Would you buy this truck?

[Skydiver]

I'll start off by saying a semi or tri axel dump is around 76,000-80,000 lbs loaded with approximately 450-500 hp and 1400ish ft lb torque. Around 160 lbs per horse power.



Today's pickup trucks 300 hp 12,000 GVWR has a 40 lb per horse power ratio.



If a manufacturer produced a 3/4 or one ton truck turbo charged diesel with one fourth that power using a 7, 8 or 9 speed transmission and GVWR the same as today's trucks.



Sure it would be slow taking off and weak on the hills loaded, but what would the fuel mileage be like? Is it true (electric or combustion, can't remember) that an engine runs most efficiently at maximum capacity?



My question is would you buy a full size underpowered 9 speed truck if it would get around 38 mpg empty, 22 mpg loaded and was dependable.



I would like to place a 1. 5 to 2. 0 liter industrial turbo diesel in a ¾ ton for better mpg.



In 1981 I bought a new V. W. Rabbit with 52 horses that got 43 mpg combined using a 4 speed.



Thoughts .

 

[Radshooter]

Depends on what I would be using it for. As a daily driver, grocery getter, or light hauler, I could live with it and enjoy the mileage. My jack-rabbit start days are long-gone. A younger generation may have different ideas though. I drive my truck like a truck, not a sports car anyway.

Now if I were replacing my present truck with it, I would not be happy at all because we tow a 17K fiver all over western USA. I don't think I would like it at all when we get into the bigger hills and mountains. Yes, it would have the low gears and yes it would get me over the hills, but when we are moving to a new assignment in the fiver, and are under a time crunch, I don't want to be doing it at 35 or 40 MPH.

Sounds like a good idea if you can find the right market for it.

Steve

 

[Skydiver]

How many on this site have made reference to the similarities our Dodge Cummins shares with a road truck? Example is over GVWR, inline engine ect.



I have never heard a member comment on "how slow semi tractors are on hills or from a stop".



What MPG do road trucks get today? 11-12 ?? Do the math for an 80,000 lb rig verses say 20,000 lb Dodge Cummins with trailer. In theory and using simple math without windage adjustments we could be getting at least 30 mpg.



Oh yea, How many times has some one made reference to the 4bt. I think you're starting to get my picture. Cummins 4bt and a Eaton or a Fuller.



What is diesel price per gallon? $3. 25 here .

 

[DCreed]

I thought an IVECO is like that?

 

[Mhannink]

How many on this site have made reference to the similarities our Dodge Cummins shares with a road truck? Example is over GVWR, inline engine ect.



I have never heard a member comment on "how slow semi tractors are on hills or from a stop".



What MPG do road trucks get today? 11-12 ?? Do the math for an 80,000 lb rig verses say 20,000 lb Dodge Cummins with trailer. In theory and using simple math without windage adjustments we could be getting at least 30 mpg.



Oh yea, How many times has some one made reference to the 4bt. I think you're starting to get my picture. Cummins 4bt and a Eaton or a Fuller.



What is diesel price per gallon? $3. 25 here .

otr trucks get just over 6 at the best ive heard of the rare truck getting 7 but i doubt its true

 

[Mhannink]

How many on this site have made reference to the similarities our Dodge Cummins shares with a road truck? Example is over GVWR, inline engine ect.



I have never heard a member comment on "how slow semi tractors are on hills or from a stop".



What MPG do road trucks get today? 11-12 ?? Do the math for an 80,000 lb rig verses say 20,000 lb Dodge Cummins with trailer. In theory and using simple math without windage adjustments we could be getting at least 30 mpg.



Oh yea, How many times has some one made reference to the 4bt. I think you're starting to get my picture. Cummins 4bt and a Eaton or a Fuller.



What is diesel price per gallon? $3. 25 here .

otr trucks get just over 6 at the best ive heard of the rare truck getting 7 but i doubt its true

 

[Skydiver]

In 1992-1995 I worked at a service dept. part time on road trucks. Still have my CDL and am very mechanically inclined.



They were getting around 6 mpg back then. I would have thought by now they would be over 10 mpg.



I do remember at this one trucking company the driver with the best fuel mileage would get a $250 bonus per month.

 

[TAbbott]

Fuel mileage on the big rigs has gone down since the late '90's. Emission regs got to them before they got to the pickup engines. That's why last year was the worst year for heavy truck sales since 2003 --- some 54. 5% lower than 2006 levels (Transport Topics, 1-21-08) Everyone bought ahead so as to avoid the latest and greatest emissions control engines and those that did buy the new stuff aren't getting much for fuel mileage at all --- with Caterpillar actually advertising that one of their test engines managed 4. 5 mpg in a truck loaded to 79,800 lbs from Denver to San Antonio (downhill all the way) running the speed limit, and actually got better mileage than the similar Cummins they were comparing it to. A well set up late 90's truck would get 6 mpg or better doing that with the mouse motors getting 6. 5 or 7 mpg doing the same job. Todays emisssions regs necessitate that roughly 40% of the air that gets pumped through a modern diesel is exhaust gas containing zero oxygen --- you still have to pay the overhead costs to pump and compress and exhaust that air and get no benefit from it other than cooler combustion temperatures and therefor, less NOX. It saps power rather than producing it which means efficiencies go south, and fuel mileage drops. Todays engines are actually larger than those of a few years ago so they can produce roughly equivalent power in a heavy duty application.



