5.9L or 6.7L?

Hi All,
I will be purchasing a 07 CTD
Not sure if I should go with a 5.9L or 6.7L
I know the 6.7L has more Power but I do not want all the emissions crap to deal with.
I will be putting 2 8" Stacks on whatever I purchase.
I do not have inspections where I live and Its not an issue.
Let me know what you guys think.

My personal vote is a 5.9 but if you find a 6.7 that you like go for it. In stock form the 6spd auto is nicer that the 48re in the 5.9 trucks. At the moment there are not alot of options if you are plaaning on making alot of power and using the 6spd auto.

Assuming that you are buying used and are not worried about the warranty, a 6.7 truck with a full delete package is a nice setup. It really depends on how much money you will have to spend on the truck after you buy it. They are both extremely addictive.

Its a tough question to ask. I've never owned a 5.9 so I don't know if I prefer to a 6.7.

If you don't have emission testing or inspections - the emission problems can be solved fairly easy. Buy an XRT or Smarty, $60 EGR delete kit and run your stacks. Then, the 6.7 will be exactly like a 5.9, but with a better stock transmission.

The only two differences between the two, from a driving and ownership perspective is the emission system and transmission.

They both make similar power, at the same rpm range, both have the same service intervals and schedules. The 6.7 has the emission system to deal with, but has a better stock transmission for extra power. The 5.9 has no emission system, but a worse stock transmission.

If you are building a performance truck, you can upgrade the 48RE to hold all the power you want. And, you can swap one behind a 6.7. All the turbos, exhaust manifolds, intercoolers, etc. that go on a 5.9, can go on a 6.7 (excluding injectors).

Like I said, I've never owned a 5.9. But I do love my 6.7 with the deletes and tuning.

I am going to go with a 1 ton dually.
I want all the towing capability I can have.
I know very little about Diesel Mods as I have been a Gas guy all my life.
So when you say 48RE I have no Idea what your referring to.

Originally Posted by befast0rbelast

I am going to go with a 1 ton dually.
I want all the towing capability I can have.
I know very little about Diesel Mods as I have been a Gas guy all my life.
So when you say 48RE I have no Idea what your referring to.

That's the automatic transmission that is in the 3rd generation 5.9's.

I've had both and the 6.7 bone stock is as fast as a 5.9 with edge EZ and straight piped. I wouldn't go back to a 5.9

Be careful with major modifications like completely removing the DPF and EGR systems if you know nothing about diesel engines. It's not as simple as "cut it off" even with the new programmers you need to know a little to make sure it is not screwed up. A good shop can do it for you, but how would you know when you found a good shop???? If you just want to tow heavy and have a good running truck there is no reason to have to pull the emissions systems off and add stacks, they are more for looks unless you are adding super high power and need the higher flow and lower restriction in the exhaust which stacks don't make any difference really. If you are bent on the stacks just for looks (b/c they're bad ass only) then just buy a 5.9L truck and be done with it. If you just want a good truck to tow with and have cash then buy a new one with the 6.7L, most of the bugs are worked out on the new ones and just leave it alone for a while and see if the emissions stuff gives you trouble.

Personally, I would jump on a 6.7. Granted, the warranty would be voided before I left the dealer's lot and within hours, all the emissions equipment would be sitting in a pile.

I mean, it's a Cummins with almost an extra liter of displacement. Why wouldn't you want that.

Originally Posted by me1magoo

Be careful with major modifications like completely removing the DPF and EGR systems if you know nothing about diesel engines. It's not as simple as "cut it off" even with the new programmers you need to know a little to make sure it is not screwed up. A good shop can do it for you, but how would you know when you found a good shop???? If you just want to tow heavy and have a good running truck there is no reason to have to pull the emissions systems off and add stacks, they are more for looks unless you are adding super high power and need the higher flow and lower restriction in the exhaust which stacks don't make any difference really. If you are bent on the stacks just for looks (b/c they're bad ass only) then just buy a 5.9L truck and be done with it. If you just want a good truck to tow with and have cash then buy a new one with the 6.7L, most of the bugs are worked out on the new ones and just leave it alone for a while and see if the emissions stuff gives you trouble.

Actually, the emission system is REALLY easy to remove. Much easier than on a Duramax or PSD. The EGR delete takes about 30 minutes with basic hand tools (plenty of step by step instructions online). To remove just the DPF, it involves loosening 8 bolts, unplugging some sensors, dropping the DPF, and installing a piece of straight pipe. Probably an hour worth of time. For a complete turbo back exhaust (new downpipe, DPF and Nox delete pipe), probably two hours - with basic hand tools.

With the Smarty or XRT, you can remove all emission components, be code-free, and the tuner does all the work. So about 15 minutes of tuning time.

So for 1-3 hours of work, with basic hand tools, all the systems can be removed.

In my opinion, the bugs will never be worked out of the 6.7's as long as they use an aggressive EGR system. Sure, they play with the parameters with each new flash, but the turbo, intake grid, intake horn, and oil all take a beating with all the soot that is recirculated.

