ISSA Transport Group (ITG), dealers for Mitsubishi, Mercedes-Benz, VW, Dodge, Audi and Chrysler, recently printed a flyer warning its customers against the usage of E10 87, the ethanol blended gasolene currently being rolled out by the nation's petrochemical concern, Petrojam.

The group said that "While we support the Government's programme to introduce the use of renewable energy sources, and move away from complete dependence on fossil fuels ... vehicles [sold by the group] should not be operated with E10/87 octane fuel. Vehicles [sold by the group] will be able to use E10/90 octane when released in 2009."

This is ominous. I drive a 2001 Mitsubishi Lancer Cedia, equipped with a 1500 cc 4G93 GDI engine. Managing director of the Issa Transport Group, Brian Stevenson, has gone as far as to say that "Mitsubishis with GDI engines [which the dealership does not carry] specifically should not use E10/87.

"While we do not recommend E10/87's usage in our vehicles at this time, all of our vehicles will be able to use the E10/90 blend whenever it rolls out in 2009." Stevenson also said that all the vehicles sold by the group are made to use 90 octane fuel; 87 should only be used as a last resort.

I have been using 87 in my GDI since 2004. We'll get back to this later.

Petrojam's blend

It is common knowledge that Petrojam's blend of E10 (10 per cent ethanol and 90 per cent gasolene) is rated at 87 octane. What is probably not as well known is that the base gasolene used in the fuel is actually rated between 82 and 84 octane, depending on the grade of crude it came from. Petrojam doesn't actually hide this little tidbit of information; technical staff at Petrojam and the affable minister of energy have both confirmed this. But I have not seen it in any of the publications from Petrojam on E10.

Ethanol is an oxygenator - it acts as an octane booster. A fuel's octane rating, or octane number, is an indication of how well the fuel withstands a phenomenon known simply as 'knock'.

Knock in your engine means that the fuel/air mix is igniting at the wrong time in your engine. When it happens, it sounds as if marbles are rolling around in your engine, and usually occurs at off idle or part throttle engine speeds.

Knock, if allowed to persist, is damaging to engines; it is akin to taking a sledgehammer rated at many tonnes and slamming it on to the piston crown in your poor engine at a time when it is ill prepared for it. Its occurrence is tied to compression ratio, engine running temperature and octane number. Not something you want.

Hygroscopic chemical

Now, ethanol is a hygroscopic chemical, in that it has a great affinity for water. During the blending process, only anhydrous ethanol can be used, i.e., ethanol containing less than one per cent water. At this level, ethanol is miscible with gasolene; it 'dissolves' in the hydrocarbon, forming a homogenous mixture.

The Petrojam blended E10 is transparent. However, if enough water is introduced into the mix, the mixture becomes cloudy with an attending decline in octane number. Adding more than 10 per cent by volume of the ethanol in E10 will result in the water 'dropping out' of solution, i.e., the alcohol becomes 'immiscible' with its 'parent' liquid, the gasolene. I know this is technical - bear with me, I'm getting there.

Now, the more ethanol is used to make the blend, the more knock- resistant it is. But because most cars are computer controlled these days, vehicles would have to be reprogrammed to use the higher blends of gasohol, like E20, E30, and E85. This is because the car's oxygen sensor would tell the car's computer that a lean condition (oxygen rich) is occurring, which it would try to compensate for.

The computer would find this impossible, so it would set an engine code and turn on the engine check dash light. Oh, and during all of this, the car would be running quite rich, which means mileage would fall off a cliff. E10 is the lowest 'common denominator' at which most of today's cars seem to function efficiently without apparent ill effects.

The problem is this. The average fuel injected car needs, at an absolute minimum, 87 octane fuel to run. Anything less than that and it will knock. As water is absorbed into the blend, this octane number will DECAY.

If left in contact with air, sedentary E10 will draw moisture from the atmosphere. In a vehicle's gas tank it is on the move, sloshing around, presenting a greater surface area for water absorption and is in an environment with a breather that is vented to air.

Tropical atmosphere

Tropical atmosphere contains up to three per cent water vapour, compared with between 0.5 and one per cent in other parts of the world. It is the blend's affinity for water in the air why the US retailed E10 has a shelf life of 90-100 days. The clock starts ticking from the day the blend is made, not from the day it is pumped into your tank. It only takes approximately one teaspoonful of water per litre to cause the blend to become cloudy, which would indicate a decrease in octane.

Likewise, I have not seen any literature from Petrojam about this.

Now, I am not saying that going green is a bad thing. There are environmental benefits to E10 use, as it replaces MTBE (a carcinogenic lead substitute) and is a cleaner burning fuel, and it is a renewable energy source. But because the possibility exists for the octane rating to drop by as much as three points, and because the fuel is marginal to start with, E10 cannot be considered a 'buy it and forget it fuel.'

There are inherent problems with it on a good day; Jamaica is a humid, tropical island. E10 is a step in the right direction. But why would ITG issue such a statement if there wasn't a perceived problem?

My GDI Mitsubishi has been running well on 87 octane gas since it was bought. Although the vehicle has a very high compression ratio - which should mandate the use of a high octane gas - because it is injected during the compression phase, almost at peak cylinder pressures, the injected gas has a cooling effect on the intake charge, which allows it to run low octane fuel. The car's literature says it will run on 87. So for ITG to say that GDI-equipped cars should not run on E10 means that something else is amiss.

Lower grade fuel

My take on it? Petrojam uses the lower grade fuel to mix its blend for a reduction in cost. The 35 per cent reduction in the ex-refinery ethanol price negotiated by Government is also a contributor to the $2 at-pump 'discount' in E10. But to use such a low octane base for the blend invites trouble on the consumer side, as E10 is many times more hygroscopic than MTBE fuel, and if water is absorbed by the blend, the octane rating will fall.

Petrojam is straddling a sharp picket fence with how it manufactures and distributes its new product. Use with caution.

- Mario James
For additional info, please visit www.fuel.te www.fuel-testers.com/2_precautions_e10_gas.html