Vehicle parts

Vehicles
Driving
Repairs
Installing and removing parts
Construction
Parts and components

Vehicles consist of parts, which can be damaged and, eventually, broken. Parts can be external, or internal (which are mounted inside the former). External parts are enclosed in [square brackets], internal parts in -dashes-.

Internal parts which are tagged as 'over' are a special case. They will be enclosed in (round brackets), override the color of the external part, and will function as armor — protecting other parts in this tile from damage (although not infallibly).

Vehicle tiles can be tagged as inside (marked as In) or outside (Out). Inside tiles protect from weather effects, while outside ones don't. To become an inside tile the tile must have a roof, and the adjacent tiles must have either roof or some impenetrable obstacle (like a closed door or windshield).

The mass, top and safe speed, acceleration, fuel consumption, noise and mobility of a vehicle is based on its composition. For example, safe speed is the speed at which engine can pull the mass without damaging the engine.

List of parts

A list of all the parts you can install in a vehicle, detailing their characteristics, the required components in order to install them and miscellaneous notes.

The Par column has different meanings depending on the type of part:

• power for engines (top speed) and solar panel (% of 1 fuel per turn, can be > 100)
• size for wheels (inches)
• capacity for fuel tanks and parts that allow storing cargo
• bonus for seatbelt (str) and muffler (%)
• energy consumption for parts that require power from the car battery to work

Steel frame, steel plating, as well as spiked plating and hard plating can be crafted with a welder by using lumps and chunks of steel.

