People seem generally very happy with the 6.7L. There must be thread on this, but a search yielded mostly garbage. What are people getting mpg in the 4x4 city/highway?

Also, found a post questioning the 6.7L at altitude. Didn't say how high. I don't live and will mostly not operate at altitude, but might go camping in the mountains. How real is this issue?

Thanks.

 

The only real altitude issue was when comparing the Ford and Chebby strategies. GM did outperform Ford in a few high-altitude towing tests, but not enough to really say anything significant. both trucks performed well, the Chebby just did a bit better due to its turbo and a couple other tweaks. If you aren't in high-altitude most of the time, The Ford should outperform the GM for you. When you *do* camp up there, take your time and feel the truck out on your first few major ascent/descent runs. It should be more than satisfactory and I doubt you'll ever feel like it's performing anything less than optimal. Just get to know your truck

edit: you also asked about MPG... this is something that is 80% dependent on your driving habits and how/where you use the truck. Personally, I was getting about 18mpg average mixed in my 4x4 (driving in 4x2) on summer fuel and in summer temps. Right now, I'm getting about 15.8, 15.2 recently with all the 4x4 ice driving I've had to do. Weather plays a major part in not only the fuel we get but how our trucks handle that fuel. Towing my fiver, about 14k loaded for a weekend trip, I get anywhere from 9.5 to 12, depending on the fuel, temps, and terrain. Pulling my 16' steel enclosed vending trailer, I get about 8-10% less... it's a lot less aerodynamic.

 

The altitude shortfall has been much overplayed in internet venues. DJJ...covered the basics. Here is a little more meat. Ford beat Chevy up Chevy's own 16% grade at the GM Milford Proving Grounds. Chevy went to a couple of media types and proposed a high altitude pull off. They knew what they were doing. The GM trucks have a larger turbo and breath a little better at altitudes above 8000 feet. The GM beat the Ford over the top by over 2 minutes. The Ford was still running over 40mph IIRC. The pull was 8 miles long. There are around 20 such mountain passes in the USA that are above 8000 feet and open year round. I looked it up. Only a few are on the Interstates. 99% of all RV'ers are unaffected by the high altitude passes.

Last week there was a comparison test published by Edmunds that ran up an 11.5 mile grade with 5% to 7% pitch. The altitude was below 7000 feet. After 11.5 miles and nearly 12 minutes of climbing, there were 8 seconds between the two trucks. That is a 1% difference. There is likely 1% difference between the next 2 trucks off either manufacturers assembly line

DJJ..is also right on about expected fuel economy

There are very few, I know about only one, owners of the new 6.7 Ford that are not happy about their decision. Most are happy beyond words. 22000 miles on my truck now with 8000 of them pulling my 13000 pound fiver. Still smile every time I start it up.

Regards

 

I was not aware of this. Kudos to Chevy for doing the better job of altitude-compensation, both through hardware and software. ...not that it's a big deal to most users...

 

There are quite a few threads, and a poll or two, but I can't find them right now either. Here's one thread with a few comments about mileage:

https://www.ford-trucks.com/forums/1...-thinking.html

Adding a little more of my own experience, the 6.7 easily outperforms all of the diesel pickups I've ever driven at higher altitudes, and I've driven a lot of 4x4 diesel pickups of all of the Big Three over several decades, but in the past 10/15 years, mostly Fords.

6.7 fuel mileage suffers a little over 4000/5000 foot altitudes, but nowhere as much as it did with my 6.0, which would drop as much as 25/30% getting up into the 8000 foot range. Powerwise, the 6.7 can run circles around the 6.0 at higher elevations, especially when towing.

Joe

 

I have made a comment or two about altitude myself, I don't think its a big deal. what I hadn't realized until recently is that the combo is at least 1500#'s heavier than my 06 dodge with the smaller trailer, couple that with larger frontal area of the new trailer I think that is why I am seeing slower speeds to the top of parleys canyon.

but then again if I was using the dodge I would have likely had to lift anyways because the EGT;s would be at 1500 or more.

 

I live at 7000+ feet, and work at up to 11,000+ feet. There is a HUGE difference in performance when I travel down to low altitudes. Very noticeable gains, even by the time I'm at 5,000 feet. Very sluggish at high altitude (without a trailer). My 6.0 did much better at altitude, but it was modified.
Recent mileage (not towing), in 4x4 mode is between 15.5 & 17.7 city/highway mix. In the Summer, I gain about 2.5 mpg. I'm sure a chip will restore some semblance of driveability for us high altitude folks.
I suspect most drivers of these trucks are at lower altitude, so this is not that important and would not come up as an issue. Does not seem to like cruising above 80 mph either, if mileage is a concern. Recently did 12.5 mpg cross country (about 2,000 miles; not towing) going East to West. A month earlier I did about 15.5 going West to East over the same stretch.

So if you are at high altitude, you may want to wait until reprogrammers are better developed, or wait until Ford acknowledges this, then decides if there are enough sales here to warrant a redesign of the offending part(s). Mine often throws codes at altitude due to the thin air, and you need to plan well ahead when accelerating or merging because the accelerator pedal is largely inert. Still, I like my truck a lot.

