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Volvo XC90 Real World MPG

13

Comments

  • jim314jim314 Posts: 491
    Analyzed one way my results do not show any significant mpg improvement with Mobile1 0W-40.

    1. Original oil was changed at 7251 mi and 385.2 gal of fuel used => 18.8 mpg. This included 1550 mi of a mostly interstate hwy trip requiring 66.75 gal, so the non-trip mileage and fuel used was 5701 mi / 318.45 gal => 17.9 mpg.

    2. Distance and fuel use on the Mobile1 0W-40 is 1715 mi /96.9 gal = 17.7 mpg.

    I still intend to use Mobile1 probably 0W-40 because that is a viscosity grade recommended in the manual.
  • qbrozenqbrozen Posts: 16,893
    We purchased an '05 2.5T AWD with 23k miles last week. I was hoping to get near the EPA highway number, but so far have been unable to. That seems to be a feat I can only achieve in a car with a manual transmission. Thus far, in somewhat mixed driving, I have averaged around 20 mpg. Still not too bad. With our '05 Pacifica AWD, we were getting 18-18.5, but with our '03 Pilot, we were getting near 21. So I'm not complaining about the volvo ... was just hoping, that's all.

    Has anyone noticed significant gains by using higher octane fuel? I'm not sure what my wife put in it. I'll have to ask. But I did tell her regular would be "ok," so that's probably what she did.

    '13 Stang GT; '86 Benz 300E; '98 Volvo S70; '12 Leaf; '08 Town&Country

  • jim314jim314 Posts: 491
    The Volvo owner's manuals for our 2004 V70 2.4L non-turbo and 2007 XC90 3.2 I6(naturally aspirated) recommend premium AKI 91 octane or better "for optimum performance", and state that AKI 87 octane is the minimum acceptable. You may get slightly better fuel economy with 91 octane. In the affluent western European countries 91 octane AKI is the "standard" fuel, and lower octane fuels are not available. Volvo designs its vehicles to work best on 91, but has engine controls which allow it to use US regular. Generally speaking turbo-charged engines require higher octane fuel than naturally aspirated engines.Unless the owner's manual recommends it, I do not think it is advisable to use regular 87 octane in a turbocharged Volvo, even the light pressure turbo.

    Check the manual!

    Some Volvo owners do use regular 87 octane and depend on the knock sensor and computer controls to protect the engine. I habitually use 91 or better, although a few times I have experimented with 89 and have used 90 octane on a trip where that was the highest available. I have had no driveability problems with any of these grades, and I have not tried to see if the higher octane gave a higher mpg.

    In my home town the pumps dispense three grades: 87 octane regular, 89 octane mid-grade, and 93 octane premium. Usually I add approximately equal vols of 89 and 93 to give 91. Once you get used to doing this it's not much trouble and my wife does it too. We save about a dollar per 20 gal over straight 93, but mostly I do it to not use higher octane fuel than the vehicle can take advantage of.

    I think there is a possibility (admittedly remote) that 91 would give slightly higher mpg than 93! My thinking (which I have not tried to verify by researching the matter) is that the energy content of 91 could be higher than 93. It could be that 90, 91 and 93 are the same base gasoline with progressively higher levels of octane boosting compounds for the higher octane fuels. These compounds (for example, ethanol, which like MTBE is both an "oxygenate" and an octane booster) have a lower energy content that the gasoline base. I want to use the fuel with the highest energy content that has the necessary octane rating.

    To keep the fuel injectors and the valves clean we use so called "top-tier gasolines" (usually Shell) because it has the highest detergent level.
  • jim314jim314 Posts: 491
    "Fuel Economy

    Do You Really Need Premium?
    And Answers to Other Gasoline Questions
    By Philip Reed, Senior Consumer Advice Editor
    Email
    Date Posted 08-30-2007
    Buying premium gas is like taking vitamins — you can't always feel the difference and yet you know it's the right thing to do. But as gas prices climb, paying the extra dime per gallon for premium is like adding insult to injury. Eventually, the thought is bound to jump into your head: Do I really need to pop for premium?
    [snip]
    Volvo cars call for "premium fuel [91 octane or better] for optimum performance and fuel economy," said Wayne Baldwin, product/segment manager for the S60/S80. "However, there is absolutely nothing wrong with using 87 octane, as the knock sensors and engine management system 'protect' the engine from knocking."

    http://www.edmunds.com/advice/fueleconomy/articles/106293/article.html

    I still plan to use 91 octane AKI fuel in both of our Volvos. I want to get the best possible fuel economy, even if it costs more money per mile to do so.
  • Stever@EdmundsStever@Edmunds YooperlandPosts: 38,931
    Buying premium gas is like taking vitamins — you can't always feel the difference and yet you know it's the right thing to do.

