What type of fuel do you use?

[bryanhoss]

Greetings, What octane fuel is everyone using? I've been putting 93 in my Xb since I purchased it March of last year. This jerk at work says I should be using regular gas and that using the high stuff could hurt the engine. I asked my service rep at the dealer when I was getting my oil changed and he said he always recommends at least 89 and that if I'm already walking down the 93 path and if I am not worried about spending the 10 cents/gallon, to keep walking the path. What benefits and disadvantages for other octanes?

[DGTLLVR]

Rule of thumb, use the lowest octane you can without causing pinging. You'll get the most performance out of it that way. That said, I always always always fill up with 91-93 octane gas. I'm just retentive like that. I think the biggest issue is to use good fuel. Chevron, Exxon, Mobil, BP or Shell. Don't use those off brand cheap gasses. I try and use Chevron gas whenever I can, they actually make a better/cleaner fuel. Don't use additives, ever. Do a few google searches if you're not content with the answers.

[Tomas]

87 octane Chevron here (except for one fill-up with Shell). That's what the xB is designed for, and there is no pinging so...

(The fill-up with Shell, oddly enough, gave me over 4 MPG less efficiency in my xB over the same routes...)

[Mr_scion]

87 quick trip or 87 shell

[bryanhoss]

My first post ever. Figures I'd screw it up and forget to "Add" the "93 or Premium" in the poll. I'm such a dolt.

[BlackBolt]

87 octane which is what my tC is designed to use (according to the salesman).

"76" Brand, which is Conoco/Phillips 66. A tank of Shell or Chevron always seems to burn up faster than "76" IMO.

[opimax]

Wouldn't waste my money on anything but regular! check the manual, car was designed for regular as stated by the people who made this wonderful vehicle. I for one wouldn't argue with the professionals. They get paid to know this stuff, you go to the phone guy when you have phone problems cuz he's the xpert, you got to the Doc when you don't fell well, cuz the the xpert. Go to the manual cuz it is the xpert

Computer is expecting 87 (R+M/2) , why mess w/it and get it confused. Don't the gas companies make enough money? If you have extra help the poor or buy a turbo so you need it

/putting soap box away\ Thansk you for your time

Brian

[bB2NER]

87 octain at Shell because I get that 5% discount with my Shell Citibank Master Card. Anything higher than 87 is a waist of money unless you have it highly modified and require it.

[ProtoCulture]

Anything more than 87 will be a waste. Furthermore, you will actually get BETTER performance from lower octane, UNLESS you have increased compression, turbo, or supercharger. Basically, use premium only if you are having poning issues.

[JDMxB]

We've been over this topic about 20 different times now.

Try searching next time, please!

87 Octane Chevron--anything over 87 is a waste of money.

[xxDOOBIExx]

i use 89 ethonal blend from quick trip. its a cleaner fuel and is cheaper than 87.

[gslippy]

The 1.5L engine is equipped with a knock sensor, whose function is to retard the ignition timing when it detects knock as an acoustic signal. Knock is the sound of the igniting gas charge trying to push the piston backwards in the cylinder, and will occur under the wrong combination of load, throttle opening, and fuel octane.

High octane gas (93) actually burns more slowly than low octane gas (87), and so the power delivery to the piston is more smooth, reducing the tendency to knock under similar load conditions.

The knock sensor is designed to eliminate the knock altogether regardless of the fuel used. This is a great mass-market idea, and eliminates lots of customer complaints to their dealers. Many cars are fitted with knock sensors. Only those that are so fitted will benefit from higher octane gas (unless you can manually advance the ignition timing), and the 1.5L is one of them.

Since the 1.5L is fitted with a knock sensor, I'd be very surprised if anyone has ever heard one ping for more than a second or two.

High octane gas should provide MORE power because it delivers the power over a broader angle of shaft rotation than does low octane gas. You could experiment with the higher octane stuff and see if it makes any difference in power or economy. With the relative price difference between the fuel grades fairly small now, I'd suggest trying it out.

[bB2NER]

Originally Posted by gslippy

The 1.5L engine is equipped with a knock sensor, whose function is to retard the ignition timing when it detects knock as an acoustic signal. Knock is the sound of the igniting gas charge trying to push the piston backwards in the cylinder, and will occur under the wrong combination of load, throttle opening, and fuel octane.

High octane gas (93) actually burns more slowly than low octane gas (87), and so the power delivery to the piston is more smooth, reducing the tendency to knock under similar load conditions.

The knock sensor is designed to eliminate the knock altogether regardless of the fuel used. This is a great mass-market idea, and eliminates lots of customer complaints to their dealers. Many cars are fitted with knock sensors. Only those that are so fitted will benefit from higher octane gas (unless you can manually advance the ignition timing), and the 1.5L is one of them.

Since the 1.5L is fitted with a knock sensor, I'd be very surprised if anyone has ever heard one ping for more than a second or two.

High octane gas should provide MORE power because it delivers the power over a broader angle of shaft rotation than does low octane gas. You could experiment with the higher octane stuff and see if it makes any difference in power or economy. With the relative price difference between the fuel grades fairly small now, I'd suggest trying it out.

