Author Topic: Is higher octane fuel worth the price?  (Read 9000 times)

MilitaryMedicineMustache

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Is higher octane fuel worth the price?
« on: July 14, 2016, 05:34:47 AM »
I took a quick look through the forum and didn't find anything on this, and it's something I've been curious about for a while, even though I don't drive all that much anymore (maybe 4k miles/year?):  is it "worth it" to put higher octane fuel in one's car?  All the car guys I've ever known have told me to put the highest grade of gasoline in and that it is bad for the engine to switch to a lower octane once a car is on the higher stuff, so that's what I've done all my life.  My own intuition is that is doesn't actually matter much/at all, though.  Any gearhead mustachians have any input on this?

clarkm04

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Re: Is higher octane fuel worth the price?
« Reply #1 on: July 14, 2016, 06:19:03 AM »
http://www.consumerreports.org/fuel-economy/why-you-might-not-actually-need-premium-gas/

Consumer Reports says no unless you feel the performance is sluggish.

2Birds1Stone

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Re: Is higher octane fuel worth the price?
« Reply #2 on: July 14, 2016, 06:27:34 AM »
With a car that has 87 octane recommended, the performance is better and MPG higher with 87 octane vs. a higher one.

For cars that recommend 91+ octane I would use what is recommended, while cars will retard timing to compensate for 87 octane you are losing performance/mpg and possibly creating a mild engine knock to save a few cents per mile.

Mongoose

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Re: Is higher octane fuel worth the price?
« Reply #3 on: July 14, 2016, 06:51:27 AM »
I found out (by real world testing on my cars) that I break even with price and mpg between high and low octane (price per mile is approximately equal; I didn't test mid-grade). However, I have older cars that don't handle ethanol well so I save a bit in reduced maintenance/repairs using ethanol free premium.

shotgunwilly

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Re: Is higher octane fuel worth the price?
« Reply #4 on: July 14, 2016, 07:50:04 AM »
Higher octane fuel does not equal better performance.  Higher octane fuels are designed for engines with higher compression ratios. (Higher octane means it needs more compression before the fuel will ignite.) If your engine manufacture calls for you to use 87 octane fuel, then putting anything higher in it is a waste of money.

ketchup

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Re: Is higher octane fuel worth the price?
« Reply #5 on: July 14, 2016, 07:57:20 AM »
Put in what your car wants.  If your car doesn't require higher octane, it's a waste.  If your car *does* require higher octane, running lower octane gas best-case scenario gives you crappy performance and efficiency, worst-case damages your engine.

However: My dad had a '94 Buick that took regular gas, but at around 140,000 miles (~2009) he switched to mid-grade.  I remember that he had a good reason, but I don't remember what it was.  I know the car ran better on mid-grade.  It could have been an ethanol-in-old-car issue like Mongoose said above.  But my '92 Buick runs fine on 87.

BlueMR2

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Re: Is higher octane fuel worth the price?
« Reply #6 on: July 14, 2016, 10:02:19 AM »
Use what the owner's manual says to use unless you have some important reason to do otherwise.

Reasons to do otherwise generally are to avoid pinging and include:
1) Modified (for performance) car which now requires higher octane to keep from blowing up.
2) Older (pre-ethanol) car which now pings on octanes that it could run fine before ethanol.

In our fleet we have a 2002 car which is designed for 87 E10 and runs fine.  I also have a 1994 motorcycle designed for 87 and runs fine on it.  However, my 1995 car is modified for performance, originally required 91 from the factory, but now requires 93.  My 1991 from the factory required 87, but it does very poorly with ethanol fuels, so I have to run a minimum of 93.  94 is better, but it's getting harder and harder to find.

Sailor Sam

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Re: Is higher octane fuel worth the price?
« Reply #7 on: July 14, 2016, 10:09:56 AM »
I have a 2010 mini cooper. The owners manual calls for 91 octane, but I ignored that for about a year. Eventually I noticed a knock-like noise on hard acceleration. Theoretically, the engine shouldn't knock because BMW engines have a engine management system to detect early detonation. Still, I could hear something. I switched to 91 octane, the sound went away, and I noticed a distinct uptick in performance. 

There is my anecdata, supporting putting higher octane if the user manual suggests it.

Edit: typo.
« Last Edit: July 14, 2016, 10:16:46 AM by Sailor Sam »

acroy

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Re: Is higher octane fuel worth the price?
« Reply #8 on: July 14, 2016, 10:15:02 AM »
If your car doesn't require higher octane, it's a waste.  If your car *does* require higher octane, running lower octane gas best-case scenario gives you crappy performance and efficiency, worst-case damages your engine.
This!

