91 Octane versus 94

[allen]

I have a 2005 Acura TL which I run on 91 Octane. I was at a Sunoco station the other day and they have a 94 ocatane available. Would I see a noticeable difference in performamnce using the 94?

[The General]

This is always a tough subject.

What I can tell is that in the winter, you will most likely not notice any difference. In the summer, potentially your car will perform slightly better. This will only be true if you're a hard driver. If you like to cruise in a normal fashion, I would not bother with the extra cost.

[The General]

Anyone else have any clearer ideas or suggestions?

[KaPtNk]

If it says premium, then engineers have calibrated the engine management to exploit this fuel's higher octane. True, if the engine is knock-sensor-equipped, lower octane fuel won't hurt it; it'll just run less efficiently, both in terms of power and economy.

If the the owner's manual recommends regular - and the engine exhibits no noticeable ping - then there's no benefit whatsoever in using a higher-octane fuel. No more power. No better economy.

[KaPtNk]

More info ...

http://tl.acurazine.com/forums/showthread.php?t=104380

http://tl.acurazine.com/forums/showthread.php?t=89432

http://tl.acurazine.com/forums/showthread.php?t=80062

Taken from the second link :
the short answer? Octane is a measure of how easily the fuel will combust in the engine. The lower the octane, the more easily it will ignite. If you run fuel that is too low, it's gonna go off to early because of the high pressure in these performance engines. You'll hear knocking, which will be a sign that the fuel is igniting too early. This affects performance and can damage the engine.

[SunnyDay]

Anyone else have any clearer ideas or suggestions?

I personal experience is that it feels more better with higher octane because the mileage is much better with a slight push of the pedal in highway thus it consumes less gas with higher mileage. With low octane, I need to push the gas a little bit harder to get my car going.
My conclusion:
Highway : High Octane
City : Low Octace

[amorak]

That's an onncorect assessment... It's what's called 'wishful thinking'

if you look at any scientific information, 91-vs 94 will do nothing for most cars, except those that 'REQUIRE' premium gas and have the capabilty to advance or redtard timing.

If your car requires REGULAR, you will notice zero difference in going to premium. if your car can run both, then you will notice no difference going from 91 to 94.

period.

[Al 1959]

That's an onncorect assessment... It's what's called 'wishful thinking'

if you look at any scientific information, 91-vs 94 will do nothing for most cars, except those that 'REQUIRE' premium gas and have the capabilty to advance or redtard timing.

If your car requires REGULAR, you will notice zero difference in going to premium. if your car can run both, then you will notice no difference going from 91 to 94.

period.

He's right!!! :thumb:

Higher octane is for higher compression engine, what it does, it resists being ignated before the right time! meaning higher octane resists higher temperature before it ignates!
So if you need 87 Octane, don't waist your $$$ for 91 Octane and up.

Just my opinion.

Al.

[Huggyd]

Good post. guys

I was told the its best to run high octane for a week before going in to do any emissions testing? I'm not sure if this makes a difference but I have always done it, and I also STAY FAR AWAY FROM ESSO :!: Their gas is pure dirt!

where would one find info on specs for this, for new cars? looking at Rangers but I've never seem an info telling me weather I can advance or redtard timing or what fule to run?

[airbalancer]

I have a 2005 Acura TL which I run on 91 Octane. I was at a Sunoco station the other day and they have a 94 ocatane available. Would I see a noticeable difference in performamnce using the 94?

Give a try, when people go to track there car they will go will the higher rating.
What was the cost difference between the two.
We have no Sunoco station here

[The General]

and I also STAY FAR AWAY FROM ESSO :!: Their gas is pure dirt!

I only gas at Esso. Many people I know only gas at Esso. In the recent past, I had a discussion with an indutry analyst and researcher and following their investigations, Esso and Ultramar has some the cleanest gas available. Shell and Petro Canada have consistently sold poorer quality gas.

What makes you say that it is dirt?

