# 6.7 cummins?



## bluefarmer (Oct 10, 2010)

Friend of mine is looking at a 2010 dodge 1 ton with a 6.7 cummins with 40,000 miles, good, bad, or what we don't know much about that motor


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## MT hayer (Mar 1, 2014)

Throw the emissions in the rhubarb and you will have a good pickup, both mileage and power. Keep the muffler on though.


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## JD4030 (Apr 3, 2014)

My 2008 3500 dually 6.7 w/6 speed manual is a great truck, totally stock, no programmer, 62,000 and no problems. I would buy another one and highly recommend the Cummins.


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## Gearclash (Nov 25, 2010)

> Throw the emissions in the rhubarb and you will have a good pickup, both mileage and power.


A mechanic friend of mine had a 2007 6.7 that he did this with, and unfortunately could not get an acceptable mileage out of it. The very best he could get was in the 13-14 mpg empty, no trailer. He was so frustrated with it that he sold it and bought a 98 24 valve, and gets 16-19 mpg. Both trucks were 1 tons, both manual trans.


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## mlappin (Jun 25, 2009)

Gearclash said:


> A mechanic friend of mine had a 2007 6.7 that he did this with, and unfortunately could not get an acceptable mileage out of it. The very best he could get was in the 13-14 mpg empty, no trailer. He was so frustrated with it that he sold it and bought a 98 24 valve, and gets 16-19 mpg. Both trucks were 1 tons, both manual trans.


I have a '99 24 valve cummins. cold air kit, modified waste gate, Juice Edge programmer and routinely get better milage than the guys at the VFW with the newer trucks. Most of them are dually's with like 4:11 rears while mine has 3:55's. That could play a large part.


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## hog987 (Apr 5, 2011)

I had a 91 dodge with the cummins. Great fuel miliage. Now i have a 2010 ford. Not as great. BUT. When you think about it. First the new engine is putting out over twice the horsepower and 1.5 times the torque. Also the new ford is 50% heavier. When i compair the fuel usage per hour per horsepower it is not so bad compared to other things on the farm.


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## Dill (Nov 5, 2010)

I've got a 6.7 in an 08. I pulled the dpf at 58k, wish I did it and mile 1. Just like most DPF systems it robs mileage. With it I was lucky to get 17 empty. It plugged completely at 57.5k and Dodge replaced it. But its not fun having a truck go into limp mode with cows in the trailer. The service adviser started to give me the stock Dodge line about not working the truck hard enough, which the mechanic squashed pretty quick. That truck has worked 97% of its life. Anyway, now I just running a tune for now egr or dpf and I'm getting 20 hauling the sap tank around.


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## mlappin (Jun 25, 2009)

hog987 said:


> I had a 91 dodge with the cummins. Great fuel miliage. Now i have a 2010 ford. Not as great. BUT. When you think about it. First the new engine is putting out over twice the horsepower and 1.5 times the torque. Also the new ford is 50% heavier. When i compair the fuel usage per hour per horsepower it is not so bad compared to other things on the farm.


Yah, original cummins in those were pretty anemic at best. Like maybe 190 hp. Don't think the original transmissions could handle much more than that.

Some guys that hop the cummins way up actually prefer the twelve valve over the 24 for some reason.


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## JD3430 (Jan 1, 2012)

Dill said:


> I've got a 6.7 in an 08. I pulled the dpf at 58k, wish I did it and mile 1. Just like most DPF systems it robs mileage. With it I was lucky to get 17 empty. It plugged completely at 57.5k and Dodge replaced it. But its not fun having a truck go into limp mode with cows in the trailer. The service adviser started to give me the stock Dodge line about not working the truck hard enough, which the mechanic squashed pretty quick. That truck has worked 97% of its life. Anyway, now I just running a tune for now egr or dpf and I'm getting 20 hauling the sap tank around.


I have DPF on my 550 6.4L and I hate it. I heard they run great with DPF blocked and a tuner.
I'm very concerned that once I turn it off, PA will pass emissions laws for diesels and my truck won't pass.
Plus the prices I'm getting quoted to do it ain't cheap.


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## Dill (Nov 5, 2010)

That's why I have the brand new dpf stashed up in the barn. The tuner was 700 and the "delete kit" basically a pipe was 250. A couple hours in the shop and done. I'm running a smarty JR on a stock tune, just set for a country that didn't require a dpf and egr.

We have a dpf in the new tdi, it seems to work. But I'm not sure how long it will continue to work well.


