Could someone explain this please?

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Tue 15 Feb 2005 19:27
Could someone explain this please? - Imagos
Drove 200ish odd motorway miles in a Kia Cerato today, Engine humming away in 5th gearand 80mph at 4000rpm made me wonder.

My own car (V6 Mondeo) at simular speeds revs at about 3200ish.

Now to me the higher revs means higher fuel use also i've heard the terms 'high geared' 'low geared' etc but what exactly does all this mean? Why are some high geared and other low? What's the advantages and disadvantages?

All in laymans terms of course!
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Tue 15 Feb 2005 22:01
Could someone explain this please? - BazzaBear {P}
5th geared for higher top speed (and therefore lower rpm while crusing:
Advantages: Lowers fuel comsumption, less noise
Disadvantages: Means gears will have to be spaced further apart, will reduce responsiveness when at that speed as revs are lower.

The disadvantages are largely negated by having a powerful (or more pertinently torquey) engine, hence you tend to get this gearing attached to larger engined cars.
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Tue 15 Feb 2005 22:21
Could someone explain this please? - Tomo
All very complex in detail but basically, comfortable and economic cruising relates to piston speed. You can reduce this by high gearing, or by having a shorter piston stroke. With the first you go the bigger engine way, with the second the multi cylinder way (Mondeo V6 a compromise, like Sonata?). Ideally I'd have large capacity and a lot of cylinders!
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