Jim2001

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Re: Is higher octane fuel worth the price?
« Reply #9 on: July 14, 2016, 10:42:12 AM »
+1 for it being a waste to pay for higher than the engineers that designed your engine recommend for all the reasons already stated.  RTFM and follow it for the optimum results.

MilitaryMedicineMustache

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Re: Is higher octane fuel worth the price?
« Reply #10 on: July 14, 2016, 05:35:31 PM »
Wow, thanks all for the great replies!  For some reason it never even occurred to me that what gas to put in would be specified in the manual, even though that makes sense.  lol.  I'll have to go check my manual...

JLee

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Re: Is higher octane fuel worth the price?
« Reply #11 on: July 14, 2016, 06:05:10 PM »
Wow, thanks all for the great replies!  For some reason it never even occurred to me that what gas to put in would be specified in the manual, even though that makes sense.  lol.  I'll have to go check my manual...

It's likely specified on the inside of your fuel door, too.

dragoncar

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Re: Is higher octane fuel worth the price?
« Reply #12 on: July 14, 2016, 06:06:13 PM »
If your car doesn't require higher octane, it's a waste.  If your car *does* require higher octane, running lower octane gas best-case scenario gives you crappy performance and efficiency, worst-case damages your engine.
This!

False.  My car doesn't require higher octane, but it will detect the higher octane and adjust the timing accordingly.  Or you could say it will detect the lower octane (via knock sensors) and adjust the timing accordingly.  The compression ratio (10:1) is high enough to benefit from high octane fuel with the proper timing.

I understand from teh internet that I could gain a few MPG from high octane.  So perhaps 10% fuel economy boost.  So assuming that is true, I should buy high octane if it is < 10% more expensive.   Right now it's about 13% more expensive so I'll pass.  But I think when gas prices were up in the $4's the premium on high octane fuel was lower (as a percentage).

Added benefit would be the extra horsepower, but that might just reduce my MPG overall due to the fun of punching it.

My manual suggests regular mostly as a marketing ploy (so they can say it runs on regular but use the higher MPG and HP in their literature).  I've always worried that, since detecting regular requires the knock sensors, using regular would cause detrimental amounts of knocking over the life of the engine.
« Last Edit: July 14, 2016, 06:08:38 PM by dragoncar »

ketchup

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Re: Is higher octane fuel worth the price?
« Reply #13 on: July 14, 2016, 08:32:44 PM »
If your car doesn't require higher octane, it's a waste.  If your car *does* require higher octane, running lower octane gas best-case scenario gives you crappy performance and efficiency, worst-case damages your engine.
This!

False.  My car doesn't require higher octane, but it will detect the higher octane and adjust the timing accordingly.  Or you could say it will detect the lower octane (via knock sensors) and adjust the timing accordingly.  The compression ratio (10:1) is high enough to benefit from high octane fuel with the proper timing.

I understand from teh internet that I could gain a few MPG from high octane.  So perhaps 10% fuel economy boost.  So assuming that is true, I should buy high octane if it is < 10% more expensive.   Right now it's about 13% more expensive so I'll pass.  But I think when gas prices were up in the $4's the premium on high octane fuel was lower (as a percentage).

Added benefit would be the extra horsepower, but that might just reduce my MPG overall due to the fun of punching it.

My manual suggests regular mostly as a marketing ploy (so they can say it runs on regular but use the higher MPG and HP in their literature).  I've always worried that, since detecting regular requires the knock sensors, using regular would cause detrimental amounts of knocking over the life of the engine.

Curious though, what kind of car is it?

chesebert

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Re: Is higher octane fuel worth the price?
« Reply #14 on: July 14, 2016, 08:55:26 PM »
If your car doesn't require higher octane, it's a waste.  If your car *does* require higher octane, running lower octane gas best-case scenario gives you crappy performance and efficiency, worst-case damages your engine.
This!

False.  My car doesn't require higher octane, but it will detect the higher octane and adjust the timing accordingly.  Or you could say it will detect the lower octane (via knock sensors) and adjust the timing accordingly.  The compression ratio (10:1) is high enough to benefit from high octane fuel with the proper timing.

I understand from teh internet that I could gain a few MPG from high octane.  So perhaps 10% fuel economy boost.  So assuming that is true, I should buy high octane if it is < 10% more expensive.   Right now it's about 13% more expensive so I'll pass.  But I think when gas prices were up in the $4's the premium on high octane fuel was lower (as a percentage).

Added benefit would be the extra horsepower, but that might just reduce my MPG overall due to the fun of punching it.

