Diesel milage

[jobar]

Anyone know what modern day diesel trucks get as far as gas mileage? A buddy said they get pretty good mileage. Im looking for an average on what they get?

 

[Hahnsb2]

Depends. My buddies 12 valve cummins gets 18 mixed and around 23 on trips. Newer engines with all the emissions junk get quite a bit less.

 

[JohnnyU]

My 04.5 CTD drops to about 14mpg IN TOWN during the colder months. It's not too hard to get 18mpg on the highway though. Burnside's 99 CTD get about 2mpg better than mine does. Anything 07+ can easily drop down into the single digits from what I've seen.

All of these numbers are EXTREMELY dependent on your driving style though....

 

[milje]

My 04.5 CTD drops to about 14mpg IN TOWN during the colder months. It's not too hard to get 18mpg on the highway though. Burnside's 99 CTD get about 2mpg better than mine does. Anything 07+ can easily drop down into the single digits from what I've seen.

All of these numbers are EXTREMELY dependent on your driving style though....

Less emissions, but gets half the mileage. Hooray.

 

[ford fanatic]

My 02 F350 Powerstroke 4X4 with 33's gets about 14mpg, but I have a heavy foot.

 

[LearjetMinako]

My dads 91' Dodge 2500 Cummis gets about 12~18 mpg city or 16~22mpg highway. Towing, it drops around 12~16mpg. This also with a new tranny (from a 3-speed to a 4-speed w/ OD, and 3.08 gears).

 

[Born24wheel]

My dads 05 f250 with the 6.0L is getting about 16-20, or 12-14 towing, and thats with stock tires. While on the subject, does anyone know how much performance chips actually increase mileage? Experience wise?

 

[hihoslvr]

Anyone know what modern day diesel trucks get as far as gas mileage? A buddy said they get pretty good mileage. Im looking for an average on what they get?

I think you actually mean fuel mileage, right? (hehe, just gotta bust yer balls a little) And are you wondering about pickups or big trucks? My '05 Freightliner Classic got about 5.4mpg's with a brand new ACERT Cat engine.

 

[Maverick]

My 04.5 CTD drops to about 14mpg IN TOWN during the colder months. It's not too hard to get 18mpg on the highway though.

All of these numbers are EXTREMELY dependent on your driving style though....

This is nearly exactly what my 01 F250 Powerstroke gets. And yes, it does depend on your driving style.

 

[jobar]

I think you actually mean fuel mileage, right? (hehe, just gotta bust yer balls a little) And are you wondering about pickups or big trucks? My '05 Freightliner Classic got about 5.4mpg's with a brand new ACERT Cat engine.

Pickups, sorry about that. I thought diseals got better mileage than that. Proves how much I know.

 

[philzilla]

I get 0 mpg when i put gas in my diesel

 

[Will]

Driving style matters a lot. A modern diesel with 300+ hp can use a hell of a lot of fuel if you use the power.

A diesels reputation for great mileage comes from the energy density of the fuel partially--it's sold and measured by volume and it quite a bit heavier than gasoline--about 20%, so there is 20% better mileage than a gasser right there. Then, a diesel doesn't have to restrict the air coming into so there are less pumping losses--that vacuum you are reading on your gauge is costing you efficency. There's probably 5% there. And since the fuel isn't compressed with the air like a gasser, the diesel runs a lot higher compression ratio which improves thermal efficiency and is probably good for another 10%. I think any diesel should whip any gas motors butt in mileage by 35%. But that means nothing if you spend all of your time with your foot down. And last is that a diesel makes more torque at low rpms because it always has too much air available and doesn't have to wait for it. That means no downshifting on hills. Having to downshift and always getting into the power circuit to gain rpms hurts your mileage a lot when you are towing. A guy with a gasser 460 knows he's going to pay a lot so he drives easier than the Cummins guy that thinks he's gaurenteed great mileage by virtue of having a diesel.

 

[Hahnsb2]

Pickups, sorry about that. I thought diseals got better mileage than that. Proves how much I know.

Most semis get 5-8 MPG, not bad when you consider how much weight they are moving.

 

[low_five]

heres a spreadsheet of every fillup Ive done since I bought my 07 duramax.
nevermind, I cant post attachments.

My best mpg is towing a trailer with all my belongings in 95 degree texas weather with the AC on. 20 mpg!

My worst was piddling around kodiak where I live 1 mile from work. 8-9mpg! no AC obviously, and nobody can accuse me of hotrodding it because theres an inch of ice everywhere. right now im back in the double digits and im happy

things you must consider.
1)some people have to run 4wheel drive full time, like me, in the winter
2)diesel is blended in the winter, which ive been told doesnt burn as well
3)people tend to idle the truck longer even if they dont realise it, even if you are just defrosting your windows
4)it takes heat to warm up all that iron, and no matter how you cut it, heat uses diesel, same with your cabin heater.
5)transmission fluid, differential grease, transfer case lube, power steering fluid is cold and thick and takes more energy to move it
6)high idle engaged will burn more fuel
7) ultra low sulfur diesel sucks balls
8) cold diesel wont atomize as well and wont burn as well

also tuners make a big difference in mileage, as well as huge tires and lifts.

the duramax has been real good to me though.

 

[low_five]

And last is that a diesel makes more torque at low rpms because it always has too much air available and doesn't have to wait for it. That means no downshifting on hills. Having to downshift and always getting into the power circuit to gain rpms hurts your mileage a lot when you are towing. A guy with a gasser 460 knows he's going to pay a lot so he drives easier than the Cummins guy that thinks he's gaurenteed great mileage by virtue of having a diesel.

also, they can pump fuel for almost the entire power cycle, so its powering the piston well past the initial "bang" of a gasser, contributing to torque. diesels also have long crankshaft throws, which add to the torque of the motor.