    We're going to have to have a little talk with Philip. Vitamins 'may shorten your life' :)

    If anyone wants to dig deeper, check out What about fuel types & gas mileage?. Using premium in a car designed solely for regular may shorten its life:

    http://townhall-talk.edmunds.com/direct/view/.ef189e7/109
  • jim314jim314 Posts: 491
    The vitamin analogy was not meant to be an endorsement of the widespread belief that vitamin supplements might, andprobably will, do some good, and certainly cannot do harm. This analogy was just uncritically tossed in to engage the reader. Personally, I think it is entirely plausible that that use of vitamin supplements is not simply a waste of money, but can be harmful, in some cases very harmful. Eating a balanced diet is both a much cheaper and a much safer route to optimum nutrition. Consuming active biochemicals in large amounts could plausibly throw a person's metabolism off, and sometimes these vitamins or supplements have toxic contaminants from a failure in the manufacturing process (like the L-tryptophane case of 20 years ago).

    Getting to the real question at hand. These days there are very few people who would use premium fuel in a vehicle which is designed to run optimally on US regular (87 octane AKI) gasoline. What we are talking about here is the question of what to use when a vehicle mfgr "recommends" premium, but states that lower octane fuel (say down to 87 octane AKI) is the "minimum acceptable". In that case should one use the octane recommended for highest maximum power (and perhaps highest attainable mpg) or can one sensibly use a lower octane fuel?

    The professional article cited goes with "minimum acceptable" is acceptable.

    The Volvo owner's manual seems to suggest that the answer depends on the demands the operator is making on the vehicle. If one hardly ever asks the engine to develop anywhere near max power, then probably the minimum octane acceptable would be the most economical fuel ($ per mile). I don't make a practice of wasting money, but still I'd rather not use 87 octane when Volvo "recommends" 91 octane. For the slight amount of extra money I feel better following Volvo's "recommendation". If the knock sensor would fail, I'd want fuel that would not case knocking.
  • Stever@EdmundsStever@Edmunds YooperlandPosts: 38,931
    Usually the trade off is less power and worse mileage. Even if you can't tell that the car is less peppy, the mileage hit may be significant enough to warrant the use of premium, even though it costs more to fill up the tank.

    Pays to keep track of your mpg in either case.
  • qbrozenqbrozen Posts: 16,893
    that's what we're going to do. Wife filled with mid-grade (89) on the first tank and now the same on the 2nd tank. After this one is gone, we'll try up or down a grade and see what happens.

    '13 Stang GT; '86 Benz 300E; '98 Volvo S70; '12 Leaf; '08 Town&Country

  • jim314jim314 Posts: 491
    According to the Edmunds site most European mfgrs specify premium required in their turbocharged gasoline engines, e.g., the 2.0L turbo 4-cyl engines in the VW Passat, the Audi A4, Saab 9-3, and in various naturally aspirated Mercedes and BMW models. In fact, the only European manufacturer I can find that varies from this is Volvo which specifies premium recommended (and states that 87 octane can be used) in their turbocharged engines and in their naturally aspirated high compression engines (CR 10.3 in the NA 2.4L 5-cyl and 10.7 in the new NA 3.2L inline 6-cyl.

    I wonder if Volvo actually has different engine controls which permit their engines to use down to US regular 87 octane AKI gasoline, or whether models from these other European mfgrs would also accept down to 87 octane. The difference in octane specifcation could be due to mfgr's perceptions of what the prospective buyers will accept. It could be that BMW, for example, thinks that prospective buyers of their vehicles are not put-off by an unqualified requirement of premium, but Volvo thinks that some of its prospective customers would react very negatively and therefore Volvo allows the use of regular.
  • qbrozenqbrozen Posts: 16,893
    well, I think it might depend on what we're comparing it to. Does the S60R/V70R require premium? What about the S60T5?

    I can see the 2.5T or S40T5 not requiring it because they aren't boosted to incredible levels. I mean, 208-220hp out of 2.5 liters is good, but it is not quite the same as 200hp out of a 2.0 liter (the VW you mention).

    The other side of the coin COULD be that the other manufacturers just don't want to take the chance(?). Better to have the customers use all the best stuff possible to get the most out of their vehicles.

    Just some thoughts.

    '13 Stang GT; '86 Benz 300E; '98 Volvo S70; '12 Leaf; '08 Town&Country

  • jim314jim314 Posts: 491
    The S60 T5 (257 hp from a 2.4L 5-cyl) is listed as "premium recommended" in the specs in the Edmunds compare vehicles feature. The Acura TL 3.2L V6, rated at 258 hp, is listed as "premium required".

