V-10 and MPG

[Cat320]

Rich...I'm the one that sent you a PM a while back about altitude, mileage and gas vs diesel. Basically, like skypilot said, the gasser loses power (about 3% per thousand feet) as it climbs to higher terrain. It's also cooler the higher you go, about 3.5 degrees for each 1000' higher. So at 10,000 you have lost 1/3 of your power, but the air is also considerably thinner and cooler...that's why pilots are always "requesting higher"...for better fuel economy. The turbo diesel does not know if it is on the coast of Florida or crossing the Rockies, so it has the advantage of the thinner cooler air and almost full power. I think your good mileage comes from careful driving and the higher altitude.

Sound to me like you are trying to justify that new diesel...better go look at them...again!

[richfaa]

Reset the computer MPG as we left the CG and Headed up to Estes Park and beyond this AM. CG is at 5173 GPS altitude. MPG to Estes Park was 10.9.. GPS altitude 7543 ft.At the highest point on the fall river trail rd, CO-34, just short of the Alpine Visitors center GPS altitude 12,138 ft, MPG 10.0. Note that most of the trip was at a speed of 20 to 40 MPG. We did not notice the loss of power but of course we are not hauling the 3400 anchor. Oh the temp from Estes Park up to the visitors center was 61 at Estes Park and 50 at the visitors center.. 73 back at the C.G at 6PM. Spectacular drive. We did drive the 6.4 for a couple of days and we were very impressed. Could never stand the smell of Diesel/Kerosene..have a complete seperate set of clothing for School bus driving and charter bus driving. Can't tell you how much clothing we have ruined fueling diesel..The new stuff does smell good tho...

[sreigle]

My mileage so far has been artificially low in that the computer flash the selling dealer installed turned out to be flawed. It was putting way too much fuel through injector number 5. The Rev A flash has now been installed and solo mileage has jumped noticeably.

The truck has 4700 miles on it now, after 3 1/2 weeks. 1662 of that is towing. Our best mileage day, towing with the flawed flash, was 11.6. We were running from 63 to 68 mph all day that day in rolling hills and some flatlands and just a slight headwind. I had the truck on cruise so it was holding speed up and downhill. If I'd manually handle the hills and let it slow down it would likely do better on mileage. As it breaks in, it should also do better. And with the revised flash it is doing better solo and I expect it to do better towing. We won't know for another three weeks as we stay put until then.

With the flawed flash I made two trips to my folks' house, 240 miles roundtrip. 12 miles of that is city stop and go. The rest is 70 mph with three stops, two toll booths and a nature call. The mileage was 18.3 on both trips. Since the revised flash I've made that trip once. Same route, same speed, same stops and got 19.3. I'll make that trip again Tuesday and will see how if it continues the better mileage. So far I'm pleased with the truck.

Rich, truck fever is a powerful pull. I know it well. While my V10 (1999 F350) did a good job, the diesel does it better and does it without working as hard. I admit to trading my 2005 6.0 at 85k because of concerns of running that engine outside of warranty. But I plan to keep this one for many years and feel I have a truck that can do that for me.

[richfaa]

I am not surprised at the MPG for the Cummings.They have always done well. Although our V-10 is a fine motor and has done a fine job our towing needs have changed and a diesel will better serve those needs.If I can get the right deal we will no doubt go diesel.

[VanMan]

Steve - is the "flash" something the dealer charges a lot extra for? or is it like computer software upgrades that the dealer does as routine maintenance. Would a 1999 V-10 maybe benefit from a flash?

[skypilot]

Steve: Wondering what you are seeing for 'regenerations'? Local dealer seeing some issues with users just driving as 'daily driver' (i.e. short trips in town, no road or highway, no towing) the opposite of your usage to date! So wondering if you seeing any change in mileage due to regens.

Thanks.

[richfaa]

Got to talk to the owner of a 08 F-350 6.4L here at the FCRV rally in Pueblo, co. It is the same truck as my 05, color and all execpt it is a 4X4 and of course the 6.4 Diesel. Exactly the truck I am considering purchasing. He is pulling a Excell fifth wheel about the same weight as the 3400. He pulled from Iowa to here over some of the same roads we have pulled with the gasser over the last month or so. His MPG for the trip..9.5MPG. I have got to say that my gaser MPG was just as good and on the pull from the last C.G near Colorado Springs over 115 south and 50 East into Pueblo, co our trip MPG computer reads 11.3mpg... I am more and more convinced that MPG is NOT a big factor in the new Diesels..at least the Ford 6.4L..power is another matter...Helen looked the truck over today, it is just a few spaces up from us and said....Nice truck...

