Mileage (MPG) for 500 HP Cummins

[PanJH]

Hi,
We are looking at a 2006 TS Select with the 500 HP Cummins . For those of you that have this engine, I'm just curious about what MPG to expect... thanks

[Steve N Sal]

Our neighbors here have it and said they get 5-6mpg.

[Perry White]

6-7 Depending how you drive. Have someone with Cummins Insite program download the ECM image and it will tell you what it is on the coach your looking at.In fact I wouldn't buy one without first having it checked for inactive alarms. Lots of things Cummins have changed, If it's on a Spartan K2 chassis you have exhaust breaking problems, EGR tubes breaking. Most big HP are close to the same. Great engine except for a few problems.

[texnet]

It is all in the way and speed you drive. We have a 400hp Cummins.

70-75 I get 6.5-6.9.
65-70 I get 7-7.8.
59-65 I get 7.9-9.0
55-60 I get anywhere from 9-11 according to flat or hilly.

I believe the 500 will average about the same.

[Perry White]

I wish

[mccsix]

I have to get something out of my under-powered 6.7 ISB (380hp).....11.4 mpg for recent 400 mile trip @61 mph, no toad, no hills.

[The Driver]

We get 9mpg when cruising @ 60, 8 when cruising @ 65. No toad. Hills, traffic, stop lights all cost mpg. Comfortable power for the rig.

[JTBond]

I have an ISX 525 Cummins and I get about the same as what texnet mentioned. Speed is everything. This is a15L engine btw.

[rvguy02]

With our 2012 Aspire and its 450 hp Cummins we are getting slightly over 8 mpg with our toad at an average speed of 65 mph. On an upcoming trip to Florida this March I am going to try and slow down to 55-60 mph and see if I can boost mpg to 9 or above.

[Larnie]

2008 Envoy 42' 400 ISL. Can't seem to get more than 6.7 mph @average speed of 65 mph. I feel like there may be an air restriction problem since the filter gage is always at the red line even with new filter and new gauge. Same problem aa earlier post. Doing the research and will report back.

[lonestarace]

Quote:

Originally Posted by PanJH Hi, with the 500 HP Cummins . For those of you that have this engine, I'm just curious about what MPG to expect... thanks

We have had 2 tag axle Monacos w/500 ISM Cummins that weigh loaded w/toad about 45k lbs. We drive 60mph. We always travel to the mountains of the western USA. We use the cruise control when the roads aren't too hilly. When we remove the diesel fuel that the 12.5kw gen burns from the mpg equation we get about 8.0 mpg.

We hope this helps

[DBeauchamp]

When I bought my coach in August the avg. on my Spartan In-dash Message Center was 35.4 Liters/100 Km which is 6.64 mpg. I went on a 26 hour trip and on the way there maintained that avg. going my usual 70-75mph. Before going back I reset the avg. meter and drove 60-65 for 13 hours. The display now shows 29.5 Liters per 100Km which is 7.97 mpgs... Engine is the 400 Cummins.

[motorhomeguy]

"...500 HP Cummins . For those of you that have this engine"

I have a 2011 Jeep Rubicon and I get around 19mpg. Opps, I'm sorry you were asking about the Cummins ISM engine, how silly of me. Never-mind...

[Lug_Nut]

Much depends on speed, but also wind resistance. If you have a headwind it can be as low as 5.5 while a tailwind may yeild 8 or so. But averagely you will probably get 6.9 MPG. In the past year I ran two 8k mile trips. Towing 6200 lbs and driving at reasonably good milage speeds, the average on each was 6.9.

Peter