Do you know how to read??? ANY THING OVER 87 OCTAIN IS A WAIST! There is that plain enough. What do you think we have??? A Big Block Chevy motor running 11 to 1 compression and make 500 plus horse power It's a tiny 1.5 4 cyl. making a whole 108 hp. the only thing that will really help it make some additional hp is a turbo or blower. Even then it may only need mid-grade fuel. Got it now

[McBain]

Originally Posted by bryanhoss

Greetings,
What octane fuel is everyone using? I've been putting 93 in my Xb since I purchased it March of last year. This jerk at work says I should be using regular gas and that using the high stuff could hurt the engine. I asked my service rep at the dealer when I was getting my oil changed and he said he always recommends at least 89 and that if I'm already walking down the 93 path and if I am not worried about spending the 10 cents/gallon, to keep walking the path. What benefits and disadvantages for other octanes?

Its obvious the jerk you work with is alot smarter than you.
So what does that make you?

[ProtoCulture]

Sorry gslippy. Your statements are simply not true. Try again pal.

[McBain]

Originally Posted by ProtoCulture

Sorry gslippy. Your statements are simply not true. Try again pal.

Agreed.. he is wrong. The car is designed to use 87 and will not take advantage of the higher octane fuel. The knock sensor is used to allow the engine to run at PEAK efficiency within its programmed limits. An engine is most efficient just before knock or ping occurs. The knock sensor is there to allow maximum timing within the range of the recommended fuel being used.

[gslippy]

Originally Posted by jethro b

Do you know how to read??? ANY THING OVER 87 OCTAIN IS A WAIST! There is that plain enough. What do you think we have??? A Big Block Chevy motor running 11 to 1 compression and make 500 plus horse power It's a tiny 1.5 4 cyl. making a whole 108 hp. the only thing that will really help it make some additional hp is a turbo or blower. Even then it may only need mid-grade fuel. Got it now

Too bad you and some others see fit to resort to insults in a forum where we are just trying to be helpful to one another.

You'll note that I never said that you'd realize any great gains from running higher octane fuel. You'll also note that I never said you NEED anything better than 87 octane. However, you WILL realize more power from an engine fitted with a knock sensor AND running higher octane fuel than one without those things.

The shop manual states that "During Fail-Safe mode, the ignition timing is retarded to maximum retardation". Perhaps you've never set the ignition timing on an engine, or understand how to actually improve power in an engine, but the purpose of the knock sensor is to maximize power in the engine with the fuel it is given, without permitting it to knock. Knock is extremely destructive to an engine.

Toyota didn't fit these engines with knock sensors just for fun. It's there so that you can get every bit of power the engine has to offer without destroying itself. Many manufacturers list their horsepower based upon using premium fuel. Such engines have knock sensors. Toyota has chosen to rate this engine at 108 HP on 87 octane. This engine with a faulty knock sensor will still develop 108 HP on 87 octane, and nothing more with 93 octane. But this engine should develop more power (how much, I don't know, but maybe 5 HP), if running on higher octane gas with a functioning knock sensor. If Toyota just wanted this engine to never knock, they could have retarded the basic timing curve to a very conservative setting, but instead they wanted it to develop some usable power for this application without the need for premium fuel all the time.

Of course this isn't a big-block with 11:1 compression. I'm just explaining the fundamentals of engine performance as it relates to fuel octane and knock sensors. Whether you want to spend the extra 20 cents on premium gas for a few extra HP is up to you. Such fuel may also get you better fuel economy because the power output is up for a given fuel delivery rate. Again, the tradeoff is up to you.

As I said in my prior post, I'd be surprised if any 1.5L has knocked on any octane fuel, because of the knock sensor. The only time you prevent knocking with higher octane gas is on a vehicle NOT fitted with a knock sensor, and whose ignition timing is overly advanced for 87 octane. So if you prefer to limit the engine to 108 HP on 87 octane and save your money, that's your choice.

As McBain said above, the knock sensor lets the engine run at peak efficiency just under the knock threshold. Peak efficiency means peak HP for the given load, because you're wasting less energy and gaining maximum power, which is the definition of efficiency.

Have any of you run this engine on a dynamometer to prove that high octane fuel is worthless in this engine?

[LowProMofo]

I use 93 in all my cars/trucks. Always have. My dad owns/runs an oil business so I've always got gas for free.

[professor-xb]

i agree with gslippy
although , i run 87 now , once i have reached my break in point, i will experiment with differnt grades of fuel and log the milage (and pay attention to power variations and throttle responce and make a chioce only after sorting the facts out myself, there are alot of variables when it comes to fuel grades and economy , for example in my part of the country they use additives in the winter that decrease fuel economy as much as 5 mpg on some cars , did takashi (the guy that wrote the manual) take this in to consideration ? experts are proven wrong all the time , and i dont mind doing a little testing on my own ( its just simple math folks ) btw , i did not know that george bush (aka LowProMofo) owned a scion or visited this board

[LowProMofo]

Originally Posted by professor-xb

i agree with gslippy
although , i run 87 now , once i have reached my break in point, i will experiment with differnt grades of fuel and log the milage (and pay attention to power variations and throttle responce and make a chioce only after sorting the facts out myself, there are alot of variables when it comes to fuel grades and economy , for example in my part of the country they use additives in the winter that decrease fuel economy as much as 5 mpg on some cars , did takashi (the guy that wrote the manual) take this in to consideration ? experts are proved wrong all the time , and i dont mind doing a little testing on my own ( its just simple math folks ) btw , i did not know that george bush (aka LowProMofo) owned a scion or visited this board

LOL Nah not that kind of oil business! It's a small to medium sized business. We sell whole-sale oil, gas and diesel to local farmers and loggers.