Cat 350 fuel mileage?

mainiac · 05-30-2007, 05:34 PM

Help me out now and you'll never get rid of me! We are new owners of a 2006 Itasca Horizon 36RD. So far, we're really happy with everything about it except fuel useage. On the trip home, with an empty coach, we got 6.8 mpg! The home has 8500 miles on it, so I'm sure it's not fully broken in, but that mileage was a shocker! Our only prevous experience was with a 2006 HR Neptune with the 300 Cummins, we opted to move to a higher end coach, but I'm hoping it's not at the expense of 3 plus mpg?
Please tell me what you think.
Thanks, Dennis and Linda Taylor
"MAINIAC"

mainiac · 05-30-2007, 05:34 PM

Help me out now and you'll never get rid of me! We are new owners of a 2006 Itasca Horizon 36RD. So far, we're really happy with everything about it except fuel useage. On the trip home, with an empty coach, we got 6.8 mpg! The home has 8500 miles on it, so I'm sure it's not fully broken in, but that mileage was a shocker! Our only prevous experience was with a 2006 HR Neptune with the 300 Cummins, we opted to move to a higher end coach, but I'm hoping it's not at the expense of 3 plus mpg?
Please tell me what you think.
Thanks, Dennis and Linda Taylor
"MAINIAC"

Pusherman · 05-30-2007, 05:44 PM

Welcome to the forum

I see this is your first post!

I posted a similar question Here in the Freightliner Forum a while back, and got some responses to my question.

I averaged 7.6 mpg on a 3200 mi trip to Florida and back. Sounds like most folks get similar mileage.

There are suggestions that mileage will improve but not until you have 20k+ miles on your coach.

I used to have the Cummins 5.9 ISB and it too returned 9-10 mpg. Same size coach. But I really love the responsiveness and power of the C-7.

Happy miles!

Gary CA · 05-30-2007, 07:03 PM

Mainiac: I have 17000 on my 2004 CAT 350. If I keep my foot light and cruise on 63-65 I get a consistent 8.5mpg. I'm good with that.

smlranger · 05-31-2007, 04:29 AM

Mainaic:

Welcome to the forum

. Congrats on your Horizon. As the others have indicated, you should expect improvement in mpg as you get more miles on the engine. While you have a C7 350 vs. my C6 330, we average 8.4 mpg at 25,000 lbs. towing a 4,700 lb car.

Enjoy the rig and come back often to share your experiences with us.

Pusherman · 05-31-2007, 05:46 AM

I am hopeful that my mileage increases towards 8.5 with this engine as I get more miles on it.

There is an interesting thread in the Freightliner forum Here which notes that for 2007 chassis's Freightliner is adding a fan clutch. Rumored to provide another 0.5 mpg. Also rumored to may be available some day as a retrofit kit for existing chassis's.

SteveG · 06-03-2007, 12:07 PM

Our 2004 Journey 36G has a Cat 330. It has about 22,000 miles and I tow about 5,500#. Mostly in FL so flat towing. I finally got 8 mph tank to tank filling. I knew mileage would be 7 to 8 and maybe more as the engine breaks in. I think I would also do better if I lightened the towing load. I drive at about 62 mph but will ocassionaly move to traffic speed as required. I like the CAT engine's strength and durablity.

From what I have read from the CAT owners forum if I can get a steady 8 mph I will have good milage. So far I have not gotten it consistently. Lots of variables such as my right foot when not on cruise control; traffic patterns; wind direction and strength. We enjoy our MH and are happy with the diesel experience. Best of luck with finding the higher mileage sweet spot.

rv rick · 06-04-2007, 04:21 PM

Our 2004 Meridian with the Cat 330 has given 7.8 mpg over 21,000 miles (using the Trip Tek computer). I can get an easy 8+ if I keep it to about 62 or so.

vicsryd · 06-05-2007, 05:15 PM

Here's my current wish list for increased mileage for my CAT C7:

- Freightliner coming up with a clutch type cooling fan retrofit like the '08's will have. This is estimated to be .5 mpg and 30hp to the road on the CAT C7. I believe it as a friends '05 Vectra has a CAT C7 with side radiator and he consistently gets better mpg than I do and his GVCW is at least 3500lbs more.

- AeroTurbine 5050L Muffler. Redlands Truck Center and Brazels RV say there is a.25 mpg and 10HP increase. Brazels has a dyno for RV's so their testing is well controlled (i.e. no wind).

