its not the weight of the load that kills me. its the drag. i can haul 2 cars at 16+mpg no sweat. i hauled a 64 chevy van (scooby doo van) alone on the same trailer, got 13mpg lol. its a flat dragging front end. i could feel how much more i had to press on the gas to get it at the same speed.

 

If you are at or below 55 MPH, then your numbers are believeable in my opinion. Damn good by most estimates but not everyone has an intercooler and turbocharger either.

I don't see what the big deal is.

 

I'm must not be making myself clear. I think you are talking about making power and I'm talking about long life and dependability. Two completely different things.

I agree, there is nothing to keep a v block from haveing as long of a stroke as an inline but, as you said, as a general rule they don't. That long stroke is good for torque. The inline crank has more main bearings, that's good for strength. It's also heavier being longer, more rotating mass, also good for torque.

Vblocks also tend to turn more rpm's than inlines. Add that to the fact V8's have more pistons and rod's bouncing up and down on fewer main bearings and they beat the mains out of them. Vblocks tend to flex more which is also hard on the main bearings. You rarely see an inline with bad mains but it's not that uncommon on Vblocks. Also rear main seal leaks are more common on vblocks because of the same reason. Cam bearings are also abused by the flex of a vblock. Add that to the main bearing abuse and it's not uncommon for a high mileage vblock to have low oil pressure issues.

Could a Vblock be strengthened enough to solve these problems? Of course, but then it would be to heavy to be practical. There is no doubt that a vblock can produce as much or more power than an inline but for the long haul (million miles plus) the long life and dependability is not there.

AS for the brand loyalty comment someone made. I'm not brand loyal at all. If it makes diesel smoke I love em all. Yeah, I'm a dieselholic.

 

What is really funny to me is when I started my driving career I was the proud owner of a 1960 Autocar.
NH 220 Cummins with a 10 speed cable shift Road Ranger transmission.
743 Cu In displacement, between 500 and 600 foot pounds of torque.
220 HP at sea level with a 5% reduction in power for every 1000 feet of elevation increase.

And I was running the entire east coast and west to the Mississippi.

73,280 pounds gross weight or toward the end of that trucks life the weights were increasing to 80,000 pounds in many states.

Everyone thinks 15 or 20,000 pounds with a 185 HP engine makes for a slow truck.

How would you like to try the continental divide on either side of the country with a 220Cummins engine and a 73,000 pound vehicle?

You guys don't even know what slow is.

Come over here in WV and try a 100,000 gross weight load of bark with an R model Mack with a 237 HP Maxidyne engine and a five speed transmission on the state highways, narrow roads, lots of curves and hills.

I could walk faster that that truck climbed the hills.

Today everyone is in such a hurry.
I find it amazing that the 2011 6.7 Power Stroke diesel has twice the HP in a pickup than the trucks I used to drive cross country in grossing over 73,000 pounds in.

I also find it amazing that the IDI in stock NA form has within 40 HP of what I used to drive carrying loads like that cross country.

Yes the 220 Cummins had more torque, but still 220 HP at 2100 RPM and at sea level was it.
Get up to 5000 feet in elevation and you are down to 165 HP.
Heaven forbid you had to cross the Rockies, 10,000 feet and you were down to 110 HP.
Loveland Pass, 12,000 feet, 88 HP.

One thing to point out here, the NA IDI diesel suffers from the same power/elevation problem the 220 Cummins engine had since it was not turbo charged either.

 

Dave S. it sounds like me and you run a lot of the same roads. My first OTR job was driving a 1964 C60 Chev, single axle. It had a 292 inline six.. gas burner. LOL I pulled a 40 foot van trailer loaded with construction jacks grossing right at 60k. Talk about slow. It had a 5 speed and 2 speed axle.

I remember on particularly slow day I was headed toward New Mexico for a job. All across Oklahoma I bucked a 30 mph headwind. 14 hours of 4th gear low range. I set a record breaking speed that day of 35mph and that was going down hill. LOL Ah, the good ole days.

