How much fuel consumption difference: 1 person vs. 2 people

[Mossyjaw]

I didn't notice a a difference on a trip with 3 people and luggage.

[dem00n]

This car isn't a Citroen 2CV...

[Churnobyl]

Originally Posted by ninedice

I'm not sure about MPGs because I'm averaging less than 20 but when I drive my co-worker home (250lbs) I notice a HUGE difference in performance. As a result I push the car harder so I'm sure the fuel economy suffers.

The second person, or a even a full tank of gas, make a noticeable difference (Stock car) in the responsiveness according to my butt dyno.

As for hard fuel economy numbers dunno.

[strat61caster]

You'd see a bigger difference by adjusting your habits than by implementing a 'no fat chicks' rule.

Seriously in a controlled environment with identical controls (impossible in the real world) 200 lbs. would be at most 1 mpg off the top of my head. I swung my highway average from ~28mpg to ~35mpg by being more conservative, no reasonable amount of mass is going to give me that kind of difference.

[stock]

Originally Posted by extrashaky

If your passenger is a woman, you would be well advised not to mention this in her presence unless you're just itching to have the "Do you think I'm fat?" conversation.

LOL.

"Does this car make me look fat?" (no, but my MPG is down for some reason...)

[Sigh-on-Rice]

It's only one example, but there is an old article I just found by googling "heavy passengers affect fuel economy".

http://www.autoexpress.co.uk/car-new...pg-mythbusters
Looks for "Three in the rear".