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Super unleaded - higher octane fuel - I don't understand!

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Super unleaded - higher octane fuel - I don't understand!

Old 6th Mar 2008, 12:31
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Super unleaded - higher octane fuel - I don't understand!

Ok someone please help!

I drive a ten year old 1.6 engine size car and do long motorway journeys regularly. Would I benefit from any of this super unleaded stuff? I keep reading articles that say "if you drive at a higher rev rating, you may benefit." So say I do about 75mph on the motorway on long journeys is there benefit to this? I don't quite understand what a higher octane rating might do for me.

Andy
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Old 6th Mar 2008, 12:48
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I drive a car that has what is locally called a "Generation Three engine" and 98 octane is recommended but it is not recommended more than about once a month for the straight forward, lower powered engines.
Hope this helps.
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Old 6th Mar 2008, 12:53
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Dushan
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If you don't experience any pinging, you don't need it. Follow what your manual recommends for your car. Any higher octane than recommended/specified for your car is a waste of money.

The higher the octane, the less likelihood of the fuel/air mixture igniting BEFORE it is intended to (pinging). If you have a high compression engine and it is very hot a low octane gas will ignite from heat/pressure before the spark goes and your engine will ping.

You would probably benefit more with a few doses of injector cleaner when you gas up.
 
Old 6th Mar 2008, 12:56
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Unless it is recommended for your car it is a waste of money.

If it is recommended for your car, your engine will run more efficiently - quicker and more economically. In my experience if you have a car that the book recommends super unleaded, you can get about 10% better MPG,by using it so it just about pays for itself. So if it's recommended you aren't saving money by using the cheap stuff. Your MPG reduces and you lose a bit of power.
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Old 6th Mar 2008, 13:08
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You might benefit more by trying some Acetone in your fuel.

Add a 100ml bottle to around 10 gallons, but make sure you get Acetone BP (100%) and don't use nail polish remover!

If it works for you, you can get it cheaper from sources other than the chemist.
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Old 6th Mar 2008, 13:35
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Blimey ask a question and get lots of answers in seconds - sod wikipedia you lot are far more useful because I don't get chemical equations to a simple question!

Acetone? ¿Que?
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Old 6th Mar 2008, 14:46
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Acetone? ¿Que?
Di-methyl Ketone

Might shift some free water (if any) in your tank, but will not add anything to your fuel quality in that concentration. If you put enough in, it'll **** up your fuel's lubricity too, would be better to add Isopropyl Alcohol to shift any water.

To anwer your original question, super unleaded will only be of benefit if your car's engine management system is designed to cope with the stuff.

As other have said, check the manual. If thats not clear, do a trial run on super and check your consumption - a simple calculation should then indicate whether its of any financial benefit.

Last edited by Mariner9; 6th Mar 2008 at 15:05.
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Old 6th Mar 2008, 15:42
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There's Mariner9's viewpoint and there's others.

Lots of debate about better mpg and smoother running but I'm not about to add to it. Google it to read lots of discussion but remember those who advocate using it are not making anything out of it if you do,
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Old 6th Mar 2008, 17:34
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Your car might benefit from higher octane. Most petrol engines give best power where the ignition advance setting is just outside the point where pinking takes place. If the engine management system can recognise a better quality fuel, (knock sensor equipped) it may allow a more advanced ignition setting (my Beemer can tell the difference). This can result in a better performance.

On older cars I have owned (got one now) there can be a marked difference. I manually adjust the ignition advance setting to compensate for quality of fuel used.

Best way is to try it for a couple of tanks full and see what happens.

(Edited to add the word "just", which should have been there in the first place to make more sense)

Last edited by ShyTorque; 6th Mar 2008 at 21:09.
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Old 6th Mar 2008, 17:37
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my Beemer can tell the difference
[PEDANTIC] Beemer is a motorcycle made by BMW, Bimmer is a car[/PEDANTIC]
 
Old 6th Mar 2008, 21:04
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[PEDANTIC] Beemer is a motorcycle made by BMW, Bimmer is a car[/PEDANTIC]
Thanks for that information, I always feel honoured when someone in authority helps out. Any helpful info on fuel grades to go with that superior knowledge, though?

P.S. My mother in law had a car called "Bummer". It wasn't even made in Germany.

PKPF, If you want scientific information ( ) you really need to put your hand in your wallet, put your own car on a rolling road and get some figures using both normal and super unleaded fuel. Some cars might be better, some might not; even two supposedly identical cars can give quite different results.
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Old 6th Mar 2008, 22:52
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Shy Torque is pretty much right. Without a knock sensor your engine can't advance the curve to take advantage of the higher octane fuel unless you manually adjust it.

However, if you just stick 98+ in without changing anything you may experience a smoother ride due to the fact the fuel ignites easier. Some say that's just a placebo effect but I definitely notice a difference.
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Old 6th Mar 2008, 23:30
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Shy,

Any helpful info on fuel grades to go with that superior knowledge, though?
If you look back you'll see that I did offer useful info, in general terms, as well as suggesting that reading the manual is the most accurate source of the information. I check my Bimmer manual, put together by the same people who designed the car, and go from there.


BTW it is pinging, not "pinking" unless you are thinking of this:

 
Old 7th Mar 2008, 00:02
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BTW - it is 'pinking' in the UK:

pink (ENGINE NOISE) UK
verb [I] (US ping)
When a car engine pinks, it makes a high knocking sound because the fuel is not burning correctly.

