MPG gurus...
Sep 1, 2005 | 05:35 PM
#1
Thread Starter
Registered User
Joined: Dec 2003
Posts: 67
Likes: 0
MPG gurus...
With gas prices rising, i'm sure i'm not the only one wanting to squeeze a few more miles out. My question is... would switching to a smaller tire give me a few more miles to the gallon? I've got a 894runner/22re/5spd/4.56gears/31x10.5. Would moving to 30x9.5 do anything? If anyone has figured out toyota mpg let me know. (I usually get about 20 flat, but the other day with the top off (more drag), surco rack loaded to the gills, 3 other guys and tons of camping gear, 50% highway/50% trail/city I got 23.5...i'm at wits end on figuring out how to get the best mileage.
Sep 1, 2005 | 05:45 PM
#3
Registered User
Joined: Dec 2003
Posts: 903
Likes: 0
If you've got an 89 getting about 20mpg, you're doing good, above average. Going back to stock size tires will help mpg obviously, but not any smaller. Act like there's an egg under your gas pedal, that's what I do. And run a search for better mpg, you might find a couple threads. 
Sep 1, 2005 | 06:39 PM
#5
Contributing Member
Joined: Nov 2004
Posts: 3,572
Likes: 1
From: Upsate SC
Take the danged rack off. I did and my gas mileage has gone up from 15 mpg to 19! Also do regular maintenance on your vehicle such as fuel filter, air filter, and clean your throttle body plate.
Sep 2, 2005 | 03:42 AM
#6
Registered User
Joined: Nov 2002
Posts: 1,066
Likes: 0
From: Far western Kentucky (transplanted from central PA)
Ditto the above. Those plus good driving habits (coasting, easy/granny starts, sense of timing, etc.) are about all you can do. I also have my tires inflated to 34 psi which reduces rolling resistance somewhat but increases the stiffness of the ride. Tire inflation pressure is a matter of preference.
Sep 2, 2005 | 04:25 AM
#7
Contributing Member
Joined: Dec 2002
Posts: 1,574
Likes: 1
From: El Paso, TX
I think my BFG AT tires cost me about 1 mpg compared to the BFG LT Highway tires I used to have on it. But the LT's had a tread separation on them at 70 mph and the 4Runner and I both lived through it. Highway tires generally have less rolling resistance. You might try some Michelins...I've always loved Michelins on my cars.
Oh yeah...I currently get 19 mpg on the '95 and 20-22 on the '99.
Oh yeah...I currently get 19 mpg on the '95 and 20-22 on the '99.
Last edited by gwhayduke; Sep 2, 2005 at 04:27 AM.
Trending Topics
Sep 2, 2005 | 05:48 AM
#8
Contributing Member
Joined: Jul 2005
Posts: 196
Likes: 0
From: Thornton, CO
Yeah, I'm getting about 15.4 mpg on my '95, but that's with the 33s and 4.88 gears. I could put the stocks back on...but it looks kinda weird with the lift. The bus station is only 7 miles away, so I'm not too concerned. However, cheapo-gas is $3.09 today. If it stays there I may slap those 31s on again.
I'm doing what Rick F. says: granny starts. I don't care who's behind me, my rig is usually bigger than their car, they can wait.
I'm doing what Rick F. says: granny starts. I don't care who's behind me, my rig is usually bigger than their car, they can wait.
Sep 2, 2005 | 06:53 AM
#10
Registered User
Joined: Nov 2004
Posts: 342
Likes: 0
Here is the business person in me coming out - sure, smaller tires may help some, but you have to figure in how long your pay-back is. Buying new tires and getting them mounted, etc costs money - figuring how much you will save in gas as a result only starts when you pay off that initial expense. May be way out there....
Go with what others have done, as stated above: Drive easy, do maintenance, don't use much A/C, and drive as little as possible, or (my personal favorite) use your wife's car when you can!
Go with what others have done, as stated above: Drive easy, do maintenance, don't use much A/C, and drive as little as possible, or (my personal favorite) use your wife's car when you can!
Sep 2, 2005 | 08:47 AM
#11
Registered User
Joined: Jan 2003
Posts: 90
Likes: 0
From: Columbia, SC
Everthing you need to know about MPG is in this equation:
And yes, air density plays a direct role. From 32F to 90F air density varies by 11%. So a large percentage of that translates to additional aerodynamic drag. This happens as you increase in elevation also.
Power = (Froll friction + Faero drag + Faccel) (v)= (f W + densityair CD AF v2 / 2 + W a/g) (v)
where the terms (and the units) are as defined below.
