Engine Power, Gearing, and Heavy vehicles

The 6.2 liter traction engine has 335 hp, according to the json, and 6 gears optimized for moving heavy loads.

The in game APC, if you replace the standard 4.0 liter engine with a 6.2 traction engine, weighs about 8 tons and has a maximum speed of 73 mph (but a safe speed of only 47 mph).

The real world Stryker APC weighs 19 tons, has a 350 hp engine, and can “sustain speeds up to 60 mph on roads”.

There’s a couple of ways to read the Stryker’s performance, but the APC’s performance seems a little underwhelming.

How can I mod the traction engine’s gear values to let vehicles in the 8-12 ton range go faster? Are there any plans to create a new high horsepower diesel better suited for vehicles like the APC?

  1. Go here and download JSONedit http://tomeko.net/software/JSONedit/
  2. Open JSONEDIT and open this file (I believe, as of 5934): cddafolder\data\json\items\vehicle engine.json
  3. Have fun. Note that while gearing is important, adjusting the maximum rpm will allow engine to run faster without damage. If you want to get really technical look up the gear ratio sets in Eaton Fuller transmissions, or the heavy duty Allisons.

No, just no. Don’t edit the base file. Create a mod.

As for the values you want? tweaking the power will up that ‘safe’ speed, possibly allowing the use of higher gears that just weren’t available due to the vehicle weight.
Something else to consider is that the traction engine is, well, for traction. It has lower speed but more power, so you might want to adjust that, or simply work from the middle diesel engine instead of the traction one.

I know how to edit json files. I don’t know how the power and gearing values relate to each other.

I did a debug test of the standard APC and the traction engine (which has something like 3x the HP of the 4.0 L diesel) makes an APC go faster. It just doesn’t make it go faster enough. So I want to keep the HP of the traction engine, only with better gears I guess.

I suppose I can make a copy of the traction engine and funk around with the gearing from the gasoline v12 and see if that helps any.

It actually seems like this was mostly an oversight from the engine rebalance, and something that I suspect will get cleaned up along with the other issues that arose from it (lack of multiple engines, fuel efficiency, etc.). The problem here, I think, is that 4.0L is a reasonable size for a van engine but really isn’t reasonable for some of the vehicles that they are now put in - a school bus or APC, for example, will have a 6 or 7 liter engine and something like a semi might have a 14L engine, none of those geared toward the low-speed operation of the existing traction engine. I suspect once we get reasonably-sized and geared engines moving vehicles in the 10-15 ton range will become practical again.

I might even put together a pull request for that, if I have the time.

Do you have an idea what the json would look like for a hypothetical 8L diesel that generates 350-400 HP and is intended for fast movement of a 8-12 ton vehicle would look like? I’m comfortable with adding one in, I just don’t know what to add.

Specifically, gearing confuses me. Power, weight, and volume aren’t hard but gearing is weird.

“id”: “8l_diesel”,
“copy-from”: “v6_diesel”,
“type”: “ENGINE”,
“name”: “truck engine (8.0L)”,
“description”: “Insert Description Here.”,
“proportional”: {
“weight”: 2,
“volume”: 2,
“power”: 4,
“start_energy”: 2
There you go, 360000 power, same gearing as the non-traction diesel.

As it turns out, if I want to have both the traction engine and the new truck engine, I need to add entry like this to data/json/vehicleparts/combustion.json:
“id”: “diesel_engine_v8_fast”,
“copy-from”: “engine_combustion”,
“type”: “vehicle_part”,
“item”: “v8_diesel_fast”,
“fuel_type”: “diesel”,
“difficulty”: 4,
“durability”: 400,
“epower”: -400,
“damage_modifier”: 80,
“breaks_into”: [
{ “item”: “steel_lump”, “count”: [ 30, 40 ] },
{ “item”: “steel_chunk”, “count”: [ 30, 40 ] },
{ “item”: “scrap”, “count”: [ 30, 40 ] }

And now my 10 ton APC can travel at a reasonable 64 mph. So I can use it as an exploration vehicle again and the gasoline sedan for day trips and looting safe areas.