My manual suggests regular mostly as a marketing ploy (so they can say it runs on regular but use the higher MPG and HP in their literature).  I've always worried that, since detecting regular requires the knock sensors, using regular would cause detrimental amounts of knocking over the life of the engine.
Fancy, fancy!!! Does your car also come with HUD and a Champaign cooler?

dragoncar

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Re: Is higher octane fuel worth the price?
« Reply #15 on: July 14, 2016, 09:09:24 PM »
It's a 7th gen Honda Accord.  Most newer cars will do this, too:

Quote
Most modern knock-sensed ignitions seek MBT timing and thus, at least in theory, profit from the added octane. Some, though, have preset ceilings beyond which they won't advance.

http://www.roadandtrack.com/new-cars/car-technology/news/a18008/premium-fuel-futures/

gooki

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Re: Is higher octane fuel worth the price?
« Reply #16 on: July 15, 2016, 02:17:20 AM »
Fancy, fancy!!! Does your car also come with HUD and a Champaign cooler?

As silly as that sounds, my 1989 Nissan Silvia had an HUD, and a glove box cooler.

MilitaryMedicineMustache

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Re: Is higher octane fuel worth the price?
« Reply #17 on: July 15, 2016, 10:20:06 AM »
From my '05 Accord driver manual:

"We recommend quality gasoline containing detergent additives that help prevent fuel system and engine deposits."  Is this the same thing as unleaded, or is there something else I should be looking for in gas?

"In addition, in order to maintain good performance, fuel economy, and emissions control, we strongly recommend, in the areas where it is available, the use of gasoline that does NOT contain manganese-based fuel additives such as MMT."  Never even heard of this?

"Some gasoline today is blended with oxygenates such as ethanol or MTBE.  Your vehicle is designed to operate on oxygenated gasoline containing up to 10 percent ethanol by volume and up to 15 percent MTBE by volume.  Do not use gasoline containing methanol."  Again, never once heard anyone mention something like this?  Non-issue these days?

It recommends 87 octane or higher.

JLee

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Re: Is higher octane fuel worth the price?
« Reply #18 on: July 15, 2016, 10:26:08 AM »
From my '05 Accord driver manual:

"We recommend quality gasoline containing detergent additives that help prevent fuel system and engine deposits."  Is this the same thing as unleaded, or is there something else I should be looking for in gas?

"In addition, in order to maintain good performance, fuel economy, and emissions control, we strongly recommend, in the areas where it is available, the use of gasoline that does NOT contain manganese-based fuel additives such as MMT."  Never even heard of this?

"Some gasoline today is blended with oxygenates such as ethanol or MTBE.  Your vehicle is designed to operate on oxygenated gasoline containing up to 10 percent ethanol by volume and up to 15 percent MTBE by volume.  Do not use gasoline containing methanol."  Again, never once heard anyone mention something like this?  Non-issue these days?

It recommends 87 octane or higher.

Most gasoline these days is E10 (up to 10% ethanol).

chesebert

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Re: Is higher octane fuel worth the price?
« Reply #19 on: July 15, 2016, 02:51:32 PM »
Fancy, fancy!!! Does your car also come with HUD and a Champaign cooler?

As silly as that sounds, my 1989 Nissan Silvia had an HUD, and a glove box cooler.

A heads up display on a 1989 car?

dragoncar

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Re: Is higher octane fuel worth the price?
« Reply #20 on: July 15, 2016, 09:33:42 PM »
Fancy, fancy!!! Does your car also come with HUD and a Champaign cooler?

As silly as that sounds, my 1989 Nissan Silvia had an HUD, and a glove box cooler.

A heads up display on a 1989 car?

Considering it was invented in the 40's and merely involves an led display aimed up from the dash at the windshield, it's not crazy

Melody

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Re: Is higher octane fuel worth the price?
« Reply #21 on: July 16, 2016, 05:25:33 PM »
Standard here in Australia is 91, with mid grade a 95 and premium 98. I wouldn't consider putting 87 in a Euro, Jap or Korean car because I am sure it was not engineered for it, even if it's been modified to accept it for sale in the US market. (95 is standard in europe I believe.) if I run my car on 98 rather than 95 I get a slight but noticeable uptick in performance and an extra 30kms per tank. (Mechanic told me not to use 91). While the extra 5% out of the tank doesn't quite make up for the extra 6 or 7% the better fuel costs, I hope it will lower repair costs, and as I drive less than 6000km (4000miles) a year, the cost is neligable.

Spork

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Re: Is higher octane fuel worth the price?
« Reply #22 on: July 16, 2016, 05:54:53 PM »
Standard here in Australia is 91, with mid grade a 95 and premium 98. I wouldn't consider putting 87 in a Euro, Jap or Korean car because I am sure it was not engineered for it, even if it's been modified to accept it for sale in the US market. (95 is standard in europe I believe.) if I run my car on 98 rather than 95 I get a slight but noticeable uptick in performance and an extra 30kms per tank. (Mechanic told me not to use 91). While the extra 5% out of the tank doesn't quite make up for the extra 6 or 7% the better fuel costs, I hope it will lower repair costs, and as I drive less than 6000km (4000miles) a year, the cost is neligable.

