premium fuels

[Wideboy]

do you think they work or is it just a placebo effect?

me personally yes, yesterday in France i topped up with 98 high octane petrol and i accelerated up to 90MPH up a steep hill with out tucking in which for 33bhp and me on the bike is not to shabby, had loads more guts than usual

when back in blighty going up the M27, still had guts

what do you think?

[northwind]

I think the Shell and BP premiums are better for carb icing, but make no difference for power- higher octane just can't, unless you have an engine that makes use of it (ie increases ignition advance or forced induction boost, or you build it with higher compression).

But that's not all that can change of course, there can be other stuff in premium fuels which might help.

[neio79]

for us mear mortals it makes no differance whatsoever, other than to our wallets.

[muffles]

I thought most bikes don't have knock sensors and the ability to retard the ignition hence higher octane fuel makes no difference...?

I know it makes a difference in cars, which often can take advantage (though how much difference is dependent on the individual car of course).

[Blue_SV650S]

I think the Shell and BP premiums are better for carb icing, but make no difference for power- higher octane just can't, unless you have an engine that makes use of it (ie increases ignition advance or forced induction boost, or you build it with higher compression).

But that's not all that can change of course, there can be other stuff in premium fuels which might help.

Indeed.

I mean why the feck put 98 octane in a restricted bike anyway? :scratch:

[Wideboy]

Indeed.

I mean why the feck put 98 octane in a restricted bike anyway? :scratch:

was sharing a pump with a R6

[northwind]

I thought most bikes don't have knock sensors and the ability to retard the ignition hence higher octane fuel makes no difference...?
.

I think most of the beemers do now. You could build your bike to only run on premium if you wanted, deck the heads or run stupidly high advance, but as standard the SV will run on rubbing alcohol :D

[yorkie_chris]

I thought most bikes don't have knock sensors and the ability to retard the ignition hence higher octane fuel makes no difference...?

I know it makes a difference in cars, which often can take advantage (though how much difference is dependent on the individual car of course).

Nope very few are that advanced. The curvy no chance, it only has throttle position and crank position sensors.


There's a slight difference in density between fuel grades which can give a very slight advantage in mixture dependant on altitude, humidity, temperature, weather and the rest...

[kwak zzr]

chuck the cheap stuff in if u can call it cheap!

[Orpheus]

On my Rs125 i thought it made a very slightly noticeable increase in performance, but i cant say for certain that it wasn't just in my mind.

[imaleon]

Forgive me if this is completely wrong, I always presumed that the higher octane fuel the more reactive it is? So developing larger amounts of power with the same amount of fuel.... provided that the air/fuel mixture is set up correctly.

[northwind]

Nope, unfortunately not... The calorific value of the fuels is about the same. But higher octane means the fuel's less likely to suffer premature detonation under compression, so you can make it work harder, ie run high boost in a turbo, or high ignition advance, or high compression. But the extra power is from the engine setup not the fuel, the fuel just makes it possible to tune for more power.

It's not quite that simple, because the premiums aren't just high octane, they tend to have other stuff, additives and the like in there too, so some testing with standard bikes and cars does show fractional power or economy increases (and decreases!). Always less than the price difference though!

I tend to put super in mine for trackdays, I sometimes think I can feel a difference in throttle response... Which may or may not be in my head, but placebo improvements are every bit as good as real ones in my book, it's about feeling good not being good :cool:

[sinbad]

I think it's confusing to refer to them as "premiums", since the cheapest stuff is called Premium Unleaded :)

I've never used it (Super Unleaded, or equivalent) unless the machine would benefit. The SV doesn't afaik. It would probably make more difference to use different (better?) brands of basic "premium" stuff. I swear I get more miles to the tank when I use my local Esso garage than I do with supermarket stuff.

[kwak zzr]

top gear did a test on it didnt they, conclusion was its worth putting super in your subaru or mitsy evo but not in your ford focus lx.