Power = the power required at the drive wheels (watts)
Froll friction = the force to overcome rolling resistance, f W (N)
Faero drag = aerodynamic drag force, rair CD AF v2 / 2 (N)
Faccel = acceleration force, W a/g (N)
v = vehicle velocity (m/s)
f = coefficient of rolling resistance (dimensionless)
W = vehicle weight (kg ´ g or N)
rair = air density (1.202 kg/m3 @ 200 m altitude)
CD = drag coefficient (dimensionless)
AF = vehicle frontal area (m2)
a = acceleration/deceleration rate (m/s2)
g = acceleration due to gravity (9.81 m/s2)
http://www.tc.gc.ca/programs/environ...nal_report.htm
And yes, air density plays a direct role. From 32F to 90F air density varies by 11%. So a large percentage of that translates to additional aerodynamic drag. This happens as you increase in elevation also.
Power = (Froll friction + Faero drag + Faccel) (v)= (f W + densityair CD AF v2 / 2 + W a/g) (v)
where the terms (and the units) are as defined below.
Power = the power required at the drive wheels (watts)
Froll friction = the force to overcome rolling resistance, f W (N)
Faero drag = aerodynamic drag force, rair CD AF v2 / 2 (N)
Faccel = acceleration force, W a/g (N)
v = vehicle velocity (m/s)
f = coefficient of rolling resistance (dimensionless)
W = vehicle weight (kg ´ g or N)
rair = air density (1.202 kg/m3 @ 200 m altitude)
CD = drag coefficient (dimensionless)
AF = vehicle frontal area (m2)
a = acceleration/deceleration rate (m/s2)
g = acceleration due to gravity (9.81 m/s2)
http://www.tc.gc.ca/programs/environ...nal_report.htm
Sep 2, 2005 | 11:08 AM
#12
Registered User
Joined: Nov 2002
Posts: 1,066
Likes: 0
From: Far western Kentucky (transplanted from central PA)
Originally Posted by DOT3
Everthing you need to know about MPG is in this equation:
And yes, air density plays a direct role. From 32F to 90F air density varies by 11%. So a large percentage of that translates to additional aerodynamic drag. This happens as you increase in elevation also.
Power = (Froll friction + Faero drag + Faccel) (v)= (f W + densityair CD AF v2 / 2 + W a/g) (v)
where the terms (and the units) are as defined below.
Power = the power required at the drive wheels (watts)
Froll friction = the force to overcome rolling resistance, f W (N)
Faero drag = aerodynamic drag force, rair CD AF v2 / 2 (N)
Faccel = acceleration force, W a/g (N)
v = vehicle velocity (m/s)
f = coefficient of rolling resistance (dimensionless)
W = vehicle weight (kg ´ g or N)
rair = air density (1.202 kg/m3 @ 200 m altitude)
CD = drag coefficient (dimensionless)
AF = vehicle frontal area (m2)
a = acceleration/deceleration rate (m/s2)
g = acceleration due to gravity (9.81 m/s2)
http://www.tc.gc.ca/programs/environ...nal_report.htm
And yes, air density plays a direct role. From 32F to 90F air density varies by 11%. So a large percentage of that translates to additional aerodynamic drag. This happens as you increase in elevation also.
Power = (Froll friction + Faero drag + Faccel) (v)= (f W + densityair CD AF v2 / 2 + W a/g) (v)
where the terms (and the units) are as defined below.
Power = the power required at the drive wheels (watts)
Froll friction = the force to overcome rolling resistance, f W (N)
Faero drag = aerodynamic drag force, rair CD AF v2 / 2 (N)
Faccel = acceleration force, W a/g (N)
v = vehicle velocity (m/s)
f = coefficient of rolling resistance (dimensionless)
W = vehicle weight (kg ´ g or N)
rair = air density (1.202 kg/m3 @ 200 m altitude)
CD = drag coefficient (dimensionless)
AF = vehicle frontal area (m2)
a = acceleration/deceleration rate (m/s2)
g = acceleration due to gravity (9.81 m/s2)
http://www.tc.gc.ca/programs/environ...nal_report.htm
Sep 2, 2005 | 11:18 AM
#13
Registered User
Joined: Nov 2004
Posts: 342
Likes: 0
Originally Posted by DOT3
Everthing you need to know about MPG is in this equation:
And yes, air density plays a direct role. From 32F to 90F air density varies by 11%. So a large percentage of that translates to additional aerodynamic drag. This happens as you increase in elevation also.
Power = (Froll friction + Faero drag + Faccel) (v)= (f W + densityair CD AF v2 / 2 + W a/g) (v)
where the terms (and the units) are as defined below.
Power = the power required at the drive wheels (watts)
Froll friction = the force to overcome rolling resistance, f W (N)
Faero drag = aerodynamic drag force, rair CD AF v2 / 2 (N)
Faccel = acceleration force, W a/g (N)
v = vehicle velocity (m/s)
f = coefficient of rolling resistance (dimensionless)
W = vehicle weight (kg ´ g or N)
rair = air density (1.202 kg/m3 @ 200 m altitude)
CD = drag coefficient (dimensionless)
AF = vehicle frontal area (m2)
a = acceleration/deceleration rate (m/s2)
g = acceleration due to gravity (9.81 m/s2)
http://www.tc.gc.ca/programs/environ...nal_report.htm
And yes, air density plays a direct role. From 32F to 90F air density varies by 11%. So a large percentage of that translates to additional aerodynamic drag. This happens as you increase in elevation also.
