Diesel or Gas?

[twinpartners]

Went from a Dodge Ram 4x4 5.7 Hemi w/5000# bags to a 3500 4x4 MegaCab 5.9 Cummins with 4" exhaust. The gas/diesel mileage comparison was a dramatic change, not to mention the torque difference. There is no comparison between the two. Got less than 8-9 mpg with the 1/2 ton when towing and around 17-18 mpg without towing. The dual rear wheel mega cab is 5500# heavier and my combined weight is 21,000# with the Sundance 3000RK. That 5.9L (only .2L more than my Hemi) recently got 17 mpg towing from Louisiana to Florida at 60 mph. On the way back it went down to 14.5 when I drove 65-70 and around 13.5 up hills/bridges. In the city I get 22-24 mpg and around 19.5 if there is a lot of stop and go. That 4" exhaust makes a big difference. The rest is all stock and the computers/tuners only give about 1 more mpg, so they are not worth the money. Spend it in the exhaust or a cold-air intake and your money is much better spent. The key to better mpg on these Cummins monsters is to stay at 1500-1700 rpms. That is where the horsepower and torque are at their peak. Rarely downshifted even on the Baton Rouge I-10 bridge. Kept it at 1500 rpms and it went up without a single downshift and was still at 55 mph the whole way. Best money I have ever spent in this truck. I will be buried in it! Dave.

'06 Dodge Ram 3500 4x4 Mega Cab Cummins 5.9L Turbo Diesel DRW
'03 Dodge Ram 1500 4x4 Quad Cab 5.7 L Hemi with Firestone 5000# Bags
2011 Sundance 3000RK

 

[jetjarv]

Interesting I had the similar setup as the previous post. North trail 31qbs and a 2003 hemi. Did ok 55mph 7mpg. Now I have a 2006 cummins 3/4 ton. 16mpg highway or city empty. 11mpg towing best ever 65mph. When u r test-driving don't look at the trip computer. Nobody on the diesel forums has ever had a computer show actual mileage.

I believe identical trucks get different mileage. Why? No idea. I wouldn't buy the diesel thinking u will get this great gas mileage. Buy it because the big truck has big brakes, heavy duty suspension, heavy duty tranny, etc. It is nice to be able to cruise down the highway and u almost forget u r pulling a trailer with the cruise control at 65.

It definitely costs more to operate, but hey.....it's a guy thing ain't it?

 

[twinpartners]

jetjarv,

Get the 4" exhaust or go with the 5" if you can get your local shop to do it. It is a world of difference. There are tons of articles out there in most of the Diesel Truck magazines in your local rack at the bookstore/gas station. There are several simple inexpensive intake modifications that you can make to your 5.9L as well. If/when you get involved you will notice that there is a big cult following when it comes to 3/4 and 1 ton diesels. Stick with the solid mods that everyone in the diesel community know about. Work on the intake and exhaust side to get the most clean air in and the exhaust out as fast as possible. It called getting the diesel to "breath" better.

Also, when comparing diesel to gas, mpg was a big factor for me. At today's prices, getting 7 mpg more over a gasser amounts to 840 more miles when using my RDS and stock tank (120 gals). The gasser would cost me $402 to fill up and the diesel $432. So, I can get 840 more miles for $30. That is a big difference. Even if I used your example of only getting a 4 mpg difference (which sounds odd to me), that would still amount to an extra 480 miles for that $30. The extra cost of buying the diesel truck will pay for itself in the long run. Just do the math.

 

[caissiel]

I pull the 15.5K 5th wheel all over the eastern states and Canada and get 14 ImpMPG or 12USGPM any day at 62MPH. When towing a 26ft TT one slide last winter for a friend the torque required to pull his 6000Lbs trailer was way more then my 5th wheel. I used the Scangauge to give me all readings to compare different speeds and loads and I realy could not believe the difference and I realy felt it above 40MPH. Under 40MPH the TT felt like nothing was being pulled but wind drag and tire drag was absolutely noticable at higher speed, no way would I tow that trailer across country.

I just come back from an 80 Miles trip return on the local roads and with cruise on at 62 MPH I was getting a rate of 31 ImpMPG or 26.5 USMPG and on the return I was getting a rate of 39 ImpMPG or 32.5 USGPM at 55MPH. We own a Toyota Matrix 4 Cyl standard, and the best we ever got has been 42 ImpMPG or 35 USMPG and it was on the same road at 55 MPH and same calibrated gauge. I will not get that in a full tank due to the heavy truck in stop and go trafic, but Hypermileage with a diesel is very efficient and surprising how we can improve mileage, its a hobby and it pays back in a big way.

P.S. I never experience better mileage with exhaust and air improvemet, but realy got a big increase in power in a non turbo diesel and gas trucks. With a turbo truck the only improvement I saw was exhaust temperature and the need to change filters often with the K&N filter on a 6.5L GM Diesel.
But my Hypertech is great for fuel economy while driving at or above 2000RPM and power in the hills rocks. In addition I am able to keep the turbo pressure much lower when towing and save lots of fuel that way. While towing economy mileage is great at lower then 10PSI boost. I could not have commented on these observation without the use of the Scangauge results at different setups, and conditions. The Scangauge has been my best investment for fuel mileage, and readings while the Hypertech has been great for protecting the truck and power.

