Premium – Regular & the Octane Story Part 2

Following on from Premium – Regular & the Octane Story Part 1 where the importance of using the right grade of fuel were explained, it’s also important to understand that there are differences in fuel formulas and how fuel grades are identified, depending on where they are sold.

There are two things to consider that are far more important than names such as Premium, Ultimate, Power, Super,  etc.  The first is the octane rating and the second is whether or not the fuel is blended with ethanol.  In this article we will deal with specifically octane ratings and how you can determine exactly which grades of fuel sold in your county are suitable for your bike or scooter.

There are two main scales used to rate fuel octane.  The most commonly used is the RON scale.  RON stands for Research Octane Number.  The test used for this scale is best suited to rate fuel used in normal road vehicles.

The other rating scale is the MON scale which stands for Motor Octane Number.  This scale is used in motor sport and aviation and is specifically designed to rate fuel for engine conditions at higher loads.

In most cases, commercially available fuel has been rated for both these scales by the testing agency and the MON will be typically 8 - 12 points lower than the RON rating.  It is not possible to reliably convert between the two scales as commercial fuels differ widely and the difference in the rated number will be higher or lower depending in the actual fuel formula.

The important thing for bike and scooter owners is knowing what octane rating is recommended for their bike or scooter and which scale has been used to specify it.  The next thing is then to match that with the fuel available in your country.

Most countries use the RON scale to specify the octane rating of fuel sold at commercial outlets.  These include all of Europe, the UK, Ireland, the Middle East, South Africa, Asia, Australia , New Zealand, most South American and some Central American countries.  In these countries 95 Octane fuel for example is 95 RON if not already specified at the outlet.

In some other parts of the world the rating system and display at the outlet is quite different however.  Canada, the USA, Mexico, Brazil, and possibly some other Central and South American countries use an average of the RON and MON which they call the AKI and which stands for “Anti Knock Index”.  At some outlets in these countries it is labelled on pumps as (R+M)/2 or by another designation POM which stands for “Pump Octane Number”.  This causes a lot of confusion for owners in these countries and also for readers of on-line forums when they are getting what seems to be contradictory “advice” from other owners about what fuel to use.

The Italian manufacturers are careful to specify the grade of fuel required and this will be detailed in the Owner’s Manuals or other technical documentation.  Fuel ratings will be in RON as this is the European standard however in some cases both RON (sometimes written NORM) and MON (sometimes written NOMM) ratings are given.  Bikes and scooters specifically for the US and Canadian market may also have fuel recommendations listed in the documentation by the (R+M)/2 method as is used in their area.

The table below shows a comparison between RON, MON and AKI with examples of some fuels in different markets.  There are however regional variations in a lot of countries so it is always best to find out the actual octane rating of the fuel you are buying rather than rely on the description.   Ratings for the reference compounds n-heptane and iso-octane as well as straight ethanol and methanol are also shown for general interest.

FUEL	RON	MON	AKI
Standard Unleaded – Europe, UK, Ireland, RSA	95	85
High Octane Premium Unleaded – Europe, UK, Ireland	102 - 97	88
Standard Unleaded  - USA, CDN	91 - 92	82	87
High Octane Premium Unleaded - USA, CDN	98 - 97	88	94
Standard Unleaded  - AUS, NZL, RSA, Asia, Mid East	91 - 92	82
Premium Unleaded  - AUS, NZL, RSA, Asia, Mid East	95	85
High Octane Premium Unleaded - AUS, NZL, RSA, Asia, Mid East	100 - 97	88
n-Heptane	0	0	0
Iso-Octane	100	100	100
Ethanol	108	90
Methanol	109	89

Premium - Regular & the Octane Story Part 1

There is a lot of confusion (particularly on the on-line forums) about grades of fuel and what grade is right for any particular bike or scooter and why.  The following will help to dispel some of the myths about fuel.

FACT 1:

In a few limited cases, using premium grade fuel can improve the performance of your bike or scooter but in most cases it does not.

FACT 2:

In all cases where an engine is designed to run on premium grade fuel, premium fuel should be used as running on lower grade fuel can potentially damage the engine.

FACT 3:

Premium fuels do not necessarily produce more motive power than standard fuels and in some cases when compared in the same engine actually produce less.

FACT 4:

The formulas used in premium fuels are designed to decrease their activation energy so that they ignite less easily and burn in a slower, more controlled manner.

Described variously as Gasoline, Petrol, Benzin, Benzina etc. - depending on where it is sold, motor fuel is made up of organic compounds distilled from crude oil.  The main difference between “Premium” or “Super” grades and what is variously referred to as “Standard”, “Regular” or “Normal” is the octane rating.  Premium fuels have a higher octane rating than standard fuels which means they burn in a more controlled manner and do not as is commonly believed, produce more power.

“Octane” is not (as is commonly believed), some kind of performance additive.  Octanes are in fact a family of hydrocarbons that are present in gasoline and one member of this family, Iso-Octane is used as a measurement benchmark of a fuel’s ability to withstand compression without pre-ignition or detonation which is the cause of the phenomenon known as “engine knock”.  This “detonation” which can usually be is heard as a pinging or knocking sound when the engine is under load is caused by the fuel pre-igniting and exploding in the cylinder rather than burning and expanding in a controlled manner.  Detonation will immediately cause the engine to become inefficient and if allowed to continue will cause major damage, even to the point of melting pistons or breaking connecting rods.

