Just wondering when you guys would change gears like at 3000rmp or 2500rmp etc... just would be instresting to know and at what rev count would be the best to change gears??

Andi

Depends how you are driving.

If your trying to go fast then there is no point in ragging it into the redline, the 8v doesnt have anymore power up there. you best to change up at 5500k and take advantage of the low end torque these engines have to offer.

if your just driving normaly then around 3-3.5k would be normal I suppose.

For economy change up when the next gear will take up power smoothly, this is not a constant across all gears.

For power, as suggested, don't wait till the redline, the power is tailing off by then.

Cheers

D

as d said.. you will loose amounts of power if you wait right until the limiter or redline..

and as for driving like everyday
i change at around 2 -2.5 k i call it the taxi driver method..
nice and friendly

5500-6500 rpm

i changed around 5k with my stock engine, bit higher with the new one as it didnt run out of power.

To give you an idea of when to change find a nice quiet stretch of national limit road. Now start at about 2000~2500rpm in 3rd and floor the throttle and just wait for the engine to start feeling breathless, check the taco and that'll give you an approximate change point. Personally I just have to play chicken with the rev limiter, but then again my cento can't be regarded as standard.

If you wana get really technical take it to a rolling road and get a thrust v's road speed graph made up of all the gears. back work the cross over points from gear to gear from speed to rpm & you're sorted.

StoneNewt said:

If you wana get really technical take it to a rolling road and get a thrust v's road speed graph made up of all the gears. back work the cross over points from gear to gear from speed to rpm & you're sorted.

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Some what unsurprisingly!! I tend not to agree.

The point to try and find is where the car really starts to pick up in each gear. So in third, around 1500 rpm accelerate. When the engine starts to accelerate better remember that road speed, then slow down and put the car into second. Accelerate back to that same road speed and you'll find the revs in 2nd that its best to change at.

You can do the same for all gears, however this assumes you only ever drive on drag strips.

In the real world the best time to change gears may not be exactly where the engine is at its best.

It may be advantageous to 'short shift', ie change up a bit earlier to get the gear change done before a corner rather than run out of revs in the middle of the corner and have to change up, thereby unsettling the car.

Cheers

D

ACT on co2 said:

Using your gears wisely by changing up a gear a little earlier can also reduce revs. If you drive a diesel car try changing up a gear when the rev counter reaches 2000rpm. For a petrol car change up at 2500rpm.

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source

So if your own about changing gears for reducing emissions... thats what the government are recommending.

4RL said:

source

So if your own about changing gears for reducing emissions... thats what the government are recommending.

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2500rpm in the cinq.. no thanks. 3000rpm is the sweet spot for pottering about if you ask me.

4RL said:

source

So if your own about changing gears for reducing emissions... thats what the government are recommending.

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co2 is not a considerable greenhouse gas, and does not cause global warming.. so please don't post that crap in here!

arc said:

co2 is not a considerable greenhouse gas, and does not cause global warming.. so please don't post that crap in here!

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only saying what the government recommend

Its all a personal preference tbh. There will be an optimum time in any given situation but that time will vary every single time you take it out.

I keep the revs low for town driving, shift early (not to early to early stress the engine)...on the lanes, there's nothing like the sound of my exhaust at 5-7rpm, even if its not the optimum performance range (more so than the 8v though), i like the sound and it makes it feel faster, I'm not fussed about the top end....If I was doing full whack, I'd end up with a ban or a lot of trouble lol

My advice, don't worry about it Concentrate more on smooth changes, positioning, braking and general control.

Kristian

//ps boring git aren't I

MiG said:

2500rpm in the cinq.. no thanks. 3000rpm is the sweet spot for pottering about if you ask me.

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Agreed, it's too gutless to change at 2.5K when pottering

check this : http://www.crich.plus.com/index.html

on the bottom graph, ignore the chiped power lines,

am i right in thinking for power the best time to change is when the bhp and troque lines cross each other ??

in this case just after 5500 rpm ?

power = (torque*pi*2*rpm)/33000
where power is bhp and torque is lbft so the crossing point will always be the same for a given axis setup, with lbft and bhp sharing an axis it'll always be just over 5600 rpm iirc.

And rallycinq, what have you been smoking? Thrust is the actual force that's doing the accelerating, torque multiplied by the gearing and divided by the rolling radius. If you use a speed/thrust grah you ideally want to track the edge that roughly travels from the top left to the bottom right. That line you've just made delivers the highest thrust for any given speed the car is capable of. As acceleration = thrust/mass, you want to maximise the thrust at any given speed, which usually isn't, in fact for road cars is almost certainly is not, the peek acceleration for a given gear. The change points you've described is really the point I don't want to short shift below unless there's a very good reason.