Bullnose Enthusiasts Forum

Dreded 460 fuel mileage

Classic

List

Threaded

32 messages Options

Rembrant

Re: Dreded 460 fuel mileage

26ftcobraBBF wrote

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.

1994 F150 4x2 Flareside. 5.0 w/MAF, 4R70W, stock.
1984 F150 4X2 Flareside. Mild 302 w/ 5spd. Sold.
1980 F150 4X4 Flareside. 300i6 w/ 5spd. Sold in 2021.
1980 F100 4X2 Flareside. 351w/2bbl w/NP435. Sold in 1995

1986F150Six

Re: Dreded 460 fuel mileage

Administrator

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

Re: Dreded 460 fuel mileage

Administrator

In reply to this post by 26ftcobraBBF

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.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

85lebaront2

Re: Dreded 460 fuel mileage

Administrator

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.

Bill AKA "LOBO" Profile

"Getting old is inevitable, growing up is optional" Darth Vader 1986 F350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator Wife's 2011 Flex Limited Daily Driver 2009 Flex Limited with factory tow package Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413

ArdWrknTrk

Re: Dreded 460 fuel mileage

Administrator

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

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: Dreded 460 fuel mileage

Administrator

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.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

ArdWrknTrk

Re: Dreded 460 fuel mileage

Administrator

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.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: Dreded 460 fuel mileage

Administrator

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.

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

Re: Dreded 460 fuel mileage

Administrator

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.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

ArdWrknTrk

Re: Dreded 460 fuel mileage

Administrator

In reply to this post by Gary Lewis

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.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

grumpin

Re: Dreded 460 fuel mileage

My truck weighs right around 6000 with my big Weatherguard toolbox, the stuff in it and me.

Dane
1986 F250HD SC XLT Lariat 4x4 460 C6-Sold
1992 Bronco XLT 4x4 351W E4OD
1998 GMC Sierra SLE K1500 350 4L60E
Arizona

Gary Lewis

Re: Dreded 460 fuel mileage

Administrator

Jim - It all adds up, and I've put a lot of "stuff" in and on Big Blue, with more to come like the air compressor. Then there's all the equipment that will go in the storage unit behind the seat.

And, the extra 4" in front height from the D60/SD/RSK certainly doesn't help the MPG. But, the ride is sooooo much better I'll happily give up some MPG.

Dane - I'll weigh BB one of these days - after I get the compressor installed. I'm going to guess that the Warn bumper, winch, extra battery, inverter, compressor, sound deadening, fancy headliner, and the little bit of extra copper wiring that Jim mentioned it may come in close to 7000 lbs.

Gary, AKA "Gary fellow": Profile