[PornMaster]

I was reading around and I have heard mix reviews about this
My 2002 solara is recommended 89 octane its the 1mz engine
I have been running it 87 and averaging 420km a tank about 65 litres
thats about 15L/ 100 km

people who run 89 or 91 say they are getting 11L/100 km

Will I notice any gain if I switch to 89 or 91?

[LiquidTurbo]

Run the fuel spec'd for the engine.

[!SG]

your ecu is advanced enough to adjust timing due to octane level of the gas.

you will notice performance and yes, gas milage as well going to a lower octane. will it hurt the car? probably not.

[bcrdukes]

You should use the recommended octane from the manufacturer.

Assuming that your car is in tip top condition, you should be able to achieve those numbers. Don't forget, if you change your tire/wheel size, it will yield different results.

[see.lai]

I noticed that my fuel for this tank has went by faster than last time.
Usually i filled up with premium in BC, til i discovered pt.roberts, and now it seems that I've lost some efficiency. I swear I was driving slow and shifting low as well.

[dangonay]

People think higher octane gasoline somehow has more energy and will create more power/better mileage. This is not true. Octane is a measure of the fuel's resistance to detonation, not how much energy is in the fuel.

Higher octane fuels actually typically have less energy than lower octane fuels. The reason why a high-performance engine can get more power with a high-octane fuel is because you can run a higher compression ratio and more aggressive ignition timing. The gains from a higher CR ratio and ignition are greater than the slight loss from using a fuel with less energy and the net gain is an increase in power.

Spending money on higher octane gas than what your engine is designed for is a waste of money and will actually lower your mielage (although it might be so slight you wouldn't be able to measure it). Add in the increased cost of high octane fuel and you're throwing a lot of money away.

[PornMaster]

Car recommendation in the manual says 89
Ive been using 87

[ree666]

^ yes you've established that, just follow the manual =.=

[sonick]

People think higher octane gasoline somehow has more energy and will create more power/better mileage. This is not true. Octane is a measure of the fuel's resistance to detonation, not how much energy is in the fuel.

Higher octane fuels actually typically have less energy than lower octane fuels. The reason why a high-performance engine can get more power with a high-octane fuel is because you can run a higher compression ratio and more aggressive ignition timing. The gains from a higher CR ratio and ignition are greater than the slight loss from using a fuel with less energy and the net gain is an increase in power.

Spending money on higher octane gas than what your engine is designed for is a waste of money and will actually lower your mielage (although it might be so slight you wouldn't be able to measure it). Add in the increased cost of high octane fuel and you're throwing a lot of money away.

:rukidding: Good post but totally out of context for the thread.

OP is using LOWER octane fuel than recommended.

Yes it could impact your fuel economy quite significantly if using lower octane than recommended.

[i-VTEC]

If your car is recommended 87, once awhile treat it 89? or 91? will the engine benefit it?

I only fill up at 1) Chev, 2) Shell, and 3) Esso, perhaps Petro(Last To Consider)

[bcrdukes]

^
Nope.

Stick with 87.

[LuHua]

If your car is recommended 87, once awhile treat it 89? or 91? will the engine benefit it?

I only fill up at 1) Chev, 2) Shell, and 3) Esso, perhaps Petro(Last To Consider)

You'd just mess with the timing, your car runs best on 87. Spend that extra money on better engine oil if you want to benefit it.

[i-VTEC]

You'd just mess with the timing, your car runs best on 87. Spend that extra money on better engine oil if you want to benefit it.

I go point roberts to fill up gas, only 30 minute drive, and their 89 91 almost same as 87, not too big of difference

[PornMaster]

Gas almost empty will try it out and report back!

[dangonay]

:rukidding: Good post but totally out of context for the thread.

OP is using LOWER octane fuel than recommended.

Yes it could impact your fuel economy quite significantly if using lower octane than recommended.
There's no reason that lower octane fuel would reduce your mileage. Under normal driving conditions your engine will only be producing a fraction of its maximum output, so you're not going to run into conditions that require higher octane (like knock from advanced timing or heavy load).