[hazmic]

Rich
I think the diesel will get better mileage when it gets broke in. There is no way that anyone can compare mileage because its a new motor and yours is just broke in. Tell Helen to bite the bullet and buy that new truck. Get what you want on it. Are you going by the read out in the dash? I found that they are just ball park figures. Ours is on our new car. The diesel just seems to not work as hard as the gasser. Just wondering where our you guys at?

[Wrenchtraveller]

Rich, read up on this article at
//www.pickuptruck.com/ and you will see that both 1/4 mile times , loaded and empty are almost identical with the V10 and new 6.4.
So if you think the mileage is the same and the power is the same, why would you want to spend an extra 6 grand for an unproven engine that starts fires? LOL.............I am teasing a little!!!

[skypilot]

Rich: Something else to note is how many times the diesel 'regenerated' the 'Diesel Particulate Filter' while doing that run; when regenerating mileage drops off some -- web postings vary wildly on just how much fuel is consumed but it appears that a noticeable amount is used. Working the truck hard (i.e. pulling the trailer) should result in less fuel being used since the exhaust is quite a bit hotter than when truck being used as a daily driver in and around town. As they 'perfect' the programming on these new trucks (all 3 major brands) I'm told to expect some improvement on overall mileage; that on top of improved mileage as the engine breaks in.

If mileage is a major point for you (or anyone else looking at a new vehicle right now); and your current TV does what you need; you may want to wait a while longer and let them get some more program flashes out. Given what happened on the 6.0 for Ford, the Duramax for GM, and the 3rd Gen 5.9L for Dodge, each update improved something and sometimes substantially. Also, as shown by Dodge on their 05 to 06 models, don't assume that all you'll need is the program flash. Dodge made such a substantial change that the 05 and before modules can't hold the newest program -- not enough memory and no retrofit. They brought out a separate reflash for the 05s and prior without some of the bells and whistles of the 06/07 5.9Ls.

[tbhd2]

Just saw a "Diesel Perfomance" magazine. In this months issue they did a comparison test 6.8 v-10 vs. 6.4 diesel. Just in case anybody is interested.

[richfaa]

There are not many folks who really understand what the regeneration process is and how it does it. I remember being at a seminar a couple of years ago put on by navstar (school busses) where we learned about that and it was not a good thing. It short you are burning fuel and you are not turning any wheels, Don.. No I don't think the power is the same. In fact I know it isn't. At high altitudes we huff and puff. This is a good gas motor but it does not have the power of a diesel. We will struggle up a good grade and the diesel blows by...such is life..Our on board computer is very close to calculated by hand MPG..In fact I think it is more accurate. I do agree that these new diesel motors are to new to come to any conclusions on MPG. As we travel..on the road.. and we see how this V-10 performs as compared to the NEW diesels, except for the power department we are more and more convinced that the difference once significant is not so any more and I think that a V-10 motor would be a good choice for many rv'ers. There is one thing..the handwriting is one the wall.. I think the days of the big gas motor are numbered..don't think the V-10 will be around in a couple of years. Helen would not object to a new truck at all..she likes big trucks and big campers. I do have new truck fever..but.. waiting may be a good idea and holding on to the V-10 is not a problem. Don..I have seen those 1/4 mile figures on that other forum and wonder why in the world would anyone buy a F-350 for a dragster???Now put That V-10 in a Honda Civic???

[Wrenchtraveller]

