Petrol Octane Rating

[earpl]

all bow down to scionic and god bless the atlantic ocean.

[scionic]

I didn't create the facts, I'm just reporting them. ;)

This isn't an issue where opinion enters the picture. It's chemistry, not philosophy.

Sorry if sounded like a d1ck. It's just the height of idiocy to argue with pure facts when you have nothing based on the scientific method to support your assertions.

I don't care if you two spend more for premium fuel, I'd just like to the the thread not become a source of misinformation for others who'd like to make an educated decision rather than an emotional one.

[reece]

all bow down to scionic and god bless the atlantic ocean.

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scionic is talking sense, reminds me of the emperors new clothes!

[s0cks]

You're my hero scionic. Couldn't have worded it better. And just to add support to scionic's posts; me and my mate both used optimax for a pre-longed period of time. And none of us can say we noticed any difference....

:)

[scionic]

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

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No crud present. Your fuel just ignites at a slightly lower temperature than 98 or 100 RON would, which is precisely what you want. That is the ONLY difference.

Fuel is supposed to combust. If it isn't combusting too early in the cycle (indicated by knocking and pinging under load) then you are doing just fine.

Choosing fuel that is more difficult to ignite doesn't sound like it would help, does it?

That's because it doesn't.

[yvvan]

Choosing fuel that is more difficult to ignite doesn't sound like it would help, does it? 

That's because it doesn't.

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Without the spark from the sparkplug you mean.

Yves.

[Red Yaris 54]

I started this thread back in March.

My original observation was that 95 and 97 RON fuels were both priced at the same price at my local Sainsburys filling station.

I asked if it would have any advantages to use 97 (at the same price as 95)

I am astonished at the amount of debate that has taken place on the forum.

Thanks for all your views. I am sure this debate will run and run.

Sad thing is that the 97 RON fuel has now gone up in price to 3p per litre more than the 95 RON :( :( at that filling station, and in those few weeks the 95 RON is now the same price as the 97 RON was everywhere else. :( :(

THATS INFLATION FOR YOU :ffs:

[scionic]

Choosing fuel that is more difficult to ignite doesn't sound like it would help, does it? 

That's because it doesn't.

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Without the spark from the sparkplug you mean.

Yves.

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Uh... YEAH.

We are talking about petrol, not diesel here.

[yvvan]

Choosing fuel that is more difficult to ignite doesn't sound like it would help, does it? 

That's because it doesn't.

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Without the spark from the sparkplug you mean.

Yves.

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Uh... YEAH.

We are talking about petrol, not diesel here.

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Maybe it does help. :)

I'll give you a hint: flame-front propagation.

Yves.

[scionic]

Go back to page 2 and click the links I posted.

[scionic]

Maybe it does help. :)

I'll give you a hint: flame-front propagation.

Yves.

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What about it?

We're talking about 100 octane fuel in an engine designed to run on 87.

I'm afraid your "hint" doesn't tell us anything at all. How does the shape and formation of the spark event going to be affected in anything but a negative way by using higher octane than what's intended? Please support your theory, if you can.

[yvvan]

Firstly we aren't talking 100 <> 87 RON, but rather 97 <> 95 RON, just in case you might think exaggerating things will help you better prove your point.

Secondly, I am not discussing that under normal driving you will see any advantage at all using a higher octane rating than needed.

Oh, yeah, before I forget. The resistance to pre-ignition a higher octane fuel has, has it's role in the flame-front propagation as it aids in preventing the spontaneous ignition of the fuel-air mixture ahead of the flame-front as a result of the rise in cylinder pressure caused by the onset of ignition by means of the spark plug.

Yves.

[seveer unaek]

all bow down to scionic and god bless the atlantic ocean.

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God bless it indeed. Even if it does (with the aid of the wind) carry america's O-zone layer destroying gasses over to us... and all it's unwanted weather.

Also, Mr Arizona.... don't mess with our boy Yves... he's the man... needs his name changing to car god!

Also, did you really need four posts earlier to answer questions... we have lots of space to write on here, please don't clog us up with posts intended for building post count.

[scionic]

Firstly we aren't talking 100 <> 87 RON, but rather 97 <> 95 RON, just in case you might think exaggerating things will help you better prove your point.

No, it was an honest mistake, but I'm still right.

Secondly, I am not discussing that under normal driving you will see any advantage at all using a higher octane rating than needed.

Sounds like we agree then!