So... it gets confusing when people in various countries talk about octane.  Like pretty much everything, we all have a different method of computing things.

Australia uses the RON octane calculation.  USA uses "(R+M)/2" ( the average of the RON and the MON methods.)  Australia's 91 is effectively the same as the US's 87.

Primm

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Re: Is higher octane fuel worth the price?
« Reply #23 on: July 17, 2016, 12:03:12 AM »
Disclaimer: using Aus numbers.

I drive a 2014 Fiat 500. Manufacturers recommendation is 95 octane. I decided to do some testing so I used 98 for 2,000km to give me good data.

I worked out that for my car, allowing for the improved fuel economy of the higher octane and the increased price, my fuel cost is about 8.8c per km using 95 octane and 8.1c using 98. So it's worth it to me to use the higher performance fuel. Your mileage may vary. 

Melody

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Re: Is higher octane fuel worth the price?
« Reply #24 on: July 17, 2016, 12:59:29 AM »
Standard here in Australia is 91, with mid grade a 95 and premium 98. I wouldn't consider putting 87 in a Euro, Jap or Korean car because I am sure it was not engineered for it, even if it's been modified to accept it for sale in the US market. (95 is standard in europe I believe.) if I run my car on 98 rather than 95 I get a slight but noticeable uptick in performance and an extra 30kms per tank. (Mechanic told me not to use 91). While the extra 5% out of the tank doesn't quite make up for the extra 6 or 7% the better fuel costs, I hope it will lower repair costs, and as I drive less than 6000km (4000miles) a year, the cost is neligable.

So... it gets confusing when people in various countries talk about octane.  Like pretty much everything, we all have a different method of computing things.

Australia uses the RON octane calculation.  USA uses "(R+M)/2" ( the average of the RON and the MON methods.)  Australia's 91 is effectively the same as the US's 87.
Wow, thanks for the correction. I had no idea!!!

MoonLiteNite

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Re: Is higher octane fuel worth the price?
« Reply #25 on: July 18, 2016, 03:47:40 AM »
It really really really depends on your car.
If your car doesn't require it, then you basically need to do HONEST tests yourself.

But generally no, it isn't worth it.

Personally i had a 5% gain in my 2000 focus, -5% in my 92 s10, and 0% on my 2010 honda fit.

Uturn

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Re: Is higher octane fuel worth the price?
« Reply #26 on: July 18, 2016, 07:24:51 AM »
Octane changes the amount of pressure the fuel can withstand before it ignites.  Higher compression engines want higher octane.  If you remove the computer and go old school manual adjusted timing, a low compression engine will lose power and efficiency on high octane, and a high compression engine will knock and ping with low octane.  All modern cars have a computer that adjusts for whatever octane it gets.  I'm sure a really high performance car has different requirements, but I doubt most people here are driving an M Series BMW or AMG Merc. 

Put 87 in it and it will run fine.  Try higher octane and see if the performance/efficiency goes up enough to justify the extra cost.  About every 5k miles, throw a bottle of RXP in it to burn off the carbon build up. 

Drifterrider

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Re: Is higher octane fuel worth the price?
« Reply #27 on: July 19, 2016, 06:25:45 AM »
Standard here in Australia is 91, with mid grade a 95 and premium 98. I wouldn't consider putting 87 in a Euro, Jap or Korean car because I am sure it was not engineered for it, even if it's been modified to accept it for sale in the US market. (95 is standard in europe I believe.) if I run my car on 98 rather than 95 I get a slight but noticeable uptick in performance and an extra 30kms per tank. (Mechanic told me not to use 91). While the extra 5% out of the tank doesn't quite make up for the extra 6 or 7% the better fuel costs, I hope it will lower repair costs, and as I drive less than 6000km (4000miles) a year, the cost is neligable.

BUT......   You guys (and Europe) use RON and not R+M/2 with your octane rating, yes?

patchyfacialhair

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Re: Is higher octane fuel worth the price?
« Reply #28 on: July 19, 2016, 07:12:23 AM »
I do what the owner's manual says I should do.

Our 03 Lexus RX and 03 Toyota Camry both require 87 octane, so I do that.

techwiz

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Re: Is higher octane fuel worth the price?
« Reply #29 on: July 19, 2016, 09:22:25 AM »
I would follow what is recommended in the owners manual.

My father in-law always insists that for lawn morrows, small engines (chain saw etc..) to always use high octane fuel.

I didn't take his advice why pay 10 cent more per litre when regular gas works just fine. Fast forward a few years and my fuel lines in my chain saw have rotted.

Turns out that the ethanol levels are higher in the regular gas (at least here in Canada). This ethanol can cause rubber parts to swell, dry out, and break apart fuel lines rot out from the inside (De-Lamination), carburetor parts swell up and block passages, diaphragms become porous, o-ring seals begin to distort and leak, etc.

