another dumb Q from the sig- PETROL

[Quiff Wichard]

yesterday my light came on- I let it run to on solid and then went to fill up..

this time I took the option of the more expensive super duper petrol..just for an idea and to try it out..

I am 100% sure that the bike is running better now!//?? cud that be?

or is it a placebo..my cage always feels like it runnin better when its clean so cud be just me !!...

I know there have been threads on this b4 but wos is the best petrol? and wot petrol shud I avoid( yesss i know diesel b4 u say it !)
avoid supermarket petrol??

[Wiltshire7]

it should make it run slightly more efficently im told. i use it too but i cant tell the difference myself.

its only something like 2% purer so i doubt u can tell the difference, maybe using the ne one for a while then going back will make it more obvious.

[Quiff Wichard]

prob-

ta for the response...

mind u I always feel liek the bike runs well with a fll tank of petrol..must be the weight...
like it need the addition with my 15 stone on it!!

[jonboy]

It's not "purer" but has an octane rating of 97RON (standard unleaded in the UK is 95). It also has various additives and cleaners that should (in time) help to clean out carb jets and injector nozzles. As for extra performance you'll not likely notice anything as this is only really gained with advanced fuel injection engines that have oxygren sensors linked to powerful engine management systems.

I tend to use this stuff (Optimax or Ultimate) as it reduces carb-icing during the winter months (which my bike sadly suffers from). I've also noticed a slight improvemnet in fuel economy.

So is it worth the extra money for every day use in an SV? Probably not.


.

[Mogs]

I read somewhere that these fuels are slightly less explosive, therefore giving a longer burn in the cylinder, this is supposed to provide a little more power and be smoother through the stroke.

I fill up up with this about 1 in 10 times, mainly for its cleaning properties. I do feel a difference, but as you say it could be down just to the change of weight. Logically, I can't quite believe that I would be able to feel the difference a microsecond of extra fire would make.

I use supermarket fuel mostly and never had a problem (I think it's sourced from Esso).

[MavUK]

I've started running with either V-Power (Shell's petrol in Holland, only 95 RON, b ut a replacement for their 98 RON fuel) or Ultimate and I think there is a diff. Plus the couple of pence extra to fill a bike makes me not care too much about the diff in cost... In the car I used it as it has improved economy so is about the same cost per KM, but supposed to be better for the engine. To be honest I have no idea if it is or not...

Stu

[BillyC]

A few things to consider... (ie: Prepare yourself for a long read!)

Avoid supermarket petrol... it has no or few engine detergents or lubricants, does not go through the same filtration processes as branded fuels, and in the longterm does no favours for your engine. This shows up as coked plugs, valves and injectors; and blown valve seals (very common on the old 205 1.9 GTi's - which weren't designed for unleaded fuel).

Interestingly enough, the Supermarkets seem to be ditching their own brands, and teaming up with recognised petrol companies to provide their petrol/diesel.

If I have a choice, I use Shell fuel. Next on the list is Texaco, and finally BP - but I try and avoid them as they're typically more expensive unless in direct competition with another forecort that's visible from theirs.

Shell, Texaco, and BP, all put fuel detergents and lubricants in their respective products. Especially so in their "Super" fuels. It's these additives that are probably producing the difference that you're perceiving.

A word about Octane levels, on RON levels; and compression:
The Octane level can be regarded as a volatility level. The higher the number, the less volatile the fuel is. Now, don't confuse this with how hard it burns. A high octane fuel takes more energy to put it in an explosive state (ie: less volatile), but when it does explode, it burns more fiercely (ie: more power).

So, imagine a piston drawing a petrol mixture into the cylinder, when the piston gets to the bottom of it's stroke, the inlet vavle closes, sealing the piston. The piston, with the motion of the engine, then rises, and compresses the fuel-air mixture that's just been drawn in. A high-compression engine, will compress this mixture more than a low-compression one. High Octane fuels need to be compressed more to achieve a full burn, than low compression fuels.

Now, the SV, relative to a car, is high compression. Therefore it should burn a "Super" petrol quite happily and cleanly. But drastic power differences may not be so obvious, as the SV engine does not have the ability to adjust it's own spark timing, based on the fuel it's been fed.

Now, just to go on a bit more, if you were to put a Low Octane (highly volatile) fuel in a high-compression engine, then you run the risk that the high compression, will trigger the ignition of the highly-volatile, low-octane fuel. This will probably happen before the spark, and before the piston has got to the top of it's stroke. The resulting explosion, forces the piston back on it's own stroke - this quickly leads to high engine temperatures, and then a broken engine!

This last problem is not really a concern for us in Europe, where the minimum Octane you can really buy on the forecort is 95. But in the US, where low compression engines are common, 83 Octane fuels are common (equivilent to our old 2-star)... putting this fuel in something like an SV, or any sports bike, could be asking for trouble.

[MavUK]

Be careful when touring Germany as well. Last time I went (2003 IIRC) most forcourts had 92 RON as their standard fuel. Then you had premium (95) and finally Super(98). Holland is the same as the UK. Never seen anything below 95.

[BillyC]

I usually use Optimax in my 306... the engine ran better, and I consistantly get better mileage to the fuel light whenever I ran a tank of it.