Power = (Froll friction + Faero drag + Faccel) (v)= (f W + densityair CD AF v2 / 2 + W a/g) (v)
where the terms (and the units) are as defined below.
Power = the power required at the drive wheels (watts)
Froll friction = the force to overcome rolling resistance, f W (N)
Faero drag = aerodynamic drag force, rair CD AF v2 / 2 (N)
Faccel = acceleration force, W a/g (N)
v = vehicle velocity (m/s)
f = coefficient of rolling resistance (dimensionless)
W = vehicle weight (kg ´ g or N)
rair = air density (1.202 kg/m3 @ 200 m altitude)
CD = drag coefficient (dimensionless)
AF = vehicle frontal area (m2)
a = acceleration/deceleration rate (m/s2)
g = acceleration due to gravity (9.81 m/s2)
http://www.tc.gc.ca/programs/environ...nal_report.htm
Sep 2, 2005 | 11:50 AM
#14
Contributing Member
Joined: Sep 2003
Posts: 10,549
Likes: 0
From: Littleton,CO
Mine's getting a tune-up next week along with a new O2 sensor since no matter how I drive I always get a little over 16mpg and I know there's a couple more MPGs in it........... or at least I hope.
Sep 3, 2005 | 09:45 AM
#17
Registered User
Joined: Jul 2003
Posts: 866
Likes: 0
Originally Posted by DOT3
Everthing you need to know about MPG is in this equation:
And yes, air density plays a direct role. From 32F to 90F air density varies by 11%. So a large percentage of that translates to additional aerodynamic drag. This happens as you increase in elevation also.
Power = (Froll friction + Faero drag + Faccel) (v)= (f W + densityair CD AF v2 / 2 + W a/g) (v)
where the terms (and the units) are as defined below.
Power = the power required at the drive wheels (watts)
Froll friction = the force to overcome rolling resistance, f W (N)
Faero drag = aerodynamic drag force, rair CD AF v2 / 2 (N)
Faccel = acceleration force, W a/g (N)
v = vehicle velocity (m/s)
f = coefficient of rolling resistance (dimensionless)
W = vehicle weight (kg ´ g or N)
rair = air density (1.202 kg/m3 @ 200 m altitude)
CD = drag coefficient (dimensionless)
AF = vehicle frontal area (m2)
a = acceleration/deceleration rate (m/s2)
g = acceleration due to gravity (9.81 m/s2)
http://www.tc.gc.ca/programs/environ...nal_report.htm
And yes, air density plays a direct role. From 32F to 90F air density varies by 11%. So a large percentage of that translates to additional aerodynamic drag. This happens as you increase in elevation also.
Power = (Froll friction + Faero drag + Faccel) (v)= (f W + densityair CD AF v2 / 2 + W a/g) (v)
where the terms (and the units) are as defined below.
Power = the power required at the drive wheels (watts)
Froll friction = the force to overcome rolling resistance, f W (N)
Faero drag = aerodynamic drag force, rair CD AF v2 / 2 (N)
Faccel = acceleration force, W a/g (N)
v = vehicle velocity (m/s)
f = coefficient of rolling resistance (dimensionless)
W = vehicle weight (kg ´ g or N)
rair = air density (1.202 kg/m3 @ 200 m altitude)
CD = drag coefficient (dimensionless)
AF = vehicle frontal area (m2)
a = acceleration/deceleration rate (m/s2)
g = acceleration due to gravity (9.81 m/s2)
http://www.tc.gc.ca/programs/environ...nal_report.htm
Sep 3, 2005 | 11:12 AM
#18
Registered User
Joined: Nov 2004
Posts: 251
Likes: 0
Originally Posted by Beartracker
I agree 100% but I would have put it this way.... You will get less drag in cool air than you will in hot air and that equates to better gas mileage. Mike
Cooler air is more dense = more drag. But also means more power.
Hot air is less dense = less drag, But also less power.
Sep 3, 2005 | 12:37 PM
#19
Contributing Member
Joined: May 2004
Posts: 3,400
Likes: 0
From: Tucson, AZ
Smaller tires will give you about 1 or 2 mpg in the city but on the highway you will not really see any diference. I just went to 31s from tires that measured 29" and that is what I have found. Definetly better acceleration on the smaller tires.
Sep 3, 2005 | 03:00 PM
#20
Registered User
Joined: Nov 2002
Posts: 1,066
Likes: 0
From: Far western Kentucky (transplanted from central PA)
Originally Posted by X-AWDriver
Mine's getting a tune-up next week along with a new O2 sensor since no matter how I drive I always get a little over 16mpg and I know there's a couple more MPGs in it........... or at least I hope.
