Petrol Octane Rating

[Xtreme_Cyborg]

It's a myth.

If you go to shell just use their standard unleaded.

Optimax is:

- Expensive

- Doesn't increase performance

- It is cleaner, but isn't gonna make much difference compared to standard unless you plan on keeping the car or a lifetime! (they never had it before and 15+yr old cars are still running fine!)

- More mpg, but high price, so it defeats the point

If you have the money, then sure get it cus it is better for the car (and in kimi's case I can understand why she has to have it).

But to be honest there is absolutely nothing wrong with sticking with 95ron and it'll save you some dosh too! However, I would suggest that you use a brand fuel rather than supermarket fuel (as supermarket fuel is just different brand fuel mixed together depending on whats cheapest - so it dirtier!).

Be thankful, in a lot of countries 90-92ron is standard (and 95ron is ultimate!) - like in new zealand 

Hi!

I can assure you that there is a difference in 95 to 98 Ron fuel's. It is pointless putting it in your 1.3's and even tsports because lets face it they don't run highly optimised/Aggressive ignition maps and all the octane does is to reduce the chance of detonation so a increased amount of ignition advance can be used allowing a increase in power.

With kimi's car it is different to all your's because of the ECU has a map in it to run just on 98+ cause on the continent that is the run of the mill fuel as most fuel stations sell the higher octance 100ron fuels as theyre performance fuel.

So there is definatly a difference in Optimax and even ultimate. i dont find ultimate any different to normal 95Ron fuels.

Chris

[seveer unaek]

Sorry DA, no meaning to offend the trade!

Also, i understand that the 1.3 is no way a performance car, suppose i was just being pedantic, but i do believe that it has made my car smoother.

Even if it hasn't, a couple of pence extra is no great shakes and it definatley is the cleanest fuel on the market, so im happy to use it, wether it's performance enhancing or not! Only the best for my Yaris!

[Viper_7]

There's nothing wrong with supermarket fuels...it's just Esso/shellP branded stuff anyway....but sure it usually is a bit of a mixture...but that's no big deal unless you drive high performance cars. as for it being dirtier?!..that's what your fuel filter is for, most of the crud gets in the tank doesn't come from the fuel, but from the tank corroding.

It's cheaper simply because they sell so much of the stuff, and also mainly entices you to shop there too. Sainsbury's fornstance quite often give you 5p off every litre if you spend £75 in the supermarket. 97RON at the above is usually 4p dearer...which makes it expesive compared to a better optimax type fuel.

As to which is better 97 at Sainsbury's or 95 pretty much indifferent..., and not worth paying the extra...at the ususal prices.

[earpl]

i noticed a big difference using ultimate (ron 97), deffanately different, i filled the tank with ultimate, and big bottle of additive today, i reset the ecu, gave it 30 miles to run in and all i can say is WOW!

[mark999]

The only difference between ordinary supermarket fuels and branded fuels is the additive package.

Optimax/Ultimate are higher octane (98RON) and are cleaner as they contain more oxygenates.

If you have a car with an ECU that can adjust itself for fuel quality you will notice a big difference.

Worth mentioning is that the Ulitimate/optimax sold in different countries is not the same in Germany it is the best you can get at 100RON

[scionic]

i noticed a big difference using ultimate (ron 97), deffanately different, i filled the tank with ultimate, and big bottle of additive today, i reset the ecu, gave it 30 miles to run in and all i can say is WOW!

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All I can say is "placebo effect" mate.

Don't mean to sound like a ubik, but the science doesn't bear that out. There is no extra power hidden in high octane fuel. All it does is resist pre-ignition more. If your car isn't engineered to use it then it won't be retarding igniton timing or knocking on regular fuel. If it's not retarding timing or knocking on regular fuel then there is no "extra" power to be gained. No cars ECU will not advance timing with higher octane fuel than it is designed for. Facts is facts, as they say. But I don't see any harm in it if it makes you happy.

Spending money on additive as well, hmm... Well you've got Audi's too so I guess you can afford to do that.

