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Scion MPG-Real World Numbers

1235710

Comments

  • altavistaaltavista Posts: 19
    FYI-

    With two adults, one infant, car seat, portable crib, stroller, weekend luggage for all three, food for the trip, diapers, etc., all highway miles averaging 75mph, some tolls with EZPass, some traffic slow downs, in a 2004 Scion xB automatic, 33mpg. Regular fuel.

    I suspect that is worst case scenario.
  • manxedoutmanxedout Posts: 5
    Thank you all for posting your mpg findings. But I'm in the process of deciding which to buy (xA or xB. I really think the xA will be too small for us if needed to haul 3 adult sized people any distances, but it gets a bit better mpg, and I love the extra room in the xB but it has a guesstimate rating of 33mpg, and was wondering what others are getting in the real world mpg for the xB.

    I live in SoCal and average 3400 miles a month, yes you read it right, 3,400 miles per month, mostly freeway, going with the flow @ approx. 70mph, or get run over. I'm not affraid to mingle in traffic (used to drive a Bug) but was concerned about real mpg numbers that xB owners might be getting here on the SoCal Raceways.

    Is there anyone out there that has any SoCal freeway at speed mpg info? Most is flat and level but some trips north to beautiful Visalia/Bakersfield and up the coast to Cambria and anywhere in between.

    Other than slowing down to 50 mph is there ways to improve the xB's mileage. No extra weight, just the driver.

    Thanks for any real mpg info
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,490
    It's pretty hard to improve fuel mileage when you're basically pushing a brick-like shape at high speed. The xA no doubt gets better mileage because it is more aerodynamic.

    If you had only 3 adults in an xA, and the rear passenger sat behind the front passenger, it's not uncomfortable back there. But 4 people for long distances, no, I don't think so.

    What seems to happen with both the xA and xB is that once you punch past 70-75 mph, the mileage is going to drop significantly.
  • manxedoutmanxedout Posts: 5
    I understand the brick concept and that the xA is more aerodynamic, and I agree. But the problem out here in SoCal is that you have to go with the flow on the freeways. Think of something along the idea of the running of the bulls, you either stay ahead of them or they move you out of the way.

    Size does not scare me, cars vs. xA/B, but a upset semi vs. the xA/B is a bit intimidating. Having driven VW Bugs and MG Midgets and Mini's, I have determined that it's better to stay out of there way than to be moved out of their way by them. Also the frewway speeds out here in SoCal are from 55 mph to 70 mph and frequently being passed by both at more than 80 mph.

    What could I expect mpg to average realisticly if it was held at a max of 70 mph and minimum city driving and stayed out of the way, and did not drive the xA/B like a mini racer. LOL

    Thanks.

    Bob
  • tundradudetundradude Posts: 588
    Since its geared low, it revs high. The xB has a 4.30 axle ratio. Otherwise, as said above, it declines in mileage as you go faster, but you still get decent gas mileage. I have never gotten below 32 ever.

    For constant highway driving, a Corolla or equivalent would be better served. However, the Corolla doesn't have the Scion's stereo, handling, and back seat room.

    I have found out that by not over gearing and cruising at whatever speed the road is, you are fine.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,490
    I think 32-35 mpg is a realistic assessment for any xA or xB doing freeway driving below 80 mph with some stop and go, and with AC on. If you add up 10,000 miles worth, that's about where it's going to fall. Sure a couple of tankfuls will do better or worse for various reasons (climate & temperature, altitude, traffic, calculation errors, etc.) but I betcha overall that's where you'll end up in that range.
  • aathertonaatherton Posts: 617
    "... Other than slowing down to 50 mph is there ways to improve the xB's mileage..."

    In 3000 miles with my manual xB the worst I have gotten is 33, and mostly it's 35 to 36. That includes hops on the urban Lousville Interstates at a steady 65 mph, not during rush hours.

    SoCal Interstate commuting, as I understand it, is 70-80 mph combined with frequent letting up and getting back on accelerator to jockey with the traffic. This is the worst kind of driving for mpg in the xB. I have heard it results in 30 mpg or less.

    If you could drive at a steady 50 mph as you suggest, you could get in the low 40's. I got 40.5 mpg by driving very gently on one tank, in mixed rural and suburban conditions.
  • manxedoutmanxedout Posts: 5
    aatherton:

    "SoCal Interstate commuting, as I understand it, is 70-80 mph combined with frequent letting up and getting back on accelerator to jockey with the traffic. This is the worst kind of driving for mpg in the xB. I have heard it results in 30 mpg or less".