Your engine would definitely produce less power at full throttle (or heavy throttle) but should still perform similarly under light throttle.

I doubt anyone could even accurately measure the difference in mileage between going up or down in octane from the recommended fuel your vehicle takes.

[PornMaster]

Any math wiz want to calculate the break even point?

[bcrdukes]

So should everybody just fill up on 87?

[ncrx]

funny no one's asked if his o2 sensor is pooped, or when the last time he did a tune up was

[bcrdukes]

Wouldn't he have a CEL pop up?

[PornMaster]

Car is well maintained and has never turned on CEL

that is why I am shocked the car takes so much gas even when I drive it like a granny

[ncrx]

doesn't always throw a cel, mileage can suffer as the o2 is slowly dying, in some cases it will others it won't.

maybe ur tires aren't properly inflated, alignment, short trips, its cold out
lots of factors

11km/100 sounds like highway mileage not city mileage for a v6 at least to me

[PornMaster]

I have a habit of recording km / tank and it always averages 420 regardless of weather for the past 2 years. Except for long trips to whistler etc I get extra 100-150km

Tires are new and I check them every month.

Just filled it up today $90 for 60L vs $82

[Manic!]

So should everybody just fill up on 87?

No just put in what ever the manufacturer recommends and don't waste your money on 94 oct from Chevron or Petro Canada.

[!SG]

i switched to shell.

91/92 octane w/ no ethanol mix.

[StylinRed]

since "regular" is mixed with a higher percentage of additives compared to the other levels of fuel, should that be a consideration to the octane level of fuel you put in? does 86 become an 85 because of the 10% (or whatever it is) mixture of ethanol/etc that they put in?

[Timpo]

There's no reason that lower octane fuel would reduce your mileage. Under normal driving conditions your engine will only be producing a fraction of its maximum output, so you're not going to run into conditions that require higher octane (like knock from advanced timing or heavy load).

Your engine would definitely produce less power at full throttle (or heavy throttle) but should still perform similarly under light throttle.

I doubt anyone could even accurately measure the difference in mileage between going up or down in octane from the recommended fuel your vehicle takes.

How do you know? Are you a car engineer?

I'm sure pretty much everywhere you look on google, they would teel you using lower octane gas will affect your gas mileage.
I'm not an engineer so I have no clue how realiable google articles are, just fyi.

Also it doesn't really matter if he's driving under "normal conditions"...what did you mean by this?

If engine has high enough compression or boost to detonate...I'd say high octane gas is necessary.
I know ECU will adjust ignition timing and stuff...but I don't think ECU can control air getting compressed and air friction igniting fuel in the combustion chamber.
Then again, I am a complete noob so...

[sonick]

since "regular" is mixed with a higher percentage of additives compared to the other levels of fuel, should that be a consideration to the octane level of fuel you put in? does 86 become an 85 because of the 10% (or whatever it is) mixture of ethanol/etc that they put in?

Actually the opposite; ethanol boosts octane rating.

[dangonay]

How do you know? Are you a car engineer?

I'm sure pretty much everywhere you look on google, they would teel you using lower octane gas will affect your gas mileage.
I'm not an engineer so I have no clue how realiable google articles are, just fyi.

Also it doesn't really matter if he's driving under "normal conditions"...what did you mean by this?

If engine has high enough compression or boost to detonate...I'd say high octane gas is necessary.
I know ECU will adjust ignition timing and stuff...but I don't think ECU can control air getting compressed and air friction igniting fuel in the combustion chamber.
Then again, I am a complete noob so...
Actually I did get my engineering degree recently - you must have missed that post when I came back to RS after my absence.

I've actually built my own ECU from scratch and also built the world's first aftermarket drive-by-wire throttle controller to integrate DBW with non-DBW ECU's. So yes, I do know a bit about how ECU's work.

Your car will never know what octane is in the tank until such time as you require more power (like heavy acceleration) at which time it will detect knock and adjust timing accordingly to compensate. Under normal driving your ECU will not know if you have regular or premium in the tank.

[freakshow]

So you're saying that there would really be no negative effects with regards to mileage or engine health for most modern stock cars to run 87 even if they require 91?

