How much fuel consumption difference: 1 person vs. 2 people - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

djmm · 04-28-2014, 06:09 AM

Has any of you ever done rough comparison in terms of fuel usage when driving the car only by yourself versus driving with 1 passenger in the car?

Muskokan · 04-28-2014, 06:36 AM

I got 2mpg better after Taco Bell shits the other day

speedrye · 04-28-2014, 06:40 AM

By myself, I typically get 6-8 mpg worse, but I don't think it's related to weight. I drive a lot more aggressively when the wife isn't with me...

DC2R · 04-28-2014, 08:06 AM

Quote:

Originally Posted by speedrye

By myself, I typically get 6-8 mpg worse, but I don't think it's related to weight. I drive a lot more aggressively when the wife isn't with me...

Must agree there

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djmm · 04-28-2014, 08:17 AM

lol - but seriously, say carrying an extra load of 1 person, which is say on average what, 120-160 pounds, that's not light at all - surely it must affect fuel consumption a bit?

CruiseZen · 04-28-2014, 08:44 AM

As stated above, driving style may have a bigger effect on gas mileage than having more weight from a passenger. I also drive more conservatively when my wife is riding with me.

ninedice · 04-28-2014, 08:58 AM

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.

Mister · 04-28-2014, 09:54 AM

I don't really notice any difference in economy unless I am seriously pushing it. 100-200lbs might be noticable on performance/track driving, but if you are just driving around town I would not imagine it would have too much of a negative impact.

With 150lb person on board you are talking about ~5% increase in vehicle weight. Therefore if it actually directly translated into a 5% fuel economy change, it would be about 0.05 * 28mpg = ~1.4mpg. However weight is not the only factor, rolling resistance of tires, aerodynamics, and grade of the road are all important factors as well. So we will say 2% (which I think is probably still a very generous amount) is more likely, 0.02 * 28mpg = ~0.55mpg. Either number is pretty easily lost in the noise of driving habits, and likely to not be noticeable for most drivers.

*disclaimer* I pulled these numbers out of my ass to make a point, please do not hold them to any standard...

blackfireball5 · 04-28-2014, 09:56 AM

I also drive more conservatively when driving with friends or family.

Scenic Driver · 04-28-2014, 10:37 AM

I don't know how it impacts fuel consumption but a body in the trunk helps with traction in the snow.

extrashaky · 04-28-2014, 10:47 AM

Quote:

Originally Posted by djmm

lol - but seriously, say carrying an extra load of 1 person, which is say on average what, 120-160 pounds, that's not light at all - surely it must affect fuel consumption a bit?

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.

speedrye · 04-28-2014, 10:48 AM

Quote:

Originally Posted by Scenic Driver

I don't know how it impacts fuel consumption but a body in the trunk helps with traction in the snow.

I have the opposite problem. Every time I have a body in the trunk and corner hard, that dead weight shifts and my rear end breaks traction...

ZionsWrath · 04-28-2014, 10:50 AM

mom in car - 35 mpg

just me - 20 mpg

Havsie · 04-28-2014, 11:11 AM

Don't know, all of my friends are far too wide to fit in the seats...

04-28-2014, 06:09 AM	#1
djmm Senior Member Join Date: Sep 2013 Drives: toyota Location: Australia Posts: 358 Thanks: 25 Thanked 163 Times in 81 Posts Mentioned: 3 Post(s) Tagged: 0 Thread(s)	How much fuel consumption difference: 1 person vs. 2 people Has any of you ever done rough comparison in terms of fuel usage when driving the car only by yourself versus driving with 1 passenger in the car?

