I was pretty shocked today. I guess I've avoided this calculation but today we averaged 7MPG while towing my Jeep. This seems pretty low. This route was pretty average...we drove from Hardeeville SC to Boone, NC. Temps were in the 50-60 range and it was cloudy. All but the last 10 miles was fairly flat.
I'd love to hear what others get with the Detroit engine.
Thanks all.
Jeff
Just bought a used 1994 Detroit the previous owner said he got 12 mpg I haven't tested his mpg forecast but he has lied abut everything so far. Hope he is telling the truth about 12 mpg.
That's in the ball park for ours Jeff sometimes a little better more like 7.5 after having a Eagle bus with a 8v92 and getting 5 or 6 were pretty happy ^.^d
Thanks Andy....I think ;D
My 91 seems to average overall about 8.3 . I have checked it on our trip to sturgis,Sd and overall mileage was 8.3. Some legs more some legs less. I also have checked it going to Daytona same report. And on a trip Ga with in-laws same.With that said there are so many variables. You have 50 more horsepower than me. Your coach probably weighs more etc. Wind, hills all add into the equation. Maybe you have not found the sweet spot RPM yet. It really does not matter what the mileage is. Look at it this way. A new or newer coach in this class is going to run you 300k-450k range right? You bought your rig way less than that I'm sure. And it is as they say, The Cream Da La Cream, Yours came pretty much turn key. The difference buys a hell of a lot of fuel even at 7mpg. That big shiny thing that just passed you isn't do any or much better.
And, When you get to the campground, Which one is everyone looking at! Look at it as the cost of Cool! 8)
Good point all, thanks Stump
Somebody once told me to drive a 4 stroke diesel pretending you have a uncooked egg between your foot and the throttle pedal. Steady pressure while accelerating so your not overfuelling it, and very little black smoke. 6v92 is a different animal to drive. How fast we're you traveling?
40' coach towing 2,700 Tracker - ISM 450HP generally about 75 MPH on the highway.
6.5 - 6.8 is about what I see on the VMSPC - some times more, less in hills and heavy winds
Your two stroke doesn't seem to be out of line for a 40' coach, but others with your combination will I am sure will chime in.
Tim Fiedler
Sure Start Soft Start (http://www.gen-pro.biz)
TCER Direct (http://www.tcerdirect.com) generator-gas-prod (http://www.generatorgasproducts.com) 630 240-9139
Gen-Pro
Phred my engine seems to just do it's thing about 1725 rpm it's about 65 66 mph it just sounds like it happy. It also likes around 1800 rpm. Not much more not much less. But 1725 is where I usually run it.
You guys shouldn't complain, just finished a 3100 mile trip in my 6 cylinder 4-stroke "fuel efficient engine" coach.
Overall average for trip.... 7.0 mpg.
Somebody once told me to drive a 4 stroke diesel pretending you have a uncooked egg between your foot and the throttle pedal. Steady pressure while accelerating so your not overfuelling it, and very little black smoke. 6v92 is a different animal to drive. How fast we're you traveling?
I am guessing Jeff has a 102" wide coach so he's pushing about 4.5 sqft more of frontal area, plus stumps is a rear radiator and that may help filling the drag behind the coach. Just s guess.
After lots of mods I had a good increase in mpg. So I tow faster now to use it up. Our coach is lighter than the coaches mentioned so any comparison is off.
Big improvement in power and mpg with a resonator, different fan drive controller and a blue tech air filter and excellent batteries and a rebuilt alternstor.
Plus the newer Michelin's better rolling resistance.
Yep! That big rear engine fan pushes me down the road just like a airboat ! Yep, Luxury Airboat for sure@ ^.^d
I must be doing something wrong. My lousy "fuel sipper" 8.2 Detroit Diesel turbocharged V8 gets 9 MPG or better, and this is the engine almost nobody likes (hi Brett). Scary to think what MPG it will get after it is broken in!! Wonder what it gets without towing our 2006 Saturn Vue. Bet the MPG is so good due to the small dinky compartments where we can't store much. Maybe the narrow width, or the aerodynamic shape? Or that we drive at 58-60 MPH? Could it be that old 1989 technology? All mechanical, no computers??
Maybe the real shiny finish lets the coach "slide" thru the air??
>:D >:D >:D :)) ^.^d
58-60 is the main factor in your equation I would think - along with the engine/trans/gearing combo.
Cant drive that slow, life is short, too many items on bucket list.
"Do what makes you happy" fits me as to my 75 - 80 MPH habit
I am amazed at how I search out the cheapest gas prices (just paid $1.95 a gallon this week in Galveston for 87 octane after grocery store rebate) and triumph over saving .02 a gallon on 20 gallons when none of that will ever make a difference in my lifestyle.
