Do you really get 25 MPGs on the highway??? I don't. I get about 21.

[mapper]

My experience mirrors shammyh's. I also don't generally use electrical devices more than necessary. I agree NOT using cruise generally nets me better mileage as my foot is lighter than the computers. Anyway I know how to get good economy. I can beat EPA estimates in my other cars and I drive one MUCH more aggressively than I drive the Volvo. On my trips to OR I drive another car up to 90-95 in the wide open stretches (with a roof box on) and still beat EPA estimated highway economy over the entire trip. It's quieter and more stable feeling. I put about 25k on per year so I'm pretty good with the tricks, although holding a lower gear is tough with the auto. Sure, you can use geartronic but it's awfully easy to forget about.

I think the issue with the Volvo is aerodynamics because the mileage "penalty" for high speed seems to be rather severe. Also accounts for surprising wind noise.

My tires are a bit heavier but I'm not seeing much difference from what I was running in summer (Scorpions). I think the rotational mass is more of an issue in city driving. In any case I heard regular reports of mid to high 20 MPGs when I was investigating the XC. I assumed that meant folks were driving Interstate speed, which is usually, realistically at least 70 (in a 65 zone). I also never expected the added speed penalty to be so high. I regularly drive 5-10 hour trips on the interstate and driving 65 rather than 75-80 is just not going to happen, especially when the cops don't bat an eye and frequently there are no other cars to be seen.

Sadly I bought this car for trips and it is just frustrating to be expecting an easy 25 but really only getting economy almost as bad as my van on road trips...a person can travel/tour/camp with dogs quite comfortably in a van vs a car.

[MBevans]

My 2007 XC70, from the time I purchased it @59k miles to 2 weeks ago @92k miles(when it was smashed by a crazed semi-tractor-trailer rig) has always given me between 24-26 mpg...

I normally run the California interstate hwy #5 between 65-75mph, and closer to 75 truth be known.

Always clean air filters and Mobil 1, I even changed the sparkplugs @ 80k miles, yet made no difference. Oh yeah, I always use regular gas, only 1 tank of premium ever.....

[KevinR]

What size wheel and tire combination are you running? Wider tires and/or heavier wheels will have an adverse effect on fuel mileage. The type of tire you use will also have an effect.

On my '02, I am running Michelin Harmony All Season tires in a 215/65-16 size on factory Tellus wheels. I keep the tires inflated to 36 psi. I drive this car almost exclusively in city traffic, running 89 octane mid-grade gasoline, and get 20-21 mpg. I have performed this calculation manually and it comes pretty close to matching what the car's computer calculates.

[sikbrik]

Like you said, speed kills. Previously, I was averaging 20 (now 21.5) around town for my daily commute which is slightly mixed 10 miles while it's still a little cold. In my car, the in car display is always within 2% of actual calculated mpg at the pump.

42psi is high on stock tires. Max sidewall pressure is 44psi...that's hot, not cold. I'm not saying I haven't done it but when I did I ran a long stretch of highway only and got 30mpg before the tune, 35 mpg after. Granted, this was at 60 to 65 mph with cruise. Normally it would have averaged 26 or 27 highway. I just ran a few tanks that were door to door trips but mostly interstate and backed the psi down to 36 and bumped the speed to between 75 and 80 to prove out the chip tuning effects. That number turned out to be 27.5mpg. This is on mostly flat roads around Philadelphia and Baltimore so some traffic but not stop and go except for the beginng 10 miles and ending 10 miles with 150 miles of highway in between, for example (oh, and 87 octane which I think hurt- it definitely decreased power.)

I think east coast gasoline is better for some reason. Also the more stops you make, the lower this will be and short cold trips will be miserable. The aero isn't really terrible on these things compared to other cars of this size.

[mapper]

Wow 30-35!!! In an XC??? You've got something special there. Are you running bumper to bumper traffic? I'll get mid-high 20s cruising in traffic due to the "drafting" effect but never out on the open road.

For those not wanting to read the whole thread:
I'm not talking about short, cold trips. I'm talking about long-distance highway cruising 700 miles in a day, stop to pee and fill-up the tank type driving.

I'm not running 42 PSI on stock tires. I'm running 225 65 16 with a load index rating of 110. Everything else aside, when stepping up in size (+1, +2 whatever) and load rating one should increase cold inflation pressure. There are tables available, do a search. Otherwise you risk overheating your tires and causing a blow out. My tires are rated for 70 something PSI max cold inflation pressure. Yes, the sidewall says "cold". Tire pressure should ALWAYS be checked cold, as in before you drive even 1 block, anyone who tells you otherwise doesn't know what they are talking about.

AT ANY RATE, I've driven 12,000 miles in this car. Only 1500 of which have been on these winter tires. The remaining 10500 have been on replacement OEM Pirelli Scorpions. There is little difference (maybe 1.x mpg).

I'm going to experiment with regular gas. My car always accelerates more than I need/want at the low end I usually barely touch the gas pedal. Maybe running lower octane will keep the ECU running more "relaxed"/"less aggressive" fuel trims in-line with the type of performance I use on a daily basis. The power will be there if I need it.

It's pretty clear from the posts thus far that folks reporting mid to high 20s are driving in the 55-65 zone. Above that fuel economy approaches a middling 20 MPG.

[KB3MMX]

Something that hasn't been suggested is trying to back your turbo wastegate off a half turn.....loosen it up slightly.
I know that our XC became MUCH more touchy/responsive when I turned it tighter by a half turn. I would go the opposite way to smooth it out.
Also, at 80mph your rpms are elevated enough that the turbo is more than likely being driven harder than is needed and consuming more fuel.

[mapper]

Something that hasn't been suggested is trying to back your turbo wastegate off a half turn.....loosen it up slightly.
I know that our XC became MUCH more touchy/responsive when I turned it tighter by a half turn. I would go the opposite way to smooth it out.
Also, at 80mph your rpms are elevated enough that the turbo is more than likely being driven harder than is needed and consuming more fuel.

Interesting, I'll investigate that more. "Touchy" is a very good description of the throttle response in my car...especially at the low end. I could definitely see how venting a bit more charge air wouldn't hurt/diminish the performance I'm getting.

[wgriswold]

Interesting, I'll investigate that more. "Touchy" is a very good description of the throttle response in my car...especially at the low end. I could definitely see how venting a bit more charge air wouldn't hurt/diminish the performance I'm getting.

Here is an additional thought.

I wouldn't call the throttle response "touchy" in my car. I am not sure that the turbo engages at all if I don't floor the accelerator. I have heard that the car somehow adapts to a driver's style; that the computer is heuristic. I can't document this but I learned it somewhere, maybe from the salesman when I bought the car. If this is so, then maybe my car is in some sort of low performance mode because of my driving style and that leads to better fuel economy.

[mrsteve]

This may upset most of you but I just did a trip down to Bristol UK in my late 05 D5 Geartronic and got over 43.5mpg cruising at 80mph in heavy traffic. I've only had the car a week and am getting the feel of it. Tyre pressures around 35psi, running 215/65 16 Pirelli Scorpions STR. It's a Diesel of course, it's the way to go. traded my 530D for this so it had to be good. I know it's only a week but I may buy another one when this one goes next year.

[Forkster]

Ah, the perks of a diesel vs petrol. Yes, if I could, I would ONLY have a diesel engine. Bloody petrol engines are fuel pigs. I had an opportunity a year back to port a D5 into my 2.5 but the cost was prohibitive. BTW - 43.5MPG Imperial = 35MPG US. Best I've ever had on my 2.5T petrol is 30MPG (36MPG Imperial).