[jane-b]

I use BP unleaded which has a 95 sticker on the nozzel, car runs great! The prices are getting stupid once again but I agree with using petrol staton fuel and not supermarket fuel

[Caz SR]

I've been told that petrol loses it's RON rating over time, so unless you've just filled up after a delivery, chances are the petrol you're buying may be a little 'off'. This also applies if you cover quite low mileage - as it's just sitting in the tank.

If you're lucky enough to find it the same price as 95, might as well give it a go. I very occasionally use a higher RON (when I'm feeling a little flush) just to experiment and see if it makes any difference. I can't say it's outstanding, hence only the occasional fill-up.

[seveer unaek]

I very occasionally use a higher RON (when I'm feeling a little flush) just to experiment and see if it makes any difference. I can't say it's outstanding, hence only the occasional fill-up.

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In that there sentence you have summed up why people don't think it makes a difference... you've got to run your car on it for a least 4 fill ups... for me thats just over a month and then you should notice the difference! I definatley did... never mind what any scientist or science says... i know it made a difference!

Science is often wrong... earth isn't flat, atom isn't the smallest thing etc etc... It's first-hand human knowledge that's fact... FACT!

[gordypix]

I would hope your Yaris can give you more than 350 to a tankful.....

I get 340 - 350 miles from full to just short of the fuel light coming on in my 190.

Maybe I have a biger tank (dunno actually - how big is the yaris tank) then that would make my MPG = rubbish........

And after that he has never gone back to it because he noticed NO difference (and this is in a performance car!).

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Well thats my mind made up then - no 97 RON for my performance car either!

The way I see it, I get 350 miles to a tank of 95 RON - ok so I might get an extra few miles with 97 RON - but the extra cost of the fuel will actually make me worse off, even with those extra few miles!

As for your comments on the psychological effect s0cks - I am a psychology student, so I guess it makes sense that I look at it that way! :D

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[gordypix]

Filling up with a higher RON once in a blue moon is pointless and a waste of money. You will only be mixing that fuel with the previous fuel and diluting it.

Several tanks full of the new stuff at least to flush all the old fuel through and then you can judge if it's any different.

[seveer unaek]

Filling up with a higher RON once in a blue moon is pointless and a waste of money. You will only be mixing that fuel with the previous fuel and diluting it.

Several tanks full of the new stuff at least to flush all the old fuel through and then you can judge if it's any different.

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Exactly my point!

In response to previous question... Yaris tank is 9.9 gal or 45 litres and i get about 300miles out of mine... but i do drive enthusistically.

[Caz SR]

Fair enough. I always run the tank near to the bottom before filling up with a higher RON so it doesn't mix as much anyway, same the other way round.

[seveer unaek]

But what about all the fuel still in your engine, the stuff left in the pipes... theres actually a fair bit there! Run it on optimax for a few fill ups, then see what difference you find... only then will you have an educated answer to whether it improves your economy, performance and cleanliness of your car!

[jonny_brin]

Don't know if everyone knows this and I'm just being stupid, but...

I know a higher RON rating means there is more octane which reduces pre-ignition of the fuel, but what exactly does RON stand for?

[gordypix]

Ok so based on a Yaris with a 45 litre tank and a Celica with 55 litre tank and me and Em doing roughly the same miles per tank......and then Seveer doing about 300 a tank

My celica average = 6.36

DM's Yaris average = 7.7 miles per litre :)

Seveer's Yaris average = 6.6

So Yarii ain't all that good now are they...........

Filling up with a higher RON once in a blue moon is pointless and a waste of money. You will only be mixing that fuel with the previous fuel and diluting it.

Several tanks full of the new stuff at least to flush all the old fuel through and then you can judge if it's any different.

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Exactly my point!

In response to previous question... Yaris tank is 9.9 gal or 45 litres and i get about 300miles out of mine... but i do drive enthusistically.

