What type of octane I should use??? - Toyota Yaris Forums

krakkhenz · 02-14-2006, 10:18 AM

Im a little confused about this, my car seller told me that I should use 95 octane gas, but the manual says I should use 91

What are the difference between 91 and 95???

My yaris got a 1.3 engine.

why? · 02-14-2006, 11:22 AM

I'd go with what the manual says.

The difference between octanes is how much pressure is required to ignite the fuel. The higher the rating the harder it is to ignite the fuel.

GabL · 02-15-2006, 09:11 AM

I thought the car (Yaris) can run on 87?

why? · 02-15-2006, 10:34 AM

Quote:

Originally Posted by GabL

I thought the car (Yaris) can run on 87?

The rest of the world measures octane differently then we do in North America.

GabL · 02-15-2006, 04:55 PM

oh, didn't saw the OP was from Panama...

as400g33k · 02-15-2006, 08:15 PM

the yaris is rated to run at 91 but can also accept higher octane. most people would claim a performance boost when using higher octane. while some would even claim better fuel efficiency with higher octane.

we use 91, as it is cheaper than 95, 98 or 100 octane. :)

GabL · 02-15-2006, 09:52 PM

Quote:

Originally Posted by as400g33k

the yaris is rated to run at 91 but can also accept higher octane. most people would claim a performance boost when using higher octane. while some would even claim better fuel efficiency with higher octane.

we use 91, as it is cheaper than 95, 98 or 100 octane. :)

100 octane!! It's gonna burn like

swng · 02-15-2006, 11:09 PM

Don't worry friend, the higher is the octane no., the harder it is for the fuel to burn

.

krakkhenz · 02-16-2006, 11:27 AM

ummm... thanx for your replies, im using 95 octanes since the first day, but im gonna try with 91 and set the trip B for the next refuel.

why? · 02-17-2006, 08:40 AM

No experience with it, I don't remember seeing anything like that marketed over here.

But additives usually do something interesting, so you could give it a try and see what it does, but since it is the same octane, it prolly will only do things like clean the engine, I don't think it would make a difference in the power output of the vehicle.

why? · 02-19-2006, 09:01 AM

ECU's from the factory can adjust. They have to adjust in case you get a bad tank of fuel, and they can adjust a little the other way as well.

AutoTech1 · 02-24-2006, 01:23 PM

There is no need to run higher octane fuel than what is stated in your manual. You'd just be wasting your money. Higher octane fuel is mostly used when some form of forced induction is introduced. This higher octane helps to prevent detonation, which can destroy a motor. Why do you think many European cars require higher octane fuels? Because they come with turbo's and superchargers from the factories...

why? · 02-25-2006, 10:16 AM

An Ecu will prolly not adjust for all octanes. I do believe it will adjust some for higher octane fuels, just as it adjusts if you get a bad tank of gas. How much it adjusts and wether or not it is actually worth it depend on the cost of fuel and are questions that cannot be answered without extensive testing.

As to what it would do, it would advance timing and lean out the fuel ratio so that a more precise explosion will happen every time, this would make the car more powerful and get better gas mileage.

There only way to find out if it benefits you is to try it and keep records of power and gas mileage you get with each octane level.

why? · 02-25-2006, 07:20 PM

Detonation is also reffered to as knock, pinging, etc.

What it means is the fuel is igniting before the engine is ready for it to explode. If it happens in a big enough quantity it can cause the pistons to be pushed clear out the other side of the engine.

This is why modern cars are created to adjust for a bad tank of fuel.

The reason to use the octane the manufacturer recommends is because the engine is designed to run on that octane with no detonation. Switching to a lower detonation could cause detonation. Switching to a higher octane should not effect detonation, as there should be none on a stock car using the manufacturers recomended octane fuel.

However on modified cars, especially forced induction vehicles, they use the highest octane they can get their hands on because it helps to prevent detonation, not to mention it means they do not have to tune the vehicle quite as much.

The biggest reason for modified vehicles having detonation is laziness of the tuners.

yariman · 02-25-2006, 10:19 PM

Hey ToTo, Simply, todays engines are designed within certain parameters to run best on a certain fuel for best performance and low emissions. The engines computor receives signals from various sensors such as how much air is being drawn in and at what temperature. timing, crankshaft position, engine speed sensors, vehicle speed sensor, EGR sensor, air-conditioning sensor, knock sensor which senses if the engine is knocking so the computor can retard timing. Oxygen sensor and on and on. The computor takes all the inputs from these sensors and adjusts whatever is needed to run at "stoichiometric" air-fuel ratio which is the air-fuel ratio which produces the most complete combustion with the fewest harmful byproducts. This gives the best compromise of power, economy and emission control. Now once again if you want to get better performance , you have to change those computor parameters. However, low emission output will be lost.

