I am looking to rebuild my truck from the ground up. I want a diesel for the increased power, longevity and fuel mileage. The final result will run 37" tires, have a 4.56 gear ratio, and have my NV4500 behind the engine. I had been told that the 5.9 Common Rail was a superb engine due to increased programming options. But I've been eying the very new 6.7L engines. The engine will be purchased along with the truck for the harness and ECM and such. But I wonder if the bigger motor is worth it. I could probably take the savings from buying the 5.9 and pump it up well past the 6.7.... AAARRRGGG! I am a patient man but I need to know what I want.

P.S. The gear calculator said I'd run about 2100 RPM's at 65, which is most of my driving. Is that too high, does a diesel like to cruise lower? Can anyone tell me what kind of fuel mileage I can expect?

 

you're right about the 5.9 cummins, it's a great long lasting engine that you can build up to surpass a 6.7. there was guy on DF that was gonna drop a 6.7 in his 2nd gen.

 

5.9L

the 6.7L has all of that emissions garbage on it that you would need hard to obtain delete programmers for...

the 5.9L doesn't come with any of that crap.

as for your gears...don't bother. I have 4.10's with my 35's and I HATE them... I would LOVE to have 3.54's in this thing with the 35's.


diesels are not like gassers...when you lug a gasser it is just kinda stuck lugging, and they have the extra rpm's to make up for running lower gears..

turbo diesels on the other hand don't know what lugging is...

when you are low rpm and load up the engine, know what happens?! the turbo spools harder and the engine makes more power to overcome the load on it

turbo diesels don't have fixed points in their power band like gassers...they can make 100% power at 1500rpm, or at 3200rpm... or anywhere in between....coming up to a steep hill? no problem...give it more pedal and that turbo will pull you up that hill with authority in high gear!

I wouldn't go past 4.10 with 37's if you put a diesel in it... remember 3250rpm is redline in the cummins... 1500-1800 is a good cruise RPM.

4500hd should be fine for the trans, but your transfer case needs to be a 241DHD. also need a dana 80 rear and dana 60 front.

dana 70 won't hold up to a common rail. dana 70 wont hold up to my engine either lol..

 

I will move you to the correct location on the forum to get more answers.

 

Interesting... Is the Common Rail the way to go? Understand, this is my baby. I bled for her for 7 years and I love her. I am not afraid of splicing and re-wiring, and I can find wrecked trucks from time to time.

 

Yeah go 5.9 for sure. I've got an 05 5.9 cummins one ton four door long bed and that thing is a pulling machine. I have a bully dog chip for it and holy cow it makes a difference. I have it set to tow/economy mode now but when you put that thing on the extreme mode it wants to run...the stock transmission doesn't like it though, it'll slip in 4th, 5th and 6th gear if I keep on it (6 speed manual) usually have to back off. How about a 12 valve cummins? those motors are very strong and run forever. They are very popular and might be hard to find for a decent price though.

 

PowerStroke!

 

I've had both the 5.9 & 6.7 Cummins and if I was building a truck and lookin to put a new diesel engine into it I would go with the 6.7 every time. All the smog stuff is REAL EASY to bypass and there are tons of tuners out there that will do it. My 08 Mega cab with the 6.7 and 6 speed tranny was awesome. The 06 Mega cab I now have is a great truck too but with no internal modifications to it that thing had POWER!!!

I am a little curious as to how your going to get that diesel into your 1/2 ton truck? Are you planning on getting a frame along with the engine?

 

Yeah, I'd be looking for a diesel 2500 or 3500. You know, since they already made a Dodge with a diesel in it....


You'll want to reinforce the entire front frame section, get higher rate springs, and if you are towing I'd go 8-lug 70 or 80 in the rear, which means hopefully upgrading the front to a 60. Be better off to just get a diesel truck IMO.

 

Don't make me high-five your face!!!

And yes, the donor truck will be purchased complete, but as a wrecked vehicle. I can get those from time to time and just have a salvage title, which doesn't bother me. But the 6.7 would come from a newer truck, be more complex and cost more. If there is just a small amount of improvement, I think the 5.9 Common Rail would be good. It would come from an 03 or newer, right? And they are more tunable?