04-28-2014, 08:44 AM	#6
CruiseZen Senior Member Join Date: Jan 2014 Drives: 2014 Ultramarine 6MT FR-S Monogram Location: North Carolina Posts: 252 Thanks: 45 Thanked 78 Times in 57 Posts Mentioned: 3 Post(s) Tagged: 0 Thread(s)	As stated above, driving style may have a bigger effect on gas mileage than having more weight from a passenger. I also drive more conservatively when my wife is riding with me. __________________ Borla axleback exhaust * mud guards * Michelin Pilot Super Sport tires * Opti-Coat * BRZ trunk lid liner * Rexpeed Wide Mirrors (heated)

04-28-2014, 10:37 AM	#10
Scenic Driver Senior Member Join Date: Feb 2013 Drives: 13 Subaru BRZ, 02 Audi TTQ Location: Orange County, NY Posts: 456 Thanks: 61 Thanked 321 Times in 168 Posts Mentioned: 7 Post(s) Tagged: 0 Thread(s)	I don't know how it impacts fuel consumption but a body in the trunk helps with traction in the snow. __________________

04-28-2014, 10:50 AM	#13
ZionsWrath Thanks Join Date: Apr 2013 Drives: BRZ Location: NY Posts: 4,163 Thanks: 5,989 Thanked 3,100 Times in 1,498 Posts Mentioned: 38 Post(s) Tagged: 3 Thread(s)	mom in car - 35 mpg just me - 20 mpg __________________

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04-28-2014, 06:36 AM	#2
Muskokan Senior Member Join Date: Aug 2013 Drives: white Sport-tech Location: Ontario Posts: 676 Thanks: 204 Thanked 320 Times in 149 Posts Mentioned: 2 Post(s) Tagged: 1 Thread(s)	I got 2mpg better after Taco Bell shits the other day

04-28-2014, 06:40 AM	#3
speedrye Senior Member Join Date: Apr 2012 Drives: White Location: Southeast US Posts: 161 Thanks: 22 Thanked 78 Times in 50 Posts Mentioned: 2 Post(s) Tagged: 0 Thread(s)	By myself, I typically get 6-8 mpg worse, but I don't think it's related to weight. I drive a lot more aggressively when the wife isn't with me...

04-28-2014, 08:17 AM	#5
djmm Senior Member Join Date: Sep 2013 Drives: toyota Location: Australia Posts: 358 Thanks: 25 Thanked 163 Times in 81 Posts Mentioned: 3 Post(s) Tagged: 0 Thread(s)	lol - but seriously, say carrying an extra load of 1 person, which is say on average what, 120-160 pounds, that's not light at all - surely it must affect fuel consumption a bit?

04-28-2014, 09:54 AM	#8
Mister Senior Member Join Date: May 2013 Drives: Firestorm FRS Location: NH Posts: 180 Thanks: 141 Thanked 78 Times in 50 Posts Mentioned: 7 Post(s) Tagged: 1 Thread(s)	I don't really notice any difference in economy unless I am seriously pushing it. 100-200lbs might be noticable on performance/track driving, but if you are just driving around town I would not imagine it would have too much of a negative impact. With 150lb person on board you are talking about ~5% increase in vehicle weight. Therefore if it actually directly translated into a 5% fuel economy change, it would be about 0.05 * 28mpg = ~1.4mpg. However weight is not the only factor, rolling resistance of tires, aerodynamics, and grade of the road are all important factors as well. So we will say 2% (which I think is probably still a very generous amount) is more likely, 0.02 * 28mpg = ~0.55mpg. Either number is pretty easily lost in the noise of driving habits, and likely to not be noticeable for most drivers. disclaimer I pulled these numbers out of my ass to make a point, please do not hold them to any standard...

04-28-2014, 09:56 AM	#9
blackfireball5 Senior Member Join Date: Jun 2012 Drives: Scion FRS Firestorm Location: Cleveland, Ohio Posts: 538 Thanks: 459 Thanked 102 Times in 74 Posts Mentioned: 7 Post(s) Tagged: 0 Thread(s)	I also drive more conservatively when driving with friends or family.

04-28-2014, 11:11 AM	#14
Havsie Member Join Date: Mar 2013 Drives: 13 FR-S Whiteout 6MT Location: NJ Posts: 96 Thanks: 1 Thanked 88 Times in 30 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Don't know, all of my friends are far too wide to fit in the seats...

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