AutoTech1 · 02-26-2006, 05:11 PM

Quote:

Originally Posted by why?

Detonation is also reffered to as knock, pinging, etc.

What it means is the fuel is igniting before the engine is ready for it to explode. If it happens in a big enough quantity it can cause the pistons to be pushed clear out the other side of the engine.

This is why modern cars are created to adjust for a bad tank of fuel.

The reason to use the octane the manufacturer recommends is because the engine is designed to run on that octane with no detonation. Switching to a lower detonation could cause detonation. Switching to a higher octane should not effect detonation, as there should be none on a stock car using the manufacturers recomended octane fuel.

However on modified cars, especially forced induction vehicles, they use the highest octane they can get their hands on because it helps to prevent detonation, not to mention it means they do not have to tune the vehicle quite as much.

The biggest reason for modified vehicles having detonation is laziness of the tuners.

That's also a great point... Most people think that adding a turbo is easy. You just go to a shop and they install it for you... That's it right? WRONG... You have to think about many things... For example: If I do this modification, how will it affect my car overall? What are the risks? What is necessary and what is optional? This goes back to modified vehicles having detonation because of lazy tuners like why? was getting at... Every step in modifying a car usually leads to another step... It's not as easy as shown in the movies, but when it's done right (And through the pain of working long hours and getting little sleep; unless you are born rich) it can sure be rewarding.

why? · 03-01-2006, 07:14 PM

Acetone used in very small amounts adds gas mileage. Acetone used in too big amounts destroys hoses and anything else in an engine that is not metal.

Note that is around .78 cc per liter or one ounce per 10 gallons. Not more than three oz. per 10 gallons.

http://pesn.com/2005/03/17/6900069_Acetone/
"Incidentally, in almost all cases, the lowest octane is best for mileage. Most modern vehicles do not have high enough compression to justify using high octane fuels. The testing indicates best mileage is usually obtained with 85 or 87 octane gasoline. Too much octane causes a loss of power and economy. BUT too little octane causes the same things plus knocking. Listen carefully to your engine for tell-tale knocks or clicks when you start out from a light. The best mileage points to the correct octane when the engine is properly tuned. See your owners manual."

swng · 03-01-2006, 08:02 PM

I would check it out with the dealership first to see if adding this kind of additive to the gas will void the warranty

.

02-14-2006, 10:18 AM	#1
krakkhenz Drives: Toyota Yaris Join Date: Jan 2006 Location: Panama Posts: 9	What type of octane I should use??? Im a little confused about this, my car seller told me that I should use 95 octane gas, but the manual says I should use 91 What are the difference between 91 and 95??? My yaris got a 1.3 engine.

02-15-2006, 11:09 PM	#8
swng Drives: 06 3-dr auto RS Join Date: Jan 2006 Location: BC Posts: 1,051	Don't worry friend, the higher is the octane no., the harder it is for the fuel to burn.

02-25-2006, 10:19 PM	#15
yariman Speed Wrenchin' Drives: 2006 Yaris 3 door, Bayou Blue Join Date: Jan 2006 Location: Delta,B.C. Canada Posts: 96	Hey ToTo, Simply, todays engines are designed within certain parameters to run best on a certain fuel for best performance and low emissions. The engines computor receives signals from various sensors such as how much air is being drawn in and at what temperature. timing, crankshaft position, engine speed sensors, vehicle speed sensor, EGR sensor, air-conditioning sensor, knock sensor which senses if the engine is knocking so the computor can retard timing. Oxygen sensor and on and on. The computor takes all the inputs from these sensors and adjusts whatever is needed to run at "stoichiometric" air-fuel ratio which is the air-fuel ratio which produces the most complete combustion with the fewest harmful byproducts. This gives the best compromise of power, economy and emission control. Now once again if you want to get better performance , you have to change those computor parameters. However, low emission output will be lost. __________________ Quench my thirst with gasoline

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02-14-2006, 11:22 AM	#2
why? Only Happy When it Rains View User's Garage Drives: Yaris LB Join Date: Jan 2006 Location: harnett county NC Posts: 4,097	I'd go with what the manual says. The difference between octanes is how much pressure is required to ignite the fuel. The higher the rating the harder it is to ignite the fuel.

02-15-2006, 09:11 AM	#3
GabL I want JDM bumpers! View User's Garage Drives: 5 Dr Yaris RS in Blazing Blue Join Date: Feb 2006 Location: Toronto Posts: 419	I thought the car (Yaris) can run on 87?

02-15-2006, 04:55 PM	#5
GabL I want JDM bumpers! View User's Garage Drives: 5 Dr Yaris RS in Blazing Blue Join Date: Feb 2006 Location: Toronto Posts: 419	oh, didn't saw the OP was from Panama...

