Poor MPG for my 2006 2.5T S60 at 89K

[mrbrian200]

The sweet speed on the FWD S60 seems to be around 45-50mph: wind loading low, it's in 5th gear (mine is AT-5 speed) with lower rpms that translates into lower engine braking when coasting downhill. At that speed with no stop and go it'll get around 45mpg. At slower speeds its in a lower gear and the number of injector pulses per given distance goes up. At higher speeds wind loading starts factoring in.

I did my research before buying the S60 and only looked at FWD 2.5T's. The only thing I would do different now would be hold out for one with the shiftable/geartronic option. At the time I didn't think I wanted it. But more recently I found a 2.5T AWD XC90 for my sister that has the geartronic option as a matter of coincidence. The 5 mile, usually no hurry, trip into town up a country road with no usually no other cars and an occasional amish buggy I discovered on the geartronic you can force a higher gear at lower speeds when it normally wouldn't go into 5th and econ spikes from high 20s to mid 30s. The XC doesn't get anywhere near what I see with the S60 on the highway. Sis wasn't as acutely concerned with econ like I am. Hers tops out around 28mpg highway with 23mpg average according to the DIM. Which is still pretty darn good for the size/weight of the vehicle. A cousin owns a Tahoe, roughly the same size/weight as the XC. He likes the truck but hates to drive it because it gets like 10mpg in mixed driving, and 17 on the highway. His daily round trip commute to work is 60 miles. A couple years ago he bought a Fusion and the Tahoe has sat in the driveway ever since. It gets moved a few feet once a week to pull the lawnmower out of the garage.

I mentioned either here or in another thread my old cloud car that got 37-38 on the highway (60mph), but that was with aggressive hypermiling techniques. The S60 gets that with the cruise set. When I say I'm getting 40-41 with the S60 I'm hypermiling without the cruise control. But I the techniques aren't applied near as aggressively as I had to do with the Chrysler.

[Botbasher]

Just got 23.6 mpg and was climbing on windy back roads. I wasn't pushing it though... GF was in car... But I wasn't going slow either!! These cars can get good mpg when tuned and driven properly.

If you're really far off the line is start to look at the basics and work it forward. Stage 0 stuff, then alignments, tires, aero.... There's got to be something holding you back!!

Edited... And the AC was on and ambient was in the low 90s around here. My biggest instant gain was when I did a complete flush with OEM Trans Fluid. I used the Idemitsu from FCP and saw a 2+mpg gain right there. I dropped nearly 200 RPM at cruise, with no other mechanical changes, so there is something to it!

K "sipping" S

[EngineeringBloke]

Thanks Botbasher for drawing my attention to this fluid. I had not been aware it was the original and I had used Mobil 3309 previously. It will be time for another ATX change soon and I plan to use the Idemitsu fluid.

I am still enjoying the revitalized response to the pedal with my new O2 sensor.

[800artfreed]

Just for discussion purposes it is 746 watts per horsepower. So I am not sure how much effect the sound system would have. Cheers

[E Showell]

I regularly get 25 mpg combined in 2006 AWD, auto V70R, using 93 octane gas, but I'm driving for mileage -- gentle acceleration, in behind (but not tailgating) trucks/busses and coasting on every downhill with foot off the gas.