Do older coaches get better mileage?

Topic: Do older coaches get better mileage? (Read 2398 times) previous topic - next topic

Re: Do older coaches get better mileage?

Reply #25 – October 27, 2011, 10:30:15 pm

I am getting 9.0 MPG for the last 2,000 miles. Texas to Chicago to Upper Peninsular of Michigan - Chicago. I drive at 65 mpg most of the time but the coach wants to go faster!

I don't think it has been mentioned but different fuel blends and bio-diesel will also affect mileage.

Biodiesel = 33.3 - 35.7 MJ/liter

Diesel = 36.4 MJ/liter

(Bigger number is better)

Cold fuel is denser than warm fuel, therefore on a mechanically injected engine cold fuel delivers more power per squirt all other things being equal. You get more energy for your dollar with cold fuel. Once fuel has sat in an underground tank it warms to about the same temperature everywhere.

Therefore follow the tanker on a very cold day and buy fuel when he drops. Of course you will burn more fuel by doing this than you will save, but if you are caring about things that much you should be riding a bicycle!

Keith

Re: Do older coaches get better mileage?

Reply #26 – October 27, 2011, 10:37:21 pm

Get yourself a boost gauge installed. Then try to keep the boost 5 pounds or less on flat ground... The idea is to figure out the boost required to maintain forward speed and no more. Once you get a feel for it, you will watch your mpg climb... It's all about smoothness.

For my coach, 62-63 mph is the sweet spot for mpg vs 'getting somewhere'. In Econ mode I can run all the way down to 52, but I get bored (plus downright dangerous on an interstate!).

Re: Do older coaches get better mileage?

Reply #27 – October 28, 2011, 08:29:52 am

For best mileage, cruise at the lowest speed cruise control will hold in top gear. For my coach, that's 60.5 mph.

Re: Do older coaches get better mileage?

Reply #28 – October 28, 2011, 09:29:30 am

While 60.5mph is a good suggestion, it is the "best mileage in top gear," not necessarily the "best mileage." For my 1999 U320 M11 better mileage is in 5th gear at 55mph (12mpg or so), and even better mileage is at 40mph (I traversed Upper Michigan at 40mph on a low traffic day once just to see what would happen).

In my 320 I need to get to 62mph to get into 6th gear. Then, as above, I can stay in 6th and get better mileage by dropping speed and staying in 6th.

best, paul

Quote

For best mileage, cruise at the lowest speed cruise control will hold in top gear. For my coach, that's 60.5 mph.

Re: Do older coaches get better mileage?

Reply #29 – October 28, 2011, 10:42:25 am

At any given weight/horse power.
Drag is to the Square of speed.

Still applies reguardless of gear

Re: Do older coaches get better mileage?

Reply #30 – October 28, 2011, 11:58:10 am

The question was, "Do older coaches get better mileage". My opinion is yes, but not because they are older. Mpg might improve a little after break in, but doubt if you would notice it due to road conditions, temperature, wind, and other variables. When I was searching for a Foretravel, I really wanted a 93 - 95 Grand Villa, but couldn't pass up what I found and haven't been sorry. Most of the earlier Grand Villa's were narrower, and weighed less than the bus style. The sloping windshield will have less drag than the almost vertical one. Aircraft are pointed both at the front and back to reduce drag. That would reduce the liveable area in a MH though. I'm with the group that thinks a speed that keeps the transmission in top gear gives the best mpg. I don't always do that. Everything is a compromise and just try to be practical about it. Headwinds hurt and tailwinds help, smoother roads help, interstate highways are better than secondary as they are more level, less slowing, and stopping, but may bypass all the local sites in villages and towns; take your pick.

Re: Do older coaches get better mileage?

Reply #31 – October 28, 2011, 09:36:32 pm

My only trip so far in my 91 U225 was just over 1000 miles from Tampa to Delaware. Water tanks empty, propane full, no "stuff" on board. Recorded 11.43 mpg with the 5.9 Cummins.

I found at times my foot was to the floor; still used to driving a car. It seemed to drive best with the cruise control on. Better throttle modulation than my right foot. Better mileage too, I expect.

Steve

Re: Do older coaches get better mileage?