    Yes that is the norm in SoCal but that is usually before or after the normal work times (everone trying to get to or leave work at the same time)

    The commuting that I do in SoCal is usually not in stop & go variety. I average 3,400 miles a month and most of it is long distance driving. Like LA to Bakersfield Calif or up the 101 from LA to Santa Maria Ca. or any where in between. I try to group my stops, either all in the same areas or in a round trip type of arrangement. Rarely do I end up on the "world's largest parking lot" and not moving. When planning my stops I try to consider what traffic is usually doing at that time. Like heading into LA when the rest of the world is headed out of it or skirting the major cities and avoiding the traffic if possible.

    I would venture that 80% of the time I'm just rolling with the cruise on and holding 65 - 70 mph, but then there are times when the only way to get out of traffic would be to use a helicopter. So far I have managed to keep all four tires on the ground. The long distance runs usually involve some frwy thru the "hills" like the "grapevine" which is the 5 frwy from north east of LA to Bakersfield approx 40 miles of 2 - 3 lane up hill and down roads but it's a major trucking route with a elevation of up to 4,000 ft asl. and then down to the flatlands.

    Last week I paced several xB's over the grapevine, they held approx. 70-75 mph but I'm positive that they did not come close to 35-40 mpg while doing it. I'm cool with that as long as when I average the mpg for the 3,400 miles of mostly flat and frwy miles I can realisticly reach 33 or higher mpg (without racing hard). And I realize weather and my foot will determine my mpg fate, but was curious if there were real world mpg numbers from the faster end of the country. I have no problem rolling at 65 mph but other people around me on the frwy would.

    Thanks,

    Bob
  • We bought our 2006 xb in January, with the Automatic transmission, alloy wheels. I burn 87 octane gas, we do not have the reformulated gas up here. In SE Georgia we drive on a lot of two lane roads through rolling hills but manage to run 55-60 mph between home and Athens, GA. 36 miles, and Anderson, SC. 42 miles. We are averaging 32.5 mpg. On a trip to Corpus Christi, TX in April running at 70 mph most of the trip and passing speeds 75 to 80 still averaged 32.5. That was with the AC going most of the time. A trip to Augusta this past week end at 65 mph and up to 70 mph on the interstate averaged 34.5 for the 187 mile round trip. I keep a log in all my vehicles and record service performed and each fill up including miles between. The best individual fill up was 37 mpg the worst was 29 mpg. Just hit 5000 miles and first oil change. Check oil every other fill up , not a drop of oil used in the first 5000 miles. Some say the car has no pep but I have to disagree, plenty of pickup to pass on the interstate no problem merging into traffic at speeds up to seventy mph. We have cruise control which I use except when on hilly curved roads. To date we couldn't be happier with the car.
  • heldmywheldmyw Posts: 1
    My Xb is regularly getting 32-35 mpg... unless my girlfriend drives it. Her last manual trans car was a Ford Probe, and apparently, revving the engine like a turbine in first and second gear is the only way to get the thing to move.

    Done with a Scion, your mileage goes into the toilet.

    I grew up with Triumphs and MG's, and, first gear was only to get you off the line. Moving into second at the earliest possible moment gave much longer 'legs' and far better mileage.

    Just a matter of driving style.
  • qwallsqwalls Posts: 406
    I've had my 2006 xB maunal for 2 weeks and 4 days, and have put between 1200-1300 miles on it so far. For my regular weekly driving, I'm getting 31 mpg so far. This is about a 70/30 highway/city, air always on. Just drove from OH to WI, 400+ miles, 70-75 mph, air on, 32.5 mpg. I'm happy so far.
  • Your 3400 miles a month are the same driving that I do monthly in the DC area. I have an 05 Box in TCM with the auto tranny that I bought with 0 miles in April '05, and now I'm closing in on the 40k mark. I have had no issues driving in the DC area highways at 75-80, or crawling thru the rush hour at 25-30. I drive 110 miles a day over mountains and along flat lands, and I average between 33 and 36 mpg depending on traffic and weather. I read all these posts about XB owners only getting 20-26 mpg an I just can't believe it. Every XB owner that I talk to at the gas station or grocery store all report mileage in the 31-35 range. My tires are stock, I have no CAI or upgrades, and I keep my foot into the gas pedal as much as possible. I broke the car in easy for 1500 miles--very few instances over 60 mph. My first tank of gas averaged 29 mpg, my 2nd was 31,and the 3rd was 33. The car has been to the dealer once for a complimentary check and tire rotation at 7500k miles. I have not even taken it in for the free oil changes, as I've done those myself. I also run synthetic oil in it since the 25k mark (what the heck, if I can change my own oil with synthetic and a filter for $23 why not use the good stuff, right). My 30k service was done at a national auto chain and cost less that 100 bucks. I take it to a local garage for tire rotations for 10 bucks. I have 4 kids that all fit comfortably. I even moved my son into his college dorm with the XB. My wife, me, son, and a semester's worth on stuff fit fine into the car. If you plan on hauling people or gear around with you I would pick the XB over the XA for the space factor, as I checked out both before I bought. Why buy a car that may be too small for your needs when your mileage will be in the 31-35 mpg range? I'm actually going to buy another because my wife likes it so much that she's vowed to give up her beloved SUV in favor of the XB. She likes the car so much that she takes it when it's in the driveway. She's even got it now up in PA for the weekend. So good luck in your purchase and keep us posted on your Scion.
  • Just got my xB this past wednesday, 36+ mpg, 5spd. I wasnt expecting it to be this good, but boy and I happy. :)
  • aathertonaatherton Posts: 617
    I went to Scion Exposed 06 at the Mid-Ohio track last weekend, a 250-mile trip each way.
    http://www.goexposed.com/06/jun06/