[sonick]

Also it doesn't really matter if he's driving under "normal conditions"...what did you mean by this?

e.g. no merging or overtaking on a highway, no going up steep hills, no living life a quarter mile at a time.

[Doubl3_H]

What about regular for a turbo car?
Posted via RS Mobile (http://www.revscene.net/forums/announcement.php?a=228)

[danny_d19]

What about regular for a turbo car?
Posted via RS Mobile (http://www.revscene.net/forums/announcement.php?a=228)
Just use what is recommended in the manual. My turbo car is tuned for 93/94 octane, so that's what I use.

[dangonay]

So you're saying that there would really be no negative effects with regards to mileage or engine health for most modern stock cars to run 87 even if they require 91?
The negative effects would be a loss in performance. The engine ECU would compensate for lower quality fuel so you're not going to blow up your engine or anything serious like that.

Keep in mind this is for more modern cars. It would be bad to run a low octane gas in an older car without some form of knock control system.

While companies always list the recommended fuel, some actually give ratings for their engine using the recommended and lower octane fuel (for example, the new Coyote engine in the Ford Mustang quotes power/torque outputs on 87 and 91 octane fuel).

You have to remember manufacturers have to allow for all sorts of scenarios from dumb drivers putting in the wrong fuel to people on a road trip at a station that doesn't sell fuel they need. Vehicles will run OK on lower octane fuel - they just perform better when running on the recommended fuel.

[PornMaster]

Few things Ive noticed ever since the switch.
1) Engine response seems faster. b4 I would press the gas down and about half a second then it would rev higher.
2) Hissing sound when car is idling is completely gone
3) Idles at 900rpm now instead of 1100

[dangonay]

^ Something is going on with your car that's not right.

There is no way a change in octane is going to affect your idle speed. And the hissing sound is more likely a cause of the previously higher idle speed drawing more air in the engine.
Posted via RS Mobile (http://www.revscene.net/forums/announcement.php?a=228)

[see.lai]

Speaking of idling, when you start up a car, it's not supposed to idle at 1500-2000rpms, right..?

When my car is warm, then it will idle at 1000. :|

[PornMaster]

^ Something is going on with your car that's not right.

There is no way a change in octane is going to affect your idle speed. And the hissing sound is more likely a cause of the previously higher idle speed drawing more air in the engine.
Posted via RS Mobile (http://www.revscene.net/forums/announcement.php?a=228)

Let me rephrase its not a hissing sound but more of a high pitch screeching sound when idling

[dachinesedude]

Few things Ive noticed ever since the switch.
1) Engine response seems faster. b4 I would press the gas down and about half a second then it would rev higher.
2) Hissing sound when car is idling is completely gone
3) Idles at 900rpm now instead of 1100

a change of octane made that much noticeable difference? LOL

i think its all in your head, placebo, butt dyno, noticing stuff that was prob there before, etc

[Soundy]

Few things Ive noticed ever since the switch.
1) Engine response seems faster. b4 I would press the gas down and about half a second then it would rev higher.
2) Hissing sound when car is idling is completely gone
3) Idles at 900rpm now instead of 1100

Let me rephrase its not a hissing sound but more of a high pitch screeching sound when idling

All three symptoms sound like a vacuum leak. Change in octane would not cause a change in the symptoms; any change would have to be coincidental.

[Timpo]

Your car will never know what octane is in the tank until such time as you require more power (like heavy acceleration) at which time it will detect knock and adjust timing accordingly to compensate. Under normal driving your ECU will not know if you have regular or premium in the tank.

ok but you still didn't tell me your definition of "normal driving"

if your definition is this:

e.g. no merging or overtaking on a highway, no going up steep hills, no living life a quarter mile at a time.

this is almost unrealistic, so basically as long as you don't rev up more than..let's say 3,000rpm or something, you're ok with low octane gas.

[trd2343]

^ Something is going on with your car that's not right.

