And the HP Wars Begin

[Lt CHEG]

Another reason to stick to the tried and proven Cummins diesel RAM with no Diesel Exhaust Fluid required and 350hp/650lb.ft. :thumbsup:

While simple is nice, I don't see the Cummins' lack of exhaust fluid as a good thing. Adding the urea injection to the Duramax seems to have significantly increased its fuel economy in an era where gasoline engines are getting better fuel economy than their diesel counterparts. Heck the hemi in my Durango G-Ride gets better gas mileage than the Cummins I test drove a month or so ago. Now I'd love to see what the Cummins could do with a urea injection system. It has always been a great performer and did so with excellent fuel economy, I'll bet the Cummins could beat out Ford and GM's diesels in fuel economy if they were to add urea injection.

 

[Dmace]

While simple is nice, I don't see the Cummins' lack of exhaust fluid as a good thing. Adding the urea injection to the Duramax seems to have significantly increased its fuel economy in an era where gasoline engines are getting better fuel economy than their diesel counterparts. Heck the hemi in my Durango G-Ride gets better gas mileage than the Cummins I test drove a month or so ago. Now I'd love to see what the Cummins could do with a urea injection system. It has always been a great performer and did so with excellent fuel economy, I'll bet the Cummins could beat out Ford and GM's diesels in fuel economy if they were to add urea injection.

Well I have yet to see any real world test prove that Urea Injection (Diesel Exhaust Fluid) actually improves fuel mileage. Plus, even if it did add a less than substantial increase in fuel mileage, that would quickly be offset by the fact that these trucks have about an 8-10 gallon tank (9.3lbs per US gal.) for the DEF that reduces the trucks payload plus you need to refill this tank at 3500-4500 mile intervals at a projected price of approx. $2.75 a gallon. Add to that the extra step of watching the levels of this DEF and having to find a station to refill it once it gets low.

The RAM cab-chassis (3500/4500/5500) Cummins powered trucks will get the DEF injection since it's much cheaper to add-on than the EGR system but the RAM 2500/3500 will continue to use the more expensive maintenance-free EGR system. It will be the only new truck with the EGR system since the other diesel manufacturers can't meet the more strict EPA regulations with EGR like the Cummins.

 

[Willl]

DEF is injected in to exhaust just before the CC thingy. The engine don't burn any of it.

How could it increase fuel mileage ?

 

[Dmace]

DEF is injected in to exhaust just before the CC thingy. The engine don't burn any of it.

How could it increase fuel mileage ?

Well with an EGR system, a portion of the exhaust is "recirculated" back into the engine to be "re-burnt" and needs to be filtered in the exhaust. When the EGR system regens, the ECU dumps extra fuel into the system to clean the particulate filter in the exhaust. This dumping of extra fuel is unnecessary with DEF but it is hardly a large amount so I doubt the DEF will make that much of an improvement. Only time will tell...

 

[jesnic]

I have an 02 dodge cummins. I am pushing around 550hp, maybe a little more. I get 22 mpg if I just cruise at 70 mph. Pulling 8,000 lbs. I get about 17 mpg still going 70 mph. The new ford is extremely expensive and extremely nice, but if you bought a cummins and saved $10K and spent about $5K on aftermarket performance mods, you could have a truck with way more power than the ford, better mileage and $5K left in your pocket. I will keep my truck till the wheels fall off, then put a new set on and keep going. The new trucks sure are nice, but WOW they are expensive.

 

[Lt CHEG]

I have an 02 dodge cummins. I am pushing around 550hp, maybe a little more. I get 22 mpg if I just cruise at 70 mph. Pulling 8,000 lbs. I get about 17 mpg still going 70 mph. The new ford is extremely expensive and extremely nice, but if you bought a cummins and saved $10K and spent about $5K on aftermarket performance mods, you could have a truck with way more power than the ford, better mileage and $5K left in your pocket. I will keep my truck till the wheels fall off, then put a new set on and keep going. The new trucks sure are nice, but WOW they are expensive.

