Looking to buy an 2002 cummins 5.9. What kind of mpg can I expect stock?? What steps would I have to take in order to get 20mpg or better?

 

What kind of 02 Cummins 5.9 are we talking about?

Is it a 3500 or 2500
Standard or Automatic
4.10s or 3.55s?

 

its an 02 2500 5.9, automatic

 

my stock 01 got 23mpg on a trip. Probably get better now with smarty.

 

A friend I have been talking to about diesels says he doesnt care what people say, a diesel always gets worse mpg than a gas.

Now I know the cost of maintainence is a bit higher than gas, more oil and changing filters more often, but what else is required that adds to the cost of owning a diesel?

 

My truck gets 20mpg at 70mph with the current mods, stock was 20mpg at 70mph. LOL!

 

I have a 96 diesel 2500 extended cab long bed 4wd. It has an 800 lb easy dumper in the back that goes everywhere with me. It has 410s I get 15-18 with it. My partner has a 98 Ram 1500 4wd gasser short bed with 355s. he gets 13-15. I cannot imagine what your friend is thinking.

I would not buy a diesel just for the fuel savings, but if you have work to do with your truck, there is a huge difference. if you don't buy a Chevy gasser. They ride nicer--like a car.

 

No disrespect to some above.... but, IMO, an automatic, 4x4 will not average much more than 18 mpg over an average tankful, and that's on the hwy.
We all have our "best ever" figures but.....?
I do regular 1000 mile calculations, to average out city, rural, heavy, empty.... and repeatedly get 16.5 - 17 mph!
And that's living in the country.
I'm also a long bed and at 7500 lbs with me and full fuel.... and I daily drive with just my Smarty and Mach 4's (about 400 hp).

texan 68 - you don't mention rear end gearing and you don't mention 2x4 or 4x4?? A 2x4 might realistically get 20 mpg.
AND, I disagree with your friend. I had a 99, auto, 4x4, 5.9L, V-8, Dodge pickup that would never get better than 13 mpg....anywhere!

And higher routine costs of a diesel are offset, IMO, by having an honest 350,000 - 500,000 miles vehicle/engine.

RJ

 

agree x50 no 1/2 ton 3/4 gasser either small block v8 or bigger v8 from dodge or ford or chevy. is going to get anything close to a 8000 lbs truck putting 300hp to 500hp on ground like our diesels. 5.2 magnum 5.9 magnum and 4.7 magnum very thirsty motors I have had them could never get better than 16 with the 4.7 empty. and i mean empty just me driving. really the maintnance of a diesel really depends on what you get yourself into. I like the fact that my truck has a 6 inch lift with 35 tires and over 8k lbs and probley have 500hp at the rear and I can change my smarty and get between 19-20 on freeway at 65mph I got close to 22 before I lifted my truck. edm injectors timing and driving habits to me are a big part in economy. tell your friend to get a toyota tacoma. he can get good fuel mileage and when he needs to haul or tow anything tell him to put his truck in back of your diesel

 

I routinely get 24 MPG on the summer fuel. My last tank was 24.2.

Any box that's adds timing will increase the mileage. The SO trucks will usually get 1.5-2 mpg. Some more, some less.

I get close to 20MPG towing my jetsled at 70MPH.

But it's in the setup. I have a cam and some other components that clearly have helped my mileage.

Dave

 

Not sure on the gearing? How do I know? Is it an easy change, say if I want to gear to get better mpg? Sorry for all the questions, but I have been driving gas most of my life. Truck now is a ford with the 5.4 triton..getting anywhere between 14-16....killing me. I have tried everything but a cold air intake, and nothing does much. Mileage is getting up to near 171,000 now, and i'll be needed to buy a newer truck shortly. I was gonna go duramax, but the fuel injector problems scared me off.

Now I know the older trucks get better fuel economy, now that the newer models have cats and what not....is it a big change in mpg?? between new and old?

I was pretty set on buying something a little over 100K miles, but I'm affraid the maintainence will be costly.......is this true?

 

Take VIN # to Parts Dept and ask for "Build Sheet". Should be free. Will list all components from factory!

Changing gears will get expensive. Take a lot of miles to repay the cost. You want 3.55 rear end gears for best mileage.

RJ

 

about how much?

 

Over $2,000.00! Closer to $2,500.00 if you have someone else do the work!
Remember you have to change the front axle gears also!

RJ

 

No comparable big gas engine will come close to mpg that a diesel will. You would need the 8.0 liter from chevy to have close power and you will get 10 mpg no matter what. At least that is what 3 guys from work get with theres. The old 12 valve dodge diesels were noted for gettin great fuel mileage, but were much lower on power. You can get a lot more power out of them than stock, if you do, i don't know what your fuel mileage would do. I haven't dealt with them. I know i love my 24 valve and the fuel mileage i get with it.