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sluggish C9 and low fuel economy(homework)

Yahoo Message Number: 27164
Just a few quick questions for Marvin, You never included...... your fuel mileage, miles on unit, air pressure in tires, size of the rig, are you pulling a toad, trailer, flat driving or hills? What speed do you travel at, do you use cruise control. Do you drive the coach with transmission gear selector to maintain constant RPM. never lugging the engine on various road conditions ? How would you expect to get" great" fuel mileage on a new coach? What do you consider "great" fuel mileage? That's your homework assignment for the weekend. We will grade your report on the next full class web session.
Keep your sense of humor.
AL

00 affinity

Re: sluggish C9 and low fuel economy(homework)

Reply #1 –
Yahoo Message Number: 27175
Hello:

Thank you for your questions to think about my question.
I would like to know more about downshifting as I only do it sparirngly.
We recorded 6.1 to 6.25 mpg. This has been no load, with 3/4ton toad loaded with my gear to go to work, uphill/downhill etc. I am not being flip here the coach seems to go the same no matter what conditions. The difference probably was my estimation of idle or generorator usage. Toad is 4 down.
Tires are at recommended pressure per my weights. 110 on the front 95 on the tag and I do not recall the rears, and it is in the shop now. Unit has 16,000 miles. I try and down shift when needed to maintain my rpm. It seems eveyone with experience says I should get 8.25 mpg. This is 25%higher than we get. I also thought some of the symptons of others might be similiar and some sort of group info sharing might result in better performance. I do think the problem has been solved and I hope to see both better accelorator reaction as well as better mpg.
Any tips here would be appreciated.
Thanks
Marvin

Quote
>From: Boateral@... >Reply-To: Country-Coach-Owners@yahoogroups.com >Subject: Re: [Country-Coach-Owners] sluggish C9 and low fuel >economy(homework)

Date: Fri, 24 Nov 2006 12:31:38 EST >

Just a few quick questions for Marvin, >You never included...... your fuel mileage, miles on unit, air pressure in >tires, size of the rig, are you pulling a toad, trailer, flat driving or >hills? What speed do you travel at, do you use cruise control. Do you >drive the

coach with transmission gear selector to maintain constant RPM. never >lugging

the engine on various road conditions ? >How would you expect to get" great" fuel mileage on a new coach? What do >you

consider "great" fuel mileage?

That's your homework assignment for the weekend. We will grade your report >on the next full class web session.
Keep your sense of humor.

AL

00 affinity
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Re: sluggish C9 and low fuel economy(homework)

Reply #2 –
Yahoo Message Number: 27177
Re; Homework

My opinion ( whatever that's worth) believe your mileage is in the acceptable range. One thing I do see is the coach mileage at 16000. Some truckers and diesel mechanics say that the diesel engines of today don't break in until 15000 miles. Keep in mind that engine longevity is 500,000 miles normal running, normal maintained. Rolling resistance of all moving parts should be smoother as your unit settles in. Use of cruise control far out pre forms driver. I usually watch RPM and try to stay around the 1500-1700 range. That being about 75% of usable power, engine temp stays constant, trans temp stays constant. Speed around 65 mph.
Use of generator and engine idle time effects mileage. My idle rule, parking 15 minutes or less. Greatest stress on a diesel engine is starting and stopping.
The other thing that always helps mileage is a steady tail wind.
Homework grade" A". Advance to next newer Country Coach.

Best regards,
AL

00 affinity #5851

Re: sluggish C9 and low fuel economy(homework)

Reply #4 –
Yahoo Message Number: 27181
If you have an Diesel heat (Hydrohot) and you are using a lot of hot water and are in cool weather; you will use a lot of diesel fuel. I think its about .4 gal/hr of burner running time. If you can use your heat pumps to save fuel.
TWI 2004 Intrigue 11731

Re: sluggish C9 and low fuel economy(homework)

Reply #5 –
Yahoo Message Number: 27182
Marv, I have had 3 cummins under 2 c/c.I have heard of guys getting 8.25 but have never actually followed one into a flying j. I have a deisel gen and a hurricane furnace. I run the tire correct tire pressure and try to run around 1600 rpm.(62mph). Maybe I do carry a little extra water but we do like our own soft water from our building. I think my furnace burns a lot of fuel but other than that, I get about 6.7 to 7.3. Sometimes, I get up to 8 if I am on flat ground without generator or furnace. It makes a difference when I do not tow the honda pilot. I have had the engine calibrated twice. For awhile I got less because at 52,000 I had to have a new charge air cooler and radiator. My coach runs strong when I want it to. I guess I am going to be happy with what ever I get and just have to say that is it. Sure beats setting home. Cheri and I just decided we will set somewhere a couple extra day and enjoy what we get. Ha! Good luck.
Gene

01Intrigue #11272

Gene Holcomb

260.343.0833 home
260.433.4058 cell
gene. holcomb@...
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Re: sluggish C9 and low fuel economy(homework)

Reply #6 –
Yahoo Message Number: 27184

We also use the generator a lot in hot weather but even at high use the generator fuel consumption is peanuts compared to the drive engine; my Onan book claims a little less than a gallon per hour with a significant load. It hurts but not as much as high speed, stop and go driving or inclines.
We also tow a heavy SUV at least 90% of the time. We have had a few tanks close to 8mpg but low to mid 7's seems to be the best average - I don't have the records here.
Cruise controls are great on relatively level roads but will increase fuel consumption in hilly/mountain routes; the cruise will attempt to keep the set speed regardless of the rpm or gear needed to get there. Under those conditions the driver can do a lot better.

