Cars – Enabling extended physics - ac-custom-shaders-patch/acc-extension-config GitHub Wiki

To make sure everybody is racing in the same conditions, to use any features of extended car physics, you need to enable extended physics first. For that, open car.ini, find [HEADER] section and add extended- to VERSION value as prefix, like so:

[HEADER]
VERSION=extended-2

For version locking (1.74+ only)

[HEADER]
VERSION=extendedV2-1 ;still can have 1 or 2 at the end

[_EXTENSION]
REQUIRED_VERSION=2142 ;this is using the 1.79 version code as an example. Can be found easily in CM->Settings->CSP->About, titled "Shaders Patch version ID"

The idea is that original AC, if it would encounter that VERSION value, would crash (because it can’t parse this value as integer). Custom Shaders Patch, on the other hand, would catch this value, stop AC from crashing and mark loading car as a car which can use extended physics.