- AFE 707105 Hi-Performance, Washable Air Filter. Again both Redlands Truck Center and Brazels RV say .25mpg and 10hp increase.

I personally am so-so on the muffler after I heard one on another coach. It sounds nice but it is definitely louder. On the other hand every little bit helps.

dakotabuckeye · 06-06-2007, 07:57 AM

Someone a while back posted this about wind resistance:

Wind resistance on a 20,000lb coach, 12' high and 8' wide:
@60mph 89.2 horsepower is needed to overcome wind resistance
@65mph 113.4 HP is needed
@70mph 141.6 HP is needed

Now my thought is, hypothetically...
If you're getting 9 mpg at 60 mph using 89.2HP
Driving 65 mph using 22% more HP than 60 mph, fuel economy drops by 22% = 7.02 mpg
Driving 70 mph using 38% more HP than 60 mph, fuel economy drops by 38% = 5.58 mpg

Md shedman · 06-07-2007, 03:14 AM

I also get about 6.8 MPG, but I do drive about the speed limit or 10mph over, pulling 5500lbs. I only have 11000 miles on it and think that this will increase. I didn't buy it for the gas milage!!!

jk_and_dog · 06-07-2007, 09:34 AM

I just got back from one short trip, overnighter into the mts of Va, pulling an s-10 and according tom trip computer got 8.0. Travel speed was 55 to 63. Second trip was 2011 miles pulling jeep grand cherokee. Average 7.9 with 7% idle time. Average speed 55 to 65. This was from Va bch to Indianapolis and back with several side trips.

Journey 36G with C-7 350 6 sp allison. Allison kicked in on 6th gear at 55 mph. Lowest spped up mtn going into beckley wv was 37 mph with tranny down to 2-5.

vicsryd · 06-07-2007, 02:36 PM

There is a fuel mileage poll in the CATRVCLUB Yahoo Group for CAT C7's here that is statistically meaningful. Join the group and take the poll to add your two cents.

jtharley · 06-08-2007, 11:38 AM

Michigan to Nashville towing a jeep liberty and I averaged 7.8 miles per gallon....traveling on average about 60-65 mph, calm headwinds......

kenbt · 06-09-2007, 10:55 AM

I have a 2005 Vectra 36RD and have 30,000 on it now. I do the math on each trip and do not rely on any software to estimate mileage...I have been averaging 7.3 mile per gallon pulling a 2005 Honda CRV. Hoping that it goes up after the 30,000 mile break in period

ppeter313 · 06-09-2007, 10:55 AM

R.I. to Dover last weekend 8.8 mpg @ 55 mph on way down, 8.1 @ 65++ mph on way back, 13,000 miles on engine, trip averages using VMSPC.

Paul

vicsryd · 06-09-2007, 12:29 PM

Here's something that came up our WIT chapter outing this weekend that kind of has me stirred up.

One of the members has a '04 Vectra 40QD with Cummins ISC (8.3L, 350hp, 1020ftlbs). He's only at about 18,000 miles and has consistently gotten 8-9mpg towing a full size Chevy pickup for the last 8,000 miles and averaging 60-65mph. About half of the miles driven are not on Interstates. And keep in mind this is here in the Pacific Northwest where nothing is flat driving is the exception.

Last month he and I drove together the same same route in a caravan for 800 miles. He got 8.4mpg and I got 8.0 flat.

Similary, another member who bought an '07 Vectra 40FD with Cummins ISL last month just finished his first 1000 mile trip. He got 8.1mpg towing a Jeep Liberty and showed me the receipts to prove it.

We all have nominal tire pressure set to the charts for our tire position weight.

So now begs the question is why a smaller displacement engine like the CAT C7 (7.2L) using more fuel to push, in my case anyway, less weight around?

I know other Vectra's with Cummins ISC that regularly get 8-8.5 even 9 mpg and an ISL that gets 7.9 mpg. For kenbt I think .5 mpg is missing because he's a rear radiator with fixed, belt driven fan whereas most of his Vectra brothers in 40 foot chassis have side radiators and hydraulic fans.

So net-net in this case is bigger rig with bigger engine gets better mileage. Go figure.

dstinch · 06-10-2007, 06:28 AM

06 journey 36,last trip out 60 mph 4600 lb toad, 8.2 mpg,350 cat

vicsryd · 06-10-2007, 07:28 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by dstinch:
06 journey 36,last trip out 60 mph 4600 lb toad, 8.2 mpg,350 cat </div></BLOCKQUOTE>Please describe route, terrain and total miles driven.