Only 200 lbs and a little different timing in the detonation. (tuning of the engine)
Get your 200lb friend in your car and go on a road trip. Won't hurt your mileage that much VS going on a road trip by yourself
The big fat 20's make the biggest difference in gas mileage. Weight on the wheels make much bigger difference than weight in the body.
I.E. Go hiking up a hill with a water bottle in hand... not to bad
Go hiking up a hill with a water bottle in hand and a 20 lb back pack... Little tougher
Go hiking up a hill with a water bottle in hand and a 20 lb back pack and 10 lb weights on each foot... Holy crap I'm tired, every time you lift your leg to step up will be work!!!
Weight on the wheels kills MPG's
I added 18lbs a wheel with new KO2's tires, with a horrible rolling resistance design and bad aerodynamics (space in between the lugs) Lost 1 mpg instantly.
Get some super light 17 inch rims, with Michelin GREENX low rolling resistant tires I guarantee you will add 1mpg with out taking any weight out of the car... Problem is LX570 would just look silly then.
Rolling resistance is this... Get in your friends car with mudders go down a small paved decline put it in neutral, the car will pick up speed but not alot.
Get in a vehicle with low rolling resistant tires and do the same thing, your picking up speed much faster!!! That is rolling resistance. It takes up lots of energy to propel a car if your rolling resistance is high.
Put a heavy front bumper with horrible aerodynamics, MT tires with horrible aerodynamics (the space in between the lugs) and a wider tire to add to horrible aerodynamic, more unsprung weight, and add a whole lot of weight in the car, with a roof rack with horrible aerodynamics. Boom your car just went to 10mpg. But man what a Vehicle it will be
Sorry for the long write up, been studying for a while and this is my excuse for a break lol. Much funner talking about this stuff