Race simulator for club racers

[Erich Stahler]

RobM77 said:

Erich makes a very valid point above: a simulation is only as good as the data that is fed in. It’s perfectly possible these days (and has been for some years) that a simulation running on a high spec home PC can run actual chassis data; for example as Erich says, modelling wishbone movement, having an accurate tyre model interpolated from a high number of data points gleaned in real life, having an accurate aero model proportional to ride height, air pressure, angle of incidence static and dynamic etc, and obviously modelling roll centres, centre of gravity, polar moments etc. A good modern sim will model all these things, unless it’s permissible to simplify (for example there’s no need to model how an engine works if you have the power and torque curves and response data). When something is very complex to model, such as a tyre or aero, the sim won’t do the calculations from scratch (imagine doing the CFD for aero in real time!!), it’ll simply have data tables from a real tyre’s response that it will then interpolate from. For simpler things, such as the movement of suspension, it would normally calculate them (e.g. motion ratio).

I’m afraid I can’t offer the insight on accuracy in real life that BertBert has done, because the car I was driving at Pro-Sim is a new one that I’ve only recently bought in real life and I was there to prepare for driving it for the first time. I had no reason to doubt the accuracy of the car I’ve been driving there though, as Adrian spent quite a few years racing the same car, so I trust his judgement. Funnily enough Bert I did wonder if the steering was too slow for my car, as I couldn’t get full lock without moving my hands, which I’ve never known in a single seater. Steering ratio though isn’t really an aspect of chassis and physics realism to be honest, it’s an easy tweak in any sim.

So to answer Erich’s question, yes, it’s very possible to map setups direct to the car if the car model is accurate enough. Modern sims are quite capable of running to that degree of accuracy, even at home. This is actually what F1 teams have been doing last week in Barcelona: they’re verifying and validating their simulation figures with real life. A modern F1 team will do most of their setup work virtually, not in reality, because of the tight testing restrictions in F1, and then it’s just a case of checking them with reality. It’s something I used to do as a physicist when I worked in simulation (not of cars though sadly, but I was modelling things we couldn’t test in real life all the time!).

As BertBert says above, it’s also possible to try general trends out on a sim and see what effect they have on that type of car, so you may not be talking exact numbers, but you can at least try setup techniques, and this is less dependent on the car model being 100% accurate.

With regard to BertBert spinning a lot, don’t worry Bert this is perfectly normal, because obviously in a sim you can’t feel the car underneath you. With time, most people find they can learn to drive from other senses and as Adrian said earlier, this can surely only make you a better driver. This brings us back to data accuracy. As Tristan said on page 1, the home PC simulation Assetto Corsa feels very natural, and I suspect this might be because they’ve tweaked their tyre model slightly away from reality to make up for the fact you can’t feel the car underneath you. Where AC scores is that their tyre model *also* feels the most realistic I’ve tried for an ‘out of the box’ home sim. As Adrian has stated on this thread, his tyre model at Pro-Sim is based faithfully on real tyre data, so it satisfies Erich’s concerns of realism completely, but of course without being able to feel the car under you, something with slicks and wings like Bert’s Radical is going to be very hard to drive with a pure tyre model because the optimum slip window is so small in such a car. If you can live with the odd spin though, you get good realism in return. I think I spun Adrian’s car about once every 15 minutes or so, compared to real life’s four or five spins in fifteen years, but again, I’d rather have the realism. Bert you’d probably find if you tried something with a visually obvious optimum slip angle, like an old 60s racer on a dusty track, you would spin far less for this reason. At home on AC I tend to prefer driving those cars for that very reason (preferably in the wet!), but in real life I prefer the fingertip subtlety of slicks and wings.

Edited by RobM77 on Wednesday 2nd March 14:39

Thanks for that very enlightening reply RobM77, so sounds like it could indeed be a very useful tool if one provides it with the right data.

[RobM77]

Erich Stahler said:

Thanks for that very enlightening reply RobM77, so sounds like it could indeed be a very useful tool if one provides it with the right data.

No problem. That does involve an element of trust though, as the details of the car are normally hidden from the user. But yes, it's certainly possible to accurately work on setups in a sim and it what F1 teams do all the time.