Technical gear vs speed

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Technical gear vs speed

devakanth

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May 28, 2006
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Hi All,

I normally put my UNO on the 5th gear when I cross 55 or reach 60 kmph. but I find that when I am slowing down, I can keep the gear on 5th and still go down to 40kmph and keep moving comfortably. Does this put load on the engine and is it a bad practice?

Does it harm the engine if you slow down the vehicle even when you are at a higher gear? Does it put too much load on the engine or something like that?

Devakanth
 
Good question!
I think it's not so much the engine as the gearbox that may be harmed. If the engine (particularly a diesel) is running slowly ('lugging'), the torque output is not as smooth, and the pulses will cause uneven loading on the gears/bearings.

Also, the fifth gear is actually in an extension to the casing on the very end of the gearbox. I could be wrong here, but I know in certain other cases the oil circulation to the 5th gear (and its selector) depends on a fairly high speed for the gears to 'fling' the oil around. I believe therefore, that 5th gear is only for use at decent speeds (I reckon 80km/h with a petrol engine, probably slightly less for a diesel) when there is likely to be maximum oil circulation and engine smoothness.

I don't think that there would be any harm from staying in 5th gear while slowing down, since the engine is effectively offering a smooth, even resistance and not much torque is transferred through the gears/bearings.

-Alex
 
That means I can deaccelerate from high speed to low using the higher gear but should not accelerate when the engine is lugging. Right?

Devakanth
 
Yes when you feel the engine under load/juddering/pinking change to a lower gear.
For fuel economy get in the highest gear you can apply gentle force on the accelerator pedal so it just ticks over.

But always remember brakes are for stopping and gears are for driving.

In the true sense of the car control you should always get your speed down then match the gear for the speed of the vehicle as this makes it more stable for whatever maneouvre you intend.
Pete
 
hmm...:confused:

having said that, I remember someone told me to downshift when i need to suddelny reduce the speeds and still want to be on road rather than applying brakes !! And I have been doing this quiet successfully for quiet some time ! Though not on my uno - I just have purchased it for one month now, and never had a chance to cross 100Kmph or to try my racing skills as the roads are all gone due to rain !!(n)

I know, I must have burned the clutch discs, but..hmm..it's worth the drive.:yum:

If I was wrong - Pls corret ..:idea:
 
HE HE

:rolleyes:

I like that..
Of course, Rules are here intact, most copied brom that of Be=ritan and USA::eek:

But the one who're in charge of implimenting the rules often needs to be taught of rules by the drivers- he heh.

And , of course, we have a MOT here , once the vehicle gets pass it's 15th yr of manufacture. But, the revalidation is for 5 yrs for private vehicles and for 1 yr for pblic vehicles(taxis and all).:slayer:

Kool ::;)
 
Re: MOT/roadworthiness

premrajeev said:
And , of course, we have a MOT here , once the vehicle gets pass it's 15th yr of manufacture. But, the revalidation is for 5 yrs for private vehicles and for 1 yr for pblic vehicles(taxis and all).:slayer:

Kool ::;)


Oh dear... ! a token gesture if ever there was.

In England they have an MOT every year. We have one every six months. Even six months is not nearly enough - not uncommon for a brake light etc. to stop working on the way home from the test, or for a suspension balljoint to wear out completely within a few days.

If you read the fine print you realise that an MOT/Warrant of Fitness means nothing legally - the onus is on the driver to keep the vehicle in a roadworthy condition.

Actually I have a good example of this. When I bought my X1/9 it had a new WOF that morning. I drove from Wellington to Hamilton the same day. Around Taumaranui I got pulled over by a police officer because one headlight was too dim. I showed him the WOF checksheet from that morning, and the bill of sale, and pleaded ignorance - and he let me off, but said it would be an $80 fine if stopped again.

My Stilo only requires a WOF every year, until it is six years old - then it becomes six months. I think in England, they don't even have MOTs at all on vehicles under a certain age... which must be interesting in the case of FIATs with bits falling off or worn out from the start :rolleyes:

Over in Australia, a few years ago there were an extraordinary number of old cars running around (their government doesn't allow used Japanese imports like ours encourages). In most states of Australia there is no roadworthiness inspection except when a vehicle is sold...

-Alex
 
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