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Which Fuel would you recommend for the NC?


MikeBike

Which Fuel would you recommend for the NC?  

146 members have voted

  1. 1. Which Fuel would you recommend for the NC? (ignore factors like there's a shell garage round the corner)

    • Regular unleaded 95 RON - cheapest you find (supermarket etc)
      88
    • Regular unleaded 95 RON - brand (Shell etc)
      28
    • Premium Unleaded 99 RON - cheapest you find (supermarket etc)
      10
    • Premium Unleaded 99 RON - (e.g. Shell Vpower etc)
      20
    • Other
      2


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MikeBike

Someone recently advised me to use the best rather than cheapest fuel for my NC - in Octane and quality - what do you use and what is your opinion as to pros and cons?

Is the extra price worth it. Maybe up to 10% more cost but about 5% more octane already, and supposedly other goodies in terms of keeping engine clean etc.

And does it matter from where (supermarket vs branded petrol)?

I was originally filling up using cheapest ASDA regular unleaded 've been filling up using Shell Vpower 99 octane for the last few tanks but haven't noticed any significant change in mpg yet.

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As Mark says, always a topic of debate and everyone has an opinion. Opinions are like ar$eholes, everyone has one but you don't usually want to hear it.   Here's mine.   Octane rating of itself

It’s the language of the over 70s and not for you youngsters😂

It wouldn’t be the first time we didn’t have a clue either..  

fred_jb

Someone recently advised me to use the best rather than cheapest fuel for my NC - in Octane and quality - what do you use and what is your opinion as to pros and cons?

Is the extra price worth it. Maybe up to 10% more cost but about 5% more octane already, and supposedly other goodies in terms of keeping engine clean etc.

And does it matter from where (supermarket vs branded petrol)?

I've been filling up using Shell Vpower 99 octane for the last few tanks but haven't noticed any significant change in mpg yet.

Hi Mike,

 

I've also tried both and don't notice any real difference.   I do use the higher octane where the only other choice is the E10 stuff, generally in France, which contains 10% ethanol, as I'm pretty dubious about putting this stuff in the bike.

 

Fred

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Rev Ken

It isn't a highly stressed engine so won't benefit from high octane petrol, at least not as much as the extra cost. However some say that it is worth getting a 'branded' petrol as it is likely to have more cleansing additives that some supermarket petrols, but personally I go to the nearest convenient garage for mine!

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steelhorseuk

Personally, I only use the higher Octane (97) as I am not using the NC to commute and it just feels to be more responsive for it and there is the benefit of a cleaner burn etc.

 -Mark-

 

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As Mark says, always a topic of debate and everyone has an opinion.

Opinions are like ar$eholes, everyone has one but you don't usually want to hear it.

 

Here's mine. :devil:

 

Octane rating of itself doesn't mean much in this context. It is a rating for the resistance to "knock" (or pinking etc). In the broadest terms providing the fuel you use meets the minimum required by the engine it is satisfactory (in the case of the NC it's 91RON, regular unleaded in Europe is 95RON, super usually 97-99Ron ballpark).

 

Normal combustion is a gradual process, the spark starts it off and the mixture burns progressively across the cylinder in a controlled manner, it depends on speed/load but the burn might take around 45deg of crank rotation.

 

Knock is when the last part of the mixture in the chamber, which is exposed to increasing temperature and pressure as the rest burns, spontaneously reacts before the flame front reaches it. The mixture undergoes chemical changes which turn it into stuff which will just react on its own without the need for an ionisation source (flame). This results in a significant amount of mixture all reacting at once which gives a very high rate of pressure rise and the sound of a knock (or a tinkling rattling sort of sound, hence the term "pinking"). Out of interest this is typically 6kHz or harmonics, 12kHz etc due to typical dimensions in combustion chambers.

 

Mild or trace knock is not really damaging, it's more an annoyance if you can hear it. Heavy knock can cause damage due to fatigue, it will pit the alum pistons and in extreme will break ring lands. Also it tends to upset the boundary layer of gas resulting in higher heat transfer to the piston and head, which of itself can lead to other more serious and dramatic problems.

