HIGH OCTANE FUELS - Page 2 - Toyota Yaris Forums

Yaris Hilton · 06-11-2009, 01:09 AM

AFAIK, all ECUs have a programmed curve for maximum advance at an optimal performance level, with a knock sensor that retards the spark a bit when detonation occurs.

intake · 06-11-2009, 02:10 PM

Quote:

Originally Posted by marcus

dejavu...is the 10% increase compensate for the extra cost of the fuel..?? just curious.

in my country the high octane fuel cost only 4% extra
here in italy we have 95, 98 and 100 octane fuel.
98 do not cost too much, only 4% more, but i'm experiencing 10% and more fuel saving.
100 octane is too much expensive, and it's used only by some rich people on ferrari

in the USA how much octane u have?

Yaris Hilton · 06-12-2009, 12:23 AM

We have a different rating method. Our 87, 89 and 91 octane ratings at the pump are comparable to your 95, 98 & 100.

eTiMaGo · 06-12-2009, 10:38 AM

actually there's about a 5 point difference

IllusionX · 06-12-2009, 12:42 PM

guys... keep in mind that higher octane fuel might have cleaning additives and possibly less E85 than regular fuel. This is just some reasons why you get better fuel economy with higher octane in an economy car like the yaris... that do NOT require premium.

UTVitz · 06-12-2009, 12:59 PM

More important to buy top tier fuels, i.e., quality from Chevron/Phillips and a few others than to play with octane, IMHO. Every mechanic I've talked to and a few were Toyota mechs. said don't waist you're money unless the manufacture recommends or sometimes specifies higher octane, or the engine is pinging. Hope this helps any fence sitters-I've been there myself.

2009Toyotoad · 06-12-2009, 01:48 PM

Maybe instead of MPG we should be looking at $ per mile. Just a thought. What I think we all want is the lowest cost of ownership, but I could be wrong.

roxy1 · 06-12-2009, 02:26 PM

Quote:

Originally Posted by IllusionX

guys... keep in mind that higher octane fuel might have cleaning additives and possibly less E85 than regular fuel. This is just some reasons why you get better fuel economy with higher octane in an economy car like the yaris... that do NOT require premium.

is their any evidence higher octane fuels use less ethanol? ive seen more indications that higher quality fuels have the additives regardless of octane. i know for a fact the stations i use have cleaning additives in their 87 octane.

since there has been some consensus from more knowledgeable people that higher than 87 octane can actually reduce your mileage in the yaris (some forum members have already shown this to be so) then the lowest cost of ownership, fuel wise, doesnt even require any thought whatsoever.

Octane Myths
• High octane gasoline improves mileage.
In general, if your car is designed to run on 87 octane gasoline, high octane gasoline will not improve
mileage. If switching to high octane gasoline does improve mileage, you might find that your engine, or its
control systems, need repair.
• High octane gasoline gives quicker starting.
No, it doesn’t.
• High octane gasoline increases power.
If your car is designed to run on 87 octane gasoline, you shouldn’t notice any more power on high octane
gasoline. Again, if it does make a noticeable difference, your engine, or the engine’s electronic control
systems, may need repair.
• High octane gasoline has been refined more – it is just a better product.
Additional refining steps are used to increase the octane; however, these additional steps do not necessarily
make the gasoline a “better” product for all engines. They just yield a different blend of hydrocarbons that
burn more slowly. The additional steps also increase the price.

intake · 06-12-2009, 03:08 PM

the extreme advanced electronic management of the yaris can see wen you use high octane fuel, and change it's timing in spark plug lightining, so you have more power

doublewam · 06-12-2009, 04:59 PM

Ever since I filled my Yaris's tank with milk, I haven't had to fill it again...

...I haven't been able to go anywhere either.

roxy1 · 06-12-2009, 08:11 PM

Quote:

Originally Posted by intake

the extreme advanced electronic management of the yaris can see wen you use high octane fuel, and change it's timing in spark plug lightining, so you have more power

Yaris Hilton · 06-13-2009, 01:22 AM

Quote:

Originally Posted by eTiMaGo

actually there's about a 5 point difference

Not so. The U.S. rating is the average of the Research and Motor octane numbers. The European numbers quoted above are Research Octane numbers.

EdgarTRD1.8 · 06-15-2009, 12:24 AM

I think high octane fuel will not help on fuel economy, because the octane is the measure of the self evaporation of the fuel in comparison with the compression. Low compression cars use regularly regular fuel because the octane is low. If you put high octane fuel into a low compression combustion chamber, when the piston is compressing the air and the fuel, the fuel will not turn into gas stage completely. So will be liquid fuel yet on the chamber and when spark fire probably doesn't burn the fuel completely (the fuel burn in both stages, liquid and gas, but in gas stage burn faster than liquid stage). The engine will not work at high efficiency like will work if is burning the entire fuel. High compression and turbo applications need high octane fuel for the compression, higher compression turn the fuel in gas faster. If you use low octane fuel in high compression and turbo applications probably the fuel will self evaporate too fast and the piston will knock.