Murphy's law states this will happen at the worst time. It happened to me just a few weeks ago. I drove over to my uncle's place to help cut up a tree that spilt in half due to a storm.  I wondered why my chainsaw would not run and it was leaking fuel everywhere. Saving a few cents a litre didn't seem that great of a idea at the time. 
 
On the bright side I now know how to replace the fuel lines, gaskets on my chainsaw and the parts were only about 10 bucks and I learned a new skill.

acroy

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Re: Is higher octane fuel worth the price?
« Reply #30 on: July 19, 2016, 09:26:34 AM »
If your car doesn't require higher octane, it's a waste.  If your car *does* require higher octane, running lower octane gas best-case scenario gives you crappy performance and efficiency, worst-case damages your engine.
This!

False.  My car doesn't require higher octane, but it will detect the higher octane and adjust the timing accordingly.  Or you could say it will detect the lower octane (via knock sensors) and adjust the timing accordingly.  The compression ratio (10:1) is high enough to benefit from high octane fuel with the proper timing.

I understand from teh internet that I could gain a few MPG from high octane.  So perhaps 10% fuel economy boost.  So assuming that is true, I should buy high octane if it is < 10% more expensive.   Right now it's about 13% more expensive so I'll pass.  But I think when gas prices were up in the $4's the premium on high octane fuel was lower (as a percentage).

Added benefit would be the extra horsepower, but that might just reduce my MPG overall due to the fun of punching it.

My manual suggests regular mostly as a marketing ploy (so they can say it runs on regular but use the higher MPG and HP in their literature).  I've always worried that, since detecting regular requires the knock sensors, using regular would cause detrimental amounts of knocking over the life of the engine.
Your statements reinforce what you claim is false.... just sayin.

dragoncar

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Re: Is higher octane fuel worth the price?
« Reply #31 on: July 19, 2016, 01:21:45 PM »
If your car doesn't require higher octane, it's a waste.  If your car *does* require higher octane, running lower octane gas best-case scenario gives you crappy performance and efficiency, worst-case damages your engine.
This!

False.  My car doesn't require higher octane, but it will detect the higher octane and adjust the timing accordingly.  Or you could say it will detect the lower octane (via knock sensors) and adjust the timing accordingly.  The compression ratio (10:1) is high enough to benefit from high octane fuel with the proper timing.

I understand from teh internet that I could gain a few MPG from high octane.  So perhaps 10% fuel economy boost.  So assuming that is true, I should buy high octane if it is < 10% more expensive.   Right now it's about 13% more expensive so I'll pass.  But I think when gas prices were up in the $4's the premium on high octane fuel was lower (as a percentage).

Added benefit would be the extra horsepower, but that might just reduce my MPG overall due to the fun of punching it.

My manual suggests regular mostly as a marketing ploy (so they can say it runs on regular but use the higher MPG and HP in their literature).  I've always worried that, since detecting regular requires the knock sensors, using regular would cause detrimental amounts of knocking over the life of the engine.
Your statements reinforce what you claim is false.... just sayin.

In what way?  ketchup said "If your car doesn't require higher octane, it's a waste."  I show at least one scenario where higher octane is not a waste, but instead increases your MPG and HP, even when not required.

Spork

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Re: Is higher octane fuel worth the price?
« Reply #32 on: July 19, 2016, 01:42:22 PM »
I would follow what is recommended in the owners manual.

My father in-law always insists that for lawn morrows, small engines (chain saw etc..) to always use high octane fuel.

I didn't take his advice why pay 10 cent more per litre when regular gas works just fine. Fast forward a few years and my fuel lines in my chain saw have rotted.

Turns out that the ethanol levels are higher in the regular gas (at least here in Canada). This ethanol can cause rubber parts to swell, dry out, and break apart fuel lines rot out from the inside (De-Lamination), carburetor parts swell up and block passages, diaphragms become porous, o-ring seals begin to distort and leak, etc.

Murphy's law states this will happen at the worst time. It happened to me just a few weeks ago. I drove over to my uncle's place to help cut up a tree that spilt in half due to a storm.  I wondered why my chainsaw would not run and it was leaking fuel everywhere. Saving a few cents a litre didn't seem that great of a idea at the time. 
 
On the bright side I now know how to replace the fuel lines, gaskets on my chainsaw and the parts were only about 10 bucks and I learned a new skill.

I second this.  My FIL told me this 10+ years ago... and I have had MUCH better luck with small engines after that.  I've also started using the Stabil that has an ethanol protector in it.  (That may be marketing BS... but... I've had ethanol issues with 2 stroke engines and old cars, so I have caved to it.)

