Hemi to diesel

2batruck · Jun 5, 2019

I currently have a 2013 Hemi 5.7 with 37 inch tires and a lift. I always have tools and supplies in the back and pull a heavy trailer once and a while a year. My truck also has 130k on it now. I found a good deal for a 3500 diesel ram who is already lifted and has 37 inch tires. I'm wondering if the diesel will get better mileage city driving but also pulling the trailer. If I want to trade trucks now is the time to do it as I already have 130k on it. What's your take guys?

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TatertotScott · Jun 5, 2019

I have been seeing guys posting 12-15 MPG hauling/towing with their 3500 Cummins trucks.

Not sure what terrain, but usually see them talk about 60 MPH.

I am excited to see what the Cummins gets with an 8 speed.

SOKY_RAM · Jun 5, 2019

I just went from hemi with 35's to Diesel with 35's. Any mileage increase you might see will be offset by the additional cost of fuel at the pump and oil /DEF/ fuel filter changes. I wouldn't base the decision on expecting any kind of money savings. However towing anything will be soooo much easier based on the added weight and torque. Is it single rear wheel or dual?

2batruck · Jun 5, 2019

SOKY_RAM said:
I just went from hemi with 35's to Diesel with 35's. Any mileage increase you might see will be offset by the additional cost of fuel at the pump and oil /DEF/ fuel filter changes. I wouldn't base the decision on expecting any kind of money savings. However towing anything will be soooo much easier based on the added weight and torque. Is it single rear wheel or dual?

It's a single rear. Dually is too hard to drive in the city. Need too much parking space. It only has 80k so it's not even broken in yet for a diesel lol

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TXCOMT · Jun 5, 2019

Hey, OP, I was thinking of doing the same thing not long ago, but based on input I received here, I've decided to stick with my Reb. I simply don't tow often and heavy enough to justify stepping up. While my 5.7's fuel mileage may pale in comparison to that of a 6.4 or a CTD while towing, I do it so little such gains end up being a wash at best.

TXCOMT

Scottly · Jun 5, 2019

If you buy a diesel, not only will you increase in length, but also in girth.

2batruck · Jun 5, 2019

Scottly said:
If you buy a diesel, not only will you increase in length, but also in girth.

Isn't that a good thing lol

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RLJ10X · Jun 6, 2019

2B, you don't say which tranny or final gears you have.

37 look really cool, but your truck was designed for 33s. I'd think you'd need 4.56s, at least. But regearing is expensive, your truck has a few miles on it already, and it sounds like you have new truck fever.

If you're going to pull a heavy load only a couple of times a year, why not consider renting a truck for a day or 2? Rent different ones. I love driving different vehicles. You'll figure it out.

0rion · Jun 6, 2019

TXCOMT said:
Hey, OP, I was thinking of doing the same thing not long ago, but based on input I received here, I've decided to stick with my Reb. I simply don't tow often and heavy enough to justify stepping up. While my 5.7's fuel mileage may pale in comparison to that of a 6.4 or a CTD while towing, I do it so little such gains end up being a wash at best.

TXCOMT

Just noticed today at gas station here....diesel and gas we're same price. $2.69. don't see that often but when I do it makes me smile.

MADDOG · Jun 6, 2019

I went from a HEMI (5.7L) to a HEMI (6.4L) and then to a Cummins and never looked back. The diesel just fits my needs to a T and the power is head and shoulders above the HEMI engines. The torque is amazing.

Diesel is priced between mid-grade gas and premium grade gas here, which is what I had to use in both HEMI trucks due to the tunes I had installed

. I've found that whether I am loaded or unloaded highway mileage is much better with the Cummins, especially when loaded. And it never runs out of power towing unlike the two HEMIs I had.

Around town mileage is not super better. Maybe I have a right foot problem.

buddy guy · Jun 6, 2019

Diesel is a lot more expensive to repair is it not?

RLJ10X · Jun 6, 2019

I used to drive a Package Car. That's a UPS Truck to the rest of the world. It had a Cummins paired to an Eaton 5 speed manual. It was a fabulous combination. That truck would be about 20 years old by now if they didn't retire and crush it. That thing weighed 9600 pounds unladen. I would make over 120 delivery and pick up stops a day. I shut the engine off at every stop. If I drove reasonably, that old Package car would still get almost 12 mpg.

I always said of that old package car: It's not that fast. But you can't slow it down. And I always enjoyed that engine and transmission.

I seldom use all my 1500 has. But if I ever needed some real muscle, I'd definitely go Cummins.

QwikKota · Jun 6, 2019

I don't think you can just throw a 1200lb engine into a 1500. The Cummins is a beast and requires a HD suspension and frame. The Hemi probably only weighs half of that.

TatertotScott · Jun 6, 2019

I don't think he is yalkung engine swap, but truck swap.

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QwikKota · Jun 6, 2019

TatertotScott said:
I don't think he is yalkung engine swap, but truck swap.

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Ah. When he said he had a lift I thought he meant a garage lift for engine work, lmao. I'm ******** this week.

muddy12 · Jun 6, 2019

Disregard, I type to slowly.

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0rion · Jun 6, 2019

buddy guy said:
Diesel is a lot more expensive to repair is it not?

Yep.....insanely more expensive. At the same time though 300k miles isn't an unreasonable expectation for mileage from a diesel. It's a tough decision. Would I own a diesel if I didn't absolutely have to? Nope. Do I regret owning a diesel when I'm towing my 5er? Never.

2batruck · Jun 6, 2019

I'm not too worried about repair costs. It will be a business vehicle and I can write part off for business expenses. I just took my trailer for camping and the Hemi works very hard going uphill. I do have 3.92 gears but with the big tires it reduces it to a 3.55.

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TXCOMT · Jun 6, 2019

I wish you guys would stop talking about the advantages of a CTD...my local CDJR dealer still has a few '18s left!

TXCOMT

Pull Ya · Jun 6, 2019

IMHO there is no reason you should need a diesel unless you tow heavy frequently---unless your laundering money through a gas station or dealership.
The initial cost and the maintenance cost are just to much more than a hemi or 6.4.
Jay

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