So if the car is not working at it high efficiency level i think it will not has fuel efficiency. The car will not work forced with this high octane "mood", but will not work like is suppose to do.

Some guys here in Puerto Rico tested them cars in a Dyno and proved that putting higher octane on the cars don't bring any HP gain, they proved with different octane booster and obtained no gains. You can use octane booster if your car has high aftermarket compression piston or turbo. I know you are talking about efficiency but I comment it for the explanation I put here is in the same way.

jambo101 · 06-15-2009, 06:37 AM

I never did understand why people buy a cheap reliable economy car then spend $0.20 more per gallon to put in premium fuel on the mistaken assumption that its going to make the car go faster and get better mileage.If you wanted a faster car buying a Yaris is a poor choice.
PS,your premium gas may only be 4% higher than regular but over the life of the car that will amount to some serious unnecessarily spent money.

andaconda · 06-15-2009, 10:31 AM

Quote:

Originally Posted by roxy1

buy higher octane, believing mileage will increase. trying to prove it now driving more conscientiously. mileage increases. kind of a self fulfilling prophecy. not due to higher octane. no scientific explanation will explain higher mpg's from higher octane.

now im going to go

.....on myself......as punishment for getting sucked into this ludicrous discussion.

Well, I'll get sucked into this discussion:

At work I drive a 2005 Buick AWD van with a large v6 engine, and average between 5,000 and 6,000 miles a month. I have had time to 'experiment' with octane ratings. For two months I used premium grade gasoline and averaged 21.8 mpg. For two months I used the lowest grade and averaged 21.9 mpg. My trips are mostly highway miles with about 5% city driving. I cover the state from corner to corner so all my trips are about the same. I use mostly the same brand of fuel. The weather conditions were about the same when I 'experimented.' I drive fairly conservative with the work car just as I would with my own car.

I see no real difference between mileage and octane rating. The van must compensate for the octane and adjust accordingly. I notice no knock on any of the gasoline changes.

JUST my 2 cents worth.

voodoo22 · 06-15-2009, 11:05 AM

Quote:

Originally Posted by jambo101

I never did understand why people buy a cheap reliable economy car then spend $0.20 more per gallon to put in premium fuel on the mistaken assumption that its going to make the car go faster and get better mileage.If you wanted a faster car buying a Yaris is a poor choice.
PS,your premium gas may only be 4% higher than regular but over the life of the car that will amount to some serious unnecessarily spent money.

Like when my brother bought a $55k BMW and put in regular. What a tard.

jambo101 · 06-15-2009, 01:34 PM

Quote:

Originally Posted by voodoo22

Like when my brother bought a $55k BMW and put in regular. What a tard.

My father in law had this strange habit of filling his pickup truck with the cheapest oil he could find usually the $0.75 a quart stuff and fill up his gas tank with the most expensive gas he could find.

Marthos · 08-05-2009, 03:01 PM

Octane is a rating, of a fuels ability to combust.

The higher the octane rating the harder it is to "burn" that fuel.

The higher the compression, the higher the octane needed.

When a low octane fuel is compressed to high it will self combust, causing preignition, that is when the fuel burns before the spark plug fires and the piston is on the downward power stroke.

A supercharged engine needs high octane fuel so the compression does not ingnite the fuel before the spark plug fires.

Always use the recomended fuel octane rating listed in the owners manual.

Only go up to a higher octane if you hear Pinging, as this can lead to major engine damage.

06-12-2009, 10:38 AM	#22
eTiMaGo vroom vroom View User's Garage Drives: lil red 5-door Join Date: Sep 2006 Location: Bangkok, Thailand Posts: 7,744	actually there's about a 5 point difference __________________ The price of freedom of religion, or of speech, or of the press, is that we must put up with a good deal of rubbish. - Robert Jackson Bye bye 1NZ...

06-12-2009, 03:08 PM	#27
intake View User's Garage Drives: yaris 2 1.3 mmt Join Date: Aug 2007 Location: italy Posts: 62	the extreme advanced electronic management of the yaris can see wen you use high octane fuel, and change it's timing in spark plug lightining, so you have more power __________________ Yaris 2007 mmt 1.3 , denso power iridium, pipercross air filter, purplepower 10/40 motor oil + zx1, simoni racing silencer, eibach , henry hausen wheels, modified air box, trd logo,oversized oil filter.