Bob Handren

'05 Country Coach Inspire 51178
'00 JGCL

Re: sluggish C9 and low fuel economy(homework)

Reply #7 –
Yahoo Message Number: 27193
Quote from: Gene Holcomb\[br\
]
Marv, I have had 3 cummins under 2 c/c.I have heard of guys getting 8.25 but have never actually followed one into a flying j.
I have a deisel gen and a hurricane furnace. I run the tire correct tire pressure and try to run around 1600 rpm.(62mph). Maybe I do carry a little extra water but we do like our own soft water from our building. I think my furnace burns a lot of fuel but other than that, I get about 6.7 to 7.3. Sometimes, I get up to 8 if I am on flat ground without generator or furnace. It makes a difference when I do not tow the honda pilot. I have had the engine calibrated twice. For awhile I got less because at 52,000 I had to have a new charge air cooler and radiator. My coach runs strong when I want it to. I guess I am going to be happy with what ever I get and just have to say that is it. Sure beats setting home. Cheri and I just decided we will set somewhere a couple extra day and enjoy what we get. Ha!

Good luck.
Gene
01Intrigue #11272
,

We have coaches that are close in build numbers (I'm #11224) and sounds like similar in preformance except in fuel mileage. I have consistantly got 8.3 MPH or better. I have the Cummins ISL 370.
Sounds like I run it like you do with regards to speed and such. I guess I'm surprised to hear that there is really that much difference between the Cat and Cummins ?? I watch the Silveleaf and confirm mileage with a hand kept log. You can follow me into Flying J anytime your out west !!

Michael

01' Intrigue #11224

Re: Low fuel economy and effect of Hurricane Heater

Reply #8 –
Yahoo Message Number: 27196
Gene

I have a 2000 Magna with aHuricane furnace. I have a Cat C-10 and get a average over 10 fillups of 8.13. By averageing over 10 fill ups I take out varitables of hills, wind and other things that degrade milage. Serveral years ago I asked the Factory Huricane rep at FMCA Pamonia rally what kind of fuel consuption for heater. He said that the Huricane heater consumed .25 gal of deasil an hour at full burner power. So I deduct .25 gal from my fuel usage per hour of heater use. I am full time and I never drive any where with aout my tow car on behind. I hope this can be of help for your milage calculations. And yes you can follow my Motor Home into Flying J any time. If you desire a copy of my excell spead sheet for milage calculatin I can e-mail offline

Bo Lee

2000 Magna 5896
2006 Jeep Wrangler

Re: Low fuel economy and effect of Hurricane Heater

Reply #9 –
Yahoo Message Number: 27204
Thanks Bo, I had no idea on the consumption on the Hurricane furnace.
Doesn't seem like a lot .25 gal for the unit. I have the C12, coach mileage is around 7.4 with all factors in my favor. But there are so many times that it seams I'am heading into the wind. I'm wondering how this new diesel fuel will effect the Onan and Hurricane ? That hasn't mentioned here.
AL

00 affinity #5851

Re: sluggish C9 and low fuel economy(homework)

Reply #10 –
Yahoo Message Number: 27212
Marvin,

I had the same problem. My mileage was anywhere from 6 to 8. I 've had this MH for 3.5 years. Finally, last summer while on a road trip with my folks and others I realized that my odometer was not working correctly. My folks and the others would travel say 280 miles and my odometer would only indicate about 220 miles. My mileage, fully loaded with a toad is now actually 8.9 mpg. So....I don't know what type of speedometer you have. Mine is a Datcon and like I said, the odometer is slow, but the speedo is perfect. You might check that next time you are out.

Mike

'95 Intrigue 10061

Re: sluggish C9 and low fuel economy(homework)

Reply #11 –
Yahoo Message Number: 27266
FYI. Been running some fuel consumption calculations on our new 06 Inspire with C9 engine after initial 7000 miles and 23 fillups as follows:-

Overall ave, with and without toad 7.43MPG No Toad load.......................8.97 over 4593 Miles With Toad..........................7.29 over 2437 Miles.
Worst consumption .................5.59 with Toad via Grants Pass at 65+.

Typically travel at 55-60mph.

No toad load includes trip from Bay area to Las Vegas via Tehachapi Pass.

With Toad load includes trip to Victoria BC, via Shasta, Grants Pass, return trip 5 hrs in Vancouver traffic and down Washington, Oregon coast 101.
Tony &P D

06 Inspire 51445

06 Cherokee Overland @ 5240lbs loaded