Oh, yeah, before I forget. The resistance to pre-ignition a higher octane fuel has, has it's role in the flame-front propagation as it aids in preventing the spontaneous ignition of the fuel-air mixture ahead of the flame-front as a result of the rise in cylinder pressure caused by the onset of ignition by means of the spark plug.

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This also does not counter any point I've made. Higher octane prevents pre-ignition in cars that require it. A car that is designed for regular octane will not pre-ignite on regular octane unless it is badly out of tune or under extreme load, such as towing a trailer up a mountain on a hot summer day and even then, it's unlikely. I think we are in total agreement here, I have no problem with anything you've said.

[reece]

Also, did you really need four posts earlier to answer questions... we have lots of space to write on here, please don't clog us up with posts intended for building post count.

seveer unaek... wind your neck in, you're not a mod. Scionic is talking sense, it's good to see a healthy debate about something sensible for once other than ‘What’s your favourite colour’ and ‘Cute kittens!’

If you want to complain about posts that clog up the forum check out 80% of other threads.

[seveer unaek]

Fair do's reece on the topic point... it is nice to have a debate. But on the clog up point, i can think of a good way to clear up the clog... just delete about 500 or so useless points delivered by yourself.

[Demonic Angel]

Also, did you really need four posts earlier to answer questions... we have lots of space to write on here, please don't clog us up with posts intended for building post count.

seveer unaek... wind your neck in, you're not a mod. Scionic is talking sense, it's good to see a healthy debate about something sensible for once other than ‘What’s your favourite colour’ and ‘Cute kittens!’

If you want to complain about posts that clog up the forum check out 80% of other threads.

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Whats wrong with cute kittens?

I am just enjoying you lot at each others throats - its good SoTOC bedtime story material!

[reece]

We’re just one big family on here, and like most families we don’t always see eye to eye. It’s good to get things off your chest and at least we can say if we don’t agree with each other.

It would be pretty boring if we all agreed all of the time

[seveer unaek]

We’re just one big family on here, and like most families we don’t always see eye to eye. It’s good to get things off your chest and at least we can say if we don’t agree with each other.

It would be pretty boring if we all agreed all of the time 

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Absolutley right.... just some of us have a better turn of phrase than others... but again, that's just people being different.

[scionic]

:group-cuddles:

[Fmrl]

Just my 2p worth (actually it's got nothing to do with the difference between 95 and 97 so please feel free to ignore this post!)...

I bought my CTS back in January and had been filling it up with Sainsburys unleaded every week up until a few of weeks ago. Average mpg was constant at 35.3 (as displayed on the dash).

I needed to fillup late one Sunday evening and I didn't think Sainsburys would be open so I visited a BP garage instead. After about 50 miles or so I noticed a slight difference in the way the car performed (bit more "revvy" and "perkier", like she'd been sucking on an Airwave or something ).

I've been using BP ever since and the average mpg has been slowly going up all the time (it just hit 35.9 this morning!!!). I should've reset it when I switched to BP.

[clarky]

Several times I've heard people referring to resetting the ecu after adding an additive or using higher ron rated petrol - how do you reset then?

[earpl]

We’re just one big family on here, and like most families we don’t always see eye to eye. It’s good to get things off your chest and at least we can say if we don’t agree with each other.

It would be pretty boring if we all agreed all of the time 

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<_<

[earpl]

Just my 2p worth (actually it's got nothing to do with the difference between 95 and 97 so please feel free to ignore this post!)...

I bought my CTS back in January and had been filling it up with Sainsburys unleaded every week up until a few of weeks ago. Average mpg was constant at 35.3 (as displayed on the dash).

I needed to fillup late one Sunday evening and I didn't think Sainsburys would be open so I visited a BP garage instead. After about 50 miles or so I noticed a slight difference in the way the car performed (bit more "revvy" and "perkier", like she'd been sucking on an Airwave or something  ).

I've been using BP ever since and the average mpg has been slowly going up all the time (it just hit 35.9 this morning!!!). I should've reset it when I switched to BP.

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i hate to burst your bubble pal, i came to post this i found out yesterday anyway. but i found out off my cousin that sainsburys buy their fuel off bp, hence sometimes you'll see un marked tankers in bp garages and bp tankers in sainsburys garages ;)

[Fmrl]

Hmmm, it's a complete mystery then!

Ever since I changed to BP my MPG has been steadily going up so I'm definitely not going to bother with Sainsburys anymore.

My mate has a mondeo and it broke down after filling up at Sainsburys once. The garage he took it to had fixed a few cars that had done exactly the same thing. After a complete flush the car was fine again.

...maybe it's just a problem with my local Sainsburys.