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## JD3430 (Jan 1, 2012)

Ok, you did what I want to do, but what if you get checked for your emissions equipment by the cops?


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## MT hayer (Mar 1, 2014)

Tell them you don't know what happened.....


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## JD3430 (Jan 1, 2012)

MT hayer said:


> Tell them you don't know what happened.....


Before or after the $3,000 fine?


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## GawasFarm (Jul 10, 2013)

Lucky for me I bought it used and don't know what those previous owners did to it


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## GawasFarm (Jul 10, 2013)

I want to do this on my ford 6.4. We don't get tested for emissions yet where we are.


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## mlappin (Jun 25, 2009)

JD3430 said:


> Ok, you did what I want to do, but what if you get checked for your emissions equipment by the cops?


Mine will roll coal under certain conditions. Like cruising along just slow enough that the torque converter is still locked and its still in overdrive with zero boost on the turbo then stand on it but not enough to downshift. Or from a dead stop just mash it to the floor. Coal will roll, don't do it with a wet road or it just goes sideways instead of ahead. My current turbo is pretty well matched to the mods I'm running so less black smoke.

I know of a guy driving a Ford with heavy fuel mods but a stock turbo, no matter how gentle you are on the peddle, that thing belches enough black smoke you'd think somebody is burning tires in the bed. Point is, people keep modifying too much without a brain in their head and all those mods will be banned no matter where you are and the fines will be a LOT higher. Or emissions tests will be brought back just for diesels.

Black smoke doesn't make power up till a certain point. Unless your well over a thousand horse more smoke doesn't mean a thing, I've seen videos of newer Dodges with the 6.7 on a drive on dynamometer making close to 800HP and no smoke whatsoever. Over a certain point you need the extra fuel (more smoke) just for the added cooling effect.


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## JD3430 (Jan 1, 2012)

My diesel hot rodding days are way behind me now. Just want a stock truck that runs correctly. stock 350HP/650 lb tq is way more than a I need to tow even 25,000lbs of hay, so the power level is fine, but the emissions crap isn't. Based on what I see coming out of the tailpipe, I'd pollute the enviroment less with the DPF removed, cause its just causing the truck to billow smoke about every 10th time I drive it.

Its embarrassing and pretty juvenile to have a company name on the side of truck being seen by potential customers trashing the air with black smoke caused by a defective DPF system.


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## Dill (Nov 5, 2010)

JD3430 said:


> Ok, you did what I want to do, but what if you get checked for your emissions equipment by the cops?


We don't have emissions testing here. And I'm not commerical. So knocking a tree trunk againist a 2x4 I should be good.

I still have muffler. And honestly I don't see much a difference between my 6.7 now and my father or my brother who both have 24v 5.9s. Its the hod rod kids that are getting the aftermarket in trouble.

I just don't get the hopped up truck thing. I stopped looking at Cummins forum because all of them tell you that the trucks need 400 hp to haul anything (not that they work their trucks), how did all those tractor trailers get by with under 300? I've got 3.42s in the back of mine and I feel like I"ve got plenty of power.


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## JD3430 (Jan 1, 2012)

Dill said:


> We don't have emissions testing here. And I'm not commerical. So knocking a tree trunk againist a 2x4 I should be good.
> I still have muffler. And honestly I don't see much a difference between my 6.7 now and my father or my brother who both have 24v 5.9s. Its the hod rod kids that are getting the aftermarket in trouble.
> I just don't get the hopped up truck thing. I stopped looking at Cummins forum because all of them tell you that the trucks need 400 hp to haul anything (not that they work their trucks), how did all those tractor trailers get by with under 300? I've got 3.42s in the back of mine and I feel like I"ve got plenty of power.


Sure, the emissions thing is fine if your state doesn't check, but tampering with an emissions system is a FED offense. Big fine. I heard the delete kits eliminate enough exhaust equipment that a routine inspection shows tampering. 
I also hear there's a ford system for the 6.4 that's undetectable and includes a tuner in case you want a little more or want to change shift strategy.
Love the look of the Banks system. Small bump in power, exhaust brake, better shift strategy.


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## JD4030 (Apr 3, 2014)

I need to get rid of that DPF also on the 08 Dodge. Should have mentioned in my earlier post that my best mileage so far has been just over 19mpg several times, straight highway driving, summer fuel. Winter blend is much lower mpg's. I have a dually quad cab, 6 speed manual and 3.42 gears. I'm sure if I had steeper gears, mileage would suffer. Oh, one other thing: On the 6.7 with manual trans, the stock clutches are junk due to the dual mass flywheel. I replaced mine at 52,000 with a South Bend dual disc and solid flywheel. That was an expensive job. First time I had ever had clutch failure in any vehicle I've owned.


