nameless_ak

^Yes, trafic is deffinetly whats giving you bad mileage. Stop and go is going to kill your mileage, and answering your question, I think about every one will agree with me when i say, no higher octane gasoline isn't going to boost your mileage at least not enough to make up the price difference, are cars run best on good ol 87 octane.

SiZzOuRcE

I agree that the price vs. mileage won't make sense to pay more for it, however I do know that alot of cars retard timing when running 87 which tends to kill MPG. But I don't know enough about these motors and how they are programmed to say for sure.

My old truck (Dodge Ram 1500 HEMI) definetaly liked 89 octane compared to 93. Its all about the computer.

xActly

^^that's directly related to compression, and the resulting heat. Some motors do a better job of managing the heat, but for the most part, higher compression requires higher octane. The 08 xB is 9.6:1, which is getting up there, but should run fine on quality 87 octane in normal temps & under normal loads. Still would probably ping (and have the ecu retard timing to compensate) on a 95 degree day with 3 passengers & luggage in the back going up a hill. If that sounds like a normal day, run 89 or better.

The 1st gen xB & the xA, however, is 10.5:1, so higher octane is warranted, despite what the owners manual says. It's certainly why I see 3mpg+ better in the wife's car on 93 than on 87.

SiZzOuRcE

I decided to test her out and just drive her normal for a while with 93. Filled up with 1mi to go on the range last night. Seems peppier and more responsive, however it could be in my head.

Ill post results in MPG when shes empty. Should be about 6 days.

xActly

I'm actually running a tank of 93 in the xB right now too. Display mpg shows no improvement...just under a half tank now. We'll see how we do on the calculation when I next fill it up.

HypnoticTealMica

My car has just under 2K today and have filled it 7 times since purchase in February.
Temperatures have been about 45 overall. Running 87 octane, 10% Ethanol.
95% driving is city streets.
Ave range - 248.9 miles
Ave gal @ fill - 11.2 gal
Ave speed - 33
Ave mpg Scion - 25.1
Ave mpg calculated - 24.3

HypnoticTealMica

My car has just under 2K today and have filled it 7 times since purchase in February.
Temperatures have been about 45 overall. Running 87 octane, 10% Ethanol.
95% driving is city streets.
Ave range - 248.9 miles
Ave gal @ fill - 11.2 gal
Ave speed - 33
Ave mpg Scion - 25.1
Ave mpg calculated - 24.3

RichB

Considering the 10% ethanol fuel, I think thats pretty good! I wish I had your attentiveness to keeping records!

808-213-503

I drive with a lead foot, about 90% city driving. I tend to average around 19-20 mpg.

I don't care that much about mileage really...I average only 5500 miles a year anyway.

HypnoticTealMica

Considering the 10% ethanol fuel, I think thats pretty good! I wish I had your attentiveness to keeping records! [/quote]

Ha! I should be more attentive when hitting the Submit button

cincinfocal

i get about 300-310 miles per tank on the stock 16's and about 28-30 mpg's...average driving speed i would say 45, mix of suburbs and highway with about 20%-25% city, fill up about 10-11 gallons

i get about 270-280 miles per tank on the 17's and about 26-28 mpg's...average driving speed i would say 45, mix of suburbs and highway with about 20%-25% city, fill up about 10-11 gallons, i would say thats because my wheels are wider than the stock ones...i think they are 225's...but overall diameter should be relatively close if i did my math right :p

thepixi

I had an XA that I traded for my XB (needed more space). In my XA I got 37 (!) MPG, and I assumed since the XB is basically the same car with just a little more weight that I'd get around that. I get avg 25 MPG in my XB. THIS SUCKS. I thought something was wrong with my car, but now I see everyone else's XBs get the same.

BTW, a trick I figured out in my XA (that also works in my XB)...instead of using a/c, turn your vent **** to defrost, temp **** to cold, and put it on fresh air. I almost NEVER use a/c, only when first cooling the car or in the 100 degree weather here in Dallas, TX. I'm assuming it saves on gas (though I have yet to see it in my XB...I still wanna get it checked out).

JMS5000

Correct me if i'm wrong, but doesn't the defrost setting override the a/c power button and automatically run the compressor? The idea is to cool the air, thus reducing its water vapor holding capacity, then rewarming the air and directing it to the inside of the windshield evaporating the water condensed there.

thepixi

I guess I wasn't specific enough...I don't use the defrost button, I just turn the vent **** to the defrost setting....you know, the one that determines which vents the air will blow out of. I have no clue why it works that way but I've tried it in other cars and it doesn't work. Only the Xa and Xb so far. It's almost as cold as having the a/c on.

Maybe this is a question for someone that knows more about the engines in these vehicles, since I know very little...after all, I'm just a GIRL right? Jk, I hope you weren't just doubting me because I'm female, but I never claimed to know the logistics, just that in my 3 years of Scion experience, it works.

xActly

To answer JMS5000's question - yes. Simply by placing the vent selector in the defrost position, you are engaging your a/c compressor. It is to dry the air, as you said. Sorry pixi. Most cars operate this way, though some don't. Personally, I'd rather have the ability to blast air on my windshield without the compressor being on, but I'm not about to rip everything apart to install a switch, so whatever.

And to speak to pixi's gas mileage - specifically this comment: "I assumed since the XB is basically the same car with just a little more weight" - they are two completely different cars. 25mpg from an 08 xB is really good! I'm assuming you're talking about an 08,. since this thread is about the 08.

EDIT - nevermind. I clicked on your profile, and I see you're talking about a 2005 xB. Not sure why you're seeing such a huge difference, but if it makes you feel any better, I never got over 27mpg from my 2005 xB (and never more than 31 from the 05 xA we still own).

wrczx3

I am up to 23.8 around town.

zio

I get 24.8 average

Not too bad I must say for a box.

Zio

scionmichigan

Just bought a used 2005 xb and I'm getting 32 city mostly driving. I love the little guy.

ravenfox

Just got back from a 2000 mile trip..Ill post details later...the highest hit highway was 36 mpg(for a long time then it began to drop) that tank avg. 32 mpg using Marathon gas 87 octane..the next tank using Shell was 31 mpg..87 octane..98% Highway...Gets best mileage between 65 and 75 mph...AJ

danos_XBox

I just filled up my 08 CSM xb2 and report 28 with mixed driving. That means you topped me by 56 miles on a full 14 g tankfull. And I didn't baby it either.