Reply #32 – October 30, 2011, 02:06:19 pm

I made my last fill of the trip at Brunswick GA (last fill Carmel Church VA). My trip odometer said 572.1 miles, Mapquest says 574. Filled as usual to the bottom of the filler neck.
My procedure is to fill both sides. The first one to trip gets closed off, then I slowly hand fill the other side until I reach the same point - bottom of the neck. There may be a differential but I always follow the same method. 9 hours of generator run time - I subtract .3 gph because it was lightly loaded (head strips for roof air and reefer). Total fill 60.1 gal so 10 mpg. Flat or downhill, 63-64 mpg, econ mode. 1 stop for overnight, 1 stop for lunch. Pretty sure I had the wind at my back too from the Noreaster...
That makes that leg 10 mpg. Previous fills: 8.8 mpg (Winchester to Carmel Church via Reading, PA, Annapolis/Pax River MD), 9.08 (Knoxville TN to Winchester VA), 9.18 (Oviedo FL to Knoxville TN).
I believe my coach is one of the lightest/most aerodynamic U320s (95 with jake, no Aquahot, overhead cabinet delete (salon/bedroom), window awning delete). The only 'weight gain' is the Tahoe, solar panels and the factory wood floor throughout. Our bays are not full of 'stuff'. My normal travel water load is 1/2 tank fresh and empty grey/black (or at least grey). Front G rated Michelins are 105# and rears are 100#. I normally use Power Service Cetane boost.
Reduce weight, wax the nose and mirrors, drive with VMSpc, cruise and econ mode on in the flats, off in the mountains.
If I get in a hurry the mpg drops to 8-8.5 in very short order.
I also believe the 400 hp M11 software uprate (from 370hp, 95 and 96 models) was the thriftiest.

Re: Do older coaches get better mileage?

Reply #33 – October 30, 2011, 02:38:58 pm

Another Tid Bit about fuel mileage, about 7-8 year ago, Cat, Cummins, DDC and Navistar engines, all 4 of these manufacturers got in trouble with our Fed Govt known as EPA, for emissions, The problem was total fuel injection timing, originally they had the timing retarded at idle and as engine speed increased the timing went to a proper advance position, while this gave better mileage and power, it produced emissions unacceptable to our beloved EPA, so large fines followed for all.
The engines all dropped mpg and all drivers/owners complained to no good. Today the new engines that use the DEF make more power due to the ability of DEF to clean the exhaust emissions.
This is what I was told by a upper level "Bright" employee of Cummins, as we got into this subject.
Crazy Huh?

Re: Do older coaches get better mileage?

Reply #34 – October 30, 2011, 03:09:30 pm

Dave, I've never been able to follow the logic that says reduce emissions per gallon of fuel burned but use more gallons to get where you're going. Could it be that the same geniuses are the ones cramming E-10 and if they get their way E-15 down our throats? The same crew that isworking on outlawing 100LL, obsoleting billions of dollars worth of aircraft powerplants?

But what really chaps me is the perception that environmentalists are, by necessity, completely lacking in common sense. Where's the fool killer when you need him?

Chuck

Re: Do older coaches get better mileage?

Reply #35 – October 30, 2011, 04:08:13 pm

Chuck, I am in total agreement. Nonsense. In closer to me event, I think it was the 2006 Ford F350 with the 6.0 Diesel, I got the note from dealer requiring it to have a computer update, not knowing, I took it in and they DID it. yup, mileage dropped by 2 mpg, when I asked what they had done to kill my mileage, and please put it back. Nope, Was informed it was done to meet the EPA emissions, saying it improved the emissions for the engine, I ask how does it help emissions when it now burns more fuel------------Duh! I am the idiot on that one I guess, no answer.

As an Ex flier who purchased a lot of 100LL, I was not aware of the new brain waves, I know I am off my rocker, (Can't say anything that even slightly smacks the liberals, sorry) will leave it blank.

Re: Do older coaches get better mileage?

Reply #36 – October 30, 2011, 05:23:45 pm

Quote from: Dave M – October 30, 2011, 04:08:13 pm

In closer to me event, I think it was the 2006 Ford F350 with the 6.0 Diesel, I got the note from dealer requiring it to have a computer update, not knowing, I took it in and they DID it. yup, mileage dropped by 2 mpg, when I asked what they had done to kill my mileage, and please put it back. Nope, Was informed it was done to meet the EPA emissions, saying it improved the emissions for the engine, I ask how does it help emissions when it now burns more fuel------------Duh! I am the idiot on that one I guess, no answer.

Dave, I think you solved my question as to my lower mileage lately.
I was at cummins earlier this year and had them add all the updates to my engine since I never had any of them done. I could not figure out why my mileage was getting worse for no reason on the same trips I had taken before but it was a noticeable difference. I never gave it a thought it might have been the updates which I thought would improve it.

Re: Do older coaches get better mileage?