    I went up on a two-lane road through many small towns, getting 37 mpg, and came back on the Interstate getting 43 mpg. I went 55-60 mpg, using AC about 1/3 of the time. The car has a manual transmission and 4000 miles. Around town it gets 35 mpg. I print all the gas tickets, keep a calculator in the car, and save the data to a spreadsheet.

    The worst mileage I ever got was 23 mpg, for the 30 miles spent that day around Mid-Ohio and doing the laps on the track.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,490
    I'm jealous of your mileage, but I do drive with my foot in it most of the time, so there you go..... :cry:

    We can't drive 55 in California, we'd be killed and shoved off a cliff.
  • pumpshypumpshy Posts: 1
    I've been looking at the xB for sometime now and finally decided to place my order but I was wondering what options I should get from the factory or from the after market to increase fuel economy. I wouldn't mind a little extra horse power and torque but it's not necessary. I just really want to squeeze every mpg I can. What should I do? Should I get manual or automatic, 18" rims or factory hubs, turbo charger or valve timing controler? ect., ect., any suggestions are appreciated.
    p.s. What could I add that would increase horse power and torque with little sacrafice to fuel economy? Thanks
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,490
    you can't increase HP and fuel economy at the same time (sounds like you already know this). Best way to save gas is to develop good driving skills for economy. "Gas-saving devices" are scams. 18" rims will probably make your engine work harder, they have no real use whatsoever. A turbo would be great but it's $$$, probably $3,000 if you do it yourself and more if you pay someone to install for you. It would make the xB really fun to drive, though.

    Probably you could gain a little bit of HP and not spend too much money, by installing a ram air cold air intake and a cat-back free flow exhaust and using synthetic oil....perhaps cumulatively 7-8 HP or so???

    Serious HP costs serious money, that's the rule.
  • aathertonaatherton Posts: 617
    I have put 5000 miles on a stock 2006 manual xB, with mpg ranging from 23 to 43. The questions indicate that you may be more interested in performance than in ecomony.

    For best mileage:
    1. Use OEM wheels, intake and exhaust.
    2. Use premium fuel.
    3. Use light throttle when accelerating and cruising, and do not vary speed.
    4. Shift at 2000 rpm.
    5. Do not exceed 60 mph.

    Not doing 1 will make it harder for you to do 3, 4 and 5.
    If you cannot do 3 and 4 with a manual, get the automatic which will help you do it.
    If you cannot do 5, get the automatic which will go 65 at the same rpm.
  • manxedoutmanxedout Posts: 5
    Well it's been about a month. I purchased my XB from Bill Wright Scion in Bakersfield,, Ca. (if anyone wants the names I will pass on the info). I was treated like a friend and would buy there again, NO hassles. Any way back to the MPG info. I have been busy and have almost reached the 5,000 mile mark in a little over a month. I have been checking the mileage from the first tank full to present and have managed to stay right at 34 mpg for the average. Some were higher and some were a bit lower.

    I believe that the weather here in SoCal plays a part. I can run the same route, at the same time and hit the same traffic basicly, but what seems to kill the XB mileage is a head wind. (a tail wind helps! )I have run round trips over the Grapevine almost 10 times in the last month, and I only see a difference when the wind is blowing.

