Dreded 460 fuel mileage

[Rembrant]

Thanks for the write up that kinda puts things in perspective. Maybe I'll try to keep her under 65mph sounds like that's my best chance at better fuel mileage. A lot of times I find myself just going with the flow of traffic which could be upwards 70-80mph.

Quite a few years ago, I switched from having a company vehicle to using my personal vehicle and getting paid mileage. I was running Volkswagens at the time...gas engine, and then diesel, and I really got into chasing MPG. I used to joke that a MPG addiction is almost as bad as a HP/performance addiction, it's just that it's opposite. The one VW that I worked on so hard to get the optimum MPG would routinely return 50 MPG, and a whopping 800 miles per tank. Man I loved that little car. Anyway, my point in all this is that I trained myself to drive much slower to the point now where I'm so used to it, it is normal for me. Before, with the company vehicle everywhere I went I was doing between 75-90 MPH (I wasn't paying for the gas lol). Driving my own though, I knocked it down to 60-65 MPH. It's a weird sensation to make a trip somewhere and have Semi's passing you all day long...lol, but I'm used to it now...and the nice side effect is that is also more relaxing for me since I'm not scanning the horizon for police anymore, because I rarely break the speed limit.

Gas is around $5/gallon here, so everything little bit that I can save is money in my pocket.

 

[1986F150Six]

Thanks for the write up that kinda puts things in perspective. Maybe I'll try to keep her under 65mph sounds like that's my best chance at better fuel mileage. A lot of times I find myself just going with the flow of traffic which could be upwards 70-80mph.

Quite a few years ago, I switched from having a company vehicle to using my personal vehicle and getting paid mileage. I was running Volkswagens at the time...gas engine, and then diesel, and I really got into chasing MPG. I used to joke that a MPG addiction is almost as bad as a HP/performance addiction, it's just that it's opposite. The one VW that I worked on so hard to get the optimum MPG would routinely return 50 MPG, and a whopping 800 miles per tank. Man I loved that little car. Anyway, my point in all this is that I trained myself to drive much slower to the point now where I'm so used to it, it is normal for me. Before, with the company vehicle everywhere I went I was doing between 75-90 MPH (I wasn't paying for the gas lol). Driving my own though, I knocked it down to 60-65 MPH. It's a weird sensation to make a trip somewhere and have Semi's passing you all day long...lol, but I'm used to it now...and the nice side effect is that is also more relaxing for me since I'm not scanning the horizon for police anymore, because I rarely break the speed limit.

Gas is around $5/gallon here, so everything little bit that I can save is money in my pocket.

As Gary previously said, speed does kill MPG.

I'll let the engineers fill in where I either misspeak or leave out details. This is my understanding [from years of being addicted to fuel efficiency, like Cory stated] - wind drag doubles with the square, so as one drives faster, the power required is not linear.

The following will give something to think about:

50 mph X 50 = 2500

55 mph X 55 = 3025

60 mph X 60 = 3600

65 mph X 65 = 4225

70 mph X 70 = 4900

75 mph X 75 = 5625

80 mph X 80 = 6400

90 mph X 90 = 8100

 

[ArdWrknTrk]

Where you at Jim?? I always look forward to your expertise.

Hi Mike!

I can't offer much more than has already been said, except that Overdrive is no way to make up mileage in one of those beasts.

A C6 is good at churning power into heat. Options are few and I do not know what your rpm's are at say 65 mph.

But every engine has an rpm for best power and if you fall below that your mileage is going to fall on its face as well.

My truck likes 2600-3k rpm. But 3k is 80!

If I try to keep it under 2,500 -even with a manual gearbox- my fuel mileage goes down instead of up.

I'm no expert at motorhomes though, and I'd imagine some basic aero could help a lot with drag.

No matter what you're leaving a huge wake.

It takes a good amount of power to push that much air out of the way.

 

[85lebaront2]

Hi Mike!

I can't offer much more than has already been said, except that Overdrive is no way to make up mileage in one of those beasts.

A C6 is good at churning power into heat. Options are few and I do not know what your rpm's are at say 65 mph.

But every engine has an rpm for best power and if you fall below that your mileage is going to fall on its face as well.

My truck likes 2600-3k rpm. But 3k is 80!

If I try to keep it under 2,500 -even with a manual gearbox- my fuel mileage goes down instead of up.

I'm no expert at motorhomes though, and I'd imagine some basic aero could help a lot with drag.

No matter what you're leaving a huge wake.

It takes a good amount of power to push that much air out of the way.

