Power button and revs
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Power button and revs
I have a 2L CDX nubira (manual shift) bit note from my owners manual that the automatic transmission version has a power/economy button which alters (sets) the revs at which the automatic changes its gear. I would be interested to know at what revs an automatic transimission changes gear in both power and economy mode. Many thanks.
Many thanks. For the MT the service book (Nubira 1.6 and 2.0) says 'if possible, drive in each gear in the low engine speed range (between approx 2000 and 3000 rpm) and maintain an even vehicle speed'. This equates to the 'economy' mode. Max torque in the 1.6 (same engine as Lanos I think) is at 5800 rpm, so that makes some sense as well.
Thanks for your response.
Thanks for your response.
what about manual tranny? i see two shifting patterns here that could be the best:
1- is it better to keep on goint till you hit 5800 RPM (max. engine power) then shift to the next gear.
2- or shift at whatever RPM that will make you start the next gear at the max. torque (i.e shift at 6000 RPM in 2nd so you start revving at 3800 RPM in 3rd).
maybe it is a combo of both where you stress on HP style (rev to 5800 RPM) in low gears that already got high torque then go for the torque band style (start gears at 3800 RPM).
what do you think??
MMamdouh
1- is it better to keep on goint till you hit 5800 RPM (max. engine power) then shift to the next gear.
2- or shift at whatever RPM that will make you start the next gear at the max. torque (i.e shift at 6000 RPM in 2nd so you start revving at 3800 RPM in 3rd).
maybe it is a combo of both where you stress on HP style (rev to 5800 RPM) in low gears that already got high torque then go for the torque band style (start gears at 3800 RPM).
what do you think??
MMamdouh
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I think that technically you are correct with (a variation of ) 2 but 1 may be the better option because..
in our cars we are mostly at 90-100% torque whereever you are in the rev range so it's not really a big thing. Power does increase dramatically with revs (almost linearly from 2500 (~40%) to peak power, 5800 (100%)), and then drops off. There is always more power at the wheels, at a given speed, in a lower gear. Therefore you should redline for max power before a gear change, and this will bring you down into the powerband except for 1 to 2 where a redline change will leave you still below peak torque (but you can't do anything about that!).
The reason why I asked my original question was because of engine wear/longevity. Very high revs (red line) must take its toll on the engine and therefore there needs to be a compromise. The manufactureres have worked out that changing at max power (not redline) is a sensible balance for the AT and I guess this equally applies to a MT as well.
in our cars we are mostly at 90-100% torque whereever you are in the rev range so it's not really a big thing. Power does increase dramatically with revs (almost linearly from 2500 (~40%) to peak power, 5800 (100%)), and then drops off. There is always more power at the wheels, at a given speed, in a lower gear. Therefore you should redline for max power before a gear change, and this will bring you down into the powerband except for 1 to 2 where a redline change will leave you still below peak torque (but you can't do anything about that!).
The reason why I asked my original question was because of engine wear/longevity. Very high revs (red line) must take its toll on the engine and therefore there needs to be a compromise. The manufactureres have worked out that changing at max power (not redline) is a sensible balance for the AT and I guess this equally applies to a MT as well.