There is no way a change in octane is going to affect your idle speed. And the hissing sound is more likely a cause of the previously higher idle speed drawing more air in the engine.
Posted via RS Mobile (http://www.revscene.net/forums/announcement.php?a=228)


I too tried explaining that to my mom, but she said the car (during acceleration) does feel more responsive and has more "ummpph" to it when she stepped on the pedal. She said she gets better mileage too though she hasn't had any hard to data to back that up. I said she must be imaging things.

Is there any possible way why the car might feel more responsive, or is it all in the head?

Only reason why people would put in 94 because it's suppose to contain more cleaning additive than all the other grades?

[Bahhbeehhaaaa]

my famiy car, a 2003 Sienna with 95,XXXkm gets about 350km 80L tank 87 octane cheveron.. soo what'ss up with the poor gas mileage?

[sonick]

I too tried explaining that to my mom, but she said the car (during acceleration) does feel more responsive and has more "ummpph" to it when she stepped on the pedal. She said she gets better mileage too though she hasn't had any hard to data to back that up. I said she must be imaging things.

Is there any possible way why the car might feel more responsive, or is it all in the head?

Only reason why people would put in 94 because it's suppose to contain more cleaning additive than all the other grades?

The only way would be if the car requires higher octane, there would be a performance difference between filling with 87 and the factory recommended grade octane.
Posted via RS Mobile (http://www.revscene.net/forums/announcement.php?a=228)

[GabAlmighty]

My turbo Volvo gets 87 cuz i'm too cheap to put in a higher octane. I'll let you all know when it blows up.

Speaking of idling, when you start up a car, it's not supposed to idle at 1500-2000rpms, right..?

When my car is warm, then it will idle at 1000. :|

Warm up sequence, 2k seems a little high. 1500 sounds about right depending on the car.

My 4runner would do abouty 1500rpm but my volvo only does a little over 1k for warm up i think.

[trd2343]

The only way would be if the car requires higher octane, there would be a performance difference between filling with 87 and the factory recommended grade octane.
Posted via RS Mobile (http://www.revscene.net/forums/announcement.php?a=228)

Nope, it's a CR-V, and recommends 87, so I don't know where she's getting the "better response thing from", although I haven't had the chance to actually test it myself.

I did a quick search on google and came across this reply on Yahoo questions.

http://answers.yahoo.com/question/index?qid=20110504084735AAgGN0T

On some occasions, you may feel an improvement in performance and fuel economy when using premium fuel in an engine designed to run on 87 octane regular fuel. Most times this improvement is slight. Many times, it is a placebo effect. You may even get a slight improvement in fuel economy.

Just to be clear, I'm no expert, nor am I saying whatever this guy is saying is right. I know that using lower octane than recommended is bad, but I've heard numerous time about experiences of increase in performance in using higher octane. I would be incline to believe what this guy said given it's also written cohesively.

[dangonay]

I too tried explaining that to my mom, but she said the car (during acceleration) does feel more responsive and has more "ummpph" to it when she stepped on the pedal. She said she gets better mileage too though she hasn't had any hard to data to back that up. I said she must be imaging things.

Is there any possible way why the car might feel more responsive, or is it all in the head?

Only reason why people would put in 94 because it's suppose to contain more cleaning additive than all the other grades?
I'd say the performance aspect is probably in her head, even if her car was actually performing better.

I'll try to explain this simply to hopefully get my point across.

Engine ECU's have what are known as "adaptations". Adaptations are what allow engines to perform consistently as operating conditions change (quality of fuel, age of engine, wear of components and so on). In simple terms, adaptations are a set of numbers which tells the ECU how to modify engine parameters like fuel & ignition.

Let's say at a certain RPM and load the ECU has a value of 20 degrees of timing stored. When the engine is running and the ignition is fired at 20 degrees the engine detects knock. So it pulls back the timing to 18 degrees and there's still a knock. It pulls timing back to 16 degrees and the knock goes away.

If this happened once-in-awhile, the ECU would not bother changing the adaptations as it can handle the occasional knock by simply pulling timing. If it's happening regularly, then the ECU might store a value of -4 degrees as an "adaptation" for ignition. The next time the engine reaches the same RPM and load, the ECU gets the 20 degree value from memory and applies the adaptation to it (in this case, -4 degrees) and then fires the ignition at 16 degrees. Knock is eliminated not because the knock sensors detected it and the ECU adjusted timing, but because the timing amount was already corrected by applying an adaptation.