    My operating assumption is that Volvo has decided that a significant fraction of the Volvo customer base is looking for value, not just ultimate performance at any price. Volvo thinks that some of these customers want to be able to run their vehicles on the cheapest grade of fuel available in the US. My view is that a Volvo is not low end value transportation and owners should expect to use premium fuel at least when they are demanding a good fraction of maximum performance from the engine.
  • jim314jim314 Posts: 491
    20.7 mpg (computer 21.4 mpg) 1-8-08 with Shell 93 octane AKI
    19.5 mpg (comp 20.3 mpg) 1-27-09 with Shell 93 octane
    17.8 mpg (comp 18.0 mpg) 2-17-08 with Shell 93 octane
    15.5 mpg (comp 16.2 mpg) 3-7-08 with Shell 93 octane
    17.3 mpg (comp 18.0 mpg) 3-23-08 with Shell 89 + 93 => 91 octane
    16.6 mpg (comp 17.5 mpg) 4-10-08 with Shell 89 + 93 => 91 octane
    19.4 mpg (comp 20.5 mpg) 4-18-08 with Shell 89 + 93 => 91 octane
    19.1 mpg (comp 19.8 mpg) 4-29-08 with Shell 89 + 93 => 91 octane

    This driving is a mixture of highway and city including some very short trips.

    Based on these data the computer gives a value which is 4.0% higher than the value calculated from the pump volumes and trip odometer readings.
  • jim314jim314 Posts: 491
    20.2 mpg (computer 20.8 mpg) 5-10-2008 with Shell 89+93 => 91 octane
    21.4 mpg (computer 22.4 mpg) 5-13-2009 with Shell 89+93
  • jim314jim314 Posts: 491
    How about a report on the mpg you've attained with the various fuels.

    Looking at the VolvoUK site, the 2008 XC90 3.2 (only comes in AWD, I think) is estimated in their tests to achieve the following fuel use:

    Urban........... 17.2 L/100km => 13.7 mpgUS
    Extra Urban... 9.2 L/100km => 25.5 mpgUS
    Combined..... 12.1 L/100km => 19.4 mpgUS

    The extra urban mpg is considerably higher than the US EPA highway estimate, and much of that may be due to a difference in the test conditons. However, the site states, "For best performance and lowest fuel consumption 98 octane RON is recommended. 93 octane RON can be used for normal driving."

    98 octane RON is equivalent to 93 or 94 octane AKI, and 93 octane RON is equivalent to 88 or 89 octane AKI. The fuel requirement for US Volvos are 87 octane AKI minimum and 91 octane AKI recommended. So it would appear that the European Volvos are tuned to require and take advantage of higher octane gasolines than the US models. This may contribute to significantly higher mpg for the European models.

    This suggests to me that the recommended 91 octane AKI might give higher fuel economy in the US models, than 87 octane AKI or 89 octane AKI. It would be interesting to see the results of tests by users.

    To me the cost difference between regular, midgrade, and premium is insufficient to use a fuel which gives a lower mpg even if it would give a lower cost per mile. I am going to use the "recommended" 91 octane AKI, if I think there is just a chance that it gives a higher mpg, even if the mpg is only say 0.5 mpg or even 0.25 mpg higher.

    One way to test the effect of octane rating of fuel on mpg would be to run the tank down to near empty and put in say 3 gal of 87 octane. Then drive a prescribed highway route at some specified speed (60 or 65 or 70 mph) and use the computer to get an average mpg over the route of perhaps 10 miles. Then put in a volume of 93 octane AKI equal to half the amount of 87 octane added (this gives 89 octane) and drive the same route at the same speed and use the compter to obtain an average mpg over the 10 mile route. Then add 93 octane AKI in the same amount as the total already added (this gives 91 octane) and redo the route.
  • qbrozenqbrozen Posts: 16,893
    What I like to do is run 3 full tanks all the way through of each fuel. That way we get at least some sort of average. Problem, of course, is that you may run into a situation during 1 tank that negates the results (major accident where you sit still for 2 hours, for instance).

    Unfortunately, my wife ain't so good at keeping track for me and she's been driving it pretty much exclusively (it is her car, after all). All I can report so far is that our first couple of tanks of regular 87 got her in the high 18s. Her past couple of tanks of mid-grade (91) have gotten nearly 21 mpg.

    But, really, this is just anecdotal. The transmission may also have been learning her driving habits.

    '13 Stang GT; '86 Benz 300E; '98 Volvo S70; '12 Leaf; '08 Town&Country

  • jim314jim314 Posts: 491
    Since you have filled a couple of tanks with 87 octane, you could spend an hour and do a good comparison of mpg with 87 and with higher octanes.

