SoCalDesertRider wrote: His 35" tires change the rpm to road speed relationship. The taller tires result in lower engine rpms at any given road speed, in comparison to stock size tires.
Exactly... To add, I have 3.73 gears. It is also why it costs me economy in seattle's bad traffic. This was ALL I-5.
2008 Cougar 310SRX 5th Wheel
2005 Dodge Ram 2500 QC 4x4 CTD
2008 Nissan Armada LE
We just got back from a camping trip, 556 miles round trip.
On our way down I drove 60-65 and averaged 8.45 mpg. On the way home I drove 65-70 and on several stretches cruised 75 mph and averaged 8.75 mpg.
I doubt that I will be slowing down, I was going to but not now.
TV: Mint 1972 Ford F-250 XLT
TT: 1969 19' Excel; entertains 6, feeds 4, sleeps 2 You don't shoot to kill, you shoot to stay alive.
I don't carry because I have to, I carry because I get to. I like new things-
- when they're 40 years old! My pictures
Good info on the mileage - and yep, taller tires help.
My F-350 6.0 has a sweet spot at about 63mph, so we use that - gain lots of miles andd don't loose any time. on the I-5 with the canopy on I can get 21. I'm getting ready to open up the intake and exhaust (but leaving the cat in - opening it to 4"), and go to a BD tuner. One of the sons did this and picked up 5 mpg empty, 3 towing.
Hope things with your dad work out OK.
2005 F-350 SRW LB Black Harley Davdsn, 6.0 Pstroke w/auto, Excite liner, ARE "Z" cap w/Yakima rails & slide/tilt window, PIAA 1500 bu lights. B&W TO Ball hitch, Firestone bags
Wife: Stef the quilter
Dog: Chase, the Golden Retriever
3 sons, 8 grandkids
First, sorry about your dad......I lost my mom in January, and Grandma and grandpa within the last 2 years, and 2 German shepards... Sucks to get old and sick....
WEll , the best I did was like 19mpg cant remmeber exactly but it was around there... Going 55mph..... but it seems like everytime I get on the highway I start off wanting to go a slower speed, but a guy in a dodge is coming and I cant let him pass me.... really though I start off with them intentions, but its hard to go slow, or always in a big hurry to get there, then get home..Or people just get on your butt.....I went on I-10 last week to go to tucson for a Doc apppointment and Man, you wouldnt think the fuel prices are that high.... Cars still going over the speed limit, and the big trucks as usual...
rsh_757 wrote: Due to an unfortunate situstion with my dad (he had a brain anurism on wed) I have been forced to commute from Auburn to Portland several times, also forced to take my ctd to bring some construction tools to finish a project he started and cannot finish. During these trips I have gone out of my way to maintain a solid 60mph for the entire trip to see how much fuel I can really save. I just filled up at the same station I fill up at all the time, topped it off at 2 click offs and made the calculations. I made a gawdi 24.7 mpg in all that hwy driving. My overhead normally reads 18-19 while making this same trip but this time it reads 26.7. My dodge has a 48RE, AEM brute force intake, no "cat" and 35x12.50 toyo m/t tires. At 60mph my rpm's are 1500 and that has pulled me up any inclines in OD without a hitch. I have heard some pretty crazy claims to mileage and always get a good laugh out of them and also knew that slower is better. But this is downright pleasing to me at 4.66 per gallon. I am posting from a blackberry so I won't see any replies (if any) until a rest stop.
2007 GMC DURAMAX,LBZ,4 by Crew, Allison
Magnaflow Turbo Back Exhaust
Predator Tuner
18by9 Helo's on BFG's
5year old boy
3 year old baby girl
Sea ray boat
Wilderness 5th wheel
SandRail
HD WideGlide
FORD Expediton
honda Eu3000
dhamblet wrote: Your RPMs with the CTD and 48re should be more like 1900 at 60 MPH. 1900 is like the peak on the torque curve which says to me its the most economical speed to run. Pulling our 38'5 fifth wheel across the US at that RPM we typically got 13MPG on the flats and 11-12 in the hills.
This is true if you're comparing full load wide open throttle operation at peak torque rpm verses full load wide open throttle operation at higher or lower rpm. For running part throttle light load, the lowest rpm you can run while still having spare power such as being able maintain speeds up the hills in that gear is where you'll get the best mileage.
I can squeeze out 19mpg empty on flat ground at 60mph/1500rpm with cruise set in my gasser but, like mentioned above, gas and diesel fuel are still pretty cheap according to the normal flow of traffic blazing past us. So I absorb the 2-mpg loss and flow with traffic. In an eight hour day of interstate driving, a vehicle traveling 70mph will be 80 miles ahead of a vehicle driving 60mph. It does make a difference.
'05 2500HD Dodge 5.7L Hemi 5spd auto/3.73 SLT. 95k miles
ex '95 Cummins,'98 12v Cummins,'01.5 Cummins,'03 Cummins
'07 KZ Jag 28JFSS.
We just got back from a camping trip, 556 miles round trip.
On our way down I drove 60-65 and averaged 8.45 mpg. On the way home I drove 65-70 and on several stretches cruised 75 mph and averaged 8.75 mpg.
I doubt that I will be slowing down, I was going to but not now.
Wow, maybe everyone should go 70mph instead of 60mph to get better fuel economy. I guess when you want to go from 60 to 70 mph you lift off the gas pedal and the engine gains RPM while using less fuel.
i too have slowed down this recent trip from CA to PA. Usually get an average of 10mpg in tow. Tow/haul mode needs to run about 57-58mph to kick into OD but when maintaining that speed mpg rose to 12-13. PRM around 18-1900. you really can't compare $ saved to time saved( about acouple of mins.)
06 F250 6.0 TD,SC,SB,4x4,Towboss,3.73 rear.Firestone air bags,285/70 R17 3795lb tires,18000 slider; 04 38' Jayo Designer "Legacy" 5er; all I need now is satilite TV and hit the lottery; NAVY,"WE'LL NEVER FORGET,land of the free because of the brave"
We just got back from a camping trip, 556 miles round trip.
On our way down I drove 60-65 and averaged 8.45 mpg. On the way home I drove 65-70 and on several stretches cruised 75 mph and averaged 8.75 mpg.
I doubt that I will be slowing down, I was going to but not now.
Wow, maybe everyone should go 70mph instead of 60mph to get better fuel economy. I guess when you want to go from 60 to 70 mph you lift off the gas pedal and the engine gains RPM while using less fuel.
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I guess when you want to go from 60 to 70 mph you lift off the gas pedal and the engine gains RPM while using less fuel.