Over a period of months, I was able to work out that the percentage extra mileage on a tank of Optimax, was greater than the percentage extra cost over normal premium unleaded.

Result: Cleaner engine, and cheaper to run - great value for money.


Not sure it'd be like this on every vehicle though... probably not an SV anyway. However, I think anything with a Lambda sensor and electronic ignition should see some measureable benefit.

[creamerybutter]

I didn't realise there was such an Issue with Supermarket fuels! I have use Asda mainly because they have the 24hr card pay lane and I go past it on the way home, convince really but if I had know their fuel was crap I would have gone slightly out of my way to use a proper petrol station.

[Steve H]

Ive got a Suzuki Ignis Sport vvt. ( a what i hear you ask!)
Suzuki actually recommend using higher rate fuel Optimax etc. in the
handbook. Not sure other car manufacturers do that as standard.

[BillyC]

I think anything with Variable-Valve-Timing is to a certain degree, be abl to adjust the compression of the engine.

Couple this with Lambda sensors to measure the burn efficiency, electronic ignition to adjust the spark timing, FI to adjust the fuel delivery, and anti-knock sensors to make sure nothing's going wrong..... then a high-octane fuel should give noticeable performance increases.

The Subaru Impreza Turbo has all of the above (except perhaps the VVT). The difference between Premium Unleaded 95 RON, and Optimax 98.5 RON; is over 40 bhp!

[Steve H]

Bill, Cheers for that.
Whilst not quite in the same performance league as the Subaru, the Suzuki is still a fairly highly strung motor in the scheme of things. (0-60 in 8.5 secs from 1.5 litre engine)
So will probably benefit from Optimax and the like.
Strangely enough, i'm only putting the better fuel in the SV at the moment! :?

[Quiff Wichard]

cheers guys

very informative

[jump]

very informative indeed. I wonder what the supermarkets claim about their fuel, and what it really delivers or contains...?

[wheelnut]

there is certainly a difference between Optimax and Ultimate and lesser fuels. my bike just feels better, it seems to run sweeter.

The additives they use are expensive, thats why the supermarkets can offer cheaper fuel.

Many people will tell you it is all the same, although many tankers will operate from one refinery, there are still special blends made for companies.

Shell will evaporate a lot faster than Asda.

MCN did a test a few months back and they agreed with me :P

[Jelster]

Believe it or not, my bike sounds different with std fuel... I always try and run with Optimax where possible (I have a number of shel garages fixed in my mind for regular trips). When running with 95 RON the exhasut note tends to be "raspy" rather than a smoother sound.

It took me a while to figure it out, but a couple of weeks ago it was making the raspy sound when I refilled with Optimax. As I was riding to work I noticed the sound had changed and thought about the fuel. To prove my theory I let the tank get very low (just under 15 litres went in) and low and behold the sound was back.....

I guess it's something to do with the way it burns coupled with the fact that my bike really over-fuels on roll off (and it tends to backfire less as well).

.

[adam]

further reading - some of it interesting :)

http://www.elektro.com/~audi/audi/toluene.html

"For turbocharged or supercharged engines, insufficient octane will also lead the engine management system to curtail the amount of boost which in turn defeats the purpose of these engines" - Going back to the subaru impreza turbo +40bhp

[adam]

Well if anyone has the time/money grab one of these and do some research http://www.sinar.co.uk/docs/portable_octane.pdf lol :)

[embee]

further reading - some of it interesting :)

http://www.elektro.com/~audi/audi/toluene.html

"For turbocharged or supercharged engines, insufficient octane will also lead the engine management system to curtail the amount of boost which in turn defeats the purpose of these engines" - Going back to the subaru impreza turbo +40bhp


Many moons ago I was slightly involved with someone doing moped racing, which was supposed to be as cheap and cheerful as you could get, buy a 50cc moped and do 6hr endurance races as teams of 3 or 4 riders.

Some sponsored teams started getting serious (dealer sponsored 2-strokes), so we thought we ought to retaliate. We had a Honda SS50 (4-stroke), and nothing in the rules outlawed pressure charging, so on went a belt driven supercharger (we used an exhaust air-injection pump used for emission control on bigger engines).

After eating a few pistons+rings, we started using 50% toluene. Since pure (laboratory) toluene is quite expensive, we hunted round and found some commercial paint thinners which was 95% toluene and cost a couple of quid a gallon.

One race a rider forgot about the reversed gear lever, over-revved it, so it came in, had a replacement engine fitted, went back out and finished sixth (it had such a big lead when it blew). :lol:

On the right gearing it would do 95mph, we reckoned about 15BHP or 300BHP/litre. :shock:

Note you should not use paint thinners as a road fuel, or you'll have lynw after you for the duty! 8-[

[adam]

I would be tempted to try using a toluene/forecourt octance/heptane mix but no way in my K4SVS lol! Maybe I'll rent a bike for a day sometime lol...

[Wiltshire7]

TOO. MUCH. INFORMATION.

ill confess i was with the 'fuel is fuel' mob.

[BillyC]

ill confess i was with the 'fuel is fuel' mob.

Put crap in, get crap out.

[wheelnut]

I am just trying to imagine a supercharged SS50 :D

Mine was, shall we say, STEADY