02-15-2006, 08:15 PM	#6
as400g33k Drives: 05 YRS Silver Lining Metallic Join Date: Jan 2006 Location: Australia Posts: 249	the yaris is rated to run at 91 but can also accept higher octane. most people would claim a performance boost when using higher octane. while some would even claim better fuel efficiency with higher octane. we use 91, as it is cheaper than 95, 98 or 100 octane. :)

02-16-2006, 11:27 AM	#9
krakkhenz Drives: Toyota Yaris Join Date: Jan 2006 Location: Panama Posts: 9	ummm... thanx for your replies, im using 95 octanes since the first day, but im gonna try with 91 and set the trip B for the next refuel.

02-17-2006, 08:40 AM	#10
why? Only Happy When it Rains View User's Garage Drives: Yaris LB Join Date: Jan 2006 Location: harnett county NC Posts: 4,097	No experience with it, I don't remember seeing anything like that marketed over here. But additives usually do something interesting, so you could give it a try and see what it does, but since it is the same octane, it prolly will only do things like clean the engine, I don't think it would make a difference in the power output of the vehicle.

02-19-2006, 09:01 AM	#11
why? Only Happy When it Rains View User's Garage Drives: Yaris LB Join Date: Jan 2006 Location: harnett county NC Posts: 4,097	ECU's from the factory can adjust. They have to adjust in case you get a bad tank of fuel, and they can adjust a little the other way as well.

02-24-2006, 01:23 PM	#12
AutoTech1 Drives: None yet Join Date: Feb 2006 Location: Farmington NY Posts: 63	There is no need to run higher octane fuel than what is stated in your manual. You'd just be wasting your money. Higher octane fuel is mostly used when some form of forced induction is introduced. This higher octane helps to prevent detonation, which can destroy a motor. Why do you think many European cars require higher octane fuels? Because they come with turbo's and superchargers from the factories...

02-25-2006, 10:16 AM	#13
why? Only Happy When it Rains View User's Garage Drives: Yaris LB Join Date: Jan 2006 Location: harnett county NC Posts: 4,097	An Ecu will prolly not adjust for all octanes. I do believe it will adjust some for higher octane fuels, just as it adjusts if you get a bad tank of gas. How much it adjusts and wether or not it is actually worth it depend on the cost of fuel and are questions that cannot be answered without extensive testing. As to what it would do, it would advance timing and lean out the fuel ratio so that a more precise explosion will happen every time, this would make the car more powerful and get better gas mileage. There only way to find out if it benefits you is to try it and keep records of power and gas mileage you get with each octane level.

02-25-2006, 07:20 PM	#14
why? Only Happy When it Rains View User's Garage Drives: Yaris LB Join Date: Jan 2006 Location: harnett county NC Posts: 4,097	Detonation is also reffered to as knock, pinging, etc. What it means is the fuel is igniting before the engine is ready for it to explode. If it happens in a big enough quantity it can cause the pistons to be pushed clear out the other side of the engine. This is why modern cars are created to adjust for a bad tank of fuel. The reason to use the octane the manufacturer recommends is because the engine is designed to run on that octane with no detonation. Switching to a lower detonation could cause detonation. Switching to a higher octane should not effect detonation, as there should be none on a stock car using the manufacturers recomended octane fuel. However on modified cars, especially forced induction vehicles, they use the highest octane they can get their hands on because it helps to prevent detonation, not to mention it means they do not have to tune the vehicle quite as much. The biggest reason for modified vehicles having detonation is laziness of the tuners.

03-01-2006, 07:14 PM	#17
why? Only Happy When it Rains View User's Garage Drives: Yaris LB Join Date: Jan 2006 Location: harnett county NC Posts: 4,097	Acetone used in very small amounts adds gas mileage. Acetone used in too big amounts destroys hoses and anything else in an engine that is not metal. Note that is around .78 cc per liter or one ounce per 10 gallons. Not more than three oz. per 10 gallons. http://pesn.com/2005/03/17/6900069_Acetone/ "Incidentally, in almost all cases, the lowest octane is best for mileage. Most modern vehicles do not have high enough compression to justify using high octane fuels. The testing indicates best mileage is usually obtained with 85 or 87 octane gasoline. Too much octane causes a loss of power and economy. BUT too little octane causes the same things plus knocking. Listen carefully to your engine for tell-tale knocks or clicks when you start out from a light. The best mileage points to the correct octane when the engine is properly tuned. See your owners manual."

03-01-2006, 08:02 PM	#18
swng Drives: 06 3-dr auto RS Join Date: Jan 2006 Location: BC Posts: 1,051	I would check it out with the dealership first to see if adding this kind of additive to the gas will void the warranty .