Just Dire Fuels

Just Dire Things ships an excellent pair of generators, the fluid-fed one for refined fuels and a solid-fuel one for tiered coal. They are also completely closed. Fluid fuels are locked to three internal types, FE values are baked into server config, and there is no public API for mods or modpacks to add a new fuel.

Just Dire Fuels works to extend that. Two new NeoForge data maps let any datapack add fuels, override existing rates, and the changes show up immediately in JEI.

What it adds

Fluid Generator T1 datapack-driven fuel acceptance

Stock JDT only accepts fluids implementing an internal RefinedFuel interface. Just Dire Fuels routes acceptance and FE-per-millibucket through the justdirefuels:fluid_fuels data map.

// data/<your-pack>/data_maps/fluid/fluid_fuels.json
{
  "values": {
    "minecraft:lava":  { "fe_per_mb": 100 },
    "yourmod:plasma":  { "fe_per_mb": 7500 }
  }
}

Both vanilla and modded fluids are valid targets. The generator's input slot, tank validator, and FE calculator all consult the same map.

Solid Generator T1 per-fuel FE/tick and burn-speed overrides

Burn time was already datapack-driven via NeoForge's furnace_fuels data map. What was not was FE per burn tick and the per-fuel burn-speed multiplier (those came from hardcoded item classes and a single global config knob).

The justdirefuels:item_fuels data map fixes that with two optional fields:

// data/<your-pack>/data_maps/item/item_fuels.json
{
  "values": {
    "minecraft:diamond":      { "fe_per_tick": 500, "burn_speed_multiplier": 8 },
    "justdirethings:coal_t2": { "burn_speed_multiplier": 6 }
  }
}

Field	If omitted
`fe_per_tick`	Falls back to JDT's `generator_t1_fe_per_fuel_tick` config (15).
`burn_speed_multiplier`	Falls back to JDT's per-item value (1 for items not specially handled by JDT).

Note: a new solid fuel item also needs a burn_time in NeoForge's furnace_fuels data map. The two are independent on purpose.

JEI integration

A new "Fluid Generator Fuels" category lists every fluid currently registered in the data map with its FE/mB rate. The Fluid Generator T1 block is the recipe catalyst, so right-clicking it in JEI takes you straight to the fuel list.

Defaults

The addon ships data map entries that exactly mirror JDT 1.5.7's stock config values (T2 = 450 FE/mB, T3 = 1300, T4 = 4000; Coal T1–T4 burn-speed multipliers 2/4/8/16).

Install it on its own and nothing changes it only kicks in when a datapack adds or overrides entries.

Sample datapack

The GitHub repo ships a working demo datapack at examples/justdirefuels_demo/ that does three things at once:

Makes vanilla lava a fluid fuel at 100 FE/mB.
Overrides JDT's T2 refined fuel from 450 to 999 FE/mB.
Makes vanilla diamond a (rather overpowered) solid fuel.

Drop it in <world>/datapacks/, /reload, and check JEI.

Requirements

Minecraft 1.21.1
NeoForge 21.1.209 or newer
Just Dire Things 1.5.7 or newer
JEI (optional; required only for the in-game fuel browser)

Compatibility

The addon does not replace or hide any JDT functionality. It mixes in additional checks in front of JDT's existing logic, so unaffected behavior is identical to stock. Any modpack already using JDT can install Just Dire Fuels without breaking saves, configs, or recipes.

Thanks

Direwolf20 for a great mod
Dinnerbeef for the addon mod idea