 

its worth noting that those 60's hp rating were all day every day ratings you could run one of them right at its limit all day long and never have a problem

I have a feeling that one of them 400hp powerchokes they getting ready to put out would kill itslef inside of a half hour if you just threw a brick on the pedal

 

I understand what you are trying to say but I can't say I agree with all of it. Best to leave it at that.

 

What is your total weight doing this and what type of load? There isnt a single stock or modified Cummins,Power Stroke,or Duramax in my area that gets 16 mpg loaded (20,000 lbs total).I live in some fairly flat country too except if you go east.Some of the new ones are doing good to get 16-17 mpg empty.

One thing not mentioned is that low sulfur diesel has hurt our power and fuel mileage.

 

*Shudder* Brings back bad memories of hauling loads out east. Real fun trying to find parking in some areas to shut down for a couple hours of r & r. Every single place to park is packed full. Even still, I miss trucking.
VT247

 

as stated many times over. 2 cars on a 32.5' deck trailer. 20k total weight. And my dads 02 psd gets the exact same mpg same load, same runs.

 

I own both, and I can tell you that my IDI with the old non gated Banks turbo was much faster than my Cummins was stock, and until I got the Cumins past 25 psi of boost, it was pretty close, but, the 6.9 has a locally built IP, not a stock one, and would easily make 15+ PSI. The Cummins now pegs my 35 psi guage, it's still stock other than much monkeying with the IP...
Put a trailer behind them, and then you see the difference, the Cummins will happily motor along with 3.54's, 35's, and 12,000 lbs behind it at 60 in 5th gear, while the 6.9, with with 33's and 3.54's, pulling the same trailer and load, you had to keep it in the sweet spot around 23-2400 rpm and drive it like a Detroit using gravity to your advantage, otherwise you would be grabbing gears on every hill to hold 65, highway towing at 55 just wasn't doable thanks to the non gated turbo, rpm was too low to make any decent boost.
As far as fuel mileage goes, The IDI ran somewhere around 16-17 empty. A recent tank without the turbo returned 19, that's all with a criuse speed around 55. Loaded, it was 12-14 on average with the turbo on it.
The Cummins, it runs around the 20-22 mark empty, and rarely drops below 16 towing. But, I can also run slower and with quite a bit less rpm that the 6.9 could.
My PSD delivers very similar numbers to the CTD mileage wise.
If you want sloooow, we have an 88 at one of our bases set up as a de-ice truck, between the weight of the manlift, boilers, genset and de-ice fluid, with a full 1000 gallon load it weighs 23,000 lbs(has a 10,000 tag axle behind the rear drive axle.) It's 7.3/C6 4x4, has about 4600 miles, and runs like brand new, put it in high range, and just to get it to move from a dead stop it requires about half pedal on nice smooth cement.

 

To get 16 mpg pulling 20,000 lbs takes 300 plus horses with enough torque that you dont have to turn lots of rpms. Are you saying that you have a 300 horse IDI?



Here I am in mid April on the Mississippi River ferry at Hickman,KY.I weigh possibly 17-18,000 lbs and often struggle to pull this load in 4th gear on level ground,especially if its windy which it was that day..The funny thing is I can weigh 24,000 on level ground and still get 7 mpg.I wouldnt attempt a load that size with any hills.


A rear view of my load.Its a 900-1000 horse 180 Allis puller on menthanol that pulls the 6000 lb class.
http://www.youtube.com/watch?v=K-aJCRipn4U

A video of it in 2007 with different sheet metal.


Heres the load that headed back to KY from the MO side.

 

truck weight is 8400, trailer apx 12000. And I'm not sure the hp, but it's no where near 300. But I'm still getting 16+ mpg and I don't give a flying f**k if you believe it. I don't take kindly to being called a liar.

 

Maybe Oreo's jacked up ride height is helping with the aerodynamic drag to the trailer load.

 

Sorry if I got under your skin but when I see mpg figures like that I tend to be somewhat skeptical as do most people.

If I absolutely knew that I could get 12-14 mpg pulling 18,000 lbs at 55-60 mph I would build a 7.3 similar to yours.I have 3 choices,live with what I have,part my truck out as no one around here wants it,or buy something else.