		Name	Dm	Du	Par	Fuel	Req Comp	S	Flags	Note
#	*	seat	60	300	100	0	seat	1	over seat boardable no_reinforce cargo beltable	You need a seat and vehicle controls in the same tile to drive.
*	#	tracking device	10	20	-63	0	vehicle tracking device	3	track unmount_on_damage
#	*	saddle	20	80	0	0	saddle	1	seat boardable
#	*	foldable seat	10	20	0	0	sheet	3	seat boardable foldable	Cannot be unfolded, thus not usable as a driver seat
#	*	bed	60	95	200	0	seat	1	over bed no_reinforce cargo
┘┐┌└^ ┼│─=H	#	frame	100	400	0	0	steel frame	1	external mount_point mount_inner	13.61kg / 30.00lbs
h	#	foldable light frame	100	50	0	0	pipe	3	mountable foldable
┘┐┌└^ ┼│─=H	#	extra light frame	100	175	0	0	extra light frame	1	external mount_point mount_inner	5.05kg / 11.13lbs
┘┐┌└^ ┼│─=H	#	heavy duty frame	100	1200	0	0	heavy duty frame	1	external mount_point mount_inner	26.00kg / 57.32lbs
^	#	handle	100	100	0	0	pipe	1	external mount_point mount_inner	It's just a decorative and weak frame variant.
┘┐┌└^ ┼│─=H	#	wooden frame	100	200	0	0	wooden frame	1		7.00kg / 15.43lbs
^	#	wooden handle	100	150	0	0	wooden frame	1
┘┐┌└^ ┼│─=H	#	light wooden frame	100	100	0	0	light wooden frame	0		4.00kg / 8.82lbs
┘┐┌ └│─	#	board	100	240	0	0	sheet metal	1	external mount_point mount_inner opaque obstacle	Like a frame, but blocks movement and vision.
┘┐┌ └│─	#	heavy duty board	100	1000	0	0	steel plating	1	opaque obstacle
┘┐┌ └│─	#	wooden board	100	300	0	0	wooden armor kit	1	opaque obstacle
┘┐┌ └│─	#	quarterpanel	100	225	0	0	sheet metal	1	obstacle	Like a board, but doesn't block vision.
┘┐┌ └│─	#	extra light quarterpanel	100	100	0	0	pipe	1	obstacle	Like a board, but doesn't block vision.
┘┐┌ └│─	#	wooden quarterpanel	100	75	0	0	wooden armor kit	1	obstacle	Like a board, but doesn't block vision.
=H	#	aisle	100	400	0	0	sheet metal	1	internal over no_reinforce aisle boardable	You can move faster through these than other car parts.
=	#	floor trunk	100	400	350	0	sheet metal	1	internal over no_reinforce aisle boardable cargo covered	You can move faster through these than other car parts. Also provides storage like a trunk or box.
h	#	stow board	100	200	250	0	sheet metal	3	obstacle opaque cargo covered
#	#	cloth roof	100	15	0	0	sheet	1	roof foldable
#	#	roof	100	240	0	0	sheet metal	1	internal roof	Only provides protection from rain -acid and normal- when surrounded by other roofs, doors, boards or windshields
#	#	heavy duty roof	100	1000	0	0	steel plating	1	roof	Only provides protection from rain -acid and normal- when surrounded by other roofs, doors, boards or windshields
+	&	door	80	225	10	0	steel frame	2	external cargo obstacle openable boardable window	It also provides limited visibility, in the experimental build these can be fitted with curtains which can be closed from the inside.
+	&	opaque door	80	240	10	0	steel frame	2	external obstacle openable opaque	A door that blocks vision.
+	&	internal door	75	240	0	0	steel frame	2	external obstacle opaque openable roof boardable no_reinforce
+	&	hatch	80	120	150	0	steel frame	2	cargo obstacle openable multisquare boardable covered
+	&	heavy duty hatch	80	360	150	0	heavy duty frame	4	cargo obstacle openable multisquare boardable covered
"	0	windshield	70	50	0	0	sheet of glass	1	over obstacle window no_reinforce	A part that blocks movement but allows vision. Relatively fragile.
-	x	blade	250	200	0	0	blade	2	external unmount_on_damage sharp protrusion no_reinforce
|	x	blade	250	200	0	0	blade	2	external unmount_on_damage sharp protrusion no_reinforce
.	x	spike	300	250	0	0	spike	2	external unmount_on_damage sharp protrusion no_reinforce
0	x	wheel	50	200	9	0	wheel	4	external mount_over wheel mount_point variable_size
O	x	wide wheel	50	400	14	0	wide wheel	5	external mount_over wheel mount_point variable_size
O	x	armored wheel	50	800	20	0	armored wheel	6	wheel variable_size
B	E	roller drum	500	7500	60	0	large steel drum	7	obstacle wheel variable_size