    I have learned to coast downhill and not "race", but I have not tried to get my XB run over by a semi or a suv. I have been running at a almost steddy 70 mph with the air on when needed, and the only one that is mad is the gas companies. I was averaging almost $700 a month and now its been averaging $350 a month.

    I also started buying gas at Costco and am paying on average $0.12 a gallon less than the Shell/Union 76 average per gallon.

    I imagine if I could run at a steady 60 mph I could get even better mpg, but I would also be dead and left somewhere on the grapevine.

    Thanks all for the input and the attempt to pass on any and all real use mpg and driving info. I am very happy with my choice and would not hesitate to recomend one to any and all people that ask me about my XB, or the dealer.

    Bob
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,490
    I've been running alternate tankfuls of regular and high test gasoline and the regular has consistently delivered better fuel mileage---not sure why this is, but seeing is believing.

    Next I'm going to have someone do a "blind" on me, and not tell me which grade they put in the tank. If it comes out the same as with the other tests, I'm going to be a believer that high test in an xA is not a good idea. But for now, it could all be co-incidence and driving conditions that account for this variance.

    Still averaging 34 mpg.
  • aathertonaatherton Posts: 617
    Alternating tanks of 87 and 91 is going to make a mix varying around 89, if the fill-ups only put 7-8 gallons in a tank that holds almost 12. So the effect of premuium gas on mileage would be hard to discern. You would be running on 88-90 all the time. To get a tank of 91, do two premium fill-ups in succession.

    Another factor makes the effect of premium even more difficult to discern. Premium is only of benefit in preventing the knock sensor from operating, and the knock sensor only operates at heavy throttle and/or high rpms. And for premium to affect the mileage of a whole tank of gas, you need to spend a lot of time at those conditions.

    If you are driving gently for economy, you will not see any improvement in mpg from premium. If you sometimes use full throttle for passing or high speed, you may feel the extra power from premium under those conditions. And when you use those conditions, less premium is required than regular to make the same power. If you use those conditions a lot, the increased mpg from premium becomes discernable.

    However, under the hardest continuous driving, the difference between a tank of regular and a tank of premium is maybe only 2 mpg. For most hard drivers, the difference may only be 1 mpg. For the average driver, the improvement will be so small that it is overcome by other variables and is not discernable.

    Would you like to see Scion info on (a) the knock sensor or (b) the extra power of premium?
  • icanoeicanoe Posts: 5
    I just purchased the Salsa Red xB this past weekend(automatic). I have only driven it 42 miles, but the gas gauge has not moved. I am not used to THAT!

    I was test driving both the Honda FIT and the xB. The xB won, because of the room, the great airconditioner, and my wife thought it was cute. kudos for me.

    I actually traded in my Grey 2000 Silverado Ext Cab 4X4 Z71 5.3 liter V8. I did really like that truck, but driving back and forth to work, 35 miles, it was eating me alive in fuel costs...at about 14 Mpg or less. If you punched it a few times you could actually see the gas gauge move. When I was a landlord and moving stuff all the time, the truck was great. Now that the property is sold...I just didn't need the truck and the gross fuel economy. I am glad I made the switch. Stay tuned for my MPH...I'll update it in a month..not like the truck where I was spending $200 per month on gas. Now the money I save on gas is my car payment!
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,490
    Yes your comments make sense, definitely. I think what surprised me is that using premium gives me markedly LESS mpg.

    There isn't, of course, any more energy in high test gasoline, or any more "power". It just burns more evenly (the "flame front") in the combustion chamber.

    So, as you say, there are times when a steady even flame front is important to the engine, and other times when it doesn't much matter. It rather depends on what you're doing with the engine at the time.

    It's always been my understanding, from the physics of automobile engine anatomy, that using high test would make more sense in stop and go or heavy duty driving than it would on a flat even highway.

    I do think, though, that the xA runs better on high test, regardless of the mpg.

    I don't fill up until about the 350 mile mark, so the tank's pretty empty.
  • aathertonaatherton Posts: 617
    HIgh octane does not burn more evenly or steady. High octane is simply harder to detonate, which means that higher compression can be used. Higher compression makes more HP.

    Conversely, if low octane is used in a high compression engine, it will detonate under load. Detonate means that it will ignite too soon on the pistons upstroke - too many degrees before top dead center. This is knocking which is destructive, can burn a hole in a piston.

    Modern high compression engines like the xB have knock sensors, which retard the ignition at the first few knocks. Retarding the ignition reduces power. Reducing the HP of an engine means more gas is needed to make up the lost power.

