Feeding the GS Super Unleaded

Feeding the GS with Super Unleaded (RON 97+) could be hazardous for your licence!

I have been running the GS on Super unleaded since i got over 2000 miles the other week, and here are my impressions so far

bbbbrrrrrrrrrrrrrrrrrroooooooom, brrrrrooooooooooooooooommmm, brrrrrooommmmmmmmmm, brroooooooooommmmmmmm, sqqquueeaallll! burble, burble, burble, clunk, brrrrom, brooom, burble burble (lights change) brrrrroooooooooooooooooooommmmmmm, brooooooooooooooooooooommmmm (etc...)

In all seriousness though, it seems to run better;

A few people have commented on the fuelling at or below 2.5K rpm, which was noticable if a put it in second and let it wander along off the throttle, this issue has disappeared on mine when running super unleaded

It appears to have a stronger pull from lower down the rev range, and even opening up the throttle at low revs it pulls more cleanly.

It also runs more efficiently, i'm getting around 10 miles more per tankful, which at 2p/litre difference between 95 and 97, it costs me less per mile to run the GS on super unleaded than regular.

Cruising on the motorway at 90+mph in 6th, if you open the throttle it seems to pull harder.

Also its much more easy to power wheelie (for those that are that way inclined)

Plus its better for the environment as i'm burning fuel more efficiently



Don't know if anyone else tried it, but these are my results so far...

Try to use nothing but 98 ron in both my GS & my Subaru.
Have noticed more power in both & better fuel economy.
Is nearly 9c/litre dearer (with fuel at au$1+ a litre), but comes more then close enough to paying for itself in extra mileage & grin factor.

Please do not do this.

And if you do go tell it to some other person who believes in fairies.

All that happens in a roadgoing motor with contemporary fuel is that HC is burned. If the knock levels are ok then all is fine. If not(too low fuel octane) engine gets f***d. If octane too high money is wasted. That is what you seem to be doing-do you work for Shell/BPor other interested party?

We are not talking about super fuels in F1 or Moto GP, so if YOU really think that YOU can differentiate by performance then go join the fairies.
Otherwise get your bike fueling etc sorted and please leave the rest of us out of this pseudo science.

Same goes for lube oil maniacs who wish to compare notes on every 100 miles use of a 6k oil change.

Please just ride it and leave the physics to those who have some idea. After all they gave you the two year guarantee.

Incidentally, what happened to the MMR versus single jab discusion for hexheads. Did any develop autism?

Sorry, must be getting old and illiberal.

Disgruntled

I wish I could have "Skinny 12" back in order to perform such experiments upom her....

...........did I mention my ABS/servo pump was bolloxed?

Chris

Fully agree with Terry. You need an engine with a higher compression ratio to make the most out of higher octane fuels.

If it runs fine on 95RON, it won't run 'better' on 98RON.

These oil companies are damn fine at marketing don't you think?? Shell Optimax my arse

OK - how come I get 25-30 more miles out of a tankful of super unleaded?

Mike

Mike O said:

OK - how come I get 25-30 more miles out of a tankful of super unleaded?

Mike

Click to expand...

Mike,
Maybe the "additive" you are using is colouring your readout of mileage.
Personally I challenge you to go to a local filling station with me, fill up and do a parallel trip of, say, 200 miles and prove it.

We each give GBP100 to a independent witness(cop/lawyer or whomever)and winner takes all.

When are you coming to play, sir.

Russ said:

bbbbrrrrrrrrrrrrrrrrrroooooooom, brrrrrooooooooooooooooommmm, brrrrrooommmmmmmmmm, brroooooooooommmmmmmm, sqqquueeaallll! burble, burble, burble, clunk, brrrrom, brooom, burble burble (lights change) brrrrroooooooooooooooooooommmmmmm, brooooooooooooooooooooommmmm (etc...)

Click to expand...

that is so.... resonant

so - seriousness aside - speaking as a novice, approximately how are you doing your power-wheelies? 2nd gear and snap the revs to 6000?

GSmonkey said:

Fully agree with Terry. You need an engine with a higher compression ratio to make the most out of higher octane fuels.

Click to expand...