 

Interesting observations, Von-Overkill. If it is true that the turbo is sized such that it is the limiting factor in high-altitude performance (this seems reasonable to me, but I do not know it to be the case), then aftermarket programming can't really help. There's a possibility of it masking the issue slightly, but if the turbo's the issue, then the turbo would need to be replaced to provide the altitude compensation you're after. Over-speeding the turbo even further (with aftermarket programming) will overheat the charge air significantly, while only providing slightly to moderately more actual air into the cylinders, and will significantly shorten the turbo's life. If, on the other hand, the issue is purely programming and inadequate altitude compensation (possible, but not common nor likely unless the turbo is sized small for high-altitude operation), then it's a different matter. Of course, everyone must choose their own tradeoffs; just thought I'd offer the info.

 

MZ5, I'm not sure where the bottleneck lies - programming or hardware limitations. We do know performance increases are dramatic at low altitudes. Right now the best programmers are claiming a 250 HP increase through programming, and a freer intake/exhaust. Is this safe power, or will it just wear out the turbo and/or other components more quickly? Well, that's the million dollar question I guess.
Had I known the dramatic performance hit I would be taking based on where I work and live, I would have hung on to my previous truck. I have no choice but to try to compensate for this shortcoming, since I personally do not find my truck's road manners safe enough to tangle with other vehicles.
Imagine having to execute a maneuver that only gives you a short window to perform it...you step on the pedal hard, then you wait 2.5 to 3 seconds before power comes on. Initially, the truck actually bogs down a bit before it lurches forward much too abruptly. This is not safe, because the lag is hard to compensate for in rapidly changing traffic conditions.

Initially I felt that perhaps something was wrong somewhere, but the performance at low altitude was dramatically different, and the lag time was only about 1/2 a second. So altitude sickness is not a myth for this model.

A previous poster noted that most people will not be affected by this limitation, since most places in this country are at a lower altitude than I find myself at. Since I am here 95% of the time, the problem is present 95% of the time.

The nearest dealer is hours away and based on previous experience, not all that competent with such issues. They rarely finish in one trip, so my average number of visits to repair any problem is 5. That means 10 trips since I have to come back for the truck each time they supposedly finish it. They never offer a rental vehicle, and they don't like it if I try and talk to the mechanic directly, to insure he understands the problem without it being interpreted by the service manager, who only seems to write down some of what you say. And since I don't speak Spanish, I probably wouldn't be able to speak to the tech anyway.

I can't really afford to take a week off to see what up, so unfortunately for me that means not using Ford dealerships, and much vehicle customization - some of it unproven and perhaps risky. So if something goes terribly wrong, I just have to suck it up.

 

I agree with VON. I have seen noticeable differences running at altitude. In the past, driving my 6.0s and 6.4s, I saw a lot of this going from 4700 where I live to LA. I would take the baby for a "ride" to nap while the wife went to Disneyland with the other kids just to drive at sea level. 6.0 mpg would go from 13-14 to 18-19 and the truck was VERY fast. Also almost no smoke. The 06 had a Banks six gun. The 6.4 had a programmer as well and went 0- Mach 3 on the on ramps. 6.4 mpg went from 2 to 3(lol). I saw 8.8 mpg while driving from San Francisco to Portland pulling the fiver (up 1.5) going 70+. My thinking is elevation has about a 20% effect. I havent run any long trips w/o the trailer so I can't compare. I had an '04 Excursion w/6.0 and a lift and that thing would get a solid 16 all 800 miles to LA going 80+. That was the best I've seen in any of my powerstrokes. That same excursion going thru WY with a 5000 lb trailer only got 7 and went way slow. Oh yea, I think barometric pressure has a huge effect on diesels, even the 6.7. I notice this when I pull a hill in Sardine Canyon leaving my town. If the pressure's low the fan clutch goes crazy, if its high it will hardly come on at all. Any thoughts?

 

That is a good estimate... It is generally accepted that gas engines lose 5% of their power for every 1,000 feet in elevation- That's why at 8,000 feet a gas vehicle has literally "run out of gas" since it has essentially lost 40% of it's power. On the same note, turbo-charged diesels are less affected by elevation and lose about half of a normally aspirated gas engine, or about 20% at 8,000 ft elevation.

 

Thank you Tom. I have not completed higher education, however, I find I'm a damn good guesser.

 

A lot of folks are very (unpleasantly) surprised at the effect which elevation plays upon their power and mpg... Just ask any of the DMax owners with their overheated 2001-2005 trucks while (trying to) tow in the Summer months

 

Von

I certainly did not mean to diminish the altitude performance shortfalls to owners like yourself that live and work at those altitudes. The shortfall is real and affects you guys. The OP is a confirmed flat lander and is in the large demographic that the altitude will never have a meaningful effect.

It was posted here that Ford's powertrain guy's were surprised and embarrassed by the thumping they took at the "Rumble". I feel certain that help is on the way. Reliability testing and EPA approvals are the likely obstacles to a quicker solution. Dodges's announcement of an upgraded 6.7 power rating may speed things up a bit.

Regards

 

Rickatic, no harm done-no offense implied. I'm just disappointed the problem is so much more noticeable than in the 6.0L and I can't do anything about it until I figure out how. I guess this is one of the few (hopefully temporary) cons of living in the mountains...