[the_lone_wolf]

top gear did a test on it didnt they, conclusion was its worth putting super in your subaru or mitsy evo but not in your ford focus lx.
in the manual from my dad's BMW 330 it recommends using a minimum octane rated fuel - most higher power cars recommend running on higher octane fuel, life the BMW K1200 engine, if the engine management system notices knocking it retards the ignition, you won't destroy the engine by using standard fuel if the car is smart enough to change the timing, but you won't be getting max performance either

my new toy is a race bike, in the manual it recommends using min 98 octane, thankfully the tank is only 7 litres so i won't notice the hole in my wallet...

[imaleon]

haha great, I've been wasting my money for years! However I only recently noticed on my Rex that it recommends high octane fuel, although it doesn't have a turbo or supercharger. I would use it if it weren't 1.20 a litre!

[Tim in Belgium]

Yes, if running a turbo motor.

[yorkie_chris]

Not exactly. Any engine with a knock sensor will benefit.

Carbed engines can be affected by the grade of fuel due to very slight density differences.

[Alpinestarhero]

I find V-power and the equivalents offered by other fuel companies DO make a differance to my restricted curvy aswell; I have noticed improved throttle response and a smoother engine on the more expensive fuels.

I used it all winter to keep the problems of carb icing at bay, and switching back to cheaper unleaded now its warmer has shown that the expensive stuff DOES make a differance - to my restricted bike, at least. I will be interested to see if there is any significant (noticable) differance in bike performance when using differant fuels when the bike is back to full power.

I'll conduct a test during july, and post the results.

Matt

[Tim in Belgium]

Yes if running a high compression motor.

[ThEGr33k]

I voted no because even though it technically is yes the difference is so small it isn't worth the extra money!

[Tim in Belgium]

Unless it fubars your engine (not an SV issue, but I guarantee my car would be after 500 miles being thrashed on normal unleaded).

[imaleon]

I find V-power and the equivalents offered by other fuel companies DO make a differance to my restricted curvy aswell; I have noticed improved throttle response and a smoother engine on the more expensive fuels.

I used it all winter to keep the problems of carb icing at bay, and switching back to cheaper unleaded now its warmer has shown that the expensive stuff DOES make a differance - to my restricted bike, at least. I will be interested to see if there is any significant (noticable) differance in bike performance when using differant fuels when the bike is back to full power.

I'll conduct a test during july, and post the results.

Matt

You'll have to remember about air density though. The differences between the density a 0 degrees and 30 can be noticeable with an engine.

[ThEGr33k]

Unless it fubars your engine (not an SV issue, but I guarantee my car would be after 500 miles being thrashed on normal unleaded).

That cos of Turbo producing high compression?

[yorkie_chris]

Kinda...

When you compress a fuel-air mix obviously the temperature increases, if it's pre-compressed already then the temperature is already higher.

Too high a temperature and pressure at the end of the compression stroke can approach the knock limit where the "end gas" where the flame front reaches last, instead of being consumed normally, will burn supersonically, giving a really big pressure spike and the characteristic "pinking" noise.

Higher octane = more resistance to detonation.


But, chances are that that car in question has a knock sensor, which would cause the ECU to back off ignition advance, richen it up a little and reduce boost. So, it would run fine, just with a little less power.

[Grinch]

I think most of the beemers do now. You could build your bike to only run on premium if you wanted, deck the heads or run stupidly high advance, but as standard the SV will run on rubbing alcohol :D

Anyone tried this? Lol...

[Grinch]

I'll conduct a test during july, and post the results. Matt

I did a whole load of tests on this and it was in my blog, on both the SV and GT750... though not a restricted bike. In the end I found out the slight mileage gain in the fuel was cancelled out by the cost, but it held add carb icing in the winter, so kept with standard unleaded as it was just bit cheaper. Though I'm not sure I could say the same now, as the price difference is so much more.