Rich, I enjoy this topic because I too will be going back to a diesel engine someday but I am thinking in about 6 years they might have the emissions thing figured out. I was absolutely sold on the superiority of the diesel as a tow engine but for me it was all about mileage. We have towed an RV down to Disneyland 9 times and our 88 460 gasser used to get between 4 to 6 MPG. We were looking for gas every 100 miles. We always stayed in the same CGs on the trip. When we got our 95 F250 PSD, it pulled the same fiver better and got between 12 and 15 MPG so we got to those same CGs, Salem, Redding, and Lost Hills CA about 3 hours earlier every day because we were not spending all our time filling up with fuel ( fueling up in S. Cal in the summer is a story in itself )
Now I believe that diesel engines are getting like the early 70 cars were with poor emission technology.I bought a 1973 Cougar XR7 and history now shows that the 73 model year was the worst ever on fuel economy. It was also the year of the big oil embargo and fuel shortages. The conspiracy people still believe it was all an evil plot and fist fights at the pumps were not all that uncommon.
Move ahead 30 years and we have the wonderful diesel engine getting an EGR (exhaust gas recirculaion) system that put soot back through the turbo wearing it out prematurely. My 04
6.0 L only had 8000 miles and the turbo was showing wear. On one of my break downs, the Ford tech wanted to replace the Turbo and was refused by the people that make warranty decisions.
There will be a lot of people replacing their own turbos on these newer diesels if they keep them too long. Replacing a turbo will wipe out every cent you ever saved on fuel over a gasser.
Now we have regeneration where the soot should be burned off some type of collector.
In the plant I work at the most, the diesel forklifts are used in a Wharehouse and to improve air quality, every 12 hours a heavy cylinder, a little larger than a paint can, is lifted off the exhaust stack, placed in an oven and cooked clean. They are exchanged and the swap out takes 5 minutes as a small electric hoist is used. My daughter runs these forklifts as a summer college student, and has explained the system to me.
I think the regeneration system we now see in all the new diesel trucks will be undergoing many changes in the next few years until we have a system that we can live with and will meet the emission standards of the future. I believe for me to buy a new diesel now would be the same mistake as when I bought my 73 Ford Cougar. That was a gutless, thirsty little car and because I was young and enjoyed working on vehicles I kept that piece of junk on the road for 13 years, usually working on it a least 2 days a month. I had the carburetor off that car several times as the aluminum spacer under it would wear out. EFI came along, got better, and gas engines got better mileage and an increase in real power. I believe the future of diesels will go the same way. The poor fuel economy of today's diesels is because of poor emission technology IMHO and I will buy a diesel when they get it right, not before.
Rich, all the best and if you buy a new diesel I sincerely hope it meets all your expectations.

[skypilot]

Would be interesting to hear from Steve (sreigle) and how his Megacab is doing concerning regenerations and mileage. He has the new 6.7L Dodge and, as I recall, he has close to 3K miles on it in just a week or so. Not broken in at all but he definitely doesn't let it sit .

[sreigle]

quote:Originally posted by VanMan

Steve - is the "flash" something the dealer charges a lot extra for? or is it like computer software upgrades that the dealer does as routine maintenance. Would a 1999 V-10 maybe benefit from a flash?

The flash was done under warranty so I have no idea the cost when out of warranty. Sorry.

They also will do the flash only if their computer system says you need it. They told me they have 30 new trucks on the lot with the flawed flash and are updating them as they can. Newly sold trucks get priority, of course.

Update on the mileage. On that next trip I got 19.0 mpg. It was over 20 when a regen started, darn it.

Rich, I carry a glove in a door panel pocket expressly for fueling the diesel. Too many pump handles are "dirty" with diesel residue or whatever it is.

Skypilot, the truck turned 5,000 miles on Wednesday, the four-week anniversary of our having taken delivery. That's mostly highway miles. Probably 95%.

I'd estimate the regens are coming at about every 150 miles or so. The ONLY way I can tell, though, is the mpg on the computer starts dropping for not obvious reason. It seems to drop for about 15 minutes, then starts climbing back up (the mpg), again for no obvious reason. Of course, overall it's losing mpg. How much it drops depends entirely on how many miles since the computer was last reset. I would like to see an indicator on the dash to tell me there is a regen taking place. Other than the mileage there is no indication at all, not even when towing. No change in power that I can detect. No change in rpm that I can detect.

We finished what we were making all those trips for so mileage accumulation will hopefully slow now. I will still make the weekly trip to see my Mom, a 270-mile round trip, for as long as we are here (until July 29). But otherwise it should slow.

On both my 2005 Ford and this Dodge, hand calculation of mpg over three tanks came out within 1/10 mpg of what the computer said so I'm using the computer from here on.

Wrenchtraveller, I can relate to the 1973 emissions problems. We bought a new 1973 Vega Kammback. When it had 38k on it we bought a second, used, '73 Kammback as a second vehicle. Big mistake. That one only got to 38k before needing an overhaul. The original got to 42k. These not only had 1973 emissions, they also were California emissions control. Biggest pieces of crap I ever owned. Well, my 1975 Chevy LUV I bought new was a close second.

Also, I read not long ago in one of the automotive online rags that they expect the DPF to be here to stay. They likened it to the cat converter. I have no idea how accurate they are.

[richfaa]

I'd estimate the regens are coming at about every 150 miles or so" Holy Moley Steve..Is that a normal interval??

