Since the release of the 1.0RC version of AC, sounds of modded cars don't work anymore. This is because AC now uses fmod sound engine. While this is a very good news from a quality point of view, it's a 'bit less exciting when it comes to modded cars, as there's is yet no official documentation about how to update/adapt to the new platform. Until Kunos will find the time to write some documentation, AC member @Stereo(<thank you) found a way to make (some?) sounds work with the new engine. Feel free to give it a try, if you especially like a modded car for which there is no sound yet. By @Stereo: "I got Abarth 500 sounds working on mod cars, goes like this: 1) copy .bank from working car, rename it to match car folder. eg. I copied abarth_500.bank to reliant_robin.bank. 2) add a section to sounds.ini of where the engine is [ENGINE] POSITION=front ; or rear I suppose. 3) open content/sfx/GUIDs.txt, find the event section of the car you're copying from, change it to match your own car's folder name. For example in the test I copied from abarth_500 and changed to reliant_robin: {0cfb15eb-581b-49e3-a190-6248d359d460} event:/cars/reliant_robin/backfire_ext {c02355e0-9e60-4a48-b985-7e4b9c20fca1} event:/cars/reliant_robin/backfire_int {2b7953dc-e66d-4712-800a-34a2b50ea14e} event:/cars/reliant_robin/bodywork {1d81aee1-d93e-4302-bfac-d102ddebb664} event:/cars/reliant_robin/door {1d467f20-0702-4ca4-ac3d-e4d938bd6b77} event:/cars/reliant_robin/engine_ext {b0d135df-9655-4da1-8643-dee1afb4d3ac} event:/cars/reliant_robin/engine_int {a8a3efde-b054-4bc8-943c-b59926cf9c30} event:/cars/reliant_robin/gear_ext {a0d612af-ca76-4ab4-9de8-321538b9652b} event:/cars/reliant_robin/gear_grind {4a80f5ee-44d9-4cfa-b1aa-89d45aaae9dc} event:/cars/reliant_robin/gear_int {1643425c-c666-4a87-a2b1-c432ce6f2a49} event:/cars/reliant_robin/horn {582b0a26-cb46-4d47-a1ae-d605b87f80a8} event:/cars/reliant_robin/limiter {896d78a7-1f58-4409-8d4e-375963e712f1} event:/cars/reliant_robin/skid_ext {f1d3d869-e641-4ab3-bc72-5cb9928ec118} event:/cars/reliant_robin/skid_int {fc65915a-abdb-4b06-8232-b5e602e0e2cf} event:/cars/reliant_robin/tractioncontrol_ext {27ba5b22-3462-43ae-9cdf-62c42f421e6e} event:/cars/reliant_robin/tractioncontrol_int {794c76ef-eb23-48ba-8c40-db4e83048014} event:/cars/reliant_robin/turbo {46882e17-772b-4689-9069-c493459ba796} event:/cars/reliant_robin/wheel {8e8da34b-0156-4064-b6d4-aa9109f68baf} event:/cars/reliant_robin/wind Save this in your car's sfx folder (content/cars/reliant_robin/sfx) as GUIDs.txt. (note that there are other sections than the "event:/cars/" - I believe they're not necessary when copying from an existing car) Voila, working Abarth 500 sounds in the Reliant Robin." Hope this help, didn't yet had time to test it myself .