Really? My DRZ400S has an 11.3:1 compression ration(1) which is similar to the GS's 11.0:1 value that you find on the net(2) - indeed, one source at least cites them as having exactly the same figure.(3)

OK, so my DRZ is a single cylinder and rather smaller - perhaps you can write-off the differences against that - but from extensive personal experience (7000 miles on-road including a tour to Italy over the Alps and back) I can state that SuperUnleaded (eg: Optimax, BP Ultimate) does have a significant performance benefit on the DRZ, including an extra few MPH on the top speed, and greater ability to accelerate with a 20st rider and 3st of luggage on it.

Perhaps you can explain why this would be, to me, please?

I have not yet done enough comparison between normal/super on the 12GS to make the same statement, but preliminary indications seem to be in agreement.

(1) cite: http://www.google.com/search?q=drz400s+compression+ratio&ie=UTF-8&oe=UTF-8

(2) cite: http://www.google.com/search?q=r1200gs+compression+ratio&ie=UTF-8&oe=UTF-8

(3) cite: http://motorcyclistonline.com/firstrides/r1200gs05first/

So if the octane rating makes no difference to power output,as a few people are suggesting,if I add a measure of paraffin to my fuel,hence lowering the rating,(very crudely,sic),the power output will not drop?
Why was 'pool petrol',(I think that was the name used),discontinued after the war if its lower octane level gave the same performance as normal fuel?
Put a bike on the dyno and record the difference,it DOES exist!

See this old technical note, still relavent (last para).

http://www.ibmwr.org/otech/octane.html

The octane rating of the fuel isn't the only issue when using branded fuels as i understand it, additional additives affect the running charactersitics of an engine and certainly have an effect on the fuel injection systems of modern bikes.

The below info is taken from this link:
http://members.tripod.com/~miniwww/gasoline.htm

4.12 Are brands different?
Yes. The above specifications are intended to ensure minimal quality standards are maintained, however as well as the fuel hydrocarbons, the manufacturers add their own special ingredients to provide additional benefits. A quality gasoline additive package would include:-

octane-enhancing additives ( improve octane ratings )
anti-oxidants ( inhibit gum formation, improve stability )
metal deactivators ( inhibit gum formation, improve stability )
deposit modifiers ( reduce deposits, spark-plug fouling and preignition )
surfactants ( prevent icing, improve vaporisation, inhibit deposits, reduce NOx emissions )
freezing point depressants ( prevent icing )
corrosion inhibitors ( prevent gasoline corroding storage tanks )
dyes ( product colour for safety or regulatory purposes ).
During the 1980s significant problems with deposits accumulating on intake valve surfaces occurred as new fuel injections systems were introduced. These intake valve deposits (IVD) were different to the injector deposits, in part because the valve can reach 300C. Engine design changes that prevent deposits usually consist of ensuring the valve is flushed with liquid gasoline, and provision of adequate valve rotation. Gasoline factors that cause deposits are the presence of alcohols or olefins. Gasoline manufacturers now routinely use additives that prevent IVD and also maintain the cleanliness of injectors. These usually include a surfactant and light oil to maintain the wetting of important surfaces. A more detailed description of additives is provided in Section 9.1.

Texaco demonstrated that a well-formulated package could improve fuel economy, reduce NOx emissions, and restore engine performance because, as well as the traditional liquid-phase deposit removal, some additives can work in the vapour phase to remove existing engine deposits without adversely affecting performance ( as happens when water is poured into a running engine to remove carbon deposits )[30]. Most suppliers of quality gasolines will formulate similar additives into their products, and cheaper lines are less like to have such additives added. As different brands use different additives and oxygenates, it is probable that important parameters, such as octane distribution, are different, even though the pump octane ratings are the same.

So, if you know your car is well-tuned, and in good condition, but the driveability is pathetic on the correct octane, try another brand.

It is true that some engines will show no discernable difference with a change of octane rating,using super-unleaded in a Bantam ain't gonna make it run better.
However,modern engines are a bit more refined.
If you want to see the ultimate con trick using 'the quality of the fuel makes no difference to the power output',do a search on Yahoo for the Pantone conversion.
People actually paid for this design!

