cargo wrote:True and funny fuel story.......................
On the Isle of Man there are lots of fuel stations................Shell, Total, Esso they are all there...............however down at the dockside there is only one big tank for petrol deliveries from the other island.....................figure that out
I'll explain.
RON (Octane rating) isn't an indicator of performance like many people belive it to be, it's the petrols 'knock-resistance' capability.
By this I mean.. how much heat / compression the petrol will take before it spontainiously combusts before it's ignited on purpose.
If you run a shitty low grade fuel (this american 85/88 gas) in a modern europe/jap motor it'll ignite before the plug sets fire to it, often as the piston is on the up-stroke.. the creates a 'knocking' sound as the piston is knokcing against the explosion momentairly, not only does this destroy the engine eventually it leads to less power.
A fuel rated at '98' RON will resisting exploding more than an 85 RON fuel.. got it?
Ordinary unleaded - 95 RON
Super unleaded - 98 RON
Leaded Four Star - 98 RON
Since all fuel is now unleaded (you can still actually buy proper 4 star at many garages.. this is LEADED fuel, not lead replacement, it's designed for classic cars and bikes that NEED it as they don't have hardned valve seats) it was 1.65 a litre when I last brought some about 18 months ago so i'm guessing it's pushing 2.00 a litre now.
This explains your single tanker... first the bog standard Unleaded (95) ron is delivered... then inside the tanker a separate container mixes additives in the fuel which raise the octane rating (and the price of the fuel) to make Super unleaded at al.
However, some manufactureres also add extra 'cleaning products' to the fuel to try and justify the 'Super' Rating (essentially they are charging more money for additives a majority of vehicles don't need or will be able to use.
The ZXR was designed to run 91 octane unleaded gas or better. This means that any grade lower in fuel will be at risk of burning unintentionally in the engine.. anything higher is surplus to requirements.
The added 'cleaning chemicals' in the fuel do nothing for this old carb'd based engine as far as I can tell.. I took apart a VFR for valve stem seal replacement i'd covered 40,000km on and only ever ran it on standard unleaded and it was spotless inside.
Some of the newer (mainly car engines) like the BMW and Merc's can benefit from increased Octane fuel.. they alter the engine conditions to deliver more power from the engine when a suitable fuel is used.. hence bmw quoting something like 190bhp standard / 200 super.
The ZXR cannot do this so the extra RON are not doing anything, remember.. extra RON are not delievering more power.. just letting the petrol be treated more agressivly if your engine can do so.
The only thing are the cleaning solvents.. ordinary fuel keeps your engine spotless anyhow... and one tank wouldnt' be enough to remove any deposits that are already there... swtiching between the two there wont' be any difference in a standard running engine as the only thing your adding are cleaners.. which for the majority of engines wont be needed as its already clean (normal petrol is not dirty!!)
Leaded fuel isn't needed as the valve seats are hardneded (try grinding them!) lead used to act as a protective lubricant to prevent against valve wear as the seats were soft (think 2 stroke lubrication in an engine)
The ZXR valve dont' wear.
There is the placebo effect where it feels better. even i've experienced this, but after trying two back to back tanks on consecutive days (i didn't look at the label of the cans till after the test) I couldnt' tell which was which.
Which!? magazine did a big feature on it a few years back too and found theres no difference at all for the majority of engines... and many drivers even drove more economically with the 'premium' fuel in resulting in more miles a tank so drivers think there getting a bargain.
The only negative is that some cheap fuel garages do sell 'recyc' this is when a fuel tank is drained all the fuel gets recycled and re-sold.. occasionally this might have a speck of diesel in it, which might cause a bit of crapp running.. I forget the term now I think it's vapor recycle or something (There was a list of garages that did this) so that might expain a bad tank of regular. Although you can get a 'bad' tank of anything if theres contamination.
Normal grade 95 regular fuel from a decent source is more than you'll ever need for the bike unless you've built some high compression advanced ignition super turbo charged beast that needs 120ron av-gas.
One of our users commented that using higher octane fuel than your engine requires actually gives no benefit and may be a waste of money. This is because virtually NO engines require 98 RON over 95, and the market for 'super' fuels seems to be based on people's misunderstanding of octane ratings and the placebo effect of filling up with 'more powerful' fuel - making motorists think their engine is running better in some way.
What do the fuel companies say then, to justify the "increased power" claims for the super grade fuels? Some companies say that while all fuels contain cleaning additives, 'super' fuels contain more or better detergents to keep the injectors cleaner than standard fuel. Others say the fuel is a few percent denser which gives slightly more power per litre. These benefits may be marginal though in comparison to the extra cost involved so it is worth ensuring that your engine will actually benefit before filling up.
Some engines actually do need higher octane fuel, such as race engines with very high compression and some turbocharged engines, such as the import version of the Nissan Skyline. Also, a few vehicles, such as the new BMW K1200R motorbike, can sense knock and adjust their engine tuning to take advantage of higher grade fuels. Another user commented that the 2004 BMW 330 also does this, according to the driver's handbook it makes 231 BHP on 98 octane and 221 BHP on 95. This ability is apparently widespread amongst German performance cars using Bosch / Siemens electronic engine controls.
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Perhaps they all get the same bog standard stuff with no additives there? Or maybe the guy at the petrol station mixes them into the pump once they're delivered...... 
