2004 ISL
We have '04 Tradition with ISL(370) Cummins, F/L chassis(chassis date July '03). We are about 3900 miles into our Alaska trip with an MPG average of 6.3. In the C/G I met a couple with an '05 Traditio...
Forum Discussion
pnordan.....There are too many variables to consider here. I have a short 36' with a 400 ISL. It got 8.2 on average for many years. As I got older and retired two years ago, I made some changes and slowed down a little. We now drive at 59-60 mph which on my coach is 1490-1510 rpm. I don't do any jack rabbit starts. I drive mainly with the cruise control, even in light traffic. I don't like the feel of the throttle so I use my SmartWheel and can thumb up or down the speed on the cruise control almost as fast as working the pedal.
Your Grand Cherokee is moderately heavy as a toad. When I enter a freeway ramp and there is room, I reasonably accelerate up to 45-50 mph, turn on the cruise and then thumb up the cruise control one mile an hour every few seconds until I'm at speed.
If I know I'm exiting in a mile or so and again, if there is no traffic, I kill the cruise and get a good coast to the off ramp. All of this helps when towing.
I run a SilverLeaf computer program on my dash and can see my instant mpg's. I will often look at this and adjust my driving habits. Sometimes, one mph slower or even faster can make you get better mileage depending on the situation. If I see the mpg's are picking up because of a downhill grade that is tough to see with the naked eye or I'm getting a favorable wind push, I may bump up the speed a mile or so an hour.
Source Engineering, is a sponsor on here and offers a replacement engine fan for rear radiator coaches. It replaces the fan you could use to fly a Cessna, with something more technologically advanced that gave me a constant .05 mpg increase with identical cooling.
Lastly, you have to average fuel over MANY fill ups and try to fill the coach the same each time. I level my coach with one jack usually when fueling so I get close to the same amount of fuel. It only takes a moment to do so.
On a long trip of 400-500 miles with no huge grades and not towing, I get 9.8-10.3 mpg if I practice all of the above. Towing my 5500 pound truck I lose about one mpg. Short trips locally, not towing, I see about 9.2 - 9.5, too much starting and stopping.
My mileage is always checked against the computer and calculated manually. My wife does the calculations while I fill up and then we compare her results to my computer as I reset the screens.
Our biggest increase in mileage was slowing down from 63-64 mph to 59-60 mph. I recently added the DigiCR computer chip to my ISL. I'm seeing improved mileage, but haven't had a long enough trip to get a good enough calculation to see if it's helping. There is an HP increase, but not a huge feel in the seat of the pants as there was with changing the fan. Will gather more info in 2 weeks with a trip to Utah and some climbing.
This was kind of a long post, but shows many things that can be changed in habits and parts to increase mileage.
Your Grand Cherokee is moderately heavy as a toad. When I enter a freeway ramp and there is room, I reasonably accelerate up to 45-50 mph, turn on the cruise and then thumb up the cruise control one mile an hour every few seconds until I'm at speed.
If I know I'm exiting in a mile or so and again, if there is no traffic, I kill the cruise and get a good coast to the off ramp. All of this helps when towing.
I run a SilverLeaf computer program on my dash and can see my instant mpg's. I will often look at this and adjust my driving habits. Sometimes, one mph slower or even faster can make you get better mileage depending on the situation. If I see the mpg's are picking up because of a downhill grade that is tough to see with the naked eye or I'm getting a favorable wind push, I may bump up the speed a mile or so an hour.
Source Engineering, is a sponsor on here and offers a replacement engine fan for rear radiator coaches. It replaces the fan you could use to fly a Cessna, with something more technologically advanced that gave me a constant .05 mpg increase with identical cooling.
Lastly, you have to average fuel over MANY fill ups and try to fill the coach the same each time. I level my coach with one jack usually when fueling so I get close to the same amount of fuel. It only takes a moment to do so.
On a long trip of 400-500 miles with no huge grades and not towing, I get 9.8-10.3 mpg if I practice all of the above. Towing my 5500 pound truck I lose about one mpg. Short trips locally, not towing, I see about 9.2 - 9.5, too much starting and stopping.
My mileage is always checked against the computer and calculated manually. My wife does the calculations while I fill up and then we compare her results to my computer as I reset the screens.
Our biggest increase in mileage was slowing down from 63-64 mph to 59-60 mph. I recently added the DigiCR computer chip to my ISL. I'm seeing improved mileage, but haven't had a long enough trip to get a good enough calculation to see if it's helping. There is an HP increase, but not a huge feel in the seat of the pants as there was with changing the fan. Will gather more info in 2 weeks with a trip to Utah and some climbing.
This was kind of a long post, but shows many things that can be changed in habits and parts to increase mileage.
