Best mpg from inline 6?
Post Fiend
Joined: Mar 2004
Posts: 24,418
Likes: 3
From: San Francisco, Ca.
Originally Posted by 74crwcb429hibPS4spd
I don't get it? How come a 300 I6 doesn't get like 22 or 23 MPG? 
. At least I do. Remember that old TV commercial where the pitchman put an egg between his foot and the accelerator pedal? They were trying to say easy on the gas pedal 
. Plus you start messing with big tires, ratios and other modifications 
and bingo; another pit stop to the ole service station 
. I used to get around 20+ 
, but now...............
More Turbo
Joined: Jul 2003
Posts: 629
Likes: 1
From: Grand Rapids, Michigan
I have always got about 12 MPG with my I-6. I drive like an old man, because I am. Don't give me that crap about an egg. My six has always got poor MPG. I have had the truck since it was new in 1979. I got it off the dealer with a 3 speed stick, not even a radio, NOTHING to affect the MPG. So you guys that get in the 20's must be smoking something other than tires.
Postmaster
Joined: May 2002
Posts: 3,241
Likes: 3
From: Broken Arrow, OK
I'm runnint 2000 rpm at 60 mph with a 5speed, 3.08 and 255/60/15's.
One thing that hasen't been mentioned as an influence on mileage is speedometer accuracy. Manufacturers are currently allowed a 4% window for accuracy. How many trucks are out there still running on the original everything? If the speedometer is off 10%, the calculated mileage could be off by even more because the truck could also be going 10% slower than indicated. For example, if your speedo says you are going 60 mph, but you are really only going 54, you will be using less gass because you are going slower. At the same time, the odometer is throwing the miles up there 10 % faster than it should. Two 10% errors can add up to a total error of about 22%.
One thing that hasen't been mentioned as an influence on mileage is speedometer accuracy. Manufacturers are currently allowed a 4% window for accuracy. How many trucks are out there still running on the original everything? If the speedometer is off 10%, the calculated mileage could be off by even more because the truck could also be going 10% slower than indicated. For example, if your speedo says you are going 60 mph, but you are really only going 54, you will be using less gass because you are going slower. At the same time, the odometer is throwing the miles up there 10 % faster than it should. Two 10% errors can add up to a total error of about 22%.
Senior User
Joined: Jul 2004
Posts: 407
Likes: 0
From: ct.
Originally Posted by Sgt Wonderful
. So you guys that get in the 20's must be smoking something other than tires.
Junior User
Joined: Feb 2004
Posts: 85
Likes: 0
From: rural PA
23.1 once on a trip to camp a few hours driving during the weekend around the mountian and back home 2 hours highway on Sunday. The truck was bone stock. 94 f150 reg cab long bed 300-6 5-speed 3.08:1 4x4. uncovered bed factory 235-75-15 station wagon type tires. Now it's lifted 6" running on 35's with 4.11:1 gears. I'm afraid to check, but I love it. 
Last edited by 96f350rcsrw460zf; Feb 8, 2005 at 03:41 PM.
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Post Fiend
Joined: Mar 2004
Posts: 24,418
Likes: 3
From: San Francisco, Ca.
When I changed the rear end ratio and went to taller tires, I went to my ford dealer and bought different speedo driven gears. Then I sat down with a calc. and crunched the numbers to see what driven gear I needed. Put in the correct gear and did mile marker test. Right on the button. And I didn't even smoke anything. And I always make sure the emergency brake is off when I drive.
Posting Guru
Joined: Jun 2002
Posts: 1,288
Likes: 1
From: redding U.S.A.
It also has a lot to do with the speed we're driving.
I believe someone on this forum posted a link to a graph that displayed average gas mileage at certain speeds. It was mainly based on wind resistance. 55mph was about the best, and the mileage started dropping rapidly on the graph at greater speeds. Granted the Y-range was probably only 4mpg but there was still a substantial difference.
I like to travel at about 70-75mph. I seem to get the best smoothness and speed at that rate. Any faster and the fact i'm driving a pickup is made pretty obvious, any slower and i get anxious.
Best mileage that i calculated was 16.1mpg. It put a huge smile on my face. I've gotten 10mpg around town, driving like a teenager.
I believe someone on this forum posted a link to a graph that displayed average gas mileage at certain speeds. It was mainly based on wind resistance. 55mph was about the best, and the mileage started dropping rapidly on the graph at greater speeds. Granted the Y-range was probably only 4mpg but there was still a substantial difference.
I like to travel at about 70-75mph. I seem to get the best smoothness and speed at that rate. Any faster and the fact i'm driving a pickup is made pretty obvious, any slower and i get anxious.
Best mileage that i calculated was 16.1mpg. It put a huge smile on my face. I've gotten 10mpg around town, driving like a teenager.
Post Fiend
Joined: Mar 2004
Posts: 24,418
Likes: 3
From: San Francisco, Ca.
Originally Posted by rhetor
It also has a lot to do with the speed we're driving.
I believe someone on this forum posted a link to a graph that displayed average gas mileage at certain speeds. It was mainly based on wind resistance. 55mph was about the best, and the mileage started dropping rapidly on the graph at greater speeds. Granted the Y-range was probably only 4mpg but there was still a substantial difference.
I like to travel at about 70-75mph. I seem to get the best smoothness and speed at that rate. Any faster and the fact i'm driving a pickup is made pretty obvious, any slower and i get anxious.
Best mileage that i calculated was 16.1mpg. It put a huge smile on my face. I've gotten 10mpg around town, driving like a teenager.
I believe someone on this forum posted a link to a graph that displayed average gas mileage at certain speeds. It was mainly based on wind resistance. 55mph was about the best, and the mileage started dropping rapidly on the graph at greater speeds. Granted the Y-range was probably only 4mpg but there was still a substantial difference.
I like to travel at about 70-75mph. I seem to get the best smoothness and speed at that rate. Any faster and the fact i'm driving a pickup is made pretty obvious, any slower and i get anxious.
Best mileage that i calculated was 16.1mpg. It put a huge smile on my face. I've gotten 10mpg around town, driving like a teenager.
Senior User
Joined: Aug 2004
Posts: 348
Likes: 0
I get 15-17mpg
bug things, 3.55 gears, maz 5 speed , stock tires, 3in body lift,
removed 2ed cat and piped with a flowmaster 40 2 1/2 in and out.
99k miles on the motor and i do 50/50 highway city and my speed is around 55-63
bug things, 3.55 gears, maz 5 speed , stock tires, 3in body lift,
removed 2ed cat and piped with a flowmaster 40 2 1/2 in and out.
99k miles on the motor and i do 50/50 highway city and my speed is around 55-63
Freshman User
Joined: Jan 2005
Posts: 47
Likes: 0
I have a 92 4X4. I keep up on the tunes ups etc. I am getting 15+ (right now in the winter with this fuel). This is on a 50/50 mix of city and highway miles. With summer fuel I expect to get a bit better 16+. I am fighting a pull to the left right now on braking and more noticable in 4x4. I plan an alignment. IF that is a problem, I will probably improve a little too. This is all stock (to the best of my knowledge). I did notice that when the exhaust detached aft of the cat, I got substantially better milage.