It can get a lot more complicated than this, but this is a general idea how adaptations work.

One key thing to remember about adaptations is it takes time for the ECU to set adaptations. It depends on the car but it can take anywhere from 15 minutes to several hours before the ECU has enough data from various driving conditions to set adaptations. This is why when your mom switches from lower octane to higher octane fuel she likely wouldn't feel an instant increase in power because the ECU would have set its adaptations for the lower quality fuel. Her car will perform better, but it will take some driving before the ECU adapts to the new fuel.


Edit: Just saw the car is a CR-V. In that case, she's just imagining things. If it was a car that required higher octane, then everything I said above applies.

[trd2343]

^I just did a quick edit on my post and added a link. Like I said, by no means believing what this guy says, but I can see where people are coming from when they say that higher octane produces better performance, after reading that.

Wait I just read what you post, so using a higher octane does produce better performance and fuel efficiency?

I'd say the performance aspect is probably in her head, even if her car was actually performing better.

[danny_d19]

^

Wait I just read what you post, so using a higher octane does produce better performance and fuel efficiency?

It's not a concrete fact for all scenarios, I think this is what you are getting hung up on. Sometimes it does, usually due to the vehicle not using the proper octane it calls for, and therefore isn't running at peak efficiency

[mauricetan]

Interesting thread! :D Any more opinions or advice?

I was just wondering is it true that the octane rating in the USA is messed up? So if your car requires 89 octane.. you should put premium when you are filling up in the USA?

[bcrdukes]

^
What?

No. They use the AKI (Anti-Knock Index) which is used in Canada as well.

[bloodmack]

:rukidding: people still believe this shit? Its common sense man. Unless you tune your car for a different Octane nothing will change. If you put a different octane in your tank when your air and fuel mix and get compressed it could combust earlier or later then its supposed to.

[freakshow]

I'd say the performance aspect is probably in her head, even if her car was actually performing better.

I'll try to explain this simply to hopefully get my point across.

Engine ECU's have what are known as "adaptations". Adaptations are what allow engines to perform consistently as operating conditions change (quality of fuel, age of engine, wear of components and so on). In simple terms, adaptations are a set of numbers which tells the ECU how to modify engine parameters like fuel & ignition.

<going to spoiler the rest for length>

Let's say at a certain RPM and load the ECU has a value of 20 degrees of timing stored. When the engine is running and the ignition is fired at 20 degrees the engine detects knock. So it pulls back the timing to 18 degrees and there's still a knock. It pulls timing back to 16 degrees and the knock goes away.

If this happened once-in-awhile, the ECU would not bother changing the adaptations as it can handle the occasional knock by simply pulling timing. If it's happening regularly, then the ECU might store a value of -4 degrees as an "adaptation" for ignition. The next time the engine reaches the same RPM and load, the ECU gets the 20 degree value from memory and applies the adaptation to it (in this case, -4 degrees) and then fires the ignition at 16 degrees. Knock is eliminated not because the knock sensors detected it and the ECU adjusted timing, but because the timing amount was already corrected by applying an adaptation.

It can get a lot more complicated than this, but this is a general idea how adaptations work.

One key thing to remember about adaptations is it takes time for the ECU to set adaptations. It depends on the car but it can take anywhere from 15 minutes to several hours before the ECU has enough data from various driving conditions to set adaptations. This is why when your mom switches from lower octane to higher octane fuel she likely wouldn't feel an instant increase in power because the ECU would have set its adaptations for the lower quality fuel. Her car will perform better, but it will take some driving before the ECU adapts to the new fuel.


Edit: Just saw the car is a CR-V. In that case, she's just imagining things. If it was a car that required higher octane, then everything I said above applies.
Lets say you run 89 fuel on a car that requires 91, the adaptation gets set to -4 over a few hours. In 4 months time, you decide to switch back to 91, how does the engine decide when to change the adaptation back to 0 instead of pre-applying the value?