From what ive read(and only know from reading) if your going to do a lot of performance mods the 5.9 is the better choice but if your just going to run stock then there is nothing wrong with the 6.7 might even be better.

a stock 6.7 will not get as good fuel mileage as the stock 5.9.
I would say go to a 6.7 but as soon as you go to a DPF delete you can not run it with out a programmer that fools the DPF system. if the programmer is removed it will throw codes but doing the DPF delete will gain you at least 2mpg.

my vote is for a 5.9. tested and proven easy to mod

Originally Posted by reddot

From what ive read(and only know from reading) if your going to do a lot of performance mods the 5.9 is the better choice but if your just going to run stock then there is nothing wrong with the 6.7 might even be better.

That's partially true. 5.9's have a wealth of parts. However, 6.7's can use any 3rd Gen 5.9 performance turbo on the market, intercooler, exhaust manifold, etc. The only parts that are not interchangeable are the CP3 and injectors.

Heck, you can even swap a 48RE into a 6.7 truck. There are plenty of 6.7's making over 750 hp. Obviously, not stock. But I know of one guy making 700 rwhp with a 66 mm turbo, 80hp injectors, Wicked Diesel CP3, Smarty and upgraded intercooler. There are some compound twin turbo 6.7's making between 750-800 rwhp.

6.7's aren't quite on the level of 5.9's making 1000 rwhp. But it won't be long before they are there.

Interesting info, I would be nervous to recommend that kind of surgery to someone who knows "nothing about diesels" for sure though. How would they know if there was a problem if the tuner is fooling everything into showing no codes or warning lights to them? I guess if someone has enough money though it doesn't matter, just dive in!

Originally Posted by me1magoo

Interesting info, I would be nervous to recommend that kind of surgery to someone who knows "nothing about diesels" for sure though. How would they know if there was a problem if the tuner is fooling everything into showing no codes or warning lights to them? I guess if someone has enough money though it doesn't matter, just dive in!

The tuner only turns off the emission system codes - not the hundreds of others that are unrelated to the DPF or EGR. They've done a good job of just turning off the 6-10 emission system codes and leaving the rest active.

I am betting most that voted 5.9 have never owned or even driven a 6.7

I'm not a betting guy. But I'd buy a 6.7 and drive it a year or two then mod the hell out of it.
Still love my 5.9

I have owned 5 5.9L Cummins Dodges............Simple and very reliable! I had NV5600's and G56 Manuals and Loved them. Did have a 47re and a 48re that both gave me issues at very low miles. I know that there are allot of people that have 100k + out of stock tranny's at stock power levels......My luck with auto's sucks!!! The new 6.7L is a great engine for what it was designed to do- - -Haul and TOW HEAVY stuff...... No grocery getter and that is where the problems are occuring. Drive like a grandma to the store and back and you will be in Regen all the time. That equals poor mileage! If you are towing heavy and dont really care about 18+ MPG on the Highway empty get the 6.7l. If you are like me and like 99% reliability then get the 5.9l with a G56 6-Speed Manual. OR a 5.9l with a built tranny and the motor at stock levels. The 6.7l is awesome! The EGR junk and regen is NOT! Yes I have drove a 6.7L... Towed with a 6.7L..... With the G56 it is slower compared to a 5.9L...... With the Auto- - - -= Faster

To me the way you are talking you want the biggest badest truck you can get. In that case you will want the 6.7.

But if you want stacks the emissions stuff might make it a little hard to do with a 6.7, you might need to move some of the exaust componets around if you dont to the PDF delete. With a 5.9 you can just cut the exaust under the cab and bring it up though the bed.

I have driven both and drove both at the time that I bought my 07 5.9 Megacab. In totally stock form I did like the 6.7 more due to the transmission probably and the engine brake was a nice feature. In the end I ending up getting the 5.9 because I couldn't come to grips with paying more money for a truck that got worse mileage and was only "slightly" faster. The addition of an EZ got my 5.9 to where the 6.7 felt as far as accelleration without all of the worries of the emissions junk that I got to pay extra for and then would have to pay more to remove just to get back to the mileage of a 5.9.

Granted, at the time I was able to still find some new 5.9's on the lot and the 6.7's were having alot of problems. Fast forward to 2009 and the "new" 5.9 is not an option and there have been big strides in both improvements from Chrysler as well as the aftermarket. It will untimately come down to what you can find for the money and what you are willing to do to the truck to achieve your goals.

[quote=Skyd Ram;3212169]I have driven both and drove both at the time that I bought my 07 5.9 Megacab. In totally stock form I did like the 6.7 more due to the transmission probably and the engine brake was a nice feature. In the end I ending up getting the 5.9 because I couldn't come to grips with paying more money for a truck that got worse mileage and was only "slightly" faster. The addition of an EZ got my 5.9 to where the 6.7 felt as far as accelleration without all of the worries of the emissions junk that I got to pay extra for and then would have to pay more to remove just to get back to the mileage of a 5.9.

QUOTE]

exactly how I based my vote. My buddy brought 6 dodges over to my house with 6.7s in that he was thinking of buying and I drove each one. they are nice but modding and fuel mileage was a concern with me.