|	x	unicycle wheel	50	40	2	0	bicycle wheel	2	wheel stable variable_size
|	x	wheelchair wheel	50	40	4	0	pair of wheelchair wheels	2	wheel stable variable_size foldable
|	x	bicycle wheel	50	40	2	0	bicycle wheel	1	external mount_over wheel mount_point variable_size
o	x	motorbike wheel	50	90	4	0	motorbike wheel	2	external mount_over wheel mount_point variable_size
o	x	small wheel	50	70	6	0	small wheel	2	external mount_over wheel mount_point variable_size
o	x	caster	50	70	6	0	set of casters	1	wheel stable variable_size foldable
|	x	wooden cart wheel	50	30	2	0	wooden cart wheel	2	wheel variable_size
|	x	banded wooden cart wheel	60	60	2	0	banded wooden cart wheel	2	wheel variable_size
*	#	1-cylinder engine	80	150	40	gasoline	1-cylinder engine	2	internal engine variable_size
*	#	V-twin engine	80	200	120	gasoline	V-twin engine	2	internal engine variable_size
*	#	Inline-4 engine	80	300	300	gasoline	Inline-4 engine	3	internal engine variable_size
*	#	V6 engine	80	400	800	gasoline	V6 engine	4	internal engine variable_size
*	#	V8 engine	80	400	800	gasoline	V8 engine	4	internal engine variable_size
*	#	V12 engine	80	600	?	gasoline	v12 engine	8	engine variable_size
*	#	electric motor	80	200	70	batteries	electric motor	3	internal engine
*	#	large electric motor	80	400	350	batteries	large electric motor	4	internal engine
*	#	small electric motor	80	120	15	batteries	small electric motor	1	engine
*	#	plasma engine	80	250	400	hydrogen	plasma engine	6	internal engine
*	#	foot pedals	50	50	60	muscle	foot crank	1	internal pedals engine foldable	An engine that doesn't require any fuel source.
*	#	hand rims	50	50	50	muscle	set of hand rims	1	hand rims engine foldable	An engine that doesn't require any fuel source.
O	#	gasoline tank (small)	80	100	6000	gasoline	small metal tank	1	fuel_tank
O	#	gasoline tank	80	150	30000	gasoline	metal tank	1	internal fuel_tank
O	#	gasoline tank (little)	80	75	650	gasoline	little metal tank	1	fuel_tank
O	#	externally mounted gas tank	80	160	110000	gasoline	55 gallon drum	1	unmount_on_damage fuel_tank protrusion
O	#	small storage battery	80	200	1000	batteries	small storage battery	1	fuel_tank
O	#	storage battery	80	300	100000	batteries	storage battery	2	internal fuel_tank
O	#	minireactor	80	580	10000	plutonium	minireactor	7	internal fuel_tank	Provides electricity for electric engines.
O	#	hydrogene tank	80	150	3000	hydrogen	metal tank	1	internal fuel_tank
O	#	water tank	80	150	400	water	metal tank	1	internal fuel_tank	Allows the storage of water for use by a kitchen unit
H	#	minifridge	80	100	300	0	minifridge	3	cargo obstacle fridge covered	Drain battery while on, can be toggled on/off with controls. Reduce spoilage rate.
H	#	trunk	80	350	650	0	steel frame	1	over cargo covered
o	#	box	60	100	275	0	steel frame	1	over cargo boardable covered
o	#	travois	60	50	205	0	light wooden frame	0	cargo boardable covered
o	#	wire basket	60	75	60	0	wire	1	cargo boardable foldable
o	#	shopping cart basket	60	75	200	0	basket	1	cargo boardable
#	#	table	60	145	15	0	table	1	cargo obstacle
$	$	controls	10	250	0	0	vehicle controls	3	internal controls foldable	Controls need to be on the same tile as a seat to be useable.
/	/	muffler	10	50	40	0	muffler	2	internal muffler	One per combustion engine to reduce noise. Additional mufflers do nothing.
,	,	seatbelt	10	35	25	0	rope - 6 ft	1	internal seatbelt	Reduces the chance of being thrown from your seat during a collision.
,	,	5-point harness	10	100	25	0	rope - 30 ft	2	seatbelt
\	0	curtain	1	200	25	0	sheet	1	openable openclose_inside opaque curtain	Can be installed on windshield and doors.
#	x	solar panel	10	20	111	0	solar panel	6	over solar_panel	Charge faster the sunnier it is.
#	x	reinforced solar panel	80	300	105	0	reinforced solar panel	6	solar_panel	Charge faster the sunnier it is.
#	x	upgraded solar panel	10	20	222	0	upgraded solar panel	8	solar_panel	Charge faster the sunnier it is.
#	x	reinforced upgraded solar panel	80	300	210	0	reinforced upgraded solar panel	9	solar_panel	Charge faster the sunnier it is.
#	x	quantum solar panel	10	30	555	0	quantum solar panel	12	solar_panel	Charge faster the sunnier it is.
u	-	water faucet	10	45	0	0	water faucet	1	faucet