    The xB and xA have the same engine and low octane is recommended for both. Both run perfectly on low octane, but will make more power on high octane. In some other post I offered to paste info on the effect of octane on the xB's power, and info on the knock sensor that allows xBs to use low octane gas. But there was no interest.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,490
    Yeah it does. High octane means a more controlled burn. That's the whole point. You get an even flame front, it's not ragged or spontaneous, and yes, this is due to the fact that it is harder to burn. So we are both saying the same thing differently.

    Personally, I don't think you get any more power out of an xA or xB with high octane. I might try to prove or disprove this on a dyno sometime soon.

    I think what we are sensing is a smoother engine.
  • aathertonaatherton Posts: 617
    "... Personally, I don't think you get any more power out of an xA or xB with high octane. I might try to prove or disprove this on a dyno sometime soon. "

    That has already been done by Scion and reported below.

    2005 xB tested on premium gas
    108 hp @ 6000 rpm
    105 ft-lb @ 4200 rpm
    http://www.automotive.com/2005/12/scion/xb/specifications/index.html

    2006 xB tested on regular gas
    103 hp @ 6000 rpm
    101 ft-lb @ 4200 rpm
    http://www.automotive.com/2006/12/scion/xb/specifications/index.html

    That was the first item I offered to post and it sounds like you asked for it indirectly. But do you understand the reason for the change? The engine did not change.

    The other item was the Scion info on the knock sensor that allows regular gas to be used. Ask and it shall be posted as well.
  • aathertonaatherton Posts: 617
    "... . High octane means a more controlled burn. That's the whole point. You get an even flame front, it's not ragged or spontaneous, and yes, this is due to the fact that it is harder to burn. So we are both saying the same thing differently. "

    We are not saying the same thing at all.

    The "burn" occurs after ignition, and is controlled by the shape of the combustion chamber, piston crown, etc.

    Before the gas burns, it must ignite. And the timing of the that ignition is what octane is about.

    High octane means more resistant to ignition. HIgh octane gas takes more compression and heat to ignite the mixture. So the mixture will not ignite so soon that it tries to drive the piston down backwards before it has crossed top dead center. That would be "knocking".

    The high compression of the xB engine tries to ignite the mixture so soon on the compression stroke that under high engine load or high rpm, either high octane must be used or the ignition timing must be retarded by the knock sensor.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,490
    From my perspective I think we are indeed saying the same thing. Pre-ignition is basically a ragged burn in other words.

    DYNO TEST--those links only show a 2005 and 2006 both on 87 octane.

    Anyway, I'd like to do the dyno test at my friend's shop. It is so easy to misinterpret dyno data or fudge the results in various ways---this way I'd get a pretty accurate reading and then I could say or not say what's up with high test on the Scion with some degree of assurance.

    I'm inherently skeptical of any claim to BOTH increased fuel mileage AND increased performance at the same time. That's a rather rare occurrence, but we'll see. I'm open-minded on it. Obviously my own anecdotal testing failed to show any improvements with high test, but the dyno is quantitative. I'll keep you all posted.
  • aathertonaatherton Posts: 617
    "... I think we are indeed saying the same thing. Pre-ignition is basically a ragged burn."

    Before there can be a burn, there has to be ignition. Pre-ignition is the mixture igniting too soon. The result is knocking, where the "burn" drives the piston down in the wrong direction, before it has reached top center.

    To stop knocking, either a higher octane must be used, or the engine must have a knock sensor to retard the ignition. The xB has a knock sensor.

    "... those links only show a 2005 and 2006 both on 87 octane."

    http://www.automotive.com/2005/12/scion/xb/specifications/index.html
    http://www.automotive.com/2006/12/scion/xb/specifications/index.html

    Damn, you are right that the 2005 link does not show that the HP was obtained on high octane. It only lists the recomended 87 octane. The moderator of ScionLife.com said Scion had to de-rate the 2006 engine to 103 HP because it had to be tested on 87 as recommended in the Owners Manual. He said 2005 engine was rated at 108 HP but that was on premium gas and to keep that rating Scion would have to recommend premium, which was not becoming for an economy car.

    I have a thick 2005 Scion brochure which lists the xB at 108 HP.
    These links also say 108 HP for 2005:
    http://www.theautochannel.com/news/2004/12/24/310183.html
    http://auto.consumerguide.com/Auto/New/reviews/full/index.cfm/id/38232/Act/Specs- /

    You may have to dyno test on the two octanes to convince yourself that the xB makes 5 more HP on high octane, because the knock sensor does not intervene to retard the igntion under maximum load.
  • aathertonaatherton Posts: 617
    "... don't think you get any more power out of an xA or xB with high octane."

