premuim unleaded/unleaded

[Martin#30]

As I understand it, the main advantage of 97/98 over 95 RON is knock resistance, i.e. the fuel's resistance to unwanted detonation in extreme cases.

This means you can get more power, in theory, by allowing a little more ignition advance, and/or a little more compression ratio, when using 98.

Unless a car/bike is mapped specifically for that fuel, or it has some sort of octane sensor in the fuel supply system, or it has an absolutely infallible knock sensor, then our vehicles cannot take advantage of that extra octane.

I run 98 on my turbocharged MX5, but then it is mapped assuming I will always use that fuel. The GTR has had 53,000 miles worth of 95 normal unleaded from everywhere and anywhere, and runs perfectly.

It is possible that 98 has more detergents in it, but if so, then that must mean it actually has slightly less real petrol in it as we buy it by the litre.

Martin.

[Charlie747]

I worked for BP for several years and had inside knowledge on the refinery side of things. Premium fuel is a waste of money, the extra 3 Ron that you get delivers a very very small octane boost, this small effect is usually wiped out by a dirty spark plug or some carbon deposits ect. sales of premium spirit only accounted for about 2% of our fuel volume and over 90% of people buying the product were accidental!

Supermarket fuel v Brand fuel. From the grangemouth refinery in Scotland we supplied most of the north of the uk, we supplied BP sites and all the major supermarkets, inc Sainsburys, morrisons, tescos and safeway. The only difference in the fuel was the additives, a tanker driver would collect his pod of fuel from the same division no matter on its final destination, the difference being that the branded fuel ( BP ESSO) had a squirt of aditives , the supermarket fuel did not get this, the additives in my opinion were questionable as they claimed more MPG, cleaner running ect.

[virginiajim]

This is a most curious thread indeed.  The US bikes are specified to run premium.  Are they not in the UK and elsewhere?  What does your manual specify?  I run premium in mine and I can tell the difference in the way the bike performs vs using mid-grade.  It's noisier running anything less than premium.  In the US we typically have 87, 89, and 92/93 at the pump.  If you are a thrasher, then you really need to use premium here (US) as the VVT can effectively change the compression ratio...higher.  Also, I try to find pumps where the grades have their own nozzles so I don't get the lesser fuels in the tank.  I try to run brand name fuels such as Gulf/BP/Sunoco if I can, but that's me.

[Ros]

I always use 98 where possible - except at the Eni garage around the corner from where I live in Monza. 

There, I fill up with their Eni Blu Super + which is 100 

http://www.eni.com/it_IT/prodotti-servizi/carburanti-combustibili/gamma-eni-blu/gamma-eni-blu.shtml

It's not exactly cheap at 1.855 EUR per litre, but then neither is any other fuel in this country.  So might as well pay for the good stuff.

Cheers

Ros

[Charlie747]

This is a most curious thread indeed.  The US bikes are specified to run premium.  Are they not in the UK and elsewhere?  What does your manual specify?  I run premium in mine and I can tell the difference in the way the bike performs vs using mid-grade.  It's noisier running anything less than premium.  In the US we typically have 87, 89, and 92/93 at the pump.  If you are a thrasher, then you really need to use premium here (US) as the VVT can effectively change the compression ratio...higher.  Also, I try to find pumps where the grades have their own nozzles so I don't get the lesser fuels in the tank.  I try to run brand name fuels such as Gulf/BP/Sunoco if I can, but that's me.

To answer the question Jim ..................................

Types of Fuel and Octane Ratings

Petrol's octane rating is a measurement of the fuel's ability to resist engine knocking. Knock occurs when the fuel-air mix in the cylinder explodes instead of burning in a controlled way. This shockwave moves within the combustion chamber, and creates a metallic 'pinging' sound.

An octane rating is often referred to as an 'anti-knock index'. If fuel has a high octane number, it will have a higher resistance to engine knocking.

Octane Numbers

Usually, there are three different octane numbers associated with all petrols. Petrol's Research Octane Number (RON) is measured under simple test conditions. Petrol's Motor Octane Number (MON) is measured under tougher test conditions and at higher engine speed and temperature.

The average of these two values is what becomes related closer to actual driving conditions. This value is known as the Road Octane Number, and is what should be used in filling stations.

Occasionally, some filling stations will confuse these different octane numbers in a bid to embellish on their octane rating claims, and advertise their fuel's Research Octane Number, which is higher than the Road Octane Number. In many European countries, the Research Octane Number is advertised on pumps, so a much higher octane value is common when travelling in certain countries.
Diesel Fuel
Diesel automatically ignites and burns when it is compressed to a very high pressure. The released energy is contained by the engine and powers the vehicle. The key difference between diesel and petrol engines is auto-ignition. A spark plug ignites the fuel in a petrol engine whereas a diesel engine auto-ignites. Diesel has a Cetane Index and Number rather than the Research Octane Number (RON) that petrol has

Leaded Four Star petrol was removed from sale on British forecourts on 1st January 2000. However, Leaded Four Star is now sold in a small amount of licensed stations in the UK.

In the UK, the most common petrol types are:

Ordinary unleaded – 95 RON

Super unleaded – 98 RON

4 star fuel
Leaded Four Star – 98 RON

So our UK basic unleaded is a higher RON than your Super fuel

When I had my Vauxhall (Holden) Monaro (Pontiac GTO to you guys) I fell about with laughter as my mates with their Scooby's and Evo's had less BHP and had to use super unleaded.................the LS2 in the Monaro was tuned for 400BHP on 92 RON fuel 

Hope this helps ?

[virginiajim]

Yes, indeed!

[viper]

top gear did a item a few years back running the same vehicle on 95 and 98 spirit, they did , 0-60, standing mile , overtakes ,  measured MPG ,everything, they got no measurable advantage from the premium spirit.

stop wasting your money!

[Charlie747]

top gear did a item a few years back running the same vehicle on 95 and 98 spirit, they did , 0-60, standing mile , overtakes ,  measured MPG ,everything, they got no measurable advantage from the premium spirit.

stop wasting your money!

[Boomer]

USA use RON+MON/2 where we just use RON. Therefore UK 95 =USA 91.

[Charlie747]

USA use RON+MON/2 where we just use RON. Therefore UK 95 =USA 91.

So our happy shopper = US rocket fuel 

[viper]

in Bavaria at the moment and all most of the fuel available is the 10% ethanol  " super E10" , that's the stuff that rots your bike from the inside out, ask OC! is this fuel the norm now ??

[virginiajim]

It's the norm over here and they want to stuff E15 down our throats, but the good fight is on and I'm crossing my fingers that govt will do the right thing......    I don't think we've seen much harm on FI engines.  It's the carb engines that are bearing the brunt of this.  Of course, every manual for any gasoline engine I have says don't use anything more than E10.  I've traded in my weed wacker for a battery powered one and it does quite well, actually.  Tired of messing with carbs.  Next mower I get will be electric.

[Andy]

http://youtu.be/gQghB4asSnI

[Richard]

Interesting, so this leads us to the next question, can the GTR appreciate the difference?

[Charlie747]

Interesting, so this leads us to the next question, can the GTR appreciate the difference?

The engines that enjoyed the higher RON fuel had forced induction