I never had a motorhome, but I towed a 30' 5th wheel with Darth, in fact that's why I bought him. Best mileage towing was 7-8, worst was towing at 70 staying with a group of mostly motorhomes going to an event in North Carolina. Lead vehicle was driven by a woman who was born in Germany and was a teenager during WWII. She thought she was on the Autobahn! Mileage on that run was about 5 as we were doing 70 into a 35 mph headwind.

Running empty or loaded with no trailer, 10 mpg, since the EFI and E4OD conversion, high was 12.5 and this is with a well used short block and topped with early EFI heads, compression ratio is probably 8:1 at best. I have yet to find something Darth won't pull even with the 3.55 gear. BTW, the 12.5 was cruising at 75 on I-70. My rpm at 55 is around 1500, used to be 22-2500 with the C6 as it depended on load and terrain.

As for comparison with Gary and Jim's trucks, Darth is a crew cab DRW F350 and weighs on a certified truck scale 6400 lbs empty (both tanks almost dry).

Hope this helps.

[ArdWrknTrk]

I never had a motorhome, but I towed a 30' 5th wheel with Darth, in fact that's why I bought him. Best mileage towing was 7-8, worst was towing at 70 staying with a group of mostly motorhomes going to an event in North Carolina. Lead vehicle was driven by a woman who was born in Germany and was a teenager during WWII. She thought she was on the Autobahn! Mileage on that run was about 5 as we were doing 70 into a 35 mph headwind.

Running empty or loaded with no trailer, 10 mpg, since the EFI and E4OD conversion, high was 12.5 and this is with a well used short block and topped with early EFI heads, compression ratio is probably 8:1 at best. I have yet to find something Darth won't pull even with the 3.55 gear. BTW, the 12.5 was cruising at 75 on I-70. My rpm at 55 is around 1500, used to be 22-2500 with the C6 as it depended on load and terrain.

As for comparison with Gary and Jim's trucks, Darth is a crew cab DRW F350 and weighs on a certified truck scale 6400 lbs empty (both tanks almost dry).

Hope this helps.

I will add that my tare weight is right up there with Bill's, but I sit a bit higher due to 4x4.

 

[Gary Lewis]

I will add that my tare weight is right up there with Bill's, but I sit a bit higher due to 4x4.

Mine's probably the "lightweight" of the bunch, but with dual batteries, winch bumper, winch, and D60 it ain't light. Then there's the tool box in the bed that although it might not be as big nor as packed as those on Jim's truck, still has chain, ratchet straps, recovery gear, hand tools, and soon to be an on-board 1.5 HP air compressor driven by a 3000 watt inverter.

Gee, I hadn't thought about all of that stuff, but it does add up.

[ArdWrknTrk]

Mine's probably the "lightweight" of the bunch, but with dual batteries, winch bumper, winch, and D60 it ain't light. Then there's the tool box in the bed that although it might not be as big nor as packed as those on Jim's truck, still has chain, ratchet straps, recovery gear, hand tools, and soon to be an on-board 1.5 HP air compressor driven by a 3000 watt inverter.

Gee, I hadn't thought about all of that stuff, but it does add up.

I seriously doubt Big Blue is lighter than Lil' Red.

Next time I'm at the transfer station I will get a printout.

I will say my 190ish pounds are included, because it is drive through, not get out and pay.

[Gary Lewis]

I seriously doubt Big Blue is lighter than Lil' Red.

Next time I'm at the transfer station I will get a printout.

I will say my 190ish pounds are included, because it is drive through, not get out and pay.

Well, you have lots of tools in yours, but .... And, BB does set a bit high, probably higher than Lil' Red, much less Darth.

Guess I'd better weigh him sometime.

[ArdWrknTrk]

Well, you have lots of tools in yours, but .... And, BB does set a bit high, probably higher than Lil' Red, much less Darth.

Guess I'd better weigh him sometime.

I imagine the D60 weighs less that TTB, but I have one battery, one tray, a tiny relay center and a whole lot less copper cable. No winch, winch bumper or front brace across my frame.

No seat base, console, up-scale headliner, carpet or electric anything.

While I do have a lumber rack.

[ArdWrknTrk]

Well, you have lots of tools in yours, but .... And, BB does set a bit high, probably higher than Lil' Red, much less Darth.

Guess I'd better weigh him sometime.

As far as highway mileage goes weight doesn't matter much unless you're headed UP.

It does matter in stop & go because all that momentum you turned into brake heat needs to be replaced.

More air under the truck is going to make a difference.

David's mileage records w/wo chin spoiler show how much difference even a little change can make.