- Added the CELECT PLUS engines and sounds
- Updated the ISX engine sounds to Kriechbaums latest (2.4)

Fixed a sound bug for the w900 engines.

Updated the Cummins ISX15 engine names to the X15 performance series engine names [ISX15 -> X15].

- Updated the Cummins ISX15 and Paccar MX-13 engines to their 2017 models.
- Reviewed all torque curves and adjusted just about every single one to be more smooth and realistic.

Note: If you are using the Engine Editor app to customize engines, then you will need to delete your AppData.db and download the 2.9.1 version to get these new changes to the default engines. You can then use the Import feature to re-import all of your custom engines/transmissions. Sorry for the inconvenience.

Fixed a bug in the 3406E engines, where there was no interior sound.

Added the Peterbilt 389 by SCS.

Gave the engines more low end torque (below 800 rpms). After some thorough testing is was evident that the engines had an extremely hard time getting up hills from a dead stop.

Updated for ATS version 1.4!

- Air horns have been fixed
- all sounds have been updated to Kriechbaums latest sound files.
- New ISX Engine Sounds

- Removed duplicate entries from the previous update.

- Fixed a bug that was causing the SCS CAT 600 from having sounds.
- Updated some documentation in some Def files.

NOTE: If you generated any engines using the ATS Engine Generator Tool, you will need to update that tool to 1.3.3, and re-create your custom engines (using the same identifiers), and then re-generate those Def files (and of course, merge again). Failure to do so will result in a crash when loading your save game.