[PornMaster]

Results are in
got 465km on the tank
usually I get 425 with 87, when I pumped it clicked at 59.xxxL so there was 1 litre away.

Not sure if its worth the extra $7

[bcrdukes]

^
Did your driving route change, by chance? i.e. any highway driving more than usual?

The weather is slowly getting warmer too but that shouldn't make that huge of a difference.

[dangonay]

Lets say you run 89 fuel on a car that requires 91, the adaptation gets set to -4 over a few hours. In 4 months time, you decide to switch back to 91, how does the engine decide when to change the adaptation back to 0 instead of pre-applying the value?
ECU's are always adjusting values to run at optimal efficiency. They do this by intentionally varying actual ignition/injection values by a small amount away from "normal" and monitoring sensors to see the results, and, if necessary, further adjusting adaptations. In fact, adaptations are always being adjusted over the life of the vehicle, usually only by very small amounts.

That said, an engine can adapt very quickly to lower octane fuel because knock will occur far more often. Switching to higher octane would take longer to adjust adaptations simply because there's no "immediate" change that the ECU would see.

Another example of this (though not related to adaptations) is an oxygen sensor response test. The ECU would intentionally make the mixture richer by increasing injector pulse width and then monitoring how long it takes for the oxygen sensor to respond. A good sensor should respond very quickly (perhaps 100ms) while a bad sensor might take much longer (600ms or more). If the sensor takes too long, you will get a check engine light and a code that says something like "O2 Sensor Aged" or "O2 Sensor Dynamic Response".

[PornMaster]

^
Did your driving route change, by chance? i.e. any highway driving more than usual?

The weather is slowly getting warmer too but that shouldn't make that huge of a difference.

Stayed routine

[1exotic]

My Jay-Dee-M vehicle is mapped for 98 RON gasoline which is about 94-95 Octane reading here... so I'm pretty much stuck on 94 Chevron. Tried 91 with Shell before but I noticed the mileage went down a bit.

[mr_chin]

I've been using 94 octane ever since I bought my car.

Here is my car's fuel recommendation

Your vehicle is designed to operate
on unleaded gasoline with a pump
octane number of 87 or higher. Use
of a lower octane gasoline can cause
a persistent, heavy metallic rapping
noise that can lead to engine damage.

You may hear a knocking noise from
the engine if you drive the vehicle at
low engine speed (below about 1,000
rpm) in a higher gear. To stop this,
raise the engine speed by shifting to
a lower gear.

We recommend using quality
gasolines containing detergent
additives that help prevent fuel
system and engine deposits.

In addition, in order to maintain good
performance, fuel economy, and
emissions control, we strongly
recommend, in areas where it is
available, the use of gasoline that
does NOT contain manganese-based
fuel additives such as MMT.

Use of gasoline with these additives
may adversely affect performance,
and cause the malfunction indicator
lamp on your instrument panel to
come on. If this happens, contact
your authorized dealer for service.

Will switching back to 87 octane mess up the timing?

And what would the bold line mean? Is ethanol considered detergent additive?

[Groot]

Anyone see this? Found it kinda interesting but wished they did a long term run.

http://www.cbc.ca/marketplace/episodes/2012/11/pumpfiction.html

[Amuse]

i switched to shell.

91/92 octane w/ no ethanol mix.
Chevron 91 has any ethanol mix?

I noticed my car runs better on Canadian Chevron 91 compared to Pt. Roberts Chevron 92.

[broken_arrow]

Correct me if I'm wrong, but Shell V-Power now has ethanol, unless the pump specifically states no ethanol...

Anyways, I use Chevron 94. I get about 340-360 km out of a 70L tank... All city driving.

[dangonay]

Anyone see this? Found it kinda interesting but wished they did a long term run.

Pump Fiction - Marketplace (http://www.cbc.ca/marketplace/episodes/2012/11/pumpfiction.html)
Saw that the other day. Though they are essentially correct in stating it's a waste putting higher octane gas than what your vehicle recommends, some of their test methods are seriously flawed.