[Huggyd]

The info comes from news reports about 2years ago (don’t quote me on the time frame) there was big new coverage on all the big gas stations in the area (Hamilton, T.O. areas) and it rated the quality of fuel that was coming out of the pumps, Esso was the poorest I think it had the highest sulfur content. I have talked to mechanics were I have been told if they see any problems related to fuel its always been people fill up with Esso. The cleanest was Sunoco which is normal one of the highest priced station in the area. This is dated info I’m going on, and if anyone has any links or real data on the madder (please post the info) I’ll be more then happy to correct my statement.

[The General]

The cleanest was Sunoco which is normal one of the highest priced station in the area.

This I agree. Unfortunately, there are no Sunoco stations in Quebec. When I go to the States or in Ontario, I always fill up.

[fedakj]

I have a Mercedes and my wife a BMW. Use only Sunoco gasoline. The Sunoco brand has a maximum of 10% alcohol (methane) which does two things, may be tree. Less harmful emmission, cleaner air mass detector, new one cost $ 800.00, which we have not had to replace.

Performance - since the engine managment system and its sensors, detecting higher level of oxigen (methane) it adjust the mixture to compensate. This results in smoother running idle and high speed driving.
Last, we use octane 91 every second fill, and octane 94 every second fill.

[R.S.]

There is no noticeable performance increase when using higher octane gasoline. Just always get the grade required by the manufacturer and save yourself some $$$.

[Huggyd]

Found some info on this subject.
"When looking at vehicle fuel requirements in the owner's manuals, it will state whether regular fuel can be used, premium fuel is recommended, or premium fuel is required. It also often has this printed right at the fuel filler. If the specifications say premium fuel is recommended, you can use regular fuel for many driving conditions, especially if you are not placing high heat or acceleration loads on the vehicle. If any pinging does occur, the engine knock sensor will detect this and cause the ignition timing to retard. This will reduce the pinging, but can decrease performance and fuel economy. If premium fuel is required, use what the manufacturer recommends."

Follow link for full details.
http://www.canadiandriver.com/articles/jk/060118.htm

[Pritch]

Yep

to sum up

the misconception of better performance on higher octane fuel when it isnt required is false. 87 vs 94 octane gas...they both have the same amount of energy available if you burn an equal amount of them, difference being that one is just harder to ignite.

The mileage argument is false too. Since there is no added power, there is no added mileage. There are so many factors contributing to mileage that you'd never be able to pin it on just changing fuel anyhow.

[fawiek]

That's an onncorect assessment... It's what's called 'wishful thinking'

if you look at any scientific information, 91-vs 94 will do nothing for most cars, except those that 'REQUIRE' premium gas and have the capabilty to advance or redtard timing.

If your car requires REGULAR, you will notice zero difference in going to premium. if your car can run both, then you will notice no difference going from 91 to 94.

period.



yep, he's right. im agreeing with this statement from personal experience as well. ive used shell vpower for a few weeks now. i decided to give it a try because i read some articles saying the vpower is reformulated to be better than most other gasolines in the market. however, im not quite sure that statement was intended to be closer to the truth or just another marketing strategy to entice consumers...probably the second one..
i drive a 2007 impreza (not the wrx)..it does not call for premium fuel. i only decided to use premium fuel as the engine is still breaking in. only recently have i started using regular fuel and i must say...i find the car runs noticeably smoother and also seems to have more kick with the premium. the added kms didnt really show much at all...maybe i'll give 89 a try and stick with that, middle of the line...

something else i wanted to bring to this forums attention...i dont think id buy shell gasoline again... i tried shell for sometime (vpower) and the kms i got was about 500km with 91 octane. (the impreza tank is 60L and well a 2.5 4cyl engine)
i tried sonoco 91 octane and reached 500kms with another 1/4 tank to go!
btw i know this 'experiment' wasnt as constant as it will be held in the lab, but my car is still breaking in which illustrates why i wouldnt be driving hard either way...

well thats my 2 cents, and a little bit..hope this helps!