&	x	kitchen unit	10	80	400	0	RV kitchen unit	4	over cargo obstacle kitchen covered roof no_reinforce	To use it the vehicle also needs a storage battery (to power it) and, optionally, a water tank (to store water)
&	x	welding rig	10	95	400	0	vehicle welding rig	4	cargo obstacle weldrig covered
&	x	FOODCO kitchen buddy	10	80	400	0	FOODCO kitchen buddy	4	cargo obstacle craftrig covered
&	x	onboard chemistry lab	10	65	400	0	onboard chemistry lab	4	cargo obstacle chemlab covered
&	x	mounted electric forge	10	180	0	0	vehicle forge rig	3	obstacle forge
t	#	mounted M249	80	400	0	.223	M249	6	over turret cargo
t	#	mounted flamethrower	80	400	0	gasoline	flamethrower	7	over turret
t	#	mounted plasma gun	80	400	0	hydrogen	Boeing XM-P Plasma Rifle	7	over turret
t	#	mounted fusion gun	80	400	0	fusion	FTK-93 fusion gun	7	turret cargo
t	#	mounted NX17	80	400	0	batteries	NX-17 charge rifle	7	turret
t	#	mounted M2 Browning	80	400	0	50	M2 Browning HMG	6	turret cargo
t	#	mounted Mark 19 grenade launcher	80	400	0	40mm	Mark 19 grenade launcher	6	turret cargo
)	)	wooden armor	100	300	0	0	wooden armor kit	3	armor
)	)	steel plating	100	1000	0	0	steel plating	3	internal armor
)	)	superalloy plating	100	900	0	0	superalloy plating	4	internal armor
)	)	spiked plating	150	900	0	0	spiked plating	3	internal armor sharp
)	)	hard plating	100	2300	0	0	hard plating	4	internal armor	3 times as heavy as regular steel plating.
)	)	military composite armor	100	3250	0	0	military composite plating	6	armor
*	*	head light	10	20	-187	0	flashlight	1	cone_light	Drain battery when on. Fragile.
*	*	reinforced head light	10	80	-187	0	reinforced head light	1	cone_light	Drain battery when on. Fragile.
\	0	reinforced windshield	80	250	0	0	sheet of reinforced glass	6	obstacle window
*	*	bicycle horn	10	75	15	0	bicycle horn	1	horn
*	*	car horn	10	100	30	0	car horn	3	horn
*	*	truck horn	10	125	45	0	truck horn	3	horn
o	#	motorbike battery	30	100	12000	batteries	motorbike battery	2	fuel_tank
o	#	car battery	50	120	30000	batteries	car battery	2	fuel_tank
o	#	truck battery	60	180	50000	batteries	truck battery	2	fuel_tank
*	#	motorbike alternator	80	250	?	batteries	motorbike alternator	3	alternator
*	#	car alternator	80	275	?	batteries	car alternator	3	alternator
*	#	truck alternator	80	325	?	batteries	truck alternator	3	alternator
+	&	trunk door	80	150	0	0	steel frame	2	obstacle openable multisquare boardable
+	&	shutter door	80	95	0	0	sheet metal	3	opaque obstacle openable multisquare boardable
+	&	sliding door	80	150	0	0	steel frame	2	obstacle openable multisquare boardable
*	-	red light	10	20	-125	0	emergency vehicle light (red)	1	circle_light oddturn	Can only be added on vehicles of multiple tiles.
*	-	blue light	10	20	-125	0	emergency vehicle light (blue)	1	circle_light eventurn	Can only be added on vehicles of multiple tiles.
=	#	cargo space	100	250	1000	0	cargo carrier	1	aisle boardable cargo covered
*	-	floodlight	10	20	-187	0	floodlight	1	circle_light
#	0	recharging station	10	20	-187	0	recharging station	3	internal recharge
o	*	wing mirror	10	20	0	0	hand mirror	1	mirror protrusion unmount_on_damage foldable	Mounted on car's sides. Easy to break.
&	&	stereo system	0	60	-1	0	stereo system	2	stereo	Requires 'music CD' to play. Uses car battery for power.
#	*	wooden seat	60	125	0	0	wooden frame	1	seat boardable beltable
.	x	wooden spike	115	150	0	0	pointy stick	2	unmount_on_damage sharp protrusion
+	&	wooden door	75	160	0	0	wooden frame	2	obstacle openable boardable window
#	#	wooden roof	100	130	0	0	wooden frame	1	roof
)	)	chitin plating	100	480	0	0	chitin armor kit	3	armor
)	)	bone plating	100	400	0	0	bone armor kit	3	armor
|	x	metal wheel	70	180	3	0	metal wheel	2	wheel variable_size