If it weren't for other efficiencies that have actually improved substantially (aerodynamics, low rolling resistance tires, more efficient drive trains, etc. ) todays trucks wouldn't break 4 miles per gallon, and if you put a late 90's engine into the equivalent chassis with previous generation fuel they'd probably be getting 8 mpg or better.



They optimum set-up today would be a small diesel hybrid (maybe 2 or 2. 5 liters of displacement running at max efficiency continuously) with battteries and an electric motor providing additional power when needed. Regenerative braking would help immensely. 1 ton truck might get as high as 35-40 mpgs and not one person out of 5,000 could afford to buy it. My $. 02.

 

[bmoeller]

TA, you nailed it on the head right there. Every bit of it. The government griped about CAFE standards, yet all of the emission regs reduce mileage. We can't win. They aren't even allowing new glider kits anymore, due to emissions.

My boss was going to buy me my first brand new KW W900L last year, but told him I didn't want a brand new one, which sure surprised him. The ONLY reason I said that, was the new emissions crap. DPF and all. So, we were able to find a low mile '04. Absolutely love it. Has a 525hp Cat, and get 5. 5-6mpg in the summer pulling a bullrack.

otr trucks get just over 6 at the best ive heard of the rare truck getting 7 but i doubt its true

7mpg is possible, at least for the trucks with the older emission controls. New ones, I really doubt it.

We have a daycab T800 KW with a 430hp C12 Cat, and consistently gets 6. 4-6. 6mpg in the summer.

The best mileage I ever got, was in a Mack with a E7- 350 with 4. 17 gears. But, I was bobtailing for the first 350 miles of that trip (was going after a new trailer in NE). After I got the trailer, I went to southern SD and picked up a load (grossing 79000#) and brought it towards home. I filled up the tanks at home and not again til I got back home. Got 9. 5mpg round trip, no BS.

They were getting around 6 mpg back then. I would have thought by now they would be over 10 mpg.

I do remember at this one trucking company the driver with the best fuel mileage would get a $250 bonus per month.

IF the engine companies were able to tune the engines for peak efficiency, and not emissions, with the technology we have today, I don't see why we couldn't see 6-9mpg more consistently on the bigger motors.

I know TMC pays fuel mileage bonuses to drivers. At least they used to when I was in tech school.

 

[EKlem]

Engine size is important in mileage but windage is much more important. Once you get to highway speeds, the majority of the power that your engine is producing goes into overcoming aerodynamic drag. Part of the problem with our trucks is that when you tow a high profile trailer, you aren't pushing all that much less wind than a semi. Since there is such a large weight difference, that does play a part too but drag is what is killing us which is why you can't scale the mileage by weight.

Yes, a smaller engine will get better mileage. The easiest way to think of it is if you are idling and producing no net power but are still burning fuel. That is super ineffecient. However, if you run full throttle, most of the power gets to the flywheel rather than is used to keep the engine rotating. Very generally speaking, the harder an engine is run, the more efficient it is because the percentage of energy produced that goes back into turning the engine is decreased. The other reason why smaller engines get better mileage is that they tend to have less power so they keep you from accelerating so hard.

I think that a 200hp 4bt with a 7speed would be a nice combo in one of our trucks.

 

[DCreed]

I heard a great many say that. But I dont think Dodge is listening, they are putting a V6 or V8 in the 1/2 ton. why? Havent the "other guys" shown how bad an idea that is?

 

[RHestand]

Engine size is important in mileage but windage is much more important. Once you get to highway speeds, the majority of the power that your engine is producing goes into overcoming aerodynamic drag. Part of the problem with our trucks is that when you tow a high profile trailer, you aren't pushing all that much less wind than a semi. Since there is such a large weight difference, that does play a part too but drag is what is killing us which is why you can't scale the mileage by weight.



Yes, a smaller engine will get better mileage. The easiest way to think of it is if you are idling and producing no net power but are still burning fuel. That is super ineffecient. However, if you run full throttle, most of the power gets to the flywheel rather than is used to keep the engine rotating. Very generally speaking, the harder an engine is run, the more efficient it is because the percentage of energy produced that goes back into turning the engine is decreased. The other reason why smaller engines get better mileage is that they tend to have less power so they keep you from accelerating so hard.



I think that a 200hp 4bt with a 7speed would be a nice combo in one of our trucks.

Ditto on the 4bt.

In Brazil, Ford has an optional 4bt in their F-250. If you had one of these with a G-56, Gearvendors, and the proper rear-end ratio, I think you could have the best of both worlds.

I have a nice 71 Chev. 3/4 ton Camper Spec. that I'm thinking about doing somthing like this to.

I would definately be interested in a 3/4 ton truck with a 4bt,preferably new and turn-key.