Feeding the GS Super Unleaded

Originally posted by Russ ....and consequently less tax[/B]
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You've won me over. If I can pay Gordon Brown one penny less I will;)
 
Re: Re: Re: Feeding the GS Super Unleaded

Russ said:
f you want to learn i'd suggest wheelie school rather than wreck your own bike
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DRZ400 on the edge of a nice, soft, ploughed field, then. :cool:
 
People in this thread seem to be getting unnecessarily aggrieved.

Firstly, Shell Optimax etc are not synonymous with 97 RON super unleaded.

AFAIK there are 3 types of unleaded petrol on sale in the UK.

95RON - as recommended by BMW in my R1150GS
97RON - super unleaded
Premium brand - e.g. Optimax, Esso Energy Supreme

My understanding of the situation is that there is no advanatge to using the "ordinary" 97RON petrol in a GS. In fact, many petrol stations have phased it out as there are very few vehicles left where the manufacturers specify it.

The claims made by the refiners about Optimax etc improving economy are nothing to do with the increased octane rating. Their claims are to do with the additive packages used. The wording in their marketing material is ambiguous:
Shell Optimax is an unleaded fuel, designed to give your bike optimum responsiveness and maximum engine protection... specially designed to clean your engine as you drive. It helps remove deposits on inlet valves and ensure fuel injector nozzles are kept in tip-top condition.

So, if someone did have a dirty fuel injection system then these products might improve consumption by improving efficiency.

IIRC the marketing blurb used to have a direct claim about improved fuel consumption. Something about an additive that improved the "flame shape" or some such pseudo science. Perhaps they have had to withdraw that claim as it does not ring true in all circumstances. This would explain the myriad of opinions reported in this thread.

(I sourced some info here )
 
It is.

And my name's not Ron.


I've found that as long as I'm not using supermarket budget fuel (they lower the price by lowering the additives they put in...some of it id crappy stuff) then any of the branded names run fine in mine.

Let's face it, the GS isn't exactly at the pinnacle of F.I technical development is it?
 
If the R1200Gs has anti-knock sensors then surely it can advance and retard the ignition timing to maximise combustion efficiency.

If this is the case, then using a higher octance fuel (e.g. Optimax) will allow the timing to be advanced further before knocking starts, will this not give a higher performance and or greater efficiency over using 95RON?

I believe the new R1200RT will run happily on 95RON - but BMW recommend 98RON so that the engine will produce the claimed 110bhp which is possible beacause of the increased compression compared to the R1200GS - even though they are essentially the same engine.
 
I expect that the next generation GS will have a multifuel capability swallowing anything from Holts bitter(poor bloody motor) to diesel via avgas.

And what with the wind turbine mounted above the screen, solar panels on the panniers and topbox, electric motors/generators integral in the hubs(for when the battery is topped out and energy recoup. on the overrun), waste heat exchangers fitted to the brake discs to operate the heated grips in winter and preheat the fuel for injection into the after burners in summer the bloody thing will be so green and economical no bloody minded anti PC person will ever buy one.

And then the poor mugs who do can really have a good time arguing about the correct super computer setup to run the monster at max efficiency and their pet program and unaudited results.

Happily I will either be dead or gaga.

Which is more than I can say for the fuel/oil freaks of today guys.
 
Mike O said:
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:)
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100% with you Mike

I have done just over 50K on this 1150 and like you have had time to compare the two. IT IS better, IT DOES improve the bikes performance. IT DOES give me better MPG.
So you who don't believe it or haven't tried it in a comparative..............go and get your knickers twisted elsewhere;)
 
TerryM said:
Please just ride it and leave the physics to those who have some idea.
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Russ was there first:

Russ said:
The GS is fitted with anti-knock sensors ...
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Most people would accept that if you retard the ignition, the power and efficiency would be reduced. Readvancing the timing would restore the lost power and efficiency.

The 1200GS, fitted with anti-knock sensors, will retard or advance the ignition timing such that the burning fuel will not knock or pink. If the engine is run on a fuel with a lower than optimum octance rating (however measured), it WILL produce less power and efficiency (ie mpg).

I don't know what the optimum octane rating for this engine is, but with the last petrol car that I used that had anti-knock sensors, the effect of using super-unleaded was very clear.

The R1150GS and R1100GS do not have anti-knock sensors. I can't explain why they perform differently with super-unleaded.

Greg
 
Thanks guys, I have now headache reading your very interesting posts; what is the conclusion then ? does 98 RON fuel give extra power without any harm to the engine ? my dealer recommend to use 95 RON as there is no improvement, according to him, with 98 RON;
 
Greg Masters said:
Russ was there first:



Most people would accept that if you retard the ignition, the power and efficiency would be reduced. Readvancing the timing would restore the lost power and efficiency.

