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Old 02-19-2006, 09:01 AM   #19
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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.
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Old 02-24-2006, 01:23 PM   #20
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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...
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Old 02-24-2006, 01:27 PM   #21
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Quote:
Originally Posted by ToTo
Hi guys! So the harder for the fuel to burn is not good in the long run? I have a TS model, I currently use 95 octane... What if I were to use 98 or 100 octane fuel, what would change? Would the car run better or would I feel a bit more power or torque, or is all this just BS?
You don't need higher octane, unless you are running some set up that requires it. You are wasting your money on protection you don't need.
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Old 02-25-2006, 10:10 AM   #22
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Quote:
Originally Posted by why?
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.
Can you tell me more about ECU's adjusting and adapting to higher or lower octane fuel? They do it automatically? What happens if you switch from 95 octane to 98-99 octane, what does the ECU do to make it good for the car, does it run better or what?
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Old 02-25-2006, 10:11 AM   #23
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Quote:
Originally Posted by AutoTech1
You don't need higher octane, unless you are running some set up that requires it. You are wasting your money on protection you don't need.
I was just curious cause many people have this issue, whether the car runs better or not, or is it better at all for the engine and such?
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Old 02-25-2006, 10:16 AM   #24
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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.
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Old 02-25-2006, 10:29 AM   #25
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Quote:
Originally Posted by why?
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.
Yeah I agree, extensive testing is necessary! How about what AutoTech1 said,

"This higher octane helps to prevent detonation, which can destroy a motor."


I don't quite understand this???
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Old 02-25-2006, 07:20 PM   #26
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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.
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Old 02-25-2006, 10:19 PM   #27
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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.
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Old 02-26-2006, 04:57 PM   #28
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Quote:
Originally Posted by ToTo
I was just curious cause many people have this issue, whether the car runs better or not, or is it better at all for the engine and such?
The car has no performance gains and it doesn't do anything more than what your recommended octane does. Octane is choosen to resist detonation. Here is a link that explains more of what I was trying get at as well as why?: http://www.geocities.com/runyardj/OctaneExplanation.htm
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Old 02-26-2006, 05:11 PM   #29
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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.
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Old 02-28-2006, 03:00 AM   #30
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Thanks guys for the inputs on the higher octane business... I will just rather stick with the recommended octane, cause I don't want to just simply waste money for nothing. At the beginning, I did think that it might help or do something to clean the engine or add a little bhp, but oh well...
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Old 02-28-2006, 09:58 AM   #31
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Quote:
Originally Posted by AutoTech1
The car has no performance gains and it doesn't do anything more than what your recommended octane does. Octane is choosen to resist detonation. Here is a link that explains more of what I was trying get at as well as why?: http://www.geocities.com/runyardj/OctaneExplanation.htm
I disagree with that statement. I believe using a higher octane might get better gas mileage and a little better performance.

I believe this because all manufacturers use 93 octane in the USA for all the testing.
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Old 03-01-2006, 03:35 PM   #32
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Originally Posted by why?
I disagree with that statement. I believe using a higher octane might get better gas mileage and a little better performance.

I believe this because all manufacturers use 93 octane in the USA for all the testing.
And what about adding acetone to fuel? What does this do, which I found on the Toyota Owners Club home page, plus also some links in the forum topic as well of this subject...
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Old 03-01-2006, 07:14 PM   #33
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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."
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Old 03-01-2006, 08:02 PM   #34
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I would check it out with the dealership first to see if adding this kind of additive to the gas will void the warranty .
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Old 03-02-2006, 01:06 AM   #35
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You would be wise to stay away from acetone. C'mon gang we are not mixing fuels for funny cars, stick in what ever octane makes you feel better. If saving some money feels good then pour in 87 octane, it's all you need in Uncle Yaris.
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Old 03-02-2006, 09:47 AM   #36
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If it works to increase gas mileage then why not use it?
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