bengines is a resource for MTA:SA 1.5 that provides custom engine sounds for vehicles. Not useful for me anymore so sharing with community.  Used on old project. Sounds are copyrighted content not owned by me.

Features

• ready to use, chooses the best engine for vehicle depending on handling!
• easy to customize & expand for Lua programmers
• 30 soundpacks for vehicles (buses, bikes, sport cars etc.)
• stable code with quite high performance used on server with 600 players
• ALS effect (exhaust flames)
• Turbo (satisfying whistle and blow-off sounds)

Videos:

• https://streamable.com/n7k40
• https://streamable.com/lp14t
• https://streamable.com/q5e9g

For programmers:

--[[ 
Element datas used by resource
[array] vehicle:engine - stores basic info about engine type, sound pack etc. (synced)
[string] vehicle:type - used for engine calculation, useful for servers. Available: Bus, Truck, Sport, Casual, Muscle, Plane, Boat, Motorbike (synced)
[string] vehicle:fuel_type - customized for each engine. Useful for servers. Available: "diesel", "petrol" (synced)
--]]

--[[
Exported functions
--]]

exports.bengines:getVehicleRPM(vehicle) -- returns RPM of given vehicle
exports.bengines:getVehicleGear(vehicle) -- returns current gear of given vehicle
exports.bengines:toggleEngines(bool) -- true / false, restore GTA engine sounds