 

[mmomega]

IMHO, definitely go with the Duramax and also I would suggest looking for someone that has an EFILive and have them re-program the truck to give it just a little more "juice". You'd be amazed.
I also saw that you mentioned possibly trading up to a 5th wheel later on, I would seriously consider looking at a dually. Especially that you say you won't be driving it too often unless you were towing something around. My friend has a Chevy '07 classic 2500HD SRW 4x4, put some Bilstein shocks and Firestone airbags on the rear and after riding with me towing my trailer he said theres no doubt in his mind that if he went to a 5th wheel he would get a dually. He pulls a 30ft TT right now. My other truck is an F350 SRW with airbags and some upgraded suspension but just the stock dually I have now trumps it hands down in stability and control.

Just my 2 cents.

 

[jetjarv]

jetjarv,

Get the 4" exhaust or go with the 5" if you can get your local shop to do it. It is a world of difference. There are tons of articles out there in most of the Diesel Truck magazines in your local rack at the bookstore/gas station. There are several simple inexpensive intake modifications that you can make to your 5.9L as well. If/when you get involved you will notice that there is a big cult following when it comes to 3/4 and 1 ton diesels. Stick with the solid mods that everyone in the diesel community know about. Work on the intake and exhaust side to get the most clean air in and the exhaust out as fast as possible. It called getting the diesel to "breath" better.

Also, when comparing diesel to gas, mpg was a big factor for me. At today's prices, getting 7 mpg more over a gasser amounts to 840 more miles when using my RDS and stock tank (120 gals). The gasser would cost me $402 to fill up and the diesel $432. So, I can get 840 more miles for $30. That is a big difference. Even if I used your example of only getting a 4 mpg difference (which sounds odd to me), that would still amount to an extra 480 miles for that $30. The extra cost of buying the diesel truck will pay for itself in the long run. Just do the math.

I hear ya on all your points. I agree. I love my truck it is great. I don't need it; I only do shorter trips,but I really wanted the cab and I have wanted a diesel for a long time.

Point I was making, but probably didn't do a good job at it is that if you are doing allot of towing a turbo d is a great idea. For some summer weekend trips,the turbo d isn't needed.

When it comes to gas mileage you will get better, however for every person who gets 20+ empty and 14-15mpg pulling, you have another 100 people getting 16mpg on the highway and 10 pulling. Diesel power magazine just had an article out on it. They got my numbers. Why do two similar trucks get different mileage? Who knows. I agree with your mods, but imnot going to expect much with MY truck.

 

[jetjarv]

My new truck gets 4-5 mpg increase because of the diesel. I don't pull much so I will never see the benefit, but hey.....Abigail turbo diesel truck.....it's a guy thing....sweet.....100% worth it!

 

[caissiel]

Its been proven that diesels are 35% better on fuel mileage for the same truck. And Diesel has more BTU rating per gallon then gasoline.

 

[lwmcguir]

If you want the best bang for the buck out there get a new Ford 6.7

You will have the best trade in value if you decide to go a different way.

 

[Moose]

I went from a 2003 Dodge RAM 2500 Quad Cab 4x4 HEMI Laramie auto to a 2008 Dodge RAM 3500 MegaCab 4x4 6.7 Cummins Turbo Diesel auto.

I would never go back to a gasser. The torque is amazing. The fuel mileage is much better. The 6 speed selectable automatic tranny is great.

If I were to do it again I would give a dually a very hard look.

Friend of mine just got a GM 3500 dually D/A and it is a beautiful truck to drive.

 

[caissiel]

I would rater Buy a used Diesel truck than a new Gas truck. They are much better then you hear the Gas owners talk about them. And I do the same as you I use my truck for work and tow and only done 40K in the last 4 years. The Cars are my everyday go getter. But when I do use the truck its working hard towing something or loaded and the cost of ownership has been much better then any Gas truck I would own.

I bought a new GM in 98 6.5L for the same price my neighbour bought a New Dodge gas and when I sold it in 2007 after towing a trailer for 9 years I got much more money then the neighbour would have got for his and he just kept it after buyiing himself a used F350 7.3L for as much money I paid for mine also.

Get on the GM Diesel sites specialy Dieselplace.com. I was a member of that site when I owned my GM's and realy gained lots of knowledge about my trucks. Enough to save me lots in unnecessary maintenance repairs that some shops were doing to other trucks like mine. The 6.5L were lemons for most owners but me at the time, I had great services with mine, might be the best vehicle I have ever owned with very little maintenance.

The 2001 to 2004 have injector Issues that GM has warrantied for 7 years or more and I would study on that if the trucks are of age.
The 2005 is a short run engine that has its heating problems with heavy loads and 2007.5 and up is the DPF problems like all the 3 Manufacture has.

I bought my 2005 Ford 6.0L for 20K in 2007 with 70K miles, and for the past 4 years it has been a great performer, its much stronger then my previous GM but the GM was a caddy compared to this one. But my signiture shows my added toys that made my truck a gem to own. I always wanted to get back in a GM but I just could not tell myself to spend 30-40K on a high mileage truck at the time.