optimax or regular unleaded

[krogoth]

i got an 05 civic, it doesnt require optimax or premium unleaded, i know some people who also have cars that dont require premium, yet they choose to run premium and recomend it

i tried it and didnt notice a huge difference in how the car drives, but ive heard that it is better for the engine to run on premium

Can someone help me to sort thru all the bullshit, am i gettin ripped off or is it worth the few extra $ every time?

[j3z3z]

the higher the octane the easier/better/more fuel burns thus give a slight performance advantage, it also gives better fuel economy and gradualy cleans your ignition chambers
this is the case between most fuels the higher octane the better for your motor. Just remeber once you get above 100 octane to change your spark plugs to suit

[crx_boy7]

ok ur car wont run better on high octane stuff unless its tuned for it so in that area ur wasting ur time however the higher octane feuls are often a better quality feul which results in more power but with low compression/retarded timing/and oem cam timing there is a point at which ur car wont make more power from higher octane.
most honda manuals recomend a feul octane rating of 95ron you may feel a slight increase in power upto the 98 mark but on a stock engine there is no extra power to be had from octand rather a cleaner feul will give better output

[crx_boy7]

all the octane rating is is a measure at which preesure/temperature the feul ignites
im open to critisisn but dont say anything if u dont know anything

[J-MuN]

Been discussed many times. Try searching next time.

Threads that discuss this topic are:

Here (http://www.ozhonda.com/forum/showthread.php?t=32881&highlight=optimax)

or

Here (http://www.ozhonda.com/forum/showthread.php?t=35954&highlight=optimax+ultimate)

There's more too. Just search. :thumbsup:

[egSi]

your manual will tell you what fuel to use.

read it and use what it says. :thumbsup:

[Limbo]

Run the premium or Hi octane better quality fuel will extend the life of your motor

[jamchen]

IMO.. i would just spend that about $5 more just to put premium instead of regular everytime i fill up the tank...
its there for a reason and $ slightly higher than regular...
we've a v6 toyota vienta which has run on premium since purchase in 99,,... it really helps the car to rum smooth... i mean very smooth when few of my parents friends feel the differences with other v6 camrys they've driven...

[mrwillz]

i use premium also
feellsssss much better IMO over 91 octane.

[aaronng]

Try a tank of each and see which is better and which gives better mileage. At most, you'll lose only $5. For me, I found that I gained 50km per tank with optimax over the 95 stuff.

[Alpine]

Found this interesting article from drive.com.au...

Filling up? Don't pay for premium

Bridie Smith
The Age
Friday February 24 2006

An RACV study shows that most cars don’t benefit from more expensive premium unleaded petrol.

Motorists paying a premium for top-of-the-range petrol are wasting their money, according to research by the state's motoring body.

Oil companies claim filling up with premium unleaded petrol, which can cost up to 10 cents a litre more than regular unleaded, delivers smoother driving, lower fuel consumption and higher performance.

But RACV research to be published next month shows cars designed to run on regular unleaded petrol fared no better when premium petrol was used.

RACV corporate and government relations manager David Cumming said cars needed to be designed to take advantage of the higher octane petrol for its use to have any benefits.

"It's all (based on) perception, but at the end of the day, we are just saying to motorists that if your car isn't designed for it, don't waste the money," Mr Cumming said.

The study, conducted at a Ford laboratory in Melbourne, tested three fuels (a regular unleaded 91 research octane number (RON), a premium 95 RON and a premium 98 RON) on two cars, a Ford Falcon and a Ford Festiva.

The tests also found that although consumption was lower with a premium fuel, motorists still ended up paying more.

"I had a gut feeling that it wouldn't be cost effective and that turned out to be the case," Mr Cumming said. "If people divide the kilometres by the price, they will find that it's not value for money."

The research showed that with motorists paying $1.20 a litre for regular unleaded petrol in late January, when the tests were conducted, those selecting premium 95 RON unleaded were in fact paying 5 per cent more for a fuel saving of 2 per cent. Motorists buying the 98 RON unleaded petrol were paying 8 per cent more for a fuel saving of 2.5 per cent.

Mr Cumming said when the premium fuels were introduced about five years ago, there was only a four-cent price difference, but it was now up to 10 cents.

"Bit by bit they have pushed the premium retail prices higher, because they found a market for it and of course they are going to charge more if there is a market," Mr Cumming said.

While the RACV believes the advantages of using premium unleaded petrol are minimal, there are circumstances when there can be greater benefits, including for cars such as V8s and imports where manufacturers recommend a premium fuel. Cars built before 1986 and designed to run on leaded fuel can also benefit.

The RACV tests did not take into account the claimed long-term benefits for engine cleaning and maintenance.

Mobil spokesman Alan Bailey said the company was not actively encouraging motorists whose vehicles are not designed to run on premium petrol to use the fuel, although he said there was a strong market for Mobil's Synergy 8000.

"There is a portion of the market that places some value on this premium fuel," Mr Bailey said. "There is certainly quite strong demand from people who want that superior quality fuel."

