Tuesday, Apr 05, 2005 at 03:48
We tow using a Landcruiser 100 turbo diesel, so my comments may or may not apply equally to the petrol Landcruiser.
First question, I guess, is what speed you would expect to cruise at? When we were novice, we used to cruise at about 102-105kmh. Whilst the LC can handle that easily, there is a noticeable increae in fuel consumption compared to the 95kmh which we cruise at now - we have found the more leisurely pace makes for a less stressful trip, and greater enjoyment of the sights.
Now at 95kmh, the LC rolls along the flat easily in normal overdrive (ie normal auto mode). However, we downshift early using the o/drove off button whenever approaching moderate grades as the vehicle will generally lose momentum otherwise on the grade. I should have added that we do use the cruise control facility, and downshifting early is helpful as the cruise control is otherwise a bit slow to kick in its own downshift until it is too late and the speed has already dropped significantly. Also, at a cruising speed of 95kmh, there is a ton of torque immediately available (using the o/drive off) if you need to overtake (eg slow moving truck).
In the case of our vehicle, once you reduce the cruising speed below about 90-92kmh, the cruise control is changing gears so often, that I think you are starting to lose fuel economy depsite the reduction in average travel speed. But others are happy to potter along at 85kmh, so it is very much a matter of personal preference and confidence.
Now, a comment about the cruise control itself - this has been designed to switch off if the speed of the vehicle falls more than 15kmh below the preset. Example, if the cruise control is set at 90kmh, and you are pottering happily up a hill with cruise control on, it will totally cut out once the speed falls to 75kmh. Why Toyota have designed it this way I am not sure, but it is very unnerving the first time it happens to you! However, I have found that if you see the speedo dropping, use the accelerator pedal (even whilst the cruise control is still engaged) and the cruise control will remain engaeged at the preset level once speed is reached again.
Now the question about the 'Power' mode - basically, this makes the cruise control more sensitive to changing gears early (ie the cruise control will down shift earlier in power mode if the vehicle speed starts to drop). This is what you want to happen if you have forgotten to use the o/drive off button to force a dwonshift yourself. We always use the power mode when towing - overall momentum is maintained more consistently - but you will notice that the gearbox is shifting more often and presumably fuel consumption will be higher also.
Now the 'second' button - this is used when starting from rest in, say, severe mud or snow conditions, and forces the vehicle to start in second gear rather than first. The idea being that there is so much power going to the wheels in first gear, that you may initally wheel spin until the vehicle gains momentum whereas in second the engine is working hard, but there is less traction going toi the wheels.
Finally, having said all that, I can understand why some people may prefer to just set and forget the o/drive permanently off when towing - I suspect they pay a higher price in fuel consumption with the higher engine revs. I choose not to drive that way, because our car lumbers along happily in o/drive for most of the time. But again I think there is no right or wrong answer, it depends a lot on personal driving preferences.
Phil
AnswerID:
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