ameristar1
The One Blue Thing
I am fielding ideas for a hotshot rig, 24-26 foot box, 10-15 mpg, has to be able to be comfortable at 75 mph. Medium duty or Class 8 based, no age limit.
Are you wanting to go broke or what?
I will let you in on a little secret, the easiest way to make a small fortune trucking, it to start with a large fortune!
Ride sucks in a MDT, 75mph is screaming in a MDT. 15mpg in an HDT (class 8 ) is a wet dream. (I think)
You didnt specify desired weight carrying capacity.
On a whim you want a Volvo 770 with a ISX cummins or a 9400 IH with an ISX
Maybe a T2000 KW with a C-15 CAT or its sister the 387 Pete same power.
I speced all "Aero" trucks to comply with your MPG constraint.
Give me a little more information and I will take off running with this one, I enjoy these kinda threads.
the money maker has to be stone reliable, but at the same time pretty fast......... Ya better buy new w/ lots of warranty.
The maximum load that I will see is 16k.......... Not gonna happen in MD or HD truck without apportioned plates and IFTA..
Being 6'2, I need to be able to stay comfortable...... Need a Volvo 770 or 780
Single axle........... Good choice here
Dock height
10-13 speeds........ Not gonna find one in a med duty, more gears only means more fuel wasted accelerating.
The main thing is to do 10 mpg or better loaded..... Good luck, ain't gonna happen at 75 mph
The Class 8 conversion would make the most sense with a small Series 60 Detroit (11.1), tall gears and a programmer. I've seen these trucks advertised for under 8000.00 all day long with mid to high miles, but since they won't be under the same stress any longer, it'll buy some time before a major. I am a big fan of the Series 60; most of them go 1.3 million before an inframe.
On the MD side, something with a 5.9 or 8.3 Cummins or a DT series engine. Inline pump. I am going to talk to Garmon's Diesel about doing some mods that can improve the power and the mpg.
The empty weight with fluids should be around 10000 pounds......... You can scratch ANY HD class 7 and 8 truck off your list as well as most class 5 and 6 trucks. class 8 day cab and sleeper Road tractors come in around 14000 - 20000 lbs. Empty 26k MD box van will be around 14 - 16k
One other thing, during the day 68-73 mph at 1600 rpms, at night ............. Do you want great fuel economy or a fast truck, you ain't getting both here. P.S. Sweet spot on most big diesels is around 1500, small diesels is 1800 - 2000
An Allison MT643 automatic (as an option on the MD)...... Much better choice than an AT545.
Consider this a scratch build.
One constant is they are pushing the OAL and OAH to the extreme.
Did somebody suggest a Cummins ISX........ This was the second biggest fuel pig I ever owned in a class 8 truck, worst was my 3406B Cat... Avg for ISX was 5 mpg in a 99 Pete 379 EX w/ super 10 and 3.55 gears on LP 22.5 rubber pulling a 53' box at 65 mph. 3406B got 3.5 mpg in an '85 LTL9000 with a 13 over 3.73 gears and tall 24.5 rubber pulling 48' ****** and box vans.
If you wanna be realistic you need a dock high class 6 rated at 26k which will prolly be about 13k - 16k with a box van on it and full of fuel, 5 or 6 speed or Allison auto and 22.5 tires and either a 5.9 Cummins or 3126 CAT (note stay under 250 hp w the cat or it won't live long) My 190 hp 5.9 12 valve w/ allison 545 and my buddies 190 hp 3126 cat w fuller 5 speed avg 9 - 10 loaded and empty (half our miles are empty)
We run around 58 mph loaded and 63 empty to get this kind of mpg avg. Factor in a head wind or higher speeds and mpg will drop 2 - 3 mpg
The lightest class 8 I have found yet was a Freightliner FLB cabover with an M11 Cummins, 9 speed single axle w/ aluminum wheels. Curb weight was 11k add 200 gallons of fuel and it's up to 12,400, stretch frame and add a box and it would be around 16 - 18k.
A Detroit 60 series or Cummins ISX is 500+ lbs heavier than an M11 Cummins or C10 Cat and an M11 is 1000 lbs heavier than a 5.9. A 9 0r 10 speed behind a big engine vs the 5 - 6 speed in a MD adds 300 lbs. A 13 speed comes in 100+ lbs heavier than a 9 or 10 speed. Aluminum wheels are half the weight of steel. Tire size also affects weight and the difference can be around 25 lbs per tire on similar wheel sizes. The size of the trucks frame rails can be anywhere from 30 lbs per linear ft of frame( thats' both sides including crossmembers) to over 100 lbs per linear ft of frame for a 3/8" thick double frame heavy haul truck.
Every little thing adds up to one big thing. Just these few items alone can make a weight difference of thousands of lbs on the weight of the truck.
Well my Aeromax has 3.21 rear with a 7 speed OD, 425HP 3406E, it is on tall 24.5 rubber, weighs a little over 33K lbs, cruises well at 75mph and...... averages 9.5mpg, although the MPG suffers in the western states where the cruise can be set a little higher.
So it CAN be done.....
My 1979 L9000 with a 444XT cummins, 8LL OD with 4.11's will turn 1350 - 1400 rpm at 65 miles per hour...which puts it at 1600 - 1700 at 75 miles per hour. I get about 7 - 9 MPG with it loaded in the hilly terrain here in Nova Scotia. Fastest top end speed truck in the quarry, while it might not be the best truck for climbing!
89 on the stock governor setting. Not bad. Take it to 2800 rpms and see what happens!