First off, thanks to everyone who tested and gave feedback on the changes in 350+351. One of our better weeks for constructive feedback, IMO. Combined with Nic's results, we've got another round of changes going in for this Friday's build which I think move us even closer to getting the cars dialed in for STM.
This week's changes:
BMW Z4 GT3: 'Softened' up the tires so there is a wider slip peak. As many picked up on, it was just too harsh in 350+351, resulting in snappy handling and the general feeling of understeer. The car feels much freer now and very grippy powering out of corners while not actually having any grip added. Default setup has been changed to fit the more neutral handling balance.
Asano X4: Same tire softening as the Z4, plus a bit of grip added. Added a marginal amount of downforce - to the point the Lift-Drag ratio is right on the border of believability - and it was apparent that they must be using some very sticky tires to get the laptimes we see. And that makes sense given that they change tires every 15 laps or so. FWIW, that 3.5G number is bogus. Maybe as a peak value they saw on telemetry for a split second somewhere, sure. On the new setup I've been seeing quick spikes to 2.75G at Badenring and times are back down to the correct range.
Caterham Classic: Small setup changes to help with the oversteer many commented on. Mainly taking it back to the settings you get from the factory: no RARB and open differential. Big fun.
Gumpert apollo S: Small setup changes, roll bars primarily. Treating it more like a race car and putting a fairly stiff front bar on got rid of the wobbly handling and oversteer we had in 350+351. FFB feels funny on this car; not sure why yet.
Ariel Atoms (all): These ones were a real bitch. With no roll bars to tune, I spent a lot of time tweaking roll center heights front and rear to help counter the roll oversteer issues. After reading a lot on atomclub.com, it seems that roll oversteer is the main handling issue owners discuss. This car should have a lot of it, with its 60% rear weight, no roll bars and poorly sized tires; we obviously had too much. Double checked all of the numbers we put in, matching to real values where possible to see what helped. 40N/mm front, 60N/mm rear springs are a very common setup and it works well on our car too. Also resorted to a bit of cheating. We've modeled the car with 205/225 tires front/rear, but it works a ton better with the optional 245s on the rear. Many owners go wider to 275, or even 295!, to better match the weight distribution of the car. All in all, the car is much better now and can be pretty fun at moderate-high speed. It's still very difficult to drive at the limit, but that just appears to be how Atoms drive, and at least it doesn't spin at the slightest hint of steering input. Act quickly enough and you can catch most slides. Do NOT lift off or brake mid corner! The 500 is a beast. Handles no better than the 300, really, but gets from corner to corner soooo quickly. Managed 7:33 on a decent, but not clean, lap at Eifelwald.
As usual, new profile and/or setups are required. A lot of the setup ranges changed on these cars, so your old stuff won't work at all.