    The ball is in your court on the issue of whether the engine makes 5 more HP on high octaine.

    Let's see if we agree that these are facts:

    1. The 2005 xB was advertised by Scion to make:
    108 hp @ 6000 rpm
    105 ft-lb @ 4200 rpm

    2. The 2006 xB was advertised to make:
    103 hp @ 6000 rpm
    101 ft-lb @ 4200 rpm

    3. The Owners Manual, Section 2, Page 114 says:
    OCTANE RATING
    Select Octane Rating 87... or higher.
    Use of unleaded gasoline with an octane rating or research octane number lower than stated above will cause persistent heavy knocking. If it is severe, this will lead to engine damage.

    Now let's see what you think of these statements:

    1. There was no change to the 2006 engine to cause the reduced power and torque.
    2. 87 octane is the minumum that the engine will run on without knocking.
    3. The engine has a knock sensor that retards the ignition to stop knocking.
    4. Retarding the ignition reduces power.
    5. The knock sensor cannot retard the ignition enough to prevent knocking on octanes below 87.
    6. The octane language in the 2005 and 2006 Owners Manuals is the same.
    7. The words "or higher" after 87 octane are significant.

    And what you think of these unsupported statements from a moderator of ScionLife.com who said he got it from a source:

    8. Scion tested the 2005 engine on premium gas.
    9. For 2006 Scion was told to either (a) retest the engine on the 87 octane gas recommended in the Owners Manual, or (b) explain that the engine would run on a minumum of 87 octane but made more power on premium. Scion chose to stay with the present language in the manual, and so had to de-rate the engine to 103 HP using 87 octane.

    If you agree with statements 1-7 but do not agree that statements 8-9 are valid, then please offer another explanation for the loss of power for 2006.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,490
    I couldn't say without more information. What you may be seeing is a correlation but not a cause and effect, in what you are reading.

    All I know for sure is that I always get worse fuel mileage when I use premium in my xA. Never fails. Why, I don't pretend to know. Just an observation. Usually drops about 2 mpg---which could in fact, just be a statistical variation.
  • aathertonaatherton Posts: 617
    You originally said: "Personally, I don't think you get any more power out of an xA or xB with high octane." I then presented a case that they do make more power on high octane.

    This is vital information for many people who are seeking an extra 5 HP by adding expensive modifications, such as intakes, exhausts, and pulleys. They may draw their own conclusion on how the 2005 engine made 5 more HP with no modifications, and how this applies to the 2006 engine.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,490
    I really don't believe their HP ratings have anything to do with the fuel. Must be engine-design related.

    Here's an interesting article that explains why higher octane might even produce less HP, which I think might be happening with my car.

    http://www.motorcycle.com/mo/mcnuts/rt-fuel1.html

    Anyway, it's fun to explore the issue.

    Maybe others have comments?
  • aathertonaatherton Posts: 617
    "... I couldn't say without more information. What you may be seeing is a correlation but not a cause..."

    Here is the information on the knock sensor, which reduces the power when kocking happens on 87 octane. On less than 87, the knock sensor cannot stop the knocking:

    Owners Manual, Page 114:
    OCTANE RATING
    Select Octane Rating 87 or higher.
    Use of unleaded gasoline with an octane rating or research octane number lower than stated above will cause persistent heavy knocking. If it is severe, this will lead to engine damage.

    Tech Literature:
    1NZ-FE ENGINE (ENGINE CONTROL SYSTEM)
    1. General
    The engine control system has following system.
    ESA
    Electronic Spark Advance
    Ignition timing is determined by the ECM based on signals from various sensors. The ECM corrects ignition timing in response to engine knocking.

    Tech Literature:
    DIAGNOSTICS - SFI SYST
    DTC P0325
    KNOCK SENSOR 1 CIRCUIT
    CIRCUIT DESCRIPTION
    Knock sensor is fitted on the cylinder block to detect the engine knocking. This sensor contains a piezoelectric element which generates a voltage when it becomes deformed, which occurs when the cylinder block vibrates due to knocking. If engine knocking occurs, the ignition timing is delayed to suppress it.
  • aathertonaatherton Posts: 617
    "... Here's an interesting article that explains why higher octane might even produce less HP, which I think might be happening with my car. http://www.motorcycle.com/mo/mcnuts/rt-fuel1.html ..."

    The article says:
    "... leaded high-octane race fuels burn slower than most unleaded fuels, and may reduce performance in stock or lightly modified motorcycles...."

