Highway gas mileage on recent trip

huzzsaba · Post by **huzzsaba** » 26 Dec 2012, 22:32

On a recent 350 mile trip, I was monitoring my gas mileage in our 2004 XC90 2.5T AWD with 248000kms ( approx 155k miles) and this is what i got....

First off the details of the conditions....

1) averaging 70 mph
2) 35 psi in tires
3) travelling east with NE winds at 25-30 mph
4) outside temperature of -8 degrees celcius ( 17.8 degrees fahrenheit)
5) combine weight of passengers and luggage 650 lbs
6) 91 octane shell gas

So with all these conditions, I was able to manage 18 mpg which i believe comes out to 12.5 litres per 100 kms.

Is this reasonable gas mileage or should i be seeing better gas mileage considering the conditions?

Planning to replace spark plugs although they were replaced 20k miles ago. O2 sensors have never been replaced i believe and planning to replace fuel filter as well.

Aside from that, PCV has been cleaned and air filter is clean. No problems with engine.

Please advise.

Post by **JDS60R** » 26 Dec 2012, 23:14

Just ran my 04 xc70 2.5T with new oxy sensors (bosch direct fit ) 110K on odometer for 700 miles from TN to IA. tires at 35 psi (fireston fr380- hate them) and got 25 mpg. New air filter,fuel filter, spark plugs and a cleaned MAF with an oil change .

I am disappointed with the 25 mpg and have it down to the tires and hilly terrain. I would replace the tires but they came with 10/32 tread so they are almost new. I look forward to a set of Yokahamas in about a year. I get 28-29 in my 07 tuned R.

I will likely build a stianless exhaust and get a tune from ARD for the xc

huzzsaba · Post by **huzzsaba** » 26 Dec 2012, 23:22

Thanks for the reply.

Im pretty sure the weather where you calculated the mileage was much warmer than mine. I too get decent mileage in the summer months but want to make sure that maybe it was the cold and possibly the windy conditions that caused my mileage to suffer.

Post by **jblackburn** » 27 Dec 2012, 06:43

Yes, a MPG drop is normal, particularly with a turbo engine and winter grade gas that contains less energy. I've lost about 5 mpg average on the Chevy just since it got real cold.

Bet the car feels more powerful though

owl · Post by **owl** » 28 Dec 2012, 07:10

During the summer I got around 23-24mpg in the highway with my XC90 2.5t AWD 100k miles. I looked and this is about the EPA estimates (actually slightly better than EPA estimates), so I wouldn't expect anything much better than that.

You got pretty cold weather, so 18mpg could be reasonable. I saw a calculation somewhere that said you could get a 20% - 30% drop in mpg due to cold weather (from 85F to 25F or less).

huzzsaba · Post by **huzzsaba** » 28 Dec 2012, 23:01

thanks for the replies guys!

I guess now that the mileage im getting is somewhat normal. I will try to up the tire pressures to 39 psi when i head back home this weekend and see if it makes any difference. I do plan to change the spark plugs and O2 sensors down the line so hopefully that should improve things.

On a side note, we had a big snow storm in montreal and i got a chance to drive in 50 cms of snow. The neighbors were hesitant to test out the unpaved street and were all looking at me to try it out first. Even my dad (a minivan person) was challenging me to see what my car could do. I was happy when the XC90 plowed through the snow with ease.