Curious as to what I would see, I reset the mileage at Big Butt trailhead and headed BEARLY down the hill. I saw up to 70mpg at one point, and here's the Journey detail after 8 miles at 70mph on the Interstate.


Still nearly 35MPG

 

Nice. What engine are you running? Would be nice to see you do it in reverse and average the two trips.

 

I edited the subject line: D90S MY23.5 P300

It.drops 2000'+ in the first 4 or 5 miles, probably going to see 13mpg or so uphill. I will do the circuit and see.

 

That's good for a petrol/gasoline engine.

l achieved 40mpg from my D250 diesel on a 120 mile run, averaging 65-70mph on the motorway/highway and just keeping up with traffic at other times.

 

I've been playing with the ECO mode recently. It's impressive how much that setting numbs the throttle response. It's like driving in syrup it's so muted.

I have a P300 and without the roof rack, lunch box and ladder I was able to get a reliable 26 with my commute.
Then I added all that stuff and cracking 20 is a challenge.

I recently picked up our race boat down by Chicago and brought it back to MN. The entire boat/trailer/etc weighs in at less than #2,500. On that 5 hour drive I was running about 75mph and 11 MPG heading right into the wind the entire drive.

The next week I went back with 4 people, towing a 14' RIB and not beating into the wind and I got 17mpg at the same speeds. The weight of that rig was similar, maybe a little heavier, and way less aerodynamic than the race rig. So the wind was a huge factor.

I also see a difference with summer and winter fuel blends. I get better MPG with summer blends for sure.

I'm going to keep playing with ECO mode. My goal is to use it non-stop for a full tank and see how high I can get the MPG. It's tough though, the acceleration is so slow that pulling out into high speed traffic is a concern when in ECO mode.

 

Here's the Journey info downhill, observed on dash was 82mpg and higher - during the initial mile which goes nearly 1000' down it hit 99.9 for a while. It can't indicate more.

Uphill I was lucky to hit 10mpg and ended up 10.2

Still - not bad...


So, we have 47.7 + 10.2 or 58 divided by 2 = 29mpg for the circuit.

 

Diddling with ECO mode, strictly headed downhill from home 1.8 miles:


Yep, 112.8 mpg. Once you hit 99.9 the dash quits tracking, unless you go under.

I got 9.9 reversed, so average is about 61mpg

 

l have also noticed ECO mode results in reduced performance and lazy throttle response.
lt also shuts off the heated seats if they're on, and sets the HVAC to economy.

lt's fine for cruising around between jobs. You can turn the heated seat back on and the vehicle stays in ECO