JLee

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Re: Is higher octane fuel worth the price?
« Reply #33 on: July 19, 2016, 01:49:03 PM »
I'm curious now if the ethanol content between 87 and 93 does vary.  I could run some through my car and check, but that means I'd be putting 87 in a car built for 93/E85, which is a bad plan. :P

Metric Mouse

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Re: Is higher octane fuel worth the price?
« Reply #34 on: July 31, 2016, 06:52:58 AM »
If your car doesn't require higher octane, it's a waste.  If your car *does* require higher octane, running lower octane gas best-case scenario gives you crappy performance and efficiency, worst-case damages your engine.
This!

False.  My car doesn't require higher octane, but it will detect the higher octane and adjust the timing accordingly.  Or you could say it will detect the lower octane (via knock sensors) and adjust the timing accordingly.  The compression ratio (10:1) is high enough to benefit from high octane fuel with the proper timing.

I understand from teh internet that I could gain a few MPG from high octane.  So perhaps 10% fuel economy boost.  So assuming that is true, I should buy high octane if it is < 10% more expensive.   Right now it's about 13% more expensive so I'll pass.  But I think when gas prices were up in the $4's the premium on high octane fuel was lower (as a percentage).

Added benefit would be the extra horsepower, but that might just reduce my MPG overall due to the fun of punching it.

My manual suggests regular mostly as a marketing ploy (so they can say it runs on regular but use the higher MPG and HP in their literature).  I've always worried that, since detecting regular requires the knock sensors, using regular would cause detrimental amounts of knocking over the life of the engine.
Your statements reinforce what you claim is false.... just sayin.

In what way?  ketchup said "If your car doesn't require higher octane, it's a waste."  I show at least one scenario where higher octane is not a waste, but instead increases your MPG and HP, even when not required.

Semantics - if your vehicle is not designed to run on higher octane, putting higher octane in is less than optimal.

gggggg

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Re: Is higher octane fuel worth the price?
« Reply #35 on: July 31, 2016, 07:36:19 AM »
My car ('15 VW GTI) calls for 91, we don't have 91, so I run 93. I've found that the brand of gas affects the vehicle as well. It feels like I add 10-15 horsepower when I use BP, for instance; it's immediately noticeable in my car.

dragoncar

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Re: Is higher octane fuel worth the price?
« Reply #36 on: July 31, 2016, 05:51:27 PM »
If your car doesn't require higher octane, it's a waste.  If your car *does* require higher octane, running lower octane gas best-case scenario gives you crappy performance and efficiency, worst-case damages your engine.
This!

False.  My car doesn't require higher octane, but it will detect the higher octane and adjust the timing accordingly.  Or you could say it will detect the lower octane (via knock sensors) and adjust the timing accordingly.  The compression ratio (10:1) is high enough to benefit from high octane fuel with the proper timing.

I understand from teh internet that I could gain a few MPG from high octane.  So perhaps 10% fuel economy boost.  So assuming that is true, I should buy high octane if it is < 10% more expensive.   Right now it's about 13% more expensive so I'll pass.  But I think when gas prices were up in the $4's the premium on high octane fuel was lower (as a percentage).

Added benefit would be the extra horsepower, but that might just reduce my MPG overall due to the fun of punching it.

My manual suggests regular mostly as a marketing ploy (so they can say it runs on regular but use the higher MPG and HP in their literature).  I've always worried that, since detecting regular requires the knock sensors, using regular would cause detrimental amounts of knocking over the life of the engine.
Your statements reinforce what you claim is false.... just sayin.

In what way?  ketchup said "If your car doesn't require higher octane, it's a waste."  I show at least one scenario where higher octane is not a waste, but instead increases your MPG and HP, even when not required.

Semantics - if your vehicle is not designed to run on higher octane, putting higher octane in is less than optimal.

Yes, it is semantics -- the branch of linguistics concerned with meaning.  I personally think meaning is important when, you know, communicating with other people.

If you mean "putting high octane is a waste if your car is not designed to use it" then say that.  That is not equivalent to saying "putting high octane is a waste if your car requires it" because not all cars that are designed to use high octane require high octane.

Have you taken the SAT yet?  If all snarks are snoobs, and some snoobs are snibs, are all snarks snibs?

In no way do my "statements reinforce what (I) claim is false".
« Last Edit: July 31, 2016, 05:57:10 PM by dragoncar »

Metric Mouse

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Re: Is higher octane fuel worth the price?
« Reply #37 on: August 01, 2016, 09:41:50 AM »
Yes, it is semantics -- the branch of linguistics concerned with meaning.  I personally think meaning is important when, you know, communicating with other people.

If you mean "putting high octane is a waste if your car is not designed to use it" then say that.  That is not equivalent to saying "putting high octane is a waste if your car requires it" because not all cars that are designed to use high octane require high octane.