(from Cambridge Advanced Learner's Dictionary)
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Old 7th Mar 2008, 00:12
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[PEDANTIC] Beemer is a motorcycle made by BMW, Bimmer is a car[/PEDANTIC]
Brilliant, from the pedant, we get ping. Ooh, lovely ping ping.

BTW it is pinging, not "pinking" unless you are thinking of this:
It's pinking ! Arse !

Got this from Wiki:

Knocking (also called detonation or spark knock, pinking in UK English or pinging in US English
There is no such thing as US English. There is English, and there is that Bastard language spoken by twatting Americans !

S_H

Last edited by Safety_Helmut; 7th Mar 2008 at 00:23.
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Old 7th Mar 2008, 00:32
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Attempting to remove foot from mouth...

OK Shy, first of all, I apologize for the jab. I honestly didn't know you guys call it "pinking". Just didn't sound right.

Safety, if you are going to quote from Wiki, then either you accept their definition or not. You cannot quote "pinking in UK English or pinging in US English ", then accept the pinking/pinging part but not accept UK English/US English.
 
Old 7th Mar 2008, 01:33
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Pre electronic management systems on engines (MGB and the like) the fuel octane required depended on the compression-ratio and the ignition timing. If your cylinder-head had been shaved (or high-compression pistons fitted) then you needed higher octane fuel and an appropriate ignition timing setting.
When first generation electronic engine management systems were introduced some had a changeover plug to accommodate (usually lower) octane fuels for use when travelling in territories where 'inferior' fuel was standard. Some had settings for higher octane fuels, particularly vehicles that were 'sporty'.
Later generation electronic engine management systems employ sensors to detect 'knock' and adjust engine timing (both ignition and injection) to keep things within certain parameters. You need to know the extent of this compensation (WRT fuel octane ranges). You might be 'lucky' and have settings that will automatically embrace all available fuels, or you might have a system that cannot adjust for super unleaded, in which case you will not harm your engine, merely your pocket.
So, as others have suggested, RTFM . . .
(or contact the manufacturer - being careful to quote the precise model designation from the vehicle identification plate (which might be reproduced in the handbook - but don't rely on it, as the manual might be the wrong one for your model) ).

Using fuel of a lesser octane rating than that which is stipulated by the manufacturer will ultimately harm the engine if you indulge in sustained full throttle use (either under load climbing hills or towing a trailer or high speed travel).

Some engines actually do need higher octane fuel, such as race engines with very high compression and some turbocharged engines, such as the import version of the Nissan Skyline. Also, a few vehicles, such as the new BMW K1200R motorbike, can sense knock and adjust their engine tuning to take advantage of higher grade fuels. Another user commented that the 2004 BMW 330 also does this, according to the driver's handbook it makes 231 BHP on 98 octane and 221 BHP on 95. This ability is apparently widespread amongst German performance cars using Bosch / Siemens electronic engine controls.
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Old 7th Mar 2008, 01:38
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And again Dush. In the UK we use Beemer to mean a BMW. It's only twattish "R&B" and (c)rap ""stars"" who seem to prefer the other version!

And the octane will make very little difference to where in the cycle the spark plugs are fired, as it's to do with the ability of the fuel/air mixture not to ignite under high pressure/temperature environments, nowt to do with how well it burns or anything like that!

As for any benefits or otherwise of using it in a particular engine, I would suggest consulting the manufacturers handbook, or if you are looking for personal experience then find a website dedicated to the vehicle you drive.

What? You expected some scientific mumbo jumbo from me? I'm just here for the fight!

Right, (rolls up sleeves) Dush, outside, NOW!!!
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Old 7th Mar 2008, 02:18
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You know, Matt, I haven't been called Dush since high school. It brings back memories. Thanks for that.

This is from Canada, as in NOT USA:

Bimmer vs. Beamer


Enthusiasts vs others
Definitions:
Bimmer - proper accepted slang for BMW cars. Most people don't know this.
Beamer/Beemer - proper accepted slang for BMW motorcycles. You will hear this term used incorrectly by many people.
Bummer - When you get a speeding ticket.
Bitter - Another German car. Very rare; hand built.

So just why is a BMW car called a 'bimmer' not a 'beemer' or 'beamer'?

The answer in part lies in knowing some BMW history and what came first.

All real BMW enthusiasts know that BMW got a big start on two wheels, what many call the real BMWs.

In those days, BMW motorcycles were quite active in racing, and one of their competitors at the track was often the BSA bikes.

Well as things would have it, a track slang developed, and the BMWs were usually referred to as 'beemers' and the BSAs were referred to as 'beesers'.

So, of course for any true enthusiast, there is no way that a BMW car could be called a 'beemer', so they were called 'bimmers'.

Unfortunately, in the US and Canada, and perhaps other countries, there was a time (kind of still is) where for various reasons, a BMW owner was considered an upwardly mobile person, and of course due to the fun in driving their BMWs most all of them had big grins on their faces.

Hence it is little surprise that the non enthusiast types out there incorrectly labeled BMW cars and their owners as 'beamers' or 'beemers'.
 
Old 7th Mar 2008, 02:24
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Dush, what a complete load of unmitigated clap trap!

I am well aware of the history of BMW. Though not a fan personally I can appreciate the engineering.

But trust me on this, in the UK the usual usage is a beemer. Bimmer is only ever heard on rap tracks!

And Canada, that's the USA's poorer little brother isn't it?
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