The 1200GS, fitted with anti-knock sensors, will retard or advance the ignition timing such that the burning fuel will not knock or pink. If the engine is run on a fuel with a lower than optimum octance rating (however measured), it WILL produce less power and efficiency (ie mpg).

I don't know what the optimum octane rating for this engine is, but with the last petrol car that I used that had anti-knock sensors, the effect of using super-unleaded was very clear.

The R1150GS and R1100GS do not have anti-knock sensors. I can't explain why they perform differently with super-unleaded.

Greg
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Greg,


What precisely was the effect of using super unleaded in the car , and how did you objectively measure it?

Did you find the motor more responsive when wound tight, which would perhaps be expected and may be measureable by stopwatch?

Or on a long straight where you could max it out did you find that the attained revs in top gear were measureably higher with the higher octane fuel? That would also be understandable.

But then what was the objective effect of higher octane on fuel consumtion, and how was the level playing field established?

As the knock sensors (engine management) only effect advance when knocking commences, and that, by definition, only happens under full throttle, what increase in efficiency due to the non-existent change in ignition advance at less than full throttle do you expect will contribute to the lower fuel consumption experienced by others and perhaps by you also?

Was the thing so much quicker and responsive to throttle that the enhanced fuel consumption was due to the driver/rider rolling it off in fear at the huge power increase?

And when the driver/rider stopped winding the motor up to max power in each gear did the enhanced fuel consumption evaporate?

My personal experience of tweaking a air cooled Porsche engine management system for the road by remapping and a more open inlet/exhaust arrangement was a estimated 30bhp at the top end giving about 10mph increase flat out and a noticeably more responsive mid range above 4300rpm where the cam on the Carrera kicks in. It made no significant difference to fuel consumption at all and I used the usual unleaded 95RON, it ran 10.3 litres per 100kms before and after. I know that all manufacturers are very conservative in compression ratio as the consequences are instant and drastic if they go near the limit. And anyhow others had trodden this path previously.

That car has run in that state of tune for more than ten years with about 245,000kms on the original motor.

Terry
 
TerryM said:
Greg,

What precisely was the effect of using super unleaded in the car , and how did you objectively measure it?

Did you find the motor more responsive when wound tight, which would perhaps be expected and may be measureable by stopwatch?

Or on a long straight where you could max it out did you find that the attained revs in top gear were measureably higher with the higher octane fuel? That would also be understandable.

But then what was the objective effect of higher octane on fuel consumtion, and how was the level playing field established?
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I didn't say that I objectively measured the effects of super-unleaded -v- 'ordinary' unleaded, but since you ask, the car (a 1990 Vauxhall Cavalier GSi) improved it's fuel consumption from 32.1mpg to 35.0mpg when measured over 1,000+ miles.

Swapping to super-unleaded, empirical evidence was that the car was more responsive.

TerryM said:
As the knock sensors (engine management) only effect advance when knocking commences, and that, by definition, only happens under full throttle...
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I'm not sure whose definition that would be, but engine bench tests when I went to college showed that you can get 'knock' at virtually any throttle setting if the fuel quality and timing were inappropriate!

TerryM said:
what increase in efficiency due to the non-existent change in ignition advance at less than full throttle do you expect will contribute to the lower fuel consumption experienced by others and perhaps by you also?
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The question contains an untrue premise. With most modern ignition maps, the timing will change even if there is no other change than the throttle position (ie the engine load). As you roll off the throttle, the ignition is likely to advance towards the MBT (minimum best timing) - the lowest value of ignition advance that produces maximum power.

TerryM said:
Was the thing so much quicker and responsive to throttle that the enhanced fuel consumption was due to the driver/rider rolling it off in fear at the huge power increase?
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No.

TerryM said:
My personal experience of tweaking a air cooled Porsche engine management system for the road by remapping and a more open inlet/exhaust arrangement was a estimated 30bhp at the top end giving about 10mph increase flat out and a noticeably more responsive mid range above 4300rpm where the cam on the Carrera kicks in. It made no significant difference to fuel consumption at all and I used the usual unleaded 95RON, it ran 10.3 litres per 100kms before and after.
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I'm pleased for you, but I'm not sure how this adds to the debate about ordinary -v- super unleaded.

Greg
 
Greg Masters said:
I didn't say that I objectively measured the effects of super-unleaded -v- 'ordinary' unleaded, but since you ask, the car (a 1990 Vauxhall Cavalier GSi) improved it's fuel consumption from 32.1mpg to 35.0mpg when measured over 1,000+ miles.