Always figured .50 a mile to move the coach - will be more or less depending on the price of diesel, but that is my basic premise
from Galveston heading to NAC for some stuff and then back to Seattle area. Credit cards will get a work out, but 150 gal tank gives me 700 miles to get the best price along the route.
Put Diesel in anytime I am down by 60 gallons or ore per VMSPC, I see a good price and I need to stop for some other biological reason.
Tim Fiedler
Sure Start Soft Start (http://www.gen-pro.biz)
TCER Direct (http://www.tcerdirect.com) generator-gas-prod (http://www.generatorgasproducts.com) 630 240-9139
Gen-Pro
Cant drive that slow, life is short, too many items on bucket list
I am amazed at how I search out the cheapest gas prices (just paid $1.95 a gallon this week in Galveston for 87 octane after grocery store rebate) and triumph over saving .02 a gallon on 20 gallons when none of that will ever make a difference in my lifestyle.
Tim I do the same thing. It is because earning the money is hard work keeping it is even harder! Even just a few pennys. There is nothing wrong with that.
X2...I don't "shop", ease of in and out is my focus, seen too many coaches dinged-up by trying to get into/out of a cheap fuel stop. Don't keep track of the mileage anymore, I know I'll never get the 15mpg the Airstream/Isuzu did, but the top end of this coach, being far in excess of the AS, more than makes up for the mileage. I love passing semis! ^.^d
I think the fuel price thing is my OCD
97 U295 36'.....3126 300 HP Cat....1700 rpm range.......63 mph....Happy place for me and the motor home towing a jeep Wrangler.....Happy when I see anything in the 7 MPG range on silverleaf........I fill at 1/2 tank too, unless I know cheaper fuel is down the road
I have had every kind of RV combo over 50+ years, never had one to get better then 8 MPG
Chris
My 1994 U300 6V92 over the last 10 years, and about 35,000 miles, has averaged about 6.5 MPG. I am towing a Jeep Grand Cherokee or Dakota P. U. 6 to 6.5 up and down hills, 7 or 7+ flat land. I do carry a lot of "stuff" that I do not need but You never know. ^.^d Keep the Air Cleaner "Clean" makes a big difference.
We do quite a bit go shopping on both gas and diesel. A mile or 2 out of my way to save 10-15 cents I'll take that any day. If you don't burn 100 gallons of fuel a year doesn't make much difference, 12-1500gal different story. As Stump says it's hard to make those nickels and dimes even harder to keep em.
O.K., I give....what's "OCD" mean? ???
Obsessive, Compulsive, Disorder. :P :P
Words to live by:
1. My father use to tell me when I was growing up and the family was RVing, "if you have to worry about the mileage and the cost of fuel you are in the wrong hobby".
2. Don't get me started on mileage of 8 cy Detroit diesels. My Chris Craft had twin 8 cy Detroit's. Use to cost me $500 bucks to travel from Sacramento to San Francisco (about 120 miles). I know, I know, "apples and oranges". Just saying.......
3. Just waxed my rig and I swear I picked up another mile to the gallon on the mileage.
1997 U295...3126 CAT...Towing Jeep Wrangler...7.9 on Silverleaf constantly...Like Chris approx. 63 MPH seems to be the sweet spot.
John
Cat 3176B ,365HP, 9.3mpg towing or not.....loves the hills ^.^d ^.^d
On a non winded flat road at 60 mpg towing our solara convertible I get 10mpg. Got over 11 one stretch in Colorado/Nebraska that I posted pictures of.
Bob Rozen(flyte10) got similar results on his 97 u320 after the sane mods.
Boring. Towing at 70 minimum and floored on every hill and revved hard my 12,000 mile average since the mods on the silver leaf is 8.1 mpg, and 97 and 87 psi in the tires
IMO the most noticeable contributions were the resonator and the tires. With Xza-2's and with the throttle off the coach slowed in traffic a noticeable amount.
With the Xza-3+'s you have to use the brakes or retarder much more.
The 3176 engine in a marquis heavier coach towing a Jeep got 8.2 mpg at 65 up and down the hills with the auto jake in use.
Customers loved it as they never moved their feet up or down hill on cruise.
The m11 is no where near that powerful regardless of ratings.
The diesel industry distributors may have turned up their engines and violated the smog law tests long ago and it was rumored that versus fix the older motors over power settings the fix was to turn down the future engines a bit so over years the fleet average emissions would balance out.
Monaco's were turned up for sure and some cats. Sold more coaches, sold more motors
Whatever turns one's crank.
Our 1989 GV is comfortable driving at speeds under 60. Over that it gets a little squirrely.
So we drive at our speed.
Our philosophy is to enjoy the journey and then enjoy the destination.
We take living the same way. We know what the destination will be--one of two places :))
There is so much country we haven't seen yet so we slow down & savor the view. MPG just happens to be a side benefit.