 

Octane rating is how resistant the fuel is to doing this, if it doesn't knock then it doesn't knock. there are different ways to test the fuel to arrive at this rating, different speed/load/temperature conditions used in a specific test engine by the fuel companies, and these methods arrive at different numbers, the one we see here in Europe is Research Octane Number (RON), the other common one is Motor Octane Number (MON) and in the USA they refer to the average of these , (RON+MON)/2.

Ron is usually 7 or 8 numbers higher than MON so 91RON will be typically 87 (R+M)/2, so be aware when reading stuff from USA writers.

 

The rating actually is a comparison to a theoretical mixture of 2 specific hydrocarbons, iso-octane which is a straight chain molecule and quite resistant to knock (defined as 100 Octane), and n-heptane which is branched and will very easily knock (defined as zero octane). Thus 95RON behaves like a mixture of 95% iso-octane and 5% n-heptane (it isn't a mixture of these, but it behaves like it).

 

Higher octane fuel allows the engine designers to use higher compression ratios (in simplest terms) in order to get better efficiency (fuel economy and/or power). Using a higher rating fuel doesn't per se give any significant benefits, but it doesn't cause any harm.

 

An incidental aspect however is that the formulation of hydrocarbons which make it less prone to knock happen to make it very slightly denser and very slightly higher calorific value (the energy content per kg). This means that your litre of 98RON will offer a little more energy than a litre of 95RON, but differences are small, typically perhaps 43.5MJ/kg instead of 42.7MJ/kg, so 2 or 3% more energy per litre. This may just about offset the oncost of the fuel per litre.

 

What you do often notice (if you're tuned in to such things) is the higher octane fuels respond slightly better to transients, and with carb engines it tends to be less prone to icing. Transient response is a very engine dependent factor, some engines are quite sensitive but others you can't tell any difference, it just depends how good the combustion system is. This is where iridium plugs also can influence things, it all affects how consistently the combustion is initiated, the first 5-10% of the mass burned.

 

It is often the case that the higher RON fuels have somewhat more effective additive packs for cleaning and anti-oxidation etc, so they can be useful in system maintenance.

 

I always recommend you try some. You may notice some difference, maybe not. You may measure a couple of percent better fuel economy but maybe not. If you like it then fine, otherwise just use 95RON.

 

Personally I find the NC doesn't respond to the RON in any noticeable way, but I have found some tank fills have been "nicer" than others though not related particularly to RON. I do have a Suzuki Cappuccino (650cc turbo) car which definitely responds nicely to V-Power.

 

You pays your money ..................................

  • Like 12
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Premium super unleaded at my local Supermarket for me. If I'm out and about I still stick to premium at a 'branded' petrol station.

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Guest dentonlad

I usually fill up at my local Morrison's. I have, in the past, used higher octane fuel occasionally. Where there was a small gain in mpg it wasn't justified by the extra cost.

I haven't noticed any difference in the way the bike runs when using higher octane fuel either, so I remain unconvinced of its benefits for the bikes I ride.

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Thanks embee, seen a lot of information over the years about this subject but never an explanation detailed enough to have meaning yet simple enough for me to understand. I expect a lot of engineers 'know their stuff' but few have the talent to pass it on to non engineers. 

 

Now onto Quantum Physics!

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steelhorseuk

Yeah, what Embee says. Just what I was thinking ... :ermm:

-Mark-

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most expensive branded stuff, cos it make me feel good to do it :muttley:

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dazznutts

I usually stay clear of Asda Petrol as i have found i dont get good mpg on my car as well as the bike

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I've tried premium fuels in the NC for several fillups but found no difference in urge or MPG.  My TDI Audi on the other hand got very gummed up on supermarket diesel (significant bio content) so I go out of my way to find a premium brand of diesel.

My brother in law worked at an oil refinery and told me when tankers call to fill up the premium fuel has additives pumped into the feed hose dependant on brand etc.  Sometimes they broke down.

I use super unleaded in my old sunbeam as the cheap stuff has a lot of ethanol in it and the moisture that seems to be released rots the tank.