For example, when the mechanic had the vehicle hooked up to a gas analyzer to monitor the exhaust emissions. Anyone who has ever used an analyzer (like trying to get cars to pass Aircare) knows that readings change even from minute to minute. There's no way you could drive a car on one tank of 87 octane, measure the readings, and then drive on a tank of premium and measure the readings again, and get any kind of meaningful result that you could attribute to the different gas. Even a difference in the weather from one day to the next could affect readings. Or the engine temperature (how long did the vehicle run before each test). Or the adaptations (which have been discussed already).

Gas analyzers are only really useful for measuring large changes or to monitor changes while you're specifically changing something (like adjusting a carb). They are absolutely useless as any form of data gathering device.

Has anyone gone to Aircare and failed then gone back and passed? That tells you right there how accurate gas analyzers are.

[mr_chin]

Correct me if I'm wrong, but Shell V-Power now has ethanol, unless the pump specifically states no ethanol...

Anyways, I use Chevron 94. I get about 340-360 km out of a 70L tank... All city driving.

Dayum, what car do you drive??

I guess it's not THAT big of a deal with 94 vs 87. The difference in like approximately $7 more and it's a peace of mind knowing I'm running on non-ethanol fuel.

[broken_arrow]

Dayum, what car do you drive??

I guess it's not THAT big of a deal with 94 vs 87. The difference in like approximately $7 more and it's a peace of mind knowing I'm running on non-ethanol fuel.

BMW M6

[xilley]

BMW M6

so cocky and proud :troll:

[EvoLove]

lol my car calls for premium unleaded =.= i use both chevron 94 i get 300km but when i use shell 91 no ethanol i get 350 on a 50L tank =.= so im :fulloffuck:

[dared3vil0]

I used to drive a 2000 Nissan Maxima, It was reccomended to use 91, I used 87 for a month or two, I averaged 14.3 l/100km, I used 91 like it said to, I averaged 11.2 l/100km. So yes, You WILL hurt fuel economy by using a lesser octane than you should be. Higher octane than reccomended IS a waste of money however.

[keitaro]

ECU's are always adjusting values to run at optimal efficiency. They do this by intentionally varying actual ignition/injection values by a small amount away from "normal" and monitoring sensors to see the results, and, if necessary, further adjusting adaptations. In fact, adaptations are always being adjusted over the life of the vehicle, usually only by very small amounts.

That said, an engine can adapt very quickly to lower octane fuel because knock will occur far more often. Switching to higher octane would take longer to adjust adaptations simply because there's no "immediate" change that the ECU would see.

Another example of this (though not related to adaptations) is an oxygen sensor response test. The ECU would intentionally make the mixture richer by increasing injector pulse width and then monitoring how long it takes for the oxygen sensor to respond. A good sensor should respond very quickly (perhaps 100ms) while a bad sensor might take much longer (600ms or more). If the sensor takes too long, you will get a check engine light and a code that says something like "O2 Sensor Aged" or "O2 Sensor Dynamic Response".

I actually had this issue happen. Kept getting "O2 Sensor Slow Response" CEL. Eventually, I changed the O2 sensor, and noticed that I was getting better gas millage.

[sonick]

Anyone see this? Found it kinda interesting but wished they did a long term run.

Pump Fiction - Marketplace (http://www.cbc.ca/marketplace/episodes/2012/11/pumpfiction.html)

LOL the instructor running the dyno at the Canadian Auto & Trucking College thought that it would make a difference, what a shitty teacher.

And asking the gas pumpers what is cleaner? Who does CBC think they are, Fuel Sommeliers? It's not like they go through a rigorous product training course before they start working, what would they know?

Whole video is pretty misleading to the general public to say the least.

[Manic!]

It's amazing how someone will trust someone making minimum wage at a gas station over what the manufacture recommends.

[mx555]

I've been using 94 octane ever since I bought my car.

Here is my car's fuel recommendation



Will switching back to 87 octane mess up the timing?

And what would the bold line mean? Is ethanol considered detergent additive?

Quality is not measured by octane. Those lines simply means don't buy gas from shady dudes from the back of their van.