Reply #37 – October 30, 2011, 05:41:17 pm

It is interesting that many of the people answering the original question mention that they have VMS-PC but no one quotes the lifetime fuel mileage of their coach. An odometer can be set up to show the data from day one. This will be from the day the engine was built unless Cummins reset it during a service event. It may not reflect the mileage the current owner sees on a given trip but it is probably a pretty good representation for the coach. Naturally those with mechanical engines won't be using this tool.

In my case, VMS-PC shows a total distance of 70,659.2 miles and an economy of 7.5 MPG. Yes, my own average is usually over 8 MPG and I suspect that I drive at a slower speed and tow a lighter vehicle than the original owner. However, a comparison of the lifetime mileage might be the most consistent figure to use and it is easy to view.

Re: Do older coaches get better mileage?

Reply #38 – October 30, 2011, 06:11:00 pm

Quote from: Monti – October 30, 2011, 05:41:17 pm

It is interesting that many of the people answering the original question mention that they have VMS-PC but no one quotes the lifetime fuel mileage of their coach. An odometer can be set up to show the data from day one. This will be from the day the engine was built unless Cummins reset it during a service event. It may not reflect the mileage the current owner sees on a given trip but it is probably a pretty good representation for the coach. Naturally those with mechanical engines won't be using this tool.

In my case, VMS-PC shows a total distance of 70,659.2 miles and an economy of 7.5 MPG. Yes, my own average is usually over 8 MPG and I suspect that I drive at a slower speed and tow a lighter vehicle than the original owner. However, a comparison of the lifetime mileage might be the most consistent figure to use and it is easy to view.

Mine is 7.3 over the 128,000 lifetime miles which is the only number I go by.

Re: Do older coaches get better mileage?

Reply #39 – October 30, 2011, 06:20:39 pm

Around 34,279.2 miles since I've owned Forrest and the last fuel fill, the average is 8.308 mpg; C8.3 mechanical towing the Honda Element full of golf clubs, coolers, and other sorta stuff like beverages.

Re: Do older coaches get better mileage?

Reply #40 – October 30, 2011, 06:22:47 pm

Quote

Snip: [Mine is 7.3 over the 128,000 lifetime miles...]

I've not found the path to displaying life-time mileage on our VMSpc; how is that done?

Re: Do older coaches get better mileage?

Reply #41 – October 30, 2011, 07:31:08 pm

Quote

"I've not found the path to displaying life-time mileage on our VMSpc; how is that done?"

One way is to create a new odometer and select the option for "Start From Day One." I keep 2 odometers on display. One I reset each time I fill the tank and the other shows lifetime data. I have them slightly overlapped in the display so that I can click on either one to see the data I want.

Re: Do older coaches get better mileage?

Reply #42 – October 30, 2011, 08:02:59 pm

Engine houre and mileage came up automatically on mine. I will look up the PID. You should have one of the simple gauges to select from...

Re: Do older coaches get better mileage?

Reply #43 – October 30, 2011, 09:04:54 pm

If you click on the Advanced heading of the VMSPC and go down to PID search, you will see the fuel category near the bottom of the list. On that line, in the far right column of the box you should see your cumulative mpg. I don't know how accurate it is on my Detroit but I am taking it in to the Detroit shop tomorrow and will ask them to verify that number. Mine is showing 7.9 mpg but I have never seen mileage that good in the year I have owned the coach.

Re: Do older coaches get better mileage?

Reply #44 – October 31, 2011, 03:56:48 pm

Kent,

We've had our '91 300GV for a year and a half. The VMSPC shows an average of 8.2 MPG for 158K.

Our experience for the 1 1/2 years & 7500 miles has been exactly 8.2 MPG.

FWIW

John

Re: Do older coaches get better mileage?

Reply #45 – October 31, 2011, 05:56:12 pm

Quote from: GMC_jon – October 31, 2011, 03:56:48 pm

Kent,

We've had our '91 300GV for a year and a half. The VMSPC shows an average of 8.2 MPG for 158K.

Our experience for the 1 1/2 years & 7500 miles has been exactly 8.2 MPG.

FWIW

John

I met a family in a '94 40' U300 from Florida at the entrance to Yellowstone last year. In five years of traveling with Chevy Tahoe toad, they averaged 7.9 mpg. Only repair was a cracked exhaust manifold a couple of weeks earlier. Pretty close to what you averaged.

I like the recessed ICC lights.

Re: Do older coaches get better mileage?

Reply #46 – November 02, 2011, 09:34:36 pm

Had my U295 about 7 years, trips all over the place pulling 20' trailer, or Jeep. According to my wallet at the fuel pump you can bet on 8 MPG. Try to keep it turning between 17-1800 RPM the ISC seems to be happy there.

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