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you & your car


My Golf GTI has the DSG six-speed transmission and is supposed to be "adaptive." So for a year now, I have been assiduously trying not to let it "adapt" to my wife's leisurely acceleration style, and also trying to get it to adapt to the fact that when I tip over and start down a (say 8 per cent) grade I like to grab a gear so the speed doesn't run up and I don't have to apply brakes to check it. I do the same ascending the same sorts of gradients so as not to lug the engine (yeah, old school I know, but it's not all about fuel mileage). I am not sure if I am seeing any evidence of the tranny's brain learning anything. Poor student? Poor teacher? Or inexperienced "marker"? – Grainger

The transmission in your VW, like all new-generation computer-controlled transmissions, is programmed and defaults to the most fuel-efficient operation.

The transmission control module (TCM) studies your driving behavior and relays its findings to the electronic control unit (ECU), which adjusts throttle response and shift points according to event-specific algorithms.

The degree of this "learning" or "adapting" varies from one manufacturer to another and commonly does so based on throttle movement. If your wife's throttle inputs are gentle and gradual, that leans toward the default settings. If yours are harsh and sudden, the algorithms set different reactions.

The ECU is constantly adapting, but it takes time for this process to take effect. Each time your wife drives the vehicle, she is telling the ECU to take into consideration a less-aggressive driver. Some manufacturer's report that these transmission take several thousand kilometres to learn a given driver's habits. The two vastly different driving styles may in fact be creating a "mean" or average algorithm.

The solution? Either keep her away from the car or start using the ability to switch to manual mode and change gears yourself.

I recently bought a used Chevrolet Impala. There was no owner's manual with it. There is a FlexFuel badge on the trunk lid. What does that mean? – Hank

It means you have a vehicle designed to run on gasoline or a blend of gasoline and up to 85 per cent ethanol.

Ethanol or ethyl alcohol is obtained from corn in America and cane sugar in Brazil – the two countries with the greatest use of the product for motor fuels. It is not a coincidence that in both countries the financially troubled farming industry has a major lobbying effort in government circles. While manufacturers have made revisions to engines so they can burn the blended fuel, you will be hard-pressed to find a filling station where E85 (85 per cent ethanol) is available. I would estimate there are fewer than a dozen in the country.

The reason? Ethanol contains about 30 per cent less BTU content or energy than gasoline. Vehicles running on a blend of 85 per cent ethanol thus will go 25 to 30 per cent less distance on a tank of fuel.

While E85 stations are rare, most regular grade fuels contain some ethanol to satisfy the regulations, commonly 10 per cent in regular grade, 5 per cent in mid-grade and none in premium.

Aside from offering less bang per unit, ethanol creates some problems when temperatures drop below 10 degrees Celsius – fairly common in this country. Thus refineries reduce the amount of alcohol in their gasoline in colder months.

Is the quality of gas sold at a discount gas station any different from that at national brand stations? – Jaffer

It can be.

Discount or independent gas stations get their fuel from the same refineries as the major retailers. Depending on the size of that contract, they either get the same fuel that goes into the Shell/Esso/Petro Canada trucks and try to make up the difference elsewhere or they may be big enough (and buy enough) to warrant their own mixture, in which case it would be possible to cut costs by having the refinery alter the amount and type of additives put into the fuel to bring the cost down, obviously using less or less expensive additives.

There is no magic solution here.