While there may be merit to your option of buying used and upgrading, this discussion is about new models. I know in my case, I am not interested in buying used as I prefer to pretty much always buy new. Also there are some features on the new trucks that I much prefer to the older ones. For example a 2002 Dodge for example didn't really have a crew cab option, which is something that I require, while the 2011 Dodge, GM and Ford trucks all have a very nice, very roomy true crew cab.

You could also argue that one could buy a used Duramax or Power Stroke and invest heavily in performance modifications and save a ton of money over new. So the Cummins is not unique in that regard. Also I have no interest in heavily modifying any new truck that I buy as one of the reasons why I like to buy new is to have a warranty. I don't do things that void warranties. Also even if I bought one of the DPF bypass kits for the Dodge Cummins and it brought back a large amount of the fuel economy loss, it would mean that I would have to take it off and reinstall it every year before and after my vehicle inspection. This is not something that I am interested in doing, not even thinking about the legality.

Lastly, I'm well aware of the capabilities of the older Cummins engines. My uncle has a 2000 Ram with the Cummins and it is a great engine. His is modified slightly and it's turning out great power and also delivering 20 mpg unloaded on the highway, better if he could drive at a reasonable speed. He's also on his 5th transmission which is not uncommon with CTD's of that era, but that is beside the point. As I've said before the Cummins is the best diesel engine out there as far as I'm concerned. It's a true medium duty truck engine in a light duty truck. Its straight 6 configuration gives better access and it seems easier to work on by all accounts. However if the new Cummins engines do not do something to increase their fuel economy then that is a huge weakness in my eyes. If that means not using the platinum catalyzed EGR system and instead going to urea injection then I am all for it, and would consider a CTD. However, when Dodge is getting 15 mpg highway unloaded with an EGR system (even if it is simpler) and Ford and GM are doing better than 20 mpg highway unloaded (as verified by numerous real world testers on various forums and print magazines in the case of the Ford) then there is just no way that a CTD will work for me. I don't keep my trucks long enough to worry about extreme long term reliability, but getting good fuel economy is extremely important to me. So for now, Dodge and Cummins just do not offer the combination of features that I need. As I said in my previous post, if Dodge was able to get the fuel economy above 20 mpg highway, even if that meant going to a exhaust fluid injection system then that would be a huge step in the right direction for me. Based upon the reaction of others on this forum at the disappointing fuel economy of newer diesels I would wager that I'm not alone in that regard either.

 

[jesnic]

Very good points. I on the other hand have no need for the true 4 doors as my kids are grown and off to college. I also don't want to have a truck payment. My wife just bought a new Honda. It gets great mileage, but the payment I could do without. I figure I will eventually by another diesel truck, but for now, I will just wait it out and let the big three fight.

 

[Raspy]

Mileage may be improved somewhat with DEF because manufacturers have had to use EGR and retarded ignition to reduce NOX. These two things also reduce mileage and power. So, hopefully with DEF, they will be able to reduce the amount of EGR a bit and advance the timng a bit and still meet the emissions requirements. DEF converts NOX to nitrogen and water, so if a bit more is made in the engine, it may not matter with DEF.

DEF freezes at 12* F and the amount used is approximately 2-3% of diesel fuel. Cost should be between $2. and $3.

My '04 Dodge with the 305 engine was the last of the good mileage, no catalytic converter engines and I'm sticking with it. 04.5s with the cats marked the beginning of lower mileage by a small amount. Then the 6.7 Cummins with EGR and DPF got worse again. Next is the DEF engines with even more complication and we'll see about the mileage.

What a mess. Using more and more fuel, and requiring more and more complication and expense, seems counterproductive.

 

[Dmace]

What a mess. Using more and more fuel, and requiring more and more complication and expense, seems counterproductive.

So true! That's what the EPA is all about, a bunch of loud mouths with no real education or engineering experience...
Yeah it emits 25% less emissions but uses 50% more fuel, real bright! :mur:

 

[Diamondpilot]

I could never understand it either. That is the primary reason I have held on to my 04 and 06 Powerstrokes. They both turn in 17mpg average and can do low 20's on the highway. Neither has any fancy emission stuff and both have needed nothing but routine maintenance.

The simple fact is they will not last forever so sooner or later I will have to buy something different. Maybe in 2 years or so they will have them all figured out and we will be back to where we started.

Chris