06-15-2009, 12:24 AM	#31
EdgarTRD1.8 Drives: SR5 Hatch Back 82' 3TC 1.8 Join Date: Jun 2009 Location: Hormigueros, Puerto Rico Posts: 88	I think high octane fuel will not help on fuel economy, because the octane is the measure of the self evaporation of the fuel in comparison with the compression. Low compression cars use regularly regular fuel because the octane is low. If you put high octane fuel into a low compression combustion chamber, when the piston is compressing the air and the fuel, the fuel will not turn into gas stage completely. So will be liquid fuel yet on the chamber and when spark fire probably doesn't burn the fuel completely (the fuel burn in both stages, liquid and gas, but in gas stage burn faster than liquid stage). The engine will not work at high efficiency like will work if is burning the entire fuel. High compression and turbo applications need high octane fuel for the compression, higher compression turn the fuel in gas faster. If you use low octane fuel in high compression and turbo applications probably the fuel will self evaporate too fast and the piston will knock. So if the car is not working at it high efficiency level i think it will not has fuel efficiency. The car will not work forced with this high octane "mood", but will not work like is suppose to do. Some guys here in Puerto Rico tested them cars in a Dyno and proved that putting higher octane on the cars don't bring any HP gain, they proved with different octane booster and obtained no gains. You can use octane booster if your car has high aftermarket compression piston or turbo. I know you are talking about efficiency but I comment it for the explanation I put here is in the same way. __________________ Tooling and die the world Last edited by EdgarTRD1.8; 06-15-2009 at 10:57 AM.

08-05-2009, 03:01 PM	#36
Marthos View User's Garage Drives: 07 3Dr LB Join Date: Jul 2009 Location: NEPA Posts: 58	Octane is a rating, of a fuels ability to combust. The higher the octane rating the harder it is to "burn" that fuel. The higher the compression, the higher the octane needed. When a low octane fuel is compressed to high it will self combust, causing preignition, that is when the fuel burns before the spark plug fires and the piston is on the downward power stroke. A supercharged engine needs high octane fuel so the compression does not ingnite the fuel before the spark plug fires. Always use the recomended fuel octane rating listed in the owners manual. Only go up to a higher octane if you hear Pinging, as this can lead to major engine damage. Last edited by Marthos; 08-06-2009 at 12:38 PM.

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06-11-2009, 01:09 AM	#19
Yaris Hilton Half a Bubble Off Plumb Drives: 2009 Yaris Sedan Join Date: Mar 2009 Location: Bristol, Tennessee, USA Posts: 1,593	AFAIK, all ECUs have a programmed curve for maximum advance at an optimal performance level, with a knock sensor that retards the spark a bit when detonation occurs.

06-12-2009, 12:23 AM	#21
Yaris Hilton Half a Bubble Off Plumb Drives: 2009 Yaris Sedan Join Date: Mar 2009 Location: Bristol, Tennessee, USA Posts: 1,593	We have a different rating method. Our 87, 89 and 91 octane ratings at the pump are comparable to your 95, 98 & 100.

06-12-2009, 12:42 PM	#23
IllusionX It's the illusion you see View User's Garage Drives: 07 Yaris Sedan Aero Join Date: Oct 2006 Location: Brossard, QC Posts: 3,888	guys... keep in mind that higher octane fuel might have cleaning additives and possibly less E85 than regular fuel. This is just some reasons why you get better fuel economy with higher octane in an economy car like the yaris... that do NOT require premium.

06-12-2009, 12:59 PM	#24
UTVitz Drives: Black Vitz Liftback Join Date: Dec 2008 Location: Salt Lake City Posts: 238	More important to buy top tier fuels, i.e., quality from Chevron/Phillips and a few others than to play with octane, IMHO. Every mechanic I've talked to and a few were Toyota mechs. said don't waist you're money unless the manufacture recommends or sometimes specifies higher octane, or the engine is pinging. Hope this helps any fence sitters-I've been there myself.

06-12-2009, 01:48 PM	#25
2009Toyotoad Drives: 2009 Yaris 3dr Join Date: May 2009 Location: California Posts: 135	Maybe instead of MPG we should be looking at $ per mile. Just a thought. What I think we all want is the lowest cost of ownership, but I could be wrong.

06-12-2009, 04:59 PM	#28
doublewam Drives: 2009 Yaris Join Date: Jun 2009 Location: USA Posts: 19	Ever since I filled my Yaris's tank with milk, I haven't had to fill it again... ...I haven't been able to go anywhere either.

06-15-2009, 06:37 AM	#32
jambo101 Drives: yaris 08 sedan Join Date: Oct 2008 Location: Montreal Canada Posts: 1,286	I never did understand why people buy a cheap reliable economy car then spend $0.20 more per gallon to put in premium fuel on the mistaken assumption that its going to make the car go faster and get better mileage.If you wanted a faster car buying a Yaris is a poor choice. PS,your premium gas may only be 4% higher than regular but over the life of the car that will amount to some serious unnecessarily spent money.