[sreigle]

Rich, I have no idea. That's just based on what I'm seeing on the mpg computer. I could be misjudging the cause of the mileage drop but it drops for about 15 minutes then starts climbing right back up. I am assuming it's doing a regen during that time. I was told by the Dodge dealer to expect it about once per tankful but this is maybe two or three times per tankful. Nevertheless, my mileage is way above what my particular V10 ever got. Yours is doing exceptionally well in my opinion.

[richfaa]

Went to a excellent Diesel seminar yesterday on the new emissions and fuel. I have been to several over the last 2 years or so and the regeneration process ,other than is happens, is little understood. This presenter, and he was talking about CAT motors and incicated that the regeneration process should not occur under normal highway driving as long as the temps are at a level high enough to burn off the particulates . Now I read on other forums that this is not the case. When I mention that I knew of a new diesel owners who thought the process was occuring every 150 miles or so he said that was not normal. The more I learn about the regeneration process in real life the more confused I am???.

Does this confuse the issue even more....

Regeneration is the process of removing the accumulated soot from the filter. This is done either passively (by adding a catalyst to the filter) or actively. On-board active filter management can use a variety of strategies:

1) Engine management to increase exhaust temperature
2) A fuel burner to increase the exhaust temperature
3) A catalytic oxidizer to increase the exhaust temperature, with after injection (HC-Doser)
4) Resistive heating coils to increase the exhaust temperature
5) Microwave energy to increase the particulate temperature
All on-board active systems use extra fuel, whether through burning to heat the DPF, or providing extra power to the DPF's electrical system. Typically a computer monitors one or more sensors that measure back pressure and/or temperature, and based on pre-programmed set points the computer makes decisions on when to activate the regeneration cycle. The additional fuel can be supplied by a metering pump. Running the cycle too often while keeping the back pressure in the exhaust system low will use extra fuel. The reverse runs risk of engine damage and/or uncontrolled regeneration and possible DPF failure. Quality regeneration software is a necessity for longevity of the active DPF system.

Diesel particulate matter combusts when temperatures above 600 degrees celsius are attained. The start of combustion causes a further increase in temperature. In some cases the combustion of the particulate matter can raise temperatures above the structural integrity threshold of the filter material, which can cause catastrophic failure of the substrate. Various strategies have been developed to limit this possibility. Note that unlike a spark-ignited engine, which typically has less than 0.5% oxygen in the exhaust gas stream before the emission control device(s), many diesel engines run above 15% oxygen pre-filter. While the amount of available oxygen makes fast regeneration of a filter possible, it also contributes to runaway regeneration problems.

Some applications use off-board regeneration. Off-board regeneration requires operator intervention (i.e. the machine is either plugged into a wall/floor mounted regeneration station, or the filter is removed from the machine and placed in the regeneration station). Off-board regeneration is not usable for on-road vehicles, except in situations where the vehicles are parked in a central depot when not in use. Off-board regenration is mainly used in industrial and mining applications. Coal mines (with the attendant explosion risk from coal damp) use off-board regeneration if non-disposable filters are installed, with the regeneration stations sited in an area where non-permissible machinery is allowed. Many forklift makes also use off-board regeneration - typically mining machinery and other machinery that spend their operational lives in one location, which makes having a stationary regeneration station practical. In situations where the filter is physically removed from the machine for regeneration there is also the advantage of being able to inspect the filter core on a daily basis (DPF cores for non-road applications are typically sized to be usable for one shift - so regeneration is a daily occurrence [1].



My MPG on the trip from Colorado Springs to Pueblo Via 115 and 50 reads 11.3 mpg>>>.

[Dave e Victoria]

I like the smell of jet fuel (kerosene) and Diesel. But, I grew up on a farm and was constantly around it. (Remember the old "distillate" we used 50 years back). Anyway, getting Diesel on my self stinks BUT getting gasolene on my hands or clothes causes severe skin drying and irritation.
Dave

[sreigle]

Rich, I could (and must) be wrong about the 150 miles. I was guessing based on watching the mpg on the computer. I have seen no other sign of regeneration in 5,300 miles. No change in power levels or discernible change in engine temperature. I don't yet have a pyrometer but have heard you can tell by the egt when it starts regenerating.

600 degrees Celcius is 1112 degrees Fahrenheit, if I did the math correctly. I don't know how much temp loss there is between exhaust manifold and dpf but I wouldn't expect to see 1112 egt for an extended period except maybe towing up a long, steep grade and that's probably still not high enough to fire the dpf so I'd probably never get it hot enough to clean out the dpf on its own (without the additional fuel). I wish the mfrs would put a light on the dash to let us know when it's regenerating.