Ethanol is not a detergent additive; it is an octane booster.

10% ethanol blend equates to roughly 3 points increase in octane. So, the 87 w/ 10% ethanol @ Chevron is actually more like 84-86 + ~3 octane from the ethanol.

Companies like Chevron, Shell, and Petro Canada are all what are referred to as "top-tier" distributors. This means that the gas that they sell is guaranteed to meet the minimum required qualities and detergent levels mandated by the EPA.
Generally speaking you're getting much more than EPA standards for detergents in your gasoline, for example, Shell's V power simply means that there are 5x the mandated amount of detergents. The mandated amount of detergents does NOT clean the engine, it only prevents more build up.
87 to 94, they all come from the same fuel farm, same pipeline. The differences between them is the amount of octane boosters blended in prior to distribution; this is also where each company blends in their additives.

Problems with alcohols:
-hydroscopic (absorbs water)
-fixed volatility (each molecule is the same size and configuration. meaning they volatize at the same temperature. gas is comprised of many different sized hydrocarbons. Light ends (short chains) are the molecules that evaporate first (good for cold starting), heavy ends are the ones that contain the most energy.
-less energy per unit compared to gasoline
-removes oil from the combustion chambers of 2 stroke motors =(


Oh PS, that 87 octane you bought from Chevron? Ya, that's more like 89 octane. The octane rating at the pump is a LEGAL MINIMUM, so they're always higher than advertised.

[broken_arrow]

so cocky and proud :troll:

:troll:

[mr_chin]

Quality is not measured by octane. Those lines simply means don't buy gas from shady dudes from the back of their van.

Ethanol is not a detergent additive; it is an octane booster.

10% ethanol blend equates to roughly 3 points increase in octane. So, the 87 w/ 10% ethanol @ Chevron is actually more like 84-86 + ~3 octane from the ethanol.

Companies like Chevron, Shell, and Petro Canada are all what are referred to as "top-tier" distributors. This means that the gas that they sell is guaranteed to meet the minimum required qualities and detergent levels mandated by the EPA.
Generally speaking you're getting much more than EPA standards for detergents in your gasoline, for example, Shell's V power simply means that there are 5x the mandated amount of detergents. The mandated amount of detergents does NOT clean the engine, it only prevents more build up.
87 to 94, they all come from the same fuel farm, same pipeline. The differences between them is the amount of octane boosters blended in prior to distribution; this is also where each company blends in their additives.

Problems with alcohols:
-hydroscopic (absorbs water)
-fixed volatility (each molecule is the same size and configuration. meaning they volatize at the same temperature. gas is comprised of many different sized hydrocarbons. Light ends (short chains) are the molecules that evaporate first (good for cold starting), heavy ends are the ones that contain the most energy.
-less energy per unit compared to gasoline
-removes oil from the combustion chambers of 2 stroke motors =(


Oh PS, that 87 octane you bought from Chevron? Ya, that's more like 89 octane. The octane rating at the pump is a LEGAL MINIMUM, so they're always higher than advertised.

It is said that ethanol is the culprit of engine knocking sounds, like someone through screws into the piston chambers.

Is this true?

Overall, is ethanol good for your engine? Or does it damage it over time?

[radioman]

:troll:

Those BMW drivers......






:troll:

[mx555]

It is said that ethanol is the culprit of engine knocking sounds, like someone through screws into the piston chambers.

Is this true?

Overall, is ethanol good for your engine? Or does it damage it over time?

Ethanol increases octane, reduces detonation.

@ current 10% blends and at near future 15% blends, your not doing anything detrimental to your car. Higher blends will start to be corrosive to the plastic/rubber parts of fuel systems in older cars. Most affected will be the 2-strokes n rotaries.

[broken_arrow]

Maybe its a placebo effect, but my car feels more responsive on no ethanol gas... I was told that NA cars perform better on no ethanol, but FI cars do better with ethanol. Is there any truth to that?

[sekin67835]

When i fill 91, the car feels more "burst" but when i fill with no ethanol(94 at chevron) it feels more "smooth". Might be my mind playing tricks though
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