    Have you been putting high octane leaded racing fuel in your xA? You can only get that at race tracks and airfields.
  • aathertonaatherton Posts: 617
    "... I really don't believe their HP ratings have anything to do with the fuel. Must be engine-design related."

    After all the information posted above, why don't you believe that HP is reduced whenever the knock sensor operates to retard the ignition on 87 fuel?

    You must not believe that retarding the ignition timing reduces power - that is where you are coming from. But the relation of timing advance to power is basic engine mechanics.

    As for a change in 1NZ-FE engine design from 2005 to 2006, I have not heard of that, and it does not show in the published specs. Do you have any details?
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,490
    That's correct, I don't believe high octane fuel will produce any more HP.

    But I don't wish to dominate the conversation so let's have other comments or anecdotal evidence on Scion fuel mileage.
  • aathertonaatherton Posts: 617
    "... I don't believe high octane fuel will produce any more HP."

    “… Our first acceleration times for the GXP were somewhat slower than Pontiac’s claims, and company officials suspected our car may have been delivered – and then tested – with regular fuel. After we retested with premium, the GXP redeemed itself, blasting to 60 mph in 5.6 seconds and through the quarter- mile in 14.2… big improvements of 1.1 and 1.2 seconds, respectively…”
    --Car & Driver, October 2006, page 119, “Road Test Soltice GXP”
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,490
    that's not producing horsepower...that's just the engine mapping advancing the timing. That engine can utilize the premium fuel, but the fuel itself has no more power in it than regular. In other words, the regular may have robbed the engine of its horsepower rating, not the other way 'round.

    So if your engine can't advance timing *substantially* to accomodate the higher octane, then premium fuel will do nothing whatsoever for performance.

    If the engineers built the engine to run on 87, that's probably where the engine's full HP will reveal itself.
  • "... the (premium) fuel itself has no more power in it than regular... the regular may have robbed the engine of its horsepower rating... if your engine can't advance timing *substantially* to accomodate the higher octane..."

    That's what I was thinking, and assuming that the engine could advance timing as much as higher octane would allow.

    But I asked Scion Customer Experience via the link on Scion.com, and was surprised to hear that gas had nothing to do with the reduction in power. Apparently there is no power advantage to octane higher than 87, so I am going back to 87.

    From: Scion
    Date: Fri, 01 Sep 2006
    To:
    Subject: Scion xB horsepower and torque [Incident: 060901-000071]
    ... The difference in the xB's horsepower rating from 2005 to 2006 is reflective of revised testing standards for horsepower set forth by the SAE. The engine design, engineering, and fuel used remains unchanged. The difference is due to the fact that previous testing for horsepower from engines did not include the parasitic drag associated with the operation of a power steering pump. The SAE revised their testing standards to test with a power steering pump operating with the engine.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,490
    that makes sense, thanks for posting it. Interesting.
  • I also asked whether premium fuel made any more power by avoiding the knock sensor at full throttle load, and received this reply:

    Scion Customer Experience Discussion Thread
    Scion xB horsepower and torque [Incident: 060901-000071]
    From: Scion
    Response (Vernon)09/06/2006 04:09 PM
    "… The vehicle is engineered and tested using 87 octane fuel. We recommend that fuel for optimum performance, reliability, and fuel economy on the vehicle. The vehicle does make the same power at maximum throttle position on 87 octane as it would on higher octane fuel."

    Furthermore, if Toyota thinks premium fuel will increase performance, they will say so in the Owners Manual, which the xB manual does not say.

    From the 2006 Tacoma Owners Manual:
    "OCTANE RATING
    2TR- FE engine - Select Octane Rating 87 (Research Octane Number 91) or higher.
    1GR- FE engine - Select Octane Rating 87 or higher. For improved vehicle performance, use premium unleaded gasoline with an Octane Rating of 91 or higher."

    (Note: the 2TR-FE is the 2.7L I-4 and 1GR-FE is the 4.0L V-6)

    While I believe there must be a theoretical power penalty for the xB's knock sensor retarding ignition under full throttle on 87 octane, Toyota does not admit in the manual the possibility of more performance on higher octane, either because it is insignificant, or because they do not want to associate a low powered economy car with premium fuel, or both. Whatever, I am not going to use premium any more.
  • My new xA got 34.7 mpg on its third tank of gas. This was with a mix of city/highway driving and with the A/C on maybe a third of the time.
  • dwynnedwynne Posts: 4,018
    . There was no change to the 2006 engine to cause the reduced power and torque.

    Yes there WAS a change for the 2006 cars - and the answer is right here on Edmunds

    The answer?

