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Possibly a silly question about top speeds.. watch

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    I was just wondering.. what happens if a car is driven at its top speed for a sustained period of time? Would it have a bad effect on the car, or should it cope ok?

    I'm mainly asking because I'm driving a Daewoo Matiz at the moment (currently with my parents in the car, but once I've passed my practical, I'll be out on my own) and the car's top speed is 90mph.

    I know you aren't meant to drive that speed legally in England, but I'm just thinking that on motorways and stuff, if I try to overtake a lorry or something, I might have to go nearish to the top speed. Would the car be alright afterwards?

    Rosie xx
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    I'm afraid to drive mine over 95mph. It starts to shake :s (It's a fiat seicento)
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    If you're doing top speed, then the revs will be very high. This will be fine for short periods (eg. overtaking something then slowing down again), but you don't want to be at top speed for a long periods as it's not particularly good for the engine to be running at the redline the whole time.
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    It will stress the bearings and everything else quite a lot, its like reving your engine constantly for 30 mins or so.

    They only have weedy little engines so 90mph is not a good idea.
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    (Original post by RosiePosiePuddingAndPie)
    I was just wondering.. what happens if a car is driven at its top speed for a sustained period of time? Would it have a bad effect on the car, or should it cope ok?

    I'm mainly asking because I'm driving a Daewoo Matiz at the moment (currently with my parents in the car, but once I've passed my practical, I'll be out on my own) and the car's top speed is 90mph.

    I know you aren't meant to drive that speed legally in England, but I'm just thinking that on motorways and stuff, if I try to overtake a lorry or something, I might have to go nearish to the top speed. Would the car be alright afterwards?

    Rosie xx
    You won't need to get past a lorry quickly at 90 mph. You will also find that for your car to get up to such a speed you will need miles, hence if you go at that speed, it will be planned.

    Your car will not like it either, no.
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    would depend. maybe not in this example but if the engine was limited the revs wouldnt necessarily be high enough to do damage right
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    Surely as long as you're not maxing it out on a regular basis, it will handle it reasonably well, since it was designed to. Obviously avoid it when possible though - it's not going to do you any favours.
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    Do stated top speeds actually mean anything in the real world?

    I remember seeing something about 0-60 times and how they generally involved a tail wind, a supurb driver and leaving the gearbox halfway down the runway.
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    (Original post by dh00001)
    would depend. maybe not in this example but if the engine was limited the revs wouldnt necessarily be high enough to do damage right
    correct, not many cars can hit the redline in the highest gear. ive kept my car at 90ish for literally hours before on the motorway and its been absolutly fine. obviously its more stress but it can cope just fine. thats what the rev limiter is for, stopping it from damaging itself.
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    (Original post by dh00001)
    would depend. maybe not in this example but if the engine was limited the revs wouldnt necessarily be high enough to do damage right
    Seen too many cars damaged from high RPM driving, the rev limiter is there to protect the engine for short periods, it doesn't help sustained use at beyond a reasonable RPM.
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    (Original post by pghstochaj)
    Seen too many cars damaged from high RPM driving, the rev limiter is there to protect the engine for short periods, it doesn't help sustained use at beyond a reasonable RPM.
    maybe badly serviced engines, ive seen many cars hit the redline many times and not once have i seen anything detrimental happen.
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    Badly serviced? An oil and spark plug change has very little odds on whether an engine car sustain high RPM for long periods. Again, it's not about a car hitting the rev limiter for short periods (which is a complete waste) - it's about sustained high RPM driving. It depends on the engine design more than anything, I would put money on a Matiz not being healthy after an hour of being driven at 90 mph. They are simply not designed or engineered to do so.

    Of course even in my first generation common rail diesel, top gear is 30 mph/1000 RPM so no issue for me
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    (Original post by pghstochaj)
    Badly serviced? An oil and spark plug change has very little odds on whether an engine car sustain high RPM for long periods. Again, it's not about a car hitting the rev limiter for short periods (which is a complete waste) - it's about sustained high RPM driving. It depends on the engine design more than anything, I would put money on a Matiz not being healthy after an hour of being driven at 90 mph. They are simply not designed or engineered to do so.

    Of course even in my first generation common rail diesel, top gear is 30 mph/1000 RPM so no issue for me
    manky oil would be a very good contributor to excessive wear on an engine, most likely wearing the shims away and causing the bottom end to knock. or causing excessive friction in the cylinders. as long as its properly serviced it will be good for driving at high speeds, i admit it will cause more wear and tear but it will be completely unoticable. reving the engine up and down in stop-start driving will cause more damage at least at a constant speed the forces in the engine are stable.

    you think cars are alot more fragile than they really are, and i dont blame you when yovue been told lots of theories your bound to. just like in the fitness forum people percieve the body to be alot weaker than it really is as they become too involved in theories and what not to do etc.
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    Depends on the engine. Your average watercooled 4 pot lump wont like it.
    Although, I wouldnt have any qualms about driving a Citroen 2cv flat out for 4 hours, for example.
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    (Original post by Dac_10)
    correct, not many cars can hit the redline in the highest gear. ive kept my car at 90ish for literally hours before on the motorway and its been absolutly fine. obviously its more stress but it can cope just fine. thats what the rev limiter is for, stopping it from damaging itself.
    Yeh I'm quite sure you can't do any damage when in top gear on modern cars.

    A 1.0l micra was still accelerating in 4th at 80-90 (left in by mistake) but in 5th it accelerates much slower at 80 and stops accelerating unless you do downhill.
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    (Original post by JC.)
    Although, I wouldnt have any qualms about driving a Citroen 2cv flat out for 4 hours, for example.
    did you see on the cannonball i think it was when a couple of guys drove one flat out at like 60mph all the way :rolleyes:
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    (Original post by Dac_10)
    did you see on the cannonball i think it was when a couple of guys drove one flat out at like 60mph all the way :rolleyes:
    Well there you go then. Anecdotal evidence supporting what I said. Although I think a 2cv in good order will top out at about 80 ish.

    p.s My car will redline quite easily in top.... although dont ask me how fast that is because the needle on the speedo is well off the scale!
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    (Original post by JC.)
    Well there you go then. Anecdotal evidence supporting what I said. Although I think a 2cv in good order will top out at about 80 ish.

    p.s My car will redline quite easily in top.... although dont ask me how fast that is because the needle on the speedo is well off the scale!
    to be fair they did have two people and lots of kit in it. i vaguly remember them getting excited about breaking their personal record and it was like 70. but wherever they were the climate was really hot.
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    (Original post by Dac_10)
    manky oil would be a very good contributor to excessive wear on an engine, most likely wearing the shims away and causing the bottom end to knock. or causing excessive friction in the cylinders. as long as its properly serviced it will be good for driving at high speeds, i admit it will cause more wear and tear but it will be completely unoticable. reving the engine up and down in stop-start driving will cause more damage at least at a constant speed the forces in the engine are stable.

    you think cars are alot more fragile than they really are, and i dont blame you when yovue been told lots of theories your bound to. just like in the fitness forum people percieve the body to be alot weaker than it really is as they become too involved in theories and what not to do etc.
    No, I have seen in enough to know the truth, not what a book might tell me.
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    With my Vauxhall, the redline is at 6500, yet the manual states a maximum continuous running speed of 6250... So im assuming that as long as you stay below this, you'll be ok.

    As for my dads new Audi S5, I suspect that would sit at 155 24/7 (Except for the regular and expensive fuel stops )
 
 
 
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