so long as I'm paying attention, I can keep it out of the wall, although I came very close to losing it during one of the final slides, but it's not supposed to be easy.
Finally the iRacing footage shows that as soon the weight starts to transfer across, it happens with such violence and speed, that I am completely unable to save the car, on both occasions with each setup.
Surely if iRacing were completely accurate, Alonso wouldn't have dared to try throwing the car about at high speed for fear of killing 100 people?
I'm not sure what causes this problem in iRacing, whether its a tyre issue, or something else, who knows, but it's not right IMO.