Vehicle Flags

The most recent list can always be find on GitHub: Cataclysm-DDA/doc/JSON_FLAGS.md

Vehicle Flag	Description
ADVANCED_PLANTER	This planter doesn't spill seeds and avoids damaging itself on non-diggable surfaces.
AISLE	Player can move over this part with less speed penalty than normal.
AISLE_LIGHT	N/A
ALTERNATOR	Recharges batteries installed on the vehicle.
ANCHOR_POINT	Allows secure seatbelt attachment.
ARMOR	Protects the other vehicle parts it's installed over during collisions.
ATOMIC_LIGHT	N/A
BATTERY_MOUNT	N/A
BED	A bed where the player can sleep.
BEEPER	Generates noise when the vehicle moves backward.
BELTABLE	Seatbelt can be attached to this part.
BOARDABLE	The player can safely move over or stand on this part while the vehicle is moving.
CAMERA	N/A
CAMERA_CONTROL	N/A
CARGO	Cargo holding area.
CHEMLAB	Acts as a chemistry set for crafting.
CHIMES	Generates continuous noise when used.
CIRCLE_LIGHT	Projects a circular radius of light when turned on.
CONE_LIGHT	Projects a cone of light when turned on.
CONTROLS	Can be used to control the vehicle.
COVERED	Prevents items in cargo parts from emitting any light.
CRAFTRIG	Acts as a dehydrator, vacuum sealer and reloading press for crafting purposes. Potentially to inclu
CTRL_ELECTRONIC	Controls electrical and electronic systems of the vehicle.
CURTAIN	Can be installed over a part flagged with WINDOW, and functions the same as blinds found on windows
DIFFICULTY_REMOVE	N/A
DOME_LIGHT	N/A
DOOR_MOTOR	N/A
ENGINE	Is an engine and contributes towards vehicle mechanical power.
EVENTURN	Only on during even turns.
EXTRA_DRAG	tells the vehicle that the part exerts engine power reduction.
FAUCET	N/A
FOLDABLE	N/A
FORGE	Acts as a forge for crafting.
FRIDGE	Can refrigerate items.
FUEL_TANK	Storage device for a fuel type.
FUNNEL	N/A
HORN	Generates noise when used.
INITIAL_PART	When starting a new vehicle via the construction menu, this vehicle part will be the initial part o
INTERNAL	Must be mounted inside a cargo area.
KITCHEN	Acts as a kitchen unit and heat source for crafting.
MUFFLER	Muffles the noise a vehicle makes while running.
MULTISQUARE	Causes this part and any adjacent parts with the same ID to act as a singular part.
MUSCLE_ARMS	Power of the engine with such flag depends on player's strength (it's less effective than MUSCLE_LE
MUSCLE_LEGS	Power of the engine with such flag depends on player's strength.
NAILABLE	Attached with nails
NEEDS_BATTERY_MOUNT	N/A
NO_JACK	N/A
NOINSTALL	Cannot be installed.
OBSTACLE	Cannot walk through part, unless the part is also OPENABLE.
ODDTURN	Only on during odd turns.
ON_CONTROLS	N/A
OPAQUE	Cannot be seen through.
OPENABLE	Can be opened or closed.
OPENCLOSE_INSIDE	Can be opened or closed, but only from inside the vehicle.
OVER	Can be mounted over other parts.
PLANTER	Plants seeds into tilled dirt, spilling them when the terrain underneath is unsuitable. It is damag
PLOW	Tills the soil underneath the part while active. Takes damage from unsuitable terrain at a level pr
POWER_TRANSFER	Transmits power to and from an attached thingy (probably a vehicle).
PROTRUSION	Part sticks out so no other parts can be installed over it.
REACTOR	N/A
REAPER	Cuts down mature crops, depositing them on the square. The bonus tag defines how productive the har
RECHARGE	Recharge items with the same flag. ( Currently only the rechargeable battery mod. )
REMOTE_CONTROLS	N/A
ROOF	Covers a section of the vehicle. Areas of the vehicle that have a roof and roofs on surrounding sec
SCOOP	Pulls items from underneath the vehicle to the cargo space of the part. Also mops up liquids. Uses
SEAT	A seat where the player can sit or sleep.
SEATBELT	Helps prevent the player from being ejected from the vehicle during an accident.
SECURITY	N/A
SHARP	Striking a monster with this part does cutting damage instead of bashing damage, and prevents stunn
SOLAR_PANEL	Recharges vehicle batteries when exposed to sunlight. Has a 1 in 4 chance of being broken on car ge
STABLE	Similar to WHEEL, but if the vehicle is only a 1x1 section, this single wheel counts as enough whee
STEERABLE	This wheel is steerable.
STEREO	N/A
TOOL_NONE	Can be removed/installed without any tools
TOOL_SCREWDRIVER	Attached with screws, can be removed/installed with a screwdriver
TOOL_WRENCH	Attached with bolts, can be removed/installed with a wrench
TRACK	Allows the vehicle installed on, to be marked and tracked on a PDA.
TURRET	Is a weapon turret.
UNMOUNT_ON_DAMAGE	Part breaks off the vehicle when destroyed by damage.
UNMOUNT_ON_MOVE	Dismount this part when the vehicle moves. Doesn't drop the part, unless you give it special handli
VARIABLE_SIZE	Has 'bigness' for power, wheel radius, etc.
VISION	N/A
WELDRIG	Acts as a welder for crafting.
WHEEL	Counts as a wheel in wheel calculations.
WINDOW	Can see through this part and can install curtains over it.