The blog details - (linky) (http://bikersview.blogspot.com/search/label/Fuel)
Averages:
BP Ultimate (97 ron):
Mpg 51.46 KM per Litre:18.21 Pence per mile:8.61 £11.87 137.7 miles
Shell Optimax (97 ron):
Mpg 52.87 KM per Litre:18.11 Pence per mile:8.27 £11.75 142.2 miles
Sainsbury's Super Unleaded (97 ron):
Mpg 51.56 KM per Litre:18.25 Pence per mile:8.12 £11.61 139.5 miles
Sainsbury's Unleaded (95 ron):
Mpg 50.37 KM per Litre:17.83 Pence per mile:8.24 £10.88 132 miles

Note: These prices where back in Sept/Oct 2006, and I'm lucky if it costs me under 15 quid now.

[Fizzy Fish]

I generally use 95 for the gixxer, but over recent months it's had a problem with the throttle being very jerky when you go on/off the gas (apparently fairly common with K6/K7 600/750s)

anyway oddly enough Shell V-Power erradicates the problem completely, BP Ultimate pretty much gets rid of it and most 'regular' 95 fuels (esp Supermarket/Texaco) bring it back with a vengeance.

But here's another thing - I've been told by Suzuki not to run 98 as they only recommend using 95 (something to do with the catalytic converter?) Now I'm confused!

[yorkie_chris]

Well you don't really have to worry about the cat on it, it doesn't need one.

[Blue_SV650S]

Well you don't really have to worry about the cat on it, it doesn't need one.


To be fair, she needs to rip all that carp off and put a full race system on it anyway!! :D

I am not sure how 98RON would kill a cat to start with??

And if it is snatchy on 95RON, then it sounds like it is set up wrong or perhaps one of the sensors is a bit faulty! .. I'd get them to have a look at it (presuming still under guarantee).

[muffles]

And if it is snatchy on 95RON, then it sounds like it is set up wrong or perhaps one of the sensors is a bit faulty! .. I'd get them to have a look at it (presuming still under guarantee).

Big can of worms....being opened....it's a big problem with a lot of them and Suzuki's never properly admitted it I think. I believe a lot of people that tried to show their dealer weren't able to - it occurs fairly randomly. Certainly did with mine, anyway.

[Fizzy Fish]

Big can of worms....being opened....it's a big problem with a lot of them and Suzuki's never properly admitted it I think. I believe a lot of people that tried to show their dealer weren't able to - it occurs fairly randomly. Certainly did with mine, anyway.

absolutely, not gonna go into all the ins and outs here - but thought it a bit odd how the difference in fuel seemed to sort it out. Trust me to get a bike that has expensive tastes!! :lol:

[muffles]

absolutely, not gonna go into all the ins and outs here - but thought it a bit odd how the difference in fuel seemed to sort it out. Trust me to get a bike that has expensive tastes!! :lol:

:lol: the fuel thing is a new one to me at least, I wonder how many other K6/K7 owners have seen that (or even know about it to try). I for one never put anything but normal unleaded in mine, so never had the chance to test it, but would have done if I had known!

[embee]

Good replies above.

Yes, Octane number is strictly the tendency to knock ("pinking"). Higher octane fuels tend to have slightly higher density and calorific value but these are very minor differences. Power increases in a true back-to-back test in a fixed tune engine will be minimal.

The higher RON fuels tend to give better ignitability and combustion stability, so an engine might respond better to sudden throttle openings or just feel generally smoother.

Different engine designs have different fuel sesitivity, generally speaking the better the combustion control the less sensitive it will be, and you'll notice less difference between fuels.

I usually try a tank of Shell V-power (guaranteed 99RON minimum) to see how it feels, if I can't tell the difference it's back to the regular gut-rot. I haven't noticed any real difference in my SV (curvey 650). I have a car which does definitely feel/respond better on V-power, and an old BMW bike which is hideously fuel sensitive (poorly controlled combustion).