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## hog987 (Apr 5, 2011)

"how did all those tractor trailers get by with under 300?"

They drove with the transmission. Had plenty of gears and did lots of shifting. Back inn the days when not everyone could drive truck.


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## Gearclash (Nov 25, 2010)

And that "only 300 hp" had lots of torque to go with it. Torque is why a diesel with a lower hp rating can out pull a gasoline engine with a higher hp rating.


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## JD3430 (Jan 1, 2012)

hog987 said:


> "how did all those tractor trailers get by with under 300?"
> 
> They drove with the transmission. Had plenty of gears and did lots of shifting. Back inn the days when not everyone could drive truck.


The first Mack triaxles I drove were under 300HP. Quad box transmissions.....my gosh made for busy right hands!


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## Dill (Nov 5, 2010)

JD4030 said:


> I Oh, one other thing: On the 6.7 with manual trans, the stock clutches are junk due to the dual mass flywheel. I replaced mine at 52,000 with a South Bend dual disc and solid flywheel. That was an expensive job. First time I had ever had clutch failure in any vehicle I've owned.


I just had to do mine at 78k. Started slipping bad. I went with the big single disc. I agree that dual mass makes it expensive. I went with TN clutch. But then I got stupid lucky, I had a mouse nest in the trans. The throwout bearing was packed with hay. Ended up being able to make an insurance claim.


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## CantonHayGuy (Sep 25, 2008)

Bluefarmer, you don't say whether that 2010 is an auto tranny or not and I can only comment on the auto. I have an '09 3500 MegaCab 4x4 dually; the motor is great, mileage does suck compared to my '95 12 valve auto dually. Everyone ....and I do say, "everyone" ... I know of that has "fixed" their emissions system on these 6.7's has seen at least a 2 mpg increase and gotten a very noticeable increase in power as a by-product. If you keep these motors in stock or mild hp form, the stock auto tranny is bullet-proof. Serious "pullers" are replacing the 68RFE trannies with the older 48RFE trannies and building up those trannies. I've got 73k miles on my truck... so far no issues with the DPF; other than robbing me of mpg's... and I don't tow that often. I like the "tow" mode of the tranny and the ability to upshift or downshift just like a manual; which I do when I'm doing a lot of city driving. I'll drive in 3rd or 4th to keep rpm's up a bit to keep the exhaust temps high enough to keep the "soot" from clogging the DPF.

I'm looking at pulling the trigger on "fixing" my emission system too; I know of the federal regs, but I also know that if/when that DPF gets clogged.... it isn't covered by warranty (outside of the 3yr/36k). It's about a $2500.00 filter. Very few places have the capability to clean them because the machine to do it, is highly expensive.

Just my 2 cents.


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## CantonHayGuy (Sep 25, 2008)

Oh yeah, ...as I understand it, idling these trucks (not that idling any diesel is a good thing) is a sure bet for clogging that DPF. I think in the earlier days of DPF usage, guys who would idle their diesels in tall grass were starting grass fires because of the DPF. Part of the reason for the lower mpg's with the 6.7's is due to the fact that extra fuel is dumped into the exhaust to burn off that "soot" in the DPF.


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## JD3430 (Jan 1, 2012)

Well, I just had a 180* turn around in my trucks performance. 
I switched fueling stops AND it just got warmer.
I don't know which is making my truck run FAR better than it used to. No more embarrassing smoke, no more rattling noise from engine for almost 2 weeks.
Runs smooth as glass, more power, no smoke.
I can't believe it.

Now what caused the change? Warmer temps or different fuel???? 
Previous diesels I had used to run better with cold air.


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## mlappin (Jun 25, 2009)

JD3430 said:


> The first Mack triaxles I drove were under 300HP. Quad box transmissions.....my gosh made for busy right hands!


I've seen em, never had to drive one, that could get old in a hurry in town.

Our thirteen speed is bad enough.



JD3430 said:


> Well, I just had a 180* turn around in my trucks performance.
> I switched fueling stops AND it just got warmer.
> I don't know which is making my truck run FAR better than it used to. No more embarrassing smoke, no more rattling noise from engine for almost 2 weeks.
> Runs smooth as glass, more power, no smoke.
> ...


Could be the fuel, mine likes cooler air, cooler the air more potential power can be had as cooler air is more dense. But mines not stock either.


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