The Skybrary
Efficiency Mod
Upgrade Category: Engine Upgrades
If you've got a long-range plane, a little of this will go a long way.
Armor (mm)
Armor Class
Ammo (rounds)
Range +5%
Max Speed
Stall Speed
Acceleration -5%
Slots Required 3 engine slot(s)
Price: 100,000Ģ
Availability: Sharif, Gonk, Alpha 7

An oddly poor upgrade when compared to Boring Out and High Efficiency Mod. Can still be effectively used if you wish you use your engine slots purely for range upgrades.

Combat Festival Candle · Increased Ammo · Mad Props · Mega Ammo · Shiny Red Light · Sleigh Bell · Super Ammo
Engine 4 Barrel Carburetor · 6 Barrel Carburetor · Boring Out · Coolant System · Efficiency Mod · High Efficiency Mod · High-Flow Air Filter · Internal Air Diversion Plates · Internal Fuel Can · Internal Fuel Tank · Larger Props · Port and Polish · R Sticker · Super Charger · Turbo Charger
Hull Additional Cargo Hold · Gutted Cargo Hold · Gutted Craft · Heavy Armor Plating · Internal Fuel Expansion · Large Internal Fuel Expansion · Light Armor Plating · Lightweight Shell · Med Armor Plating · Steel Reinforced Hull · Streamlined Hull · Wood Reinforced Hull
Wing Drop Tanks · High-Lift Wings · High-Performance Wings · Improved Wings · Large External Cargo Hold · Large External Fuel Tank · Med External Cargo Hold · Med External Fuel Tank · Small External Cargo Hold