Community Forums

winningteam · 01-27-2019, 10:21 AM

Just over 100,000

1. Cummins 8.3L ISC powertrain
2. 1,050 lbs ft of torque or power
3. 350 horsepower
4. Allison 6 speed 3000 automatic transmission

We love taking trips and always try and get the best gas mileage possible. Fully loaded with a Toad that we keep at 3/4 full on gas for emergencies. based on the road, the elevations, etc we have been getting anywhere from 6 - 10 mpg.

Just wondering what others get to know if we should be able to get better than we do and what you do to improve

2 Stroker · 01-27-2019, 12:08 PM

I have had a high of 8.2 and a low of 5.4 My Silverleaf has an overall of 6.3mpg.
Hope for a tail wind.

2 stroker

TR4 · 01-27-2019, 07:51 PM

On my ISL it’s been around 8 lately. I tow a four thousand pound toad and drive at 62. I use paper and pencil to figure mileage.

Here’s another thread to read;
http://www.irv2.com/forums/f258/dies...pg-427197.html

Bill

p1havasu · 01-28-2019, 01:18 PM

Hi Winningteam,

Have the exact same coach with 4 slides. Was getting about 5.2 mpg and fixed a charge air cooler hose leak. Then went to 8 mpg. Now generally in the 8-8.5 range Do also tow a car.

Mike

Mr_D · 01-28-2019, 01:31 PM

With my 45' Vivaldi and it's ISX 650 I'm getting 7.7 over 50,000 miles.

CarlAda · 01-28-2019, 01:50 PM

C13 Cat pushing a 42 foot Inspire comes in at a whopping 5.8MPG average.

2-Nickels · 01-28-2019, 01:58 PM

Getting 7 MPG (Diesel Mileage) with our ISX always towing a 5000lb toad. My average driving speed is 62MPH. 38,000 miles (15,000 since rebuild).

**CountryFit** · 01-28-2019, 08:24 PM

Quote:

Originally Posted by Mr_D

With my 45' Vivaldi and it's ISX 650 I'm getting 7.7 over 50,000 miles.

7.7 is an excellent number for that size. I recently looked at a 45' with a C13 engine. The ECM report showed its life time 51000 miles average 6 mpg.

CarlAda · 01-29-2019, 10:55 AM

Quote:

Originally Posted by CountryFit

7.7 is an excellent number for that size. I recently looked at a 45' with a C13 engine. The ECM report showed its life time 51000 miles average 6 mpg.

I can affirm that the C13 is a thirsty engine. Good engine, but just like to burn diesel fuel.

BernieK · 01-29-2019, 08:43 PM

I have a 45ft 2008 CC with a 2006 c13 and in the hills I'll get 5 to 5.5mpg . Today between Corning Ca. and Bakersfield Ca. I averaged 6.4mpg. . I tried to keep it around 63 to 65mph but averaged 54.2mph on my Silverleaf . It may like fuel but it never given me a problem . 84k miles

CarlAda · 01-30-2019, 09:50 AM

I agree Bernie. Although it gets poor mileage (especially in the hillier areas where I live), it's a very good engine. On the flats, I see significantly better avg mileage. I've got around 88K on mine, as well.

Smitty77 · 01-30-2019, 11:08 AM

We just left on a trip yesterday from San Diego to Lost Dutchman State Park in Apache Junction. We were trying to make it the park early to see a friend that was going to pop in around 2:00PM, but had hard have to leave no later then 3:30PM... And, I forgot about the hour time change from to AZ. So we left the toad off to drive at freeway legal speeds thru California, vs 55MPH with the toad in tow. Then stopped took a dog out of the coach break in AZ, and hooked back up the toad for the balance of the trip. Many stretches the posted speed was either 70 or 75MPH, I kept the Cruise Control set to run at 68MPH, which I do for RPM reasons, and I just don't like driving at 70MPH in these things

!

We filled in Apache Junction, and I had a calculated 7.47 MPG for that run. Considering climbing the hills out of San Diego going East on I8, and a few other stretches smaller climbs too in AZ, and the speed being driven, Toss in full water and full fuel when we started, and freshly stocked for a two month or so trip (Those bottles of vino do add some weight!!) - I was pleased with that MPG.

We have a CAPS era ISL370 (Cummins programmed to 400HP). 40' with tag, two slides. The toad is a CRV, but has about 500LBS of gear in it. And we upsized our battery bank to X's 4 L16's years ago, and that added an additional 260 or so lbs over our OEM bank of house batteries.

We turned 72K miles on this trip. I noticed back around 50K miles or so, that our MPG was going up, assume it was from the engine finally breaking in.

We normally drive 58-62MPH in California while towing, and 64-66MPH the balance of the time (This varies, depending upon where we are, and our schedule.). Silver Leaf reports the MPG is now Lifetime just at 7.9MPG, which was up from the 7.2MPG Lifetime that I had written down at about 30K miles or so, believe it was 7.0MPG when we bought the coach with just under 13K on it.

So their some hmmmm info sharing

!

As has been said a few times here, and on other threads, the cost of fuel is a very minor part of our overall budgets for RV traveling

! I'd personally rather have a bit larger engine, with more power to weight ratio then we have now... And would take the hit on MPG to do so. Not just for the extra power, but just as important to me, is the larger engine displacement's Braking Horse Power... (Not as much of a factor with the ISC Exhaust Brake system....).

Best to all,
Smitty