[jamchen]

um...it only convinced me as it appears the way it leads us to think.....
there are advantages to use premium... different cars will perform differently to premium and it got me hard to believe as they only tested them based only on two cars...
the premiums burn/bust better thsan regular... and it will help u to clean out the deposits inside the engine...
a pack less of ciggs will give u enough money to pay for premium for daily drivers,,,

[crx_boy7]

man u guys are all confused
the quality of the feul has nothing to do with the octane!!!
octane is simply a measure for the feuls ignition temprature not its engine cleaning propertys and not how well it burns!!!!!
however it is possible that feul refining companies such as bp can add cemicals to ur petrol to help clean the engine
also be aware that ethanol is not a benefitial addative the only benefit it can sometimes have is to help raise the octane as ethanol has a very high octane on its oun
otherwise ethanol can also cause your oil to loose its thick propertys wear/rust/block injectors and also leave extra deposits in your engine
it is also allot harder to separate from water than feul
BTW tid you know at your local feul station 10%-30% of their underground feul tanks are filled with WATER!!!!!

[RyDC5S]

Optimax and BP Ultimate. Good milage and cleaner fuel.
For myself, gains of about 60-70km over 95RON fuel.

Avoid regular unleaded, unless you are sure about how clean it is. I had clogged injectors in my old EK Civic from 'bad' fuels.

[liberx]

CRX_boy7 is correct, but the pressure/temp of ignition is only part of the explanation.

The octane rating is also a measure for the fuels resistance to "knock" or "ping". In plain terms it is how progressive/controlled the burn is after ignition. A fuel that causes pinging is actually burning too quickly in an uncontrolled (and less efficient) manner, producing masses of force before the piston reaches top dead centre.

For quite a good explanation I found this link: http://www.fitchfuelcatalyst.com/techinfo/aboutfuel.html

[dek]

IMO, the only noticeable factor of using premium over your standard unleaded petrol is fuel economy.

Should just run a quick test on your car, 1 tank of premium, 1 tank of standard

Should easily see the difference.

[krogoth]

thanks for the advice guyz

[xcwizit]

with my SOHC `96 Civic, i only get about 330 kms and lower from 91ron & 95ron, i noticed i was getin higher than 330 kms. regarding that.. why da f|_|k am i just getting this much out of a full tank??

[J-MuN]

btw crx_boy7, its fuel not feul.

[iamhappy46]

98 octane fuel has more energy stored in its chemical matrix, so imagine if 98RON was C4 plastic explosive and 91RON fuel was gun powder. The C4 spec 98RON fuel will require more energy to ignite it while the gunpowder spec fuel can be lit with a match(yes, I know they both can be lit with a match)

98RON fuel requires slightly advanced ignition timing so that the slower burning combustion rate can ignite all the fuel and get the biggest fireball.

If you use 98RON and use it for a tank of two, you will notice the difference as the ECU alters timing to take advantage of the better brew. More energy will be released, which will mean the car can be propelled forward with less throttle input and therefore conserve fuel.

[krogoth]

btw, i did some research first, most of wat i found was test results from fords and holdens, not hondas, i guessed that there would be some differeces
__________________________________________________ __
ma mate has a 206, and it requires premium unleaded,WTF

[crx_boy7]

aktually the higher octanes resistance to pinging is directly related to the octane of a fuel say for example 91ron combusts at 300degrees then 95 ron will combust at 340 and 98 ron at 380. these values are incorect and are used only as an example

the reason you get pinging is that the fuel combusts before the spark plug ignites it by catching fire from hot particles in your combustion camber ie the little metal peice sticking out of your spark plug( this can become red hot and ignite the fuel prematurely) this leads to severe engine damage
yes the vtec ecu will set back the timing if it senses pinging but setting it back only works if the timing has been set incorectly it will do nothing to stop the feul from catching fire from other factors excluding the spark timing!!!

i have also heard that higher ron fuel burns faster and is therefore beneficial in high reving engines(appart from the compression requireing it) but i dont want to be misleading and am not sertain that this is true.

btw thnx for the spelling report - man im dum, cant even spell feul. lol

[crx_boy7]

and also the comments about c4 and gunpowder are actually a better description of feul quality rather than ron
let me give u an exampe
feule = 95ron
ethanol = 124ron(aprox.)
whitch do you think will make your car run faster and why??
the feul being easyer to burn and also cleaner is burnt better and produces more power!!
however an engine designed to use the high octane ethanol will be more powerfull than its petrol counterpart as it can have more compresion and more advanced timing
understand???

[iamhappy46]

Hi RON fuel actually burns slower and is why it is beneficial for engines that 'knock' on standard fuels. It takes just that little bit longer to ignite and hence give a true power stroke.

The 'pinging' you describe is also called 'pre-ignition' where 2 or more fireballs are created and increase the burn rate so that the combustion process occurs prior to TDC.

The C4/dynamite is actually a good example as the 98RON fuel does require more energy input(either compression/timing,etc) to release the power.