I know my friend who has a '89 GV has the same observation. I notice no difference with ours at different speeds having the Torsilastic suspension, newer KONI shocks and wider Michelin tires.
Reflecting back on my post ,with driving 65 to 68 being the sweet spot, with a wide body and weight being 33,000 lbs gross.
^.^d
Seeing that this topic has strayed from just the DD6v92, to CATs and other DD's, I will throw out our little Cummins 8.3.
On our almost 9000 mile trip to California and back to FL, we averaged 10.2 mpg with no toad. I had to back out the fuel used by the genset so I used the .7 gal per hour figure that I have seen posted on the forum and the hours on the Gen hour meter. Passed thru the Badlands, Black Hills, Beartooth Mtns to Yellowstone. Then thru the Tetons to Idaho and Oregon, down to Northern Cal then Yosimite.
Las Vegas, Grand Canyon to the 4 corners area before heading thru NM and OK, then back to FL.
Did all of our sightseeing in the Coach...... was happy with the 10 mpg plus............. ^.^d
Sorry for the long post! :-[
In over 100,000 miles, using the Pro-Link 9000, it reads exactly 8.0 mpg. When we bought it at 60K, the Pro-Link read 7.9 mpg so we have gained 0.10 mpg in the last 45,000 miles. We live in the Sierras so it's all Jake and then full throttle and Jake again. Mileage is mostly pulling a 2990 pound RAV4. Going down to San Francisco at 55 mpg, we can get 12 plus but that at a slower speed and flat or downhill. Check my older posts for the photo of the Pro-Link readout.
Any coach with a 4 speed is really penalized with a short final drive. The six speeds should deliver .5 mpg better at least.
Since Detroits are 2 cycles, they only sound like you are abusing them. The max torque is not that far above idle and ours has a fuel cutoff at 2100 rpm. Our old 4107 bus with a non-turbo 8V-71 w/235hp was narrower and lighter and with a VW Rabbit behind, got 10.3 for the worst mpg and on flat ground, it would get just into the teens. It did have a manual gearbox and since it was ex Greyhound, it had a very tall final drive with a top speed of about 90 mph. It got all of it's torque very low and the fuel cutoff was at 1800 rpm. Not even a tachometer was on the dash.
So, the idea of 12 mpg with a 102" 40 foot coach is a fairy tale. Plan on about 8 mpg with a mix of mountain and plains driving with about 65 mph as the normal highway speed. 75 mph will cut it to 6 plus mpg while 55 mph may be a little better. Don't listen to some who boast more on a trip but if the computer readout is looked at over the life of the coach, the mpg will be less. Less with a heavy coach, more with a lighter and narrower U225/240 with a Cummins or CAT. The earlier GVs can average 11 mpg.
Pierce
Good info pierce. Here's a run across Nebraska at 65 with no wind. 4K altitude. Charged batteries and zero wind. The 11.9 was at 60. Boring
Actual torque and horsepower curves seem to cross at 70. Lose mpg from wind
We have even got as low as 4 MPG bucking a 30-35 MPH headwind while going 56 MPH.
Sure don't like headwinds & hills.
We don 't have onboard computers or any type of electronics that record MPG over the life of our coach. (Remember those days?)
So, being that we suffer from voluntary inertia, we only compare what MPG we got on previous trips to our latest fill of fuel.
We have noticed that we are very slowly getting better MPG. Possibly due to the engine getting broke-in? Bought the coach when it had about 62,000 miles on it and now we have almost 84,000 miles on the odometer. Not sure if replacing the stock muffler with a straight pipe affected the MPG much, but it did increase the feeling of more, quicker power.
As I had posted awhile back I found the cruise control wiring problem and fixed that so we do use the cruise control a lot more than we used to, so that likely helps the mileage.
I compare the mileage on each fill-up because any drastic change is, to me, an indicator that something might be going wrong. Being a totally mechanical engine the MPG check is a tool we use to monitor the engine/drive train.
On my recent trip over the holidays of about 250 miles I averaged 8.4 mpg towing my little Suzuki Sidekick (2700 lbs) and checked with the Pro-Link Trip Data.
This was running about 62 t0 65 mph and no dash air. Mileage has increased from 8.0 to 8.4 (5%) as Hankook advertised since replacing the old Michelin XZA-1 with the Hankook AL07+ tires. I ran them at 105 psi this time. I like the smooth ride but will try them at 110 psi next time to see if I can gain a little more mpg with the same ride quality.
Bottom line is I like to open the driver's side window just to listen to that DD6v92 rev up and the roar of the Jake. Makes me feel good no matter what the mpg!
Jerry
Just finished a trip from Omaha to Waco, TX and back.
No TOAD, tail wind/no wind both ways (EXTREMELY UNUSUAL), no generator run the entire trip.
9.3 MPG