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[earpl]

i only get about 250miles per tank.............:0

SCIONIC, i assure you it does pal, video 's dont lie, im never happy with feeling faster, i have to have proof ;)

[seveer unaek]

Gordy... if i drive sensibly, and do longer trips, it's easy to get 45mpg+, but i drive 'enthusiastically' so mpg drops greatly!

Jonny... RON stands for Research Octane Number.

[jonny_brin]

Cheers...

[Blue84]

The Blue had supermarket fuel (95 ron) in her when I got her from MrT which disappeared so quickly, and I've filled her with BP Ultimate since and it really lasts much longer..infact I can't even notice a difference between the consumption in the Blue compared to my previous 1.0L. I usually fill up every 2.5 weeks, and at the moment do a 15 mile either way trip to work and back 4 days a week so it lasts me, and I will pay more for that. no matter what anyone says.

[Demonic Angel]

Well I'm not convinced and I shall not be paying ludicrous 97 RON prices just to gain another couple of miles to the tank! :shutit:

Ok so based on a Yaris with a 45 litre tank and a Celica with 55 litre tank and me and Em doing roughly the same miles per tank......and then Seveer doing about 300 a tank

My celica average = 6.36 crybaby.gif

DM's Yaris average = 7.7 miles per litre smile.gif

Seveer's Yaris average = 6.6 eek.gif

So Yarii ain't all that good now are they........... laugh.gif

Yayyyy for my 7.7 miles per litre of "full of crud" 95 RON!

[scionic]

I very occasionally use a higher RON (when I'm feeling a little flush) just to experiment and see if it makes any difference. I can't say it's outstanding, hence only the occasional fill-up.

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In that there sentence you have summed up why people don't think it makes a difference... you've got to run your car on it for a least 4 fill ups... for me thats just over a month and then you should notice the difference! I definatley did... never mind what any scientist or science says... i know it made a difference!

Science is often wrong... earth isn't flat, atom isn't the smallest thing etc etc... It's first-hand human knowledge that's fact... FACT!

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Science is about being objective.

Driving your car on high octane and "thinking" it "feels" more powerful is the opposite of objective.

A seat of the pants evaluation doesn't provide measurable results that can be reproduced.

This is why man created science.

But you are free to do what you wish, as always.

[scionic]

But what about all the fuel still in your engine, the stuff left in the pipes... theres actually a fair bit there! Run it on optimax for a few fill ups, then see what difference you find... only then will you have an educated answer to whether it improves your economy, performance and cleanliness of your car!

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How would that provide an educated answer?

What are you using to measure the variables besides your **** in the seat?

Do a dyno run with regular fuel and with high octane, then you'll have an educated answer.

Did you know higher octane than you need can actually reduce performance?

Maybe these will help, if you are genuinely interested in learning more about the topic:

http://www.aaawa.com/news_safety/news_room...ding_octane.asp

http://www.eric-gorr.com/techarticles/Fuel_Basics.htm

http://www.skillcentre.com/gas.html

EVEN oil companies THEMSELVES admit higher octane than the engine is designed for does nothing:

http://www.mobil.com/USA-English/GFM/Produ...asoline_FAQ.asp

I'm not sure if you're interested in the truth or not though, it is up to each person that reads this post to decide what is more logical. Some stranger on the internet insisting higher octane fuel gives a car better performance than the fuel it's designed to use? Or the weight of the entire science community and even the oil industry that has a vested interest in conning you into buying more expensive fuel?

The only other explaination is that you were getting poor quality fuel before and you've found a better service station to buy your petrol. In that case, just buy the regular octane fuel at that station.

Or be a victim of marketing hype and self-induced placebo effect. Up to you, mate.

[scionic]

i only get about 250miles per tank.............:0

SCIONIC, i assure you it does pal, video 's dont lie, im never happy with feeling faster, i have to have proof ;)

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You should hold a press conference then, because you've discovered something that counters absolutely all the research in the field of petrochemicals and internal combustion engines.

[scionic]

for me thats just over a month and then you should notice the difference! I definatley did... never mind what any scientist or science says... i know it made a difference!

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Sort of how people just KNEW the sun revolved around the earth no matter what any silly scientist said, right?