[Pritch]

Just for a reality check, although I know that people "say" they get better mileage on super

The following are a few things that can affect your mileage

Windows, up or down
passenger / cargo load
use of heater / AC / Defrost
Exterior temperature
ture pressures
wind
your route (ie more or less hills)
how long you let the engine warm up before driving it
elevation
how bright or overcast it is outside

theres SO much going on. so if you get 10 clicks more out of a tank, it could have been a billion other things than your fuel!

Decides engines which arent breaken in are usually inconsistent anyhow.

It's been an interesting thread!

[yncy515]

yes you will definitely feel a much faster accelleration but i suggest you to be consistent with the fuel youre using including the brand because if we use different fuel our sparkplugs will be filled with carbon much faster.

[Mr Car Guy]

If your car does not use a knock sensor, then use the octane recommended by the manufacturer. You will see no benefit from using a higher octane fuel.

If you car does use a knock sensor, then if the fuel you use is less octane than recommended, your knock sensor may reduce the engine's ignition timing to safely allow that fuel to not damage your engine. If you use fuel rated higher than recommended, you likely may not see any benefit. The correct octane will allow the engine's timing to run as advanced as possible, using a higher octane will not advance it more than it is designed to do.

The most important thing, after using the correct octane fuel, is the quality of the fuel. A poor quality, high octane fuel, can cause engine knock easier than a lower grade of quality fuel, in some cases. Quality fuel also keeps your fuel and intake systems cleaner.

The quality of the fuel is a bigger factor in getting maximum fuel mileage, than the octane is.

[regan612]

I have been told many times only use what grade is recommended by the manufacturer for your car, if you upgrade you're just wasting money. But I've always been curious and ran tests with my cars to see if there is any difference in performance & fuel economy. Currently I have a Pontiac that recommends 87 and a BMW that recommends 89. Neither car has shown any benefit when I used 91+ octane gas.

Previously I owned a '02 Acura RSX, the manual only recommended 87 octane. This car performed much better with 91 octane and I got 100 -150 km's further per tank. So it was worth while to upgrade the fuel. I heard that Acura has since recommended premium fuel in new years of this car.

[regan612]

Given the experience I had with an Acura, I'd try running a few tanks of 94. If you notice a substantial difference in performance &/or economy it may be worthwhile, if not don't continue to waste money.

I do also believe that fuel companies market and try to "brainwash" drivers into thinking that their car runs better and cleaner on premium. The reality is that they just make more profits!!

[bill03948]

and I also STAY FAR AWAY FROM ESSO :!: Their gas is pure dirt!


Then let me grab my shovel and fill my car from the backyard...

This has to be one of the oldest urban legends around... When Canada started to extract oil from the sands in Alberta it was called "dirty fuel" and only sold to cut rate no name gas stations. It then became Petro Canada and now Esso.

I use to be in the fuel business and delivered the fuel. Hate to burst your bubble but around the major cities ALL majors SHARE PRODUCT with each other. If "Esso" runs out of premium and needs procudt from sunoco, They mix mid grade and ultra 94 to get the required 91 octaine.

So much for the cut rate no name gas stations myth of selling lighter fluid as fuel or Esso with dirt in their gas. Oh yes, even if there was... That is why the pumps AND YOUR CAR have FUEL FILTERS to remove anything...

Maybe someone didn't like you and put sand in your tank after filling up at Esso? Possible! Maybe the Petro Canada Gods?

Back on topic... Octaine levels are scientific numbers for flash levels. The lower the number, the more heat it requires for combustion. Usually unless your car requires 91 or higher from the manufacture you would only use it (or 104 octaine boost/nos) if you have a lazy engine. Using too high of an octaine can cause damage to your car and could void any warranty.

Lets face it... Your car is no race car. So why bother and spend all that extra money for maybe a couple horsepower that would be useless?