Speed

This page is about the internal speed representation, speed limits, and speed inflation. For related information about lengths and map size, check out the Map page and fuel-map repository.

The game tracks the vehicle's speed internally in m/s; this is the length of the velocity vector of the vehicle and will be referred to as the "true speed" or "uninflated speed". This true speed is the value the PersoSPEED command shows on the "Spd" line. The speedometer HUD element shows a converted speed in km/h or mph. If you ever do the math and try to convert that to m/s and compare it to the PersoSPEED overlay, you will notice that it doesn't match. This is because the speedometer shows an "inflated speed" value. The inflated speed is the true speed multiplied by 1.15. Presumably, they thought increasing the speed values shown to the player by 15% would make the vehicles "feel" faster.

The inflated speed is used consistently, and the 1.15 constant has a lot of Xrefs; even the Profile > General Info > Records page in the pause menu shows the inflated speed for the "Peak speed" record. Confusingly, however, the odometer directly beneath the speedometer ticks up in accordance with the true speed. So if you travel 1 km (on the odometer) in 25 seconds at a constant speed, you would expect that speed to have been 144 km/h, but the speedometer would have read 165 km/h the whole time. As a side note, the orange colored right most digit of the odometer is the tenths place, the dial in the lower left of the speedometer HUD is the vehicle damage indicator, and the main large dial is the gear.

The DeBugInfos command shows 3 different speed values, all of which are inflated. ESpd: engine speed, basically how fast the vehicle wants to be going. WSpd: wheel speed, the average speed of all the wheels on the vehicle, and CSpd: chassis speed. how fast the main body of the vehicle is going. The meaning of the first letter is mostly an educated guess on my part based on how the values are calculated. The same command overlay also shows detailed gear torque graphs in the top left of the screen.

If you've been tuning your VehiclesParam.tsc and just can't seem to get the Damoclese to go faster than 345 km/h (inflated), you aren't alone. The game actually imposes a hard-coded speed limit on vehicles. This limit is 83.339996 m/s (true), which comes out to 300 km/h (true) or 345 km/h (inflated). Each wheel's true speed is clamped between -83.339996 m/s and 83.339996 m/s, and the chassis's true speed only has an upper bound, also of 83.339996 m/s.

Float constant	Address
83.339996	FUEL.exe+005DCB5C
-83.339996	FUEL.exe+005DCF14
1.15	FUEL.exe+005DCAF8

These constants are only used by speed-related code, so it should be safe to modify them without breaking anything else. Addresses are from USA retail, as always.

They picked the speed limit based on the Damocles's natural max speed, so even after increasing the limit, you will have to tune the vehicle to exceed the old limit. If you edit the params for MESH_ID_BONUS_ROAD_3 to match the ones below, it should reach 420+ km/h (inflated) (nice) on the highway quickly.

VehiclePP 327 100000
VehiclePP 356 1
VehiclePP 364 1.5

If you are using a mod that edits files, like FUEL: REFUELED, be careful that your changes aren't overwritten.