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Written by Joe Le Corre

Wednesday saw the launch of the 2020 GT World Challenge Europe DLC for ACC and the implementation of version 1.6.0. This article will be solely focused on the technical changes to ACC, so if you’re expecting to see pretty pictures of Ferraris at Imola, this isn’t the right place. Instead, it will be full of graphs, diagrams, and technical language. Fun, right? I’ll try and keep it as simple as possible as I run through the changes that have been made in V1.6.0…

New Tyre Model And DHE Compound

ACC has one of the best tyre models out of the majority of sims, so instead of letting the other titles catch up a bit, they pushed the boat out even further with some very serious changes to the tyre model. A huge amount of research and data have been smashed together in order to portray the nuances of a Pirelli GT3 tyre in a more realistic manner.

Aris has gone to great lengths to explain what the changes in “tyre realignment forces” do and why it’s important for anyone that races in ACC. Essentially, the way in which the tyre regains its structure and grip once the limit of adhesion has been exceeded is more realistic and will provide the driver with more confidence to do massive skids. It’s not really meant to be used as a method of slithering a GT3 around world famous race tracks, but the changes in the realignment forces have made the car much kinder when the grip limit is exceeded, it would be rude not to do a few slides.

People that are Audi and Lamborghini fans will be lapping up these improvements since they make these cars in particular much more forgiving during slow speed direction changes, which were areas where the Audi and Italian Audi would struggle the most. 

It isn’t just those fancy realignment forces that have been given a makeover, the new tyre model also changes the relationship on the tyre pressure and rolling resistance. In the previous tyre model it was possible to run the tyre pressures really high, but with high downforce levels. The reasoning as to why a select few tried to do this is because they get the best of both worlds. They get the higher top speeds from the higher tyre pressures without the loss of grip, because they whack the wing and splitter angles to the max. From now on, this exploit will be completely useless, due to the change in how the tyre pressures influence the rolling resistance. When you first pull out of the pit lane and begin your first out lap with the new tyre model, you’ll notice that there is far less grip than before. That’s down to these changes in the tyre model.

As a part of the 2020 GTWCE, there is a new tyre compound for the 2020 season. Named DHE, this new tyre is a bit harder, but that doesn’t mean there’s any less grip. The stiffer side walls of the DHE tyre compared to the 2019 DHD2 tyres, provide more traction in the low speed corners and greatly improved stability at high speeds where the emphasis on tyre rigidity is massive. There is no change to the ideal pressure window, which remains at 27.3 to 27.9 psi. 

It is important to note that you do not need to buy the new DLC to get the DHE tyre model.

Improved Aero Model

It’s not just the tyre model that’s been given a workover. The aerodynamic model has been tweaked so that there is now an improvement in how yaw angles affect the efficiency of aerodynamic elements. Now I know I just said a lot of fancy words there, so I’ll break it down. Yaw is what happens when you drift, the angle is determined by how far the centre line of the car is off of the intended direction of travel. As you can imagine, a higher yaw angle will mean that the aero devices on the car won’t produce as much downforce (with some exceptions, I’ll get onto that later). Instead of being a linear drop off in downforce when you get a skid on, it’s now a progressive drop off (see diagram).

Image from Aristotelis Vasilakos (aka Aris) @ Kunos

When I said there were some exceptions into the downforce dropping off as the yaw angle increases, I wasn’t just trying to stir the pot. Think about the dive planes on the sides of the front bumper. When the car is traveling straight, these dive planes are sat at an angle, due to how the bumper is naturally shaped. However, when the car slides slightly, let’s say it slides to the right like it is in the diagram above, the dive plane that is on the right will actually be facing directly forwards, thus increasing its efficiency slightly. It’s not enough to make sliding the car around a quicker way of driving, but it does make it easier to catch the car at lower speeds. This isn’t what dive planes are actually for, but it is a happy side effect.

So there it is, a look at the new simulation orientated improvements to Assetto Corsa Competizione. I hope this wasn’t too difficult to follow, but if you do have any extra questions feel free to join the OTL Discord server and ping me a message (@Joe Le Corre).

Now get out there and enjoy the new tyres and aero in all their glory!