Swapping to super-unleaded, empirical evidence was that the car was more responsive.

I'm not sure whose definition that would be, but engine bench tests when I went to college showed that you can get 'knock' at virtually any throttle setting if the fuel quality and timing were inappropriate!

Quite so, but who would deliberately set up the engine management to yield that result? So knock is for all practical purposes apparent under full load(throttle)as distinct from max revs or power.
TM
The question contains an untrue premise. With most modern ignition maps, the timing will change even if there is no other change than the throttle position (ie the engine load). As you roll off the throttle, the ignition is likely to advance towards the MBT (minimum best timing) - the lowest value of ignition advance that produces maximum power.

I think not,for the answer ignores the fact that the limit for advance shift to MBT is prescribed in the mapping, and cannot deviate outside that limit. That, at least, is what I thought a reader would deduce. Hence the premise is reasonable.
TM
No.

I'm pleased for you, but I'm not sure how this adds to the debate about ordinary -v- super unleaded.

I had thought that it would be evident that with enhanced breathing in a similarly configured air cooled motor of like cylinder capacity and specific output, using a mildly tweaked map for advance and fueling, the minimised timing and effectively higher compression due to better breathing had been easily accommodated by the same 95RON unleaded fuel. And that in a two valve motor which might be expected to be less tolerant than a more modern four valve design, such as the 12GS.

The test route was 200kms round trip daily(Cologne-Dortmund-Cologne) with about 150kms on autobahn cruising regularly in the 120mph+ range and up to 160mph for short periods. That was my routine for 31/2 years.

So unless the CR was increased and the map adjusted if necessary, how would 98RON or super whatever improve matters? All the data I have seen for what amount to race fuels suggest a very modest(2/3%-ish)increase in top end power only. Even in quite highly tuned Jap fours said to be running CRs in the 13:1 range at 12/13k rpm. And it is apparent that such small increments can creep into inertia dyno tests due to operator variables and other factors far removed from the motor output. So how it would play out in our garden variety toys at under 8k rpm seems moot.

I would like to think that significant performance enhancements and 10% better consumption could be gained out of the pump/super lube. But so far the back to back testing is elusive.

When someone comes along with the free fuel/lube and is willing to pay for any damage to my toys in testing their product claims I may be tempted. For the moment I multiply all such claims by a credulity constant of 0.1.
TM

I am also at a loss to know quite what to do with the small power increase and the pence saved if the super whatever works! But I have a funny feeling that the manufacturer/vendor/G.Brown Esq. will resolve the latter for me

Greg
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Dolphin said:
Believe what you will, but the FACT is I do get more kilometers
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Ah ...............

Here's part of the problem.

Here, in Britain, we are still using old fashioned time-tested miles and not these johnny-come-lately Continental kilometre thingies.

But, no matter which measure of distance is used, I have to say that I can discern no difference between ordinary unleaded from Tesco and Shell Optimax - apart from in my wallet.
 
Mike O said:
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:)
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I’ve got a gsa2018 and regular returns 65mpg last trip two up luggage riding from Catalico spain to biarritz and back over Pyrenees 72mpg and before smart arse says riding like a vicar (I’m not a straight line monkey)Colouring or not It does better mileage in mountains than 80 on motorway only does 49 at that speed,years ago when a V power came out my bmwr1100rsse (which I did 101000 mile on)was noticeably faster when regular riding with my mate on his zzr1100 using superunleaded and it was him that said it that it seemed faster,tell dingbat that superunleaded contains more detergents which make your engine cleaner and just because they have knock sensors means that it retards or advances ignition so it doesn’t pre ignite which reduces power , if don’t need to retard it’s gets the full dose.i agree with you mike , if he’s got £100 to splash about tell him To try it on superunleaded
 
How do you think the petroleum company’s arrive at the price of the difference between unleaded and super unleaded,
You get slightly more mpg with super and pay more per litre which equals cost per mile, it. Works out exactly the same cost per mile with either and that’s why they do it , if it cost less using super then why make normal and if unleaded gave better value and no performance gains then why use it.
 
geoff1200gs said:
How do you think the petroleum company’s arrive at the price of the difference between unleaded and super unleaded,
You get slightly more mpg with super and pay more per litre which equals cost per mile, it. Works out exactly the same cost per mile with either and that’s why they do it , if it cost less using super then why make normal and if unleaded gave better value and no performance gains then why use it.
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https://www.autoexpress.co.uk/fuel/...ing-more-for-premium-diesel-or-premium-petrol

Some vehicles really do require 97/98 ron fuel. I doubt a humble GS does.
 
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