Wheels

Every vehicle needs wheels to be able to move. A vehicle without wheels can only be dragged.

In general, a vehicle needs at least two wheels. Wheels need to be positioned in such a way that the center of weight is roughly above them. There is no requirement that the wheels have similar shapes or sizes.

The most important stat of the wheel is its total area. The sum of all wheel areas reduces the slowdown that vehicle mass has on the speed, but also worsens the vehicle's dynamics. Ideal wheel area is often much lower than the one vehicle spawned with. For example, a Military Cargo Truck will be much faster if all but 2 of its wheels are removed. Being able steer said cargo motorcycle is a whole different issue, however, which brings us to...

Wheel area

Area of a single wheel is (width * diameter / 9). Diameter is the stat in item's name, width is displayed when installing the wheel.

Note: this area is rounded down, so very small wheels (casters) may have no area. Such a wheel still contributes to wheel configuration validity (center of mass over wheels), but does not change vehicle dynamics.

A vehicle with 0 total wheel area won't be able to move by itself.

Boats

Boat boards are technically wheels. If the vehicle has at least one boat board, it is a boat and not a land vehicle and thus can only move over water. Total wheel area of a boat is 13 regardless of how many boards it has installed.

Ideal wheel configuration

Ideal wheel configuration depends mostly on the vehicle's mass. When trying to maximize safe speed, total wheel area should be ~1.58 sqrt( mass ). Here "sqrt" means square root and mass is in kilograms.

Increasing the wheel area above that may increase acceleration, but it will decrease safe speed and thus also maximum speed and fuel economy.

For example, a 2500 kg (5512 lbs) truck should have a total wheel area of around 79. This can be achieved by installing just a single maximum sized armored wheel (20 width * 36 diameter / 9 = 80 area). The truck still needs more than one wheel to move, but the second wheel can be just a set of casters.