    A. Full test: Wait till you have say 1/4 or 1/8 tank left use the computer to estimate how much fuel is in the tank. Use the computer ave mpg and the trip odometer since last fillup to determine how much fuel is in the tank. Fuel used since fillup = distance travelled / ave mpg. Subtract that from the tank capacity of 21 gal.

    Now reset the computer ave mpg and ave speed just before starting a freeway constant speed run of at least 1 mile. (Five miles would be better.) Record that as mpg at 87 octane.

    Now add 93 octane in an amount equal to half the amount of 87 octane you calculated was in the tank and redo the test, resetting the computer mpg and ave speed just before the run. This is mpg at 89 octane.

    Now add 93 octane in an amount equal to the total vol in the tank at the start of the 89 octane run, reset the computer and redo the test. This is mpg at 91 octane.

    At this point you could fillup with 93 octane and redo the test.

    If you do this and report your computer readings and pump volume data, we can check you calculations.

    B. Simpler test: Wait till you have 1/3 tank (~ 7 gal) remaining and then do a certain route at constant speed, resetting the computer mpg and ave speed just before the test. You could do the route twice to see what is the variability.

    Now fill up with 93 octane (fuel in tank is now 91 octane) and redo the test run.
  • qbrozenqbrozen Posts: 16,893
    good grief. I can't even get my wife to calculate at each fillup. "What did you get, hun?" .. "ohhh... I dunno. I think it was 20-something."

    What you ask wouldn't be much different than me requesting she go outside and change the head gasket on my Alfa. I would get a confounded look in return in either instance.

    '13 Stang GT; '86 Benz 300E; '98 Volvo S70; '12 Leaf; '08 Town&Country

  • jim314jim314 Posts: 491
    I should have left out the "Full Test" bit. I got carried away.

    What about you doing the quickie test B?

    Wait till she's got 1/3 tank or less of 87 octane. Then you take the vehicle out for a test run. Get the engine to full operating temp. Reset the mpg function at speed just before doing a run of a mile or two at constant speed, then read the ave mpg. This is mpg at 87 octane.

    Now fill up with 93 octane, and repeat the same test run at the same constant speed. Of course, just as you start the run you reset the ave mpg on the computer, and read the ave mpg at the end of the run. This is the mpg at 91 octane (or higher if the tank was less than 1/3 full for the first run).

    This test might take an hour max and you'd deliver your wife's car back to her with the gas tank full.

    Latest results with my wife's 2007 XC90 3.2 FWD
    19.5 mpg (computer 20.9 mpg, ave speed 23 mph) 5-23-2008 with Shell 89+93 => 91 octane
  • qbrozenqbrozen Posts: 16,893
    Well, we just completed 3 full tanks of 89 octane all with pretty similar driving (mostly her commute to and from work). Results were 20.9, 20.5, and 20.9. All calculated. We didn't use the trip computer to test results.

    Prior to this, we used regular twice and got ~18. But, like I said before, the truck was new to us at that point, so I don't necessarily trust those readings. Anyway, I filled up with 92 octane today and I'll get her to do the same for the next 2 tanks and see what happens.

    Again, for those keeping score, this is a 2005 2.5T AWD.

    '13 Stang GT; '86 Benz 300E; '98 Volvo S70; '12 Leaf; '08 Town&Country

  • jim314jim314 Posts: 491
    20.7 mpg (computer 21.4 mpg) 1-8-08 with Shell 93 octane AKI
    19.5 mpg (comp 20.3 mpg) 1-27-09 with Shell 93 octane
    17.8 mpg (comp 18.0 mpg) 2-17-08 with Shell 93 octane
    15.5 mpg (comp 16.2 mpg) 3-7-08 with Shell 93 octane
    17.3 mpg (comp 18.0 mpg) 3-23-08 with Shell 89 + 93 => 91 octane
    16.6 mpg (comp 17.5 mpg) 4-10-08 with Shell 89 + 93 => 91 octane
    19.4 mpg (comp 20.5 mpg) 4-18-08 with Shell 89 + 93 => 91 octane
    19.1 mpg (comp 19.8 mpg) 4-29-08 with Shell 89 + 93 => 91 octane
    20.2 mpg (computer 20.8 mpg) 5-10-2008 with Shell 89+93 => 91 octane
    21.4 mpg (computer 22.4 mpg) 5-13-2009 with Shell 89+93
    19.5 mpg (computer 20.9 mpg) 5-23-2008 with Shell 89+93 => 91 octane
    15.0 mpg (computer 16.0 mpg) 6-14-2008 with Shell 93, all urban short trips
    23.5 mpg (computer 24.9 mpg) 6-16-2008 with Chevron 93, includes 361 mi road trip much of which was urban, some at slow speed in state park

    Overall fuel economy to date since purchase 11,244 mi / 597.1 gal = 18.8 mpg
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