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Guest Thwaitie

I felt the higher octain was smoother, and more responsive especially at lower revs, in turn giving higher urban mileage.  But these slight advantages are outweighed by the difference in price, more so when burning up the miles nearer motorways speeds. 

Cheap supermarkets generally fulfil the need.

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Guest bonekicker

All the supermarket fuel come from the same fuel suppliers-- I tried higher octane and found no difference at all --But if you get some sort of weird pleasure out of paying more--who am I to disagree ??  :baby:

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Guest Big Shot

I have noticed on previous bikes and cars over the years that high octane (99) works well on engines with turbos and superchargers and some manufactures even stipulate this. When I have made some mods to my bikes, filter, decat, exhaust etc even on little 250's 99 octane makes them run better and feel more responsive. I would be interested what a dyno would actually show

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Guest Thwaitie

What did prove frustrating is the way they confusingly name these different octane fuels.

Given the choice of two green handled pumps labelled "Super" or "Premium", one could easily assume the latter represents the highest rated and thus more expensive option, when super simply infers an above average standard.

 

And I was disgusted when starting to fill at one station that displayed an acceptable premium price, when finding the only pump was in fact dispensing an atrociously expensive super grade. 

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.........

I use super unleaded in my old sunbeam as the cheap stuff has a lot of ethanol in it and the moisture that seems to be released rots the tank.

All UK pump fuel is permitted to contain the same amount of alcohols, up to 5%, without having to specifically state the content. The introduction of 10% ethanol content (E10) raised the issue of maintaining  "protected fuels" with no more than 5% for the older fleet requirements, but as far as I'm aware that has not been necessary yet with the 5% limit remaining in force for anything not labelled as E10 or similar.

 

The issues with older vehicles isn't usually specifically to do with water, but the reactions you get between ethanol and certain metals such as "ternecoat" used for fuel tanks and certain combinations of copper based alloys, brasses etc and light metals, aluminium etc. Rubbers have to be selected carefully for compatibility with solvents and fuels, traditionally petrol environments used nitrile or more expensive "Viton" (fluorocarbon) or fluorosilicone rubbers, or PTFE. High ethanol content fuels can cause issues with nitrile (NBR etc) and fluorocarbons. For a guide to compatibilities see for example http://mykin.com/rubber-chemical-resistance-chart , for petrol see  "gasoline". It's a tricky business.

 

Most vehicles made in the last few years (I forget the cut-off) are compatible with E10, there are listings available confirming this if you search.

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MikeBike

E

 

As Mark says, always a topic of debate and everyone has an opinion.

Opinions are like ar$eholes, everyone has one but you don't usually want to hear it.

 

Here's mine. :devil:

 

...

Embee,

Thank you so much for all the detailed information. I have learned lots from reading it. I mistakenly thought the octange was a measure like calorific value. As GunnerNC says you have a knack of being able to express detailed technical information in a way which is undertsandable. NOt only that but it is interesting as well. You should write a book on everything youmight want to know and understand about how your car/bike works... And if there was a prize for the most useful contributor here, well,,, embee has it. I'm so glad we have you on the forum.

 

So back to cheapo unleaded for me... (except that comment about ASDA petrol)

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Rocker66

most expensive branded stuff, cos it make me feel good to do it :muttley:

As it does the Chancellor of the exchequer  :) :)

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Yes brilliant embee,

 

 

Just a thought,

 

If the higher octane stuff has more additives in it then surly you end up with less petrolly bang part for every litre you buy!!

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If the higher octane stuff has more additives in it then surly you end up with less petrolly bang part for every litre you buy!!

I'm not sure what the exact values are but generally the additives are in very small quantities, so I wouldn't worry about losing any bang. Additives are something I'm aware of but have little real idea of the intricacies of the chemistry, just what they are there for. If you want a taster as to how geeky the subject is, try https://en.wikipedia.org/wiki/1,2-Diaminopropane

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TheEnglishman

I did a month(~1400 miles) of super unleaded with the NC and noticed absolutely no difference in performance or economy. 

 

My R1200GS really liked it though - I'd get 10-15% better economy for ~10% more cost, so was well worth it as I'd get 3 and a half days commuting instead of 3 so less filling up.

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