I too am and advocate of accuracy in speech, and completely agree with your post. Well said, but with many more words than I used.

alsoknownasDean

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Re: Is higher octane fuel worth the price?
« Reply #38 on: August 02, 2016, 06:12:11 AM »
Standard here in Australia is 91, with mid grade a 95 and premium 98. I wouldn't consider putting 87 in a Euro, Jap or Korean car because I am sure it was not engineered for it, even if it's been modified to accept it for sale in the US market. (95 is standard in europe I believe.) if I run my car on 98 rather than 95 I get a slight but noticeable uptick in performance and an extra 30kms per tank. (Mechanic told me not to use 91). While the extra 5% out of the tank doesn't quite make up for the extra 6 or 7% the better fuel costs, I hope it will lower repair costs, and as I drive less than 6000km (4000miles) a year, the cost is neligable.

BUT......   You guys (and Europe) use RON and not R+M/2 with your octane rating, yes?

Yes that's correct (as per Spork's comment earlier).

I've been running el cheapo regular unleaded (or E10 at times). I mentioned to my mechanic earlier that the fuel economy wasn't as good as I expected (I was thinking a dodgy O2 sensor). He suggested to try running it on a different brand (and higher octane) fuel.

I might just give it a whirl. Surely a 1.4L manual hatchback should do better than 8-9.5L/100km (mid to high 20's MPG US), even if it's mostly city driving? Official fuel economy figures are 5.4L/100km (43MPG US) highway and 7.6L/100km (31MPG US) city :)

acroy

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Re: Is higher octane fuel worth the price?
« Reply #39 on: August 03, 2016, 08:40:57 AM »
If your car doesn't require higher octane, it's a waste.  If your car *does* require higher octane, running lower octane gas best-case scenario gives you crappy performance and efficiency, worst-case damages your engine.
This!

False.  My car doesn't require higher octane, but it will detect the higher octane and adjust the timing accordingly.  Or you could say it will detect the lower octane (via knock sensors) and adjust the timing accordingly.  The compression ratio (10:1) is high enough to benefit from high octane fuel with the proper timing.

I understand from teh internet that I could gain a few MPG from high octane.  So perhaps 10% fuel economy boost.  So assuming that is true, I should buy high octane if it is < 10% more expensive.   Right now it's about 13% more expensive so I'll pass.  But I think when gas prices were up in the $4's the premium on high octane fuel was lower (as a percentage).

Added benefit would be the extra horsepower, but that might just reduce my MPG overall due to the fun of punching it.

My manual suggests regular mostly as a marketing ploy (so they can say it runs on regular but use the higher MPG and HP in their literature).  I've always worried that, since detecting regular requires the knock sensors, using regular would cause detrimental amounts of knocking over the life of the engine.
Your statements reinforce what you claim is false.... just sayin.

In what way?  ketchup said "If your car doesn't require higher octane, it's a waste."  I show at least one scenario where higher octane is not a waste, but instead increases your MPG and HP, even when not required.

Semantics - if your vehicle is not designed to run on higher octane, putting higher octane in is less than optimal.

Yes, it is semantics -- the branch of linguistics concerned with meaning.  I personally think meaning is important when, you know, communicating with other people.

If you mean "putting high octane is a waste if your car is not designed to use it" then say that.  That is not equivalent to saying "putting high octane is a waste if your car requires it" because not all cars that are designed to use high octane require high octane.

Have you taken the SAT yet?  If all snarks are snoobs, and some snoobs are snibs, are all snarks snibs?

In no way do my "statements reinforce what (I) claim is false".

I should probably leave this alone but here goes:
ketchup: $X investment is a waste. Unless required. If required, lack of $X investment may cause damage
Me: agree
dragoncar: above statements are false. In my case, $X investment yields negative return. Positive return is hypothetically possible.

Negative return on investment is waste. Waste = 'to use or expend carelessly, extravagantly, or to no purpose.

dragoncar

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Re: Is higher octane fuel worth the price?
« Reply #40 on: August 03, 2016, 12:53:10 PM »
If your car doesn't require higher octane, it's a waste.  If your car *does* require higher octane, running lower octane gas best-case scenario gives you crappy performance and efficiency, worst-case damages your engine.
This!

False.  My car doesn't require higher octane, but it will detect the higher octane and adjust the timing accordingly.  Or you could say it will detect the lower octane (via knock sensors) and adjust the timing accordingly.  The compression ratio (10:1) is high enough to benefit from high octane fuel with the proper timing.

I understand from teh internet that I could gain a few MPG from high octane.  So perhaps 10% fuel economy boost.  So assuming that is true, I should buy high octane if it is < 10% more expensive.   Right now it's about 13% more expensive so I'll pass.  But I think when gas prices were up in the $4's the premium on high octane fuel was lower (as a percentage).

