Sim racing prep before a real track day - waste of time or genuinely useful?

I always lean towards doing the minimal sim time just to nail the geometry, but absolutely nothing beats putting the car on the track, especally if the circuit has wierd camber or elevation changes. My last big unfamiliar race was at Speichert on a weekend where it threatened rain, and I spent maybe an hour in Assetto Corsa just to map out the esses. That was enought to feel comfortable with the basic racing lines. But the first full session is always a shock.

When I got in the actual car, the weight transfer felt nothing like the digital representation. The sim makes the suspension movement look clean, but in real life, when you push through a turn, the chassis just breathes differently, especially on those old curbing sections. You quickly realize the sim can tell you where to put the brakes, but it cannot tell you how the tire heat affects your grip on a specific patch of track.

For me, the middle ground is starting with just a few focused sessions on the track, rather than just hitting the pedals in the sim for hours. You need to feel the physical feedback from the steering wheel and the suspension reaction to the track surface. That tactile understanding is what eventually translates into better lap times when the conditions shift, wether it's the kerbs or the wet patches.

I found that focusing on overall lap time in a simulation is usally a dead end. When I tested the circuit at Fuji a couple of seasons ago, spending ten hours simulating the full lap did nothing for my actual performance. What worked better was breaking the track down into sections and running specific scenarios in the sim til the theoretical car data aligned with what I expected to feel on track. For example, I spent a full hour in the sim just focusing on braking into Turn 11 becuase the real-world grip decay was so inconsistent that I needed a model that reflected that degradation. The sim should be a diagnostic tool, not a rehearsal for the entire outing.

I would recommed using the sim for about three to four focused bursts to understand the physics of the weird parts, like a tight hairpin or a massive change in camber. Once you feel confident about the transition physics in those specific spots, then the track time is simply about dialing in the car's setup in those real-world conditions. That way, your physical sessions aren't wasting time on things the virtual physics alredy proved.

It felt like the biggest jump in speed came when I stopped trying to learn the whole thing virtually and just started trusting the data from those concentrated sim runs.

The one thing I found sims surprisingly good for was practicing mistakes. I'd spin it at the tricky corner on purpose, save the replay, figure out what went wrong, then run it again. Costs nothing, and you can't do that in a test day without chewing through tires and track time. Only caveat is you've gotta force yourself to reset properly after a crash in the sim. I got lazy about it and started carrying bad habits into the real car, braking way too late into one corner because the virtual consequence was just a reset button. Anyone else use it for that stuff, or is that just me being weird?

I instruct at around fifteen track days a season and the guys who show up fast at unfamiliar circuits all do the same thing before they even touch a sim or a test session: they walk the place. You can do a full lap on foot in under an hour at most tracks and you notice things no screen shows you, like how much the surface drops away on exit or where the marshal posts sit. Pair that with onboard video played at real speed rather than the usual 2x skim and you turn up knowing the place before your first flying lap. Cheaper than sim gear too, assuming you can handle the walking.

As someone who's never raced anything but is reading this whole thread with envy, the walking the track bit makes weird sense to me. I did that once at a local kart place, just wandered around on foot while my mate queued up, and suddenly the corner that kept catching me out made total sense because I could see the dip you couldn't see from the seat.

Question though, when you guys talk about doing focused sessions instead of long ones, how short are we talking? Like a few laps then sit and think, or half a day?

Not sure I buy the bit about needing to feel the suspension to learn a track though. When I did my one and only race at a circuit up north, I'd never driven the place and my rig at home was basically a wheel clamped to a desk with no motion at all. Still turned up knowing every braking marker and which corners fed into each other, and that was most of the battle. The feel of the car catches up in a couple of sessions anyway, but walking into turn one with no idea what's over the crest is what acutally costs you laps. The sim isn't trying to be the real car, it's a map you can drill into your head.