Engines: load vs strain

Load is (engine power used)/(maximum engine power output). In case of a single undamaged engine, this translates to (engine power)/(max power). Damaged engine's power output is proportional to it's remaining hp percentage. Multiple engines' output is multiplied by 4/(num_engines + 3). Note that adding a weak engine to a powerful engine can actually decrease the overall power output (and thus increase engine load for a given speed).

Load affects fuel usage, smoke and noise. Load is processed twice: once for driving, once for having an active engine. When driving, load is equal to percentage of acceleration used (ie. if acceleration is 50 and vehicle accelerates from 0 to 24, load is 0.48). The second load is equal to sum of alternator loads or 0.01, whichever is higher.

Strain is (|current velocity| - safe velocity)/(max velocity - safe velocity). Strain greatly increases fuel consumption (100 times more on max velocity than on safe velocity) and causes engine damage, unless the engine is powered by muscles. Muscle powered engines will instead drain extra resources from the driver (5 times as much at max velocity as on safe velocity).

Turrets

Turrets fire automatically at enemies as long as they have ammo and are turned on. They can shoot at your own car, but they can only damage it with area attacks (bullets that hit the turret's car will not damage it). They will avoid shooting the player, but it can be unreliable, especially when standing close to the turret.

Stats

Turrets use stats from the weapons used to create them, modified by their ammo. The exception is the range - most turrets have automatic targeting range far below weapon range. Turrets track AoE (area of effect) of their projectiles and will not target enemies too close to hit without damaging self. Effective area of effect used for safety calculations is bigger than actual one: by 1 if it was 1 before, by 2 if it was 2 or more before.

Turret shoots like an NPC with 8 in specific weapon skill (for example, rifles), 4 in marksmanship, 16 strength, 8 dexterity and 12 perception. An active turret will take one shot or burst every turn (6 seconds) it can. It has no speed stat, nor does it accumulate moves.

Turrets have different recoil mechanics from regular guns. Their recoil always starts at 25% of their vehicle's velocity in MPH and is reset at the start of the turn. Recoil from previous shots in burst is respected.

IFF (player's safety)

When the player is visible to the turret and close enough to it, it will not target any enemy within (30 + 2 * AoE) degree cone centered at the player. This includes enemies much closer to the turret than the player. As the player gets closer to the turret, the cone is widened to 60 degrees (at 2 tile distance) and then 120 degrees (when adjacent). "Close enough" depends on turrets range: (range + AoE) * 1.5 + 6.

Shooting limitations

Turrets can shoot all creatures not covered by roofs of their own vehicle (except player, who only needs to be on any part of the vehicle). Roof over player's head does NOT stop the IFF.

Turrets can't damage own vehicle with bullets alone, though it can do so with AoE projectiles.

Automatic targeting

An active turret will try to target any visible hostile creatures. Friendlies are ignored (neither targeted nor avoided). Closer enemies are preferred (unless too close to target with AoE). Turrets can't see in the darkness and will not consider invisible player's safety. Automatic targeting has a severe range limitation - 12 tiles in case of most turrets, 5 in case of flamethrowers.

Turret's aiming system is purely visual and has no night vision ability.

Manual targeting

Manual targeting forces a target for the turret. It won't make it shoot faster or more accurately than otherwise, but it can make it shoot much further (up to gun+ammo range). Turret's configuration (burst/once) is respected. If the turret was disabled before aiming, it will be enabled for one burst, then disabled.

Aiming takes some time and does not consider player's safety (IFF). If the vehicle moves between aiming and shooting, the target point will be shifted by in the same direction and the same distance as the vehicle (rotation is ignored).

Manual targeting can make the turret shoot over opaque parts of turret's vehicle.

Settings

Turrets start out disabled. To make them shoot, you need to configure them and turn on the vehicle's turret system. Each turret can be configured to shoot in bursts, only once per turn or not at all.