A friend of mine logged his fuel usage over 15,000 miles in a smart car using ordinary unleaded and Optimax and found no difference in mpg and didn't feel it improved performance.

In my BMW 330ci I do get an extra 30-40 miles per tank - have measured it ...

the vehicle itself does make a difference - I know that the handbook for my car recommends 98ron fuel but says it will operate on 95 ron.

Believe what you will, but the FACT is I do get more kilometers using 98 ron then i do the lawnmower grade standard petrol as provided in Australia.
Sorry if my tests prove your theory wrong.

If what people are saying is true re. tank range etc., it may be something to do with the anti-knocking system. Not quite sure what effect this would have on the engine, but obviously higher octane fuels are less likely to knock

TerryM said:

Mike,
Maybe the "additive" you are using is colouring your readout of mileage.
Personally I challenge you to go to a local filling station with me, fill up and do a parallel trip of, say, 200 miles and prove it.

We each give GBP100 to a independent witness(cop/lawyer or whomever)and winner takes all.

When are you coming to play, sir.

Click to expand...

I'm not quite sure why you seem to be getting bent out of shape about this. I know that I get significantly better mpg when I use Super Unleaded - I wouldn't use it otherwise. I'm happy for you to believe what you will - 86k miles in the last 2 years using a variety of fuels has provided me with the evidence I need.

Mike

GSmonkey said:

If what people are saying is true re. tank range etc., it may be something to do with the anti-knocking system. Not quite sure what effect this would have on the engine, but obviously higher octane fuels are less likely to knock

Click to expand...

The GS is fitted with anti-knock sensors (and more computing power than was required to land man on the moon....unless of course TerryM wants us to believe it was all staged in the Utah desert somehwere ) and since the bike can detect the fuel quality (not just the octane rating) and adjust the combustion settings appropriately therefore a better quality fuel (irrespective of its RON number) will burn more efficiently...hence the second set of sparkie plugs!

Oil companies make little profit (comparitively) in the UK from the bog standard silt so a premium brand which will cost a few pence more but will have been better refined and be of better quality. I don't buy the Optimax and other fancy branded fuels, paying 5 pence per litre more fuel that will not net me back the equivalent cost saving over the standard unleaded, however at 2 pence per litre more super unleaded is the ideal halfway house, you only need to get 5 more miles from a tankful in the GS (or around 1mpg) and you break even, plus the bike runs better to boot, so those like me getting 10-30 miles extra per tankful are better off, as we are helping the environment by being more fuel efficient, and the government is reaping less money in fuel tax

When i product becomes so common and normal, market forces affect its profitability or the amount of profit that can be made from it (becuase everyone is doing it) so the quality can be affected in order to maintain profitability. For me doing around 13,000 miles per year my fuel bill is around £1290 (@ 82.9p/litre), but switching to super unleaded and getting an average extra 20 miles from a tankful (or 5mpg) it means that i pay £130 less per year for fuel (and consequently less tax).

Now imagine 100,000 people switched to super unleaded and gained the same advantage (not inconcievable in a car with even more fuel system technology) made the same sort of mileage and the same savings, the government coffers would be short of £1million for that year, not much you say, but its better in my pocket than theirs

Re: Re: Feeding the GS Super Unleaded

alecmuffett said:

that is so.... resonant

so - seriousness aside - speaking as a novice, approximately how are you doing your power-wheelies? 2nd gear and snap the revs to 6000?

Click to expand...

Nope, pull away as usual in first with halfish throttle to say 3 or 4 thousand rpm, then just snap the throttle to the stop and up comes the front, then use the throttle to control the height of the front wheel (of course i don't recommend this in public highways, and if you want to learn i'd suggest wheelie school rather than wreck your own bike)

Re: Re: Re: Feeding the GS Super Unleaded

Russ said:

Nope, pull away as usual in first with halfish throttle to say 3 or 4 thousand rpm, then just snap the throttle to the stop and up comes the front, then use the throttle to control the height of the front wheel (of course i don't recommend this in public highways, and if you want to learn i'd suggest wheelie school rather than wreck your own bike)

Click to expand...

.........I'd say this is more intersting that the super unleaded debate