The octane rating of fuel is tested using a specially calibrated laboratory engine to measure the fuel’s performance relative to two of the hydrocarbon compounds, n-heptane which has very low resistance to detonation and iso-octane which has high resistance.  The measurement is calibrated so that an octane rating of zero would be equal to a fuel made up of 100% n-heptane and an octane rating of 100 would equal a fuel made up of 100% iso-octane. 

This does not mean that 100 octane gasoline is pure iso-octane.  It is not.  It is made up of many compounds that when combined, give it that rating and this is why some types of fuel have ratings above 100.

The thing that determines which fuel is right for your bike or scooter’s engine is the actual design of the engine itself and primarily its compression ratio which is the measure of how much the air / fuel mixture is squeezed or “compressed” in the combustion chamber as the mixture ignites.  A range of other factors are also relevant such as the combustion chamber shape, method of fuel delivery (Carburettor or EFI) ignition system design, the type of cooling system and in the case of EFI engines, the software design and level of engine management sophistication.

A more highly tuned engine with a high compression ratio will be more efficient and produce more power, however it will need fuel with a higher octane rating to achieve this without detonation occurring.  While it seems contradictory that some high octane fuels actually have lower energy content by volume and burn less easily than standard gasoline, highly tuned engines need this more stable type fuel to develop maximum power.

So the choice is simple.  Use whatever grade of fuel the manufacturer specifies as this is what the engine is designed for.  Using higher octane fuel will cost more and in almost all cases will not improve performance of your scooter or bike.  Using lower octane fuel than is specified may save you money in the short term but will in all likelihood damage the engine.

New Three Valve Engine

Piaggio have developed a new 3 valve engine to replace the existing two valve “Leader” 125cc & 150cc series.  Like the Leader,  the “3V” is air cooled, is similar in physical size and shape and weighs about 1kg less.  In addition to the three valve cylinder head, (two inlets and one exhaust) the 3V boasts a number of major technical improvements.  The single over head camshaft is supported by anti-friction bearings and the valves are operated via roller type rockers.  The crankshaft is new as well and has been designed, like the valve train to reduce friction losses.  The cylinder bore to stroke ratio is different as is (not surprisingly) the valve timing.  Advancements have also been made to the cooling system, starter and ignition components.

The 3Vs will all be fuel injected and will come fitted with Marelli’s latest integrated ECU / throttle body know as the G3.  Advanced software design including a new approach to three dimensional fuel and ignition mapping are features of this system.

Performance increases of up to 10% are claimed while fuel consumption is reduced by as much as 30%.  Exhaust emission levels are also improved.

The new engine was developed at the Pontedera design facility and will be produced at Piaggio’s manufacturing facilities in Italy, India and the new engine plant outside Hanoi.

The 3V will be first seen in the Vespa LX and S 125 – 150 scooters and will be progressively rolled out to other Piaggio group models designed for this engine size such as Fly, Liberty, Typhoon etc.

New Piaggio Group Diagnostic System

Piaggio now has another diagnostic system: PADS (Piaggio Advanced Diagnostic System)
It’s doesn’t seem so long since they introduced their version of the TEXA Navigator with PGDS to replace the Axone for Aprilia / Guzzi bikes and the old Scooter Tester for Piaggio, Vespa and Gilera Scooters



Upgrades for PGDS will stop at the end of 2013 and while the tool will still be usable. New models and updated maps will only be available for PADS.
While the Navigator is a very good system, any new service agents out there should only consider PADS .
TEXA also have their proprietary system IDC4 (PGDS is based on this) which can do diagnostic all the Piaggio Group Vehicles but not re-mapping.

Piaggio Group Vehicles & E10 (Gasoline with 10% Ethanol)

The following Table and Exception List shows Piaggio, Vespa, Gilera, Aprilia, Moto Guzzi, Scarabeo and Derbi Bikes and Scooters compatibility with E10 (10% Ethanol) fuel.

Basically all EFI bikes and scooters over 50cc are ok with E10 unless they are shown in the exception list.

E10 FUEL COMPATIBILITY INDEX - SCOOTERS & MOTORCYCLES

Piaggio - Vespa - Gilera - Moto Guzzi - Aprilia - Scarabeo - Derbi
Engine	Fuel Supply	E10 compatibility
50cc	Carburettor or EFI	No
Over 50cc	Carburettor	No
Over 50cc	EFI	Yes

EXCEPTION LIST: (Motorcycles and Scooters not compatible with E10)

PIAGGIO

- X9 500

- Beverly 400 & 500

- Beverly Cruiser 500 (before May 2008 – before chassis ZAPM3450000010306)

- Beverly Tourer 400 (before May 2008 – before chassis ZAPM3440000002740)

GILERA

- Nexus 500 (version Euro 2)

SCARABEO

- 500 GT

APRILIA

- Atlantic 500

- SL Falco 1000cc

- RSV 1000cc 1998 - 2003

- Tuono 1000cc 2002 - 2006

- Shiver 750cc

- RS 125cc

- RX / SX 125cc

- Pegaso (Rotax engine)

- RXV / SXV 450cc & 550cc

MOTO GUZZI

- V7 Classic: Before chassis ZGULW0001BM115002

- V7 Cafè: Before chassis ZGULWA006BM112067

- V7 Racer: Before chassis ZGULWB00XBM100722

- California 1100: other than chassis ZGUKDE, ZGUKDG, ZGUKDH, ZGUKDL, ZGUKDM

- Breva: 750

- Griso 850: Before chassis ZGULSB0016M111528

- Griso 1100: Before chassis ZGULS00017M1133321

- Griso 1200: Before chassis ZGULSE - ZGULSG

DERBI

- All motorcycles