Fuel economy with a diesel truck ?

[drtydeed]

Builder,

Thanks again. Yes, mine has overdrive but it can't be turned off with a button, just have to shift down to 3. I just thought that 5.13's are a little low, but I realize that the 6.5TD is not a real powerhouse. But again, for what I need it for it should not be a problem.

I do have a service code coming on now for "turbo boost performance". That could be a little costly , but we'll see.

Yes, it was a state (or municipal) truck (with 57K on it). But most importantly, it had a "landscape bed" with sides that fold down. My machine cannot reach high so it's perfect for what I need.

 

[drtydeed]

Oh Yeah, and the nasty color matches the Kubota..

 

[Builder]

Builder,

Thanks again. Yes, mine has overdrive but it can't be turned off with a button, just have to shift down to 3. I just thought that 5.13's are a little low, but I realize that the 6.5TD is not a real powerhouse. But again, for what I need it for it should not be a problem.

I do have a service code coming on now for "turbo boost performance". That could be a little costly , but we'll see.

Yes, it was a state (or municipal) truck (with 57K on it). But most importantly, it had a "landscape bed" with sides that fold down. My machine cannot reach high so it's perfect for what I need.

Maybe it's just a simple lose hose clamp.

 

[DavidVT]

99 Dodge 2500 3.54 4x4 solid 23mpg on the highway
mild oversize injectors
Stacked first Gen 'Edge' box with 'Smarty'

MPG always seemed to improve as HP was increased. The overhead computer thinks it is even better than reality but that is due to the fueling added by the boxes.

 

[drtydeed]

Maybe it's just a simple lose hose clamp.

Well, I'm not hearing any turbo whine. I think it's gonna take some more investigating. I do recall reading about some problems with waste gates on these. Did find a pretty good site www.dieselplace.com, will check for codes on there.

 

[john_bud]

, what is that "sweet spot" on a tach ?
Jim

Normally, the mpg sweetspot is where the torque peak occurs. Turbo diesels will have that point around 1600 rpm. It's tough to run there, but between there and about 2000 rpm seems to be generically pretty good. Economy really seems to tank after 1900-2100 rpm. Every 100 rpm you seem to drop a mpg. If 2000 rpm is 55 mph, you will probably be at 1650 or so at 45 mph. (Funny, that matches what Builder said. Almost like he knows...'cuz he does!)

Don't forget wind resistance goes up much faster than speed and trucks are as aero as bricks.

jb

 

[gemini5362]

I believe on the duramaxes the best fuel economy is supposed to be around 1800 rpm. I know that if I keep mine down to around 2000rpm I get really good fuel mileage. Unfortunatly that is about 70 and I rarely drive that slow

 

[MrJimi]

JB I agree with ya 100%, That Builder guy does know his stuff !
Thanks Builder
Jim

 

[Diamondpilot]

Normally, the mpg sweetspot is where the torque peak occurs. Turbo diesels will have that point around 1600 rpm. It's tough to run there, but between there and about 2000 rpm seems to be generically pretty good. Economy really seems to tank after 1900-2100 rpm. Every 100 rpm you seem to drop a mpg. If 2000 rpm is 55 mph, you will probably be at 1650 or so at 45 mph. (Funny, that matches what Builder said. Almost like he knows...'cuz he does!)

Don't forget wind resistance goes up much faster than speed and trucks are as aero as bricks.

jb

That is why the Ford 6.0 gets good millage, its peak torque is 1900 rpm. Thats 79 mph on my truck with 3.73 gears.

Chris

 

[john_bud]

That is why the Ford 6.0 gets good millage, its peak torque is 1900 rpm. Thats 79 mph on my truck with 3.73 gears.

Chris

Yeah, I've heard the 6.0 gets good "millage", but I'd rather get good "mileage".

Just yank'n yer chain over a typo!

But seriously,what do you get at 79 mph>? 15? 20? 25? The Duramax is at 20 at 75 mph in the summer. 2000 mile trip to Yellowstone averaged 20.6 and speeds were mostly 75. At 80, it's notably less.

That's why around here, I drive like a Q-tip. People expect to see a wisp of white hair and 2 knuckles on the wheel when they zip past me.