    In other news, the xB's horsepower rating drops from 108 to 103 due to new SAE testing procedures.

    See, they just test now using difference standards - same actual power, lower rating for 06.

    Premium contains additives to prevent pre-ignition and since we buy gas by the gallon, that means a gallon of premium contains less "gas" than a gallon of regular. If your car is not designed (or changed) to run on premium then you are just wasting your money pumping in anything over the minimum.

    Gas is high, but premium has a "premium" price - around here $0.30 or more per gallon more and at today's pump price this is about a 12% up-charge (the percentage gets less the higher the gas, today regular was around $2.50). So even IF premium "worked" it would have to produce 12% more MPGs just to break even. So if you get 30mpg around town you have to get 33.6mpg to break even and more to really save money. Even if you delude yourself you will not get that much better :D

    Dennis
  • There was an actual 5 HP drop in power due to the inclusion of the power steering pump, according to Scion:

    Scion xB horsepower and torque [Incident: 060901-000071]
    From: Scion
    Response (Vernon) 09/01/2006 03:04 PM
    We appreciate your inquiry. The difference in the xB's horsepower rating from 2005 to 2006 is reflective of revised testing standards for horsepower set forth by the SAE. The engine design, engineering, and fuel used remains unchanged. The difference is due to the fact that previous testing for horsepower from engines did not include the parasitic drag associated with the operation of a power steering pump. The SAE revised their testing standards to test with a power steering pump operating with the engine.

    The amount of additives to increase octane is negligible. I have some bottles of now illegal tetraethyl lead to raise the octane for my old bike engines, and the ratio for 98 octane is 1/2 ounce per gallon.

    Scion says this about fuel for the xB:

    Scion xB horsepower and torque [Incident: 060901-000071]
    From: Scion
    Response (Vernon) 09/06/2006 04:09 PM
    … The vehicle is engineered and tested using 87 octane fuel. We recommend that fuel for optimum performance, reliability, and fuel economy on the vehicle. The vehicle does make the same power at maximum throttle position on 87 octane as it would on higher octane fuel.
  • I have a 2006 xB 5-speed. I keep a spreadsheet showing date, odometer reading, tripmeter reading, gallons bought, mpg, and type of driving.

    From 3,000 to 6,000 miles I used 93 octane and the overall average was 35.0 mpg. The low mpg was 23 on a racetrack, and the high mpg was 42.8 on a 250-mile 60 mph Interstate trip, holding the speed very steady with no tie-ups or stops.

    I went from 6,000 to 8,500 miles last week on a trip that included slow and fast Interstate driving from Louisville to New Hampshire, plus 2-lane mountain driving in the states of PA, NH and VT. During the 2,500 miles I used both 93 and 87 octane under various conditions. The overall average was 35.2 mpg, with a high of 36.5 mpg on regular Interstate driving and a low of 32.8 on fast Interstate driving. I could not tell any difference in either mpg or power between 93 and 87 octane.

    The xB struggled on mountain grades, often requiring 4000 rpm in 4th gear to maintain 60 mph. But the rest of the mountains were fun due to the xB's willing engine and gearbox, and its handling.

    On flat Interstates it could cruise easily with much power to spare at 4000 rpm in 5th at an indicated 80 mph (74 mph according to the ECU as displayed on a ScanGuage). For the trip I had bought and installed a Rostra cruise control, which was welcome on the long Interstate stretches. I was also glad I had changed to SensaTrac rear shocks immediately after delivery, to smooth the ride.

    It was an enjoyable trip, and the xB made every mile fun. It was also not so comfortable as to cause sleep. It is the only car I have never felt sleepy in.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,490
    Thanks for that great report. Your figures sound very realistic and reasonable.

    Was the cruise control difficult to install?
  • 37.1 mpg
  • I bought the Rosta cruise control online from AllScion. Studied the printed and PDF instruction, and the installation threads on ScionLife.com. Removed my strut bar to make installation easier. Did a dry run and felt the installation would technically be no more difficult than the fog lights I had installed, but would take 3-4 hours intead of 1 hour. However, I felt I could not work under the dash that much. I am too old, tall and stiff, and bifocals could not look upward and see connections 4 inches from my face. So I went to the place that installs for the dealers here, and they charged $150 and did it in an hour while I waited.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,490
    Yeah, I hate under-dash work too. I've seen that unit from AllScion. Might improve fuel mileage enough to pay for itself in a few years?

    I hit my highest mileage thus far (12,500 miles) at 39 mpg. Drove the whole day up and down the coast for $12.88. Gotta love it.
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