Added benefit would be the extra horsepower, but that might just reduce my MPG overall due to the fun of punching it.

My manual suggests regular mostly as a marketing ploy (so they can say it runs on regular but use the higher MPG and HP in their literature).  I've always worried that, since detecting regular requires the knock sensors, using regular would cause detrimental amounts of knocking over the life of the engine.
Your statements reinforce what you claim is false.... just sayin.

In what way?  ketchup said "If your car doesn't require higher octane, it's a waste."  I show at least one scenario where higher octane is not a waste, but instead increases your MPG and HP, even when not required.

Semantics - if your vehicle is not designed to run on higher octane, putting higher octane in is less than optimal.

Yes, it is semantics -- the branch of linguistics concerned with meaning.  I personally think meaning is important when, you know, communicating with other people.

If you mean "putting high octane is a waste if your car is not designed to use it" then say that.  That is not equivalent to saying "putting high octane is a waste if your car requires it" because not all cars that are designed to use high octane require high octane.

Have you taken the SAT yet?  If all snarks are snoobs, and some snoobs are snibs, are all snarks snibs?

In no way do my "statements reinforce what (I) claim is false".

I should probably leave this alone but here goes:
ketchup: $X investment is a waste. Unless required. If required, lack of $X investment may cause damage
Me: agree
dragoncar: above statements are false. In my case, $X investment yields negative return. Positive return is hypothetically possible.

Negative return on investment is waste. Waste = 'to use or expend carelessly, extravagantly, or to no purpose.

There is purpose to using higher octane.  As discussed, improved power output.  Some people value this.  There is also the potential for positive economic effect which depends on prevailing local rates.  So it is still incorrect to categorically state that it is waste.

worms

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Re: Is higher octane fuel worth the price?
« Reply #41 on: August 04, 2016, 01:08:48 AM »
My car ('15 VW GTI) calls for 91, we don't have 91, so I run 93. I've found that the brand of gas affects the vehicle as well. It feels like I add 10-15 horsepower when I use BP, for instance; it's immediately noticeable in my car.

Where I live there seems to be a placebo effect on people's fuel choices.  People will swear to the power benefits or mpg benefits of fuel bought from one outlet or another, big oil company versus supermarket, upmarket supermarket versus discount store etc.  Strange thing is that it all comes in on the same coastal tanker and goes through the same bulk tank either into the retailers own distribution tankers or to generic haulage, with no added processing...

dragoncar

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Re: Is higher octane fuel worth the price?
« Reply #42 on: August 04, 2016, 12:41:33 PM »
My car ('15 VW GTI) calls for 91, we don't have 91, so I run 93. I've found that the brand of gas affects the vehicle as well. It feels like I add 10-15 horsepower when I use BP, for instance; it's immediately noticeable in my car.

Where I live there seems to be a placebo effect on people's fuel choices.  People will swear to the power benefits or mpg benefits of fuel bought from one outlet or another, big oil company versus supermarket, upmarket supermarket versus discount store etc.  Strange thing is that it all comes in on the same coastal tanker and goes through the same bulk tank either into the retailers own distribution tankers or to generic haulage, with no added processing...

There may be a difference.  All things being equal, I'd rather choose a well maintained station with high volume so the gas doesn't sit too long in an aging, possibly leaking or rusting tank.  Maybe all tanks are frequently checked, but older gas could still have higher water content or some other issue.  In my case, the cheapest gas is at Costco and I trust that they have high turnover and decent maintenance so it doesn't really affect my choice.  But some ancient station on a barely traveled road?  I might think twice

There are also five separate refineries in my area (Chevron in Richmond, Shell in Martinez, Valero in Benicia, Tesoro north of Concord, and Phillips 66 in Rodeo) so it's certainly not true that every station has gas from the same tanker.  They also have different additives as some are top tier and some are not.
« Last Edit: August 04, 2016, 12:44:31 PM by dragoncar »

dignam

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Re: Is higher octane fuel worth the price?
« Reply #43 on: August 04, 2016, 01:32:25 PM »
Seems to be a some misleading info in this thread.  A lot of it sounds like placebo and good old "butt dyno".

If your car is rated to run on 87 Octane, putting in higher Octane will do NOTHING to improve performance or mileage (some cars, however, can retard the engine timing to compensate for a lower octane.  In that case you may feel a difference).  Otherwise, only difference will be that you have a lighter wallet.  Higher octane does not mean higher performance.

The octane rating == resistance to detonation.  If your engine needs that higher resistance (generally sportier cars, most turbocharged engines), then you need higher octane fuel because engine detonation is bad, mmm k?  If you run 87 in a car rated for 91 or 93, there's a high chance you hear pinging, etc.
« Last Edit: August 04, 2016, 01:34:29 PM by dignam »