Changing to 2nd at about 20kph / 3,000 rpm is certainly sensible. If you are only driving at 15kph, then leave it in first doing ~2,000 prm. This doesn't harm anything and wont waste fuel because you notice how light the accelerator needs to be pushed to keep up that speed. If you change to 2nd at that point you will be below 1500 prm, and the engine wont run smoothly, and you wont be saving any gas because of that.
Ideal speed of gear changes depends on your particular car, engine and gearbox. What my car does is different and with a larger engine and more gear ratios it can change up @2,000 rpm, and still pull well in the next gear.
The engine will be fine reving up to whatever the red mark on the speedo says, maybe 6,000 rpm. Sure it will make more noise, and use more gas, but it wont harm the engine in any way. With a smaller engine you don't have the cubic capacity, so they are designed to rev higher to develop any useful power.
> if i change earlier i can feel lugging
There's your answer. Lugging is VERY bad. 2500 - 3000 RPM is not over-revving.
> sometimes i have to drive and stay in 1st gear around 2500rpm
That's OK. If you're risking lugging the engine in second gear, keep it in first.
hi,
im the one who asked question.
Thank you all for replys.
I asked because 4 cyc. 1st gear 3000rpm and lack of isolation, engine sound really hurts my ears.
like it says "shift up!"
carbureted cars are different class, low rpm not means high mpg.
if is it OK to use car 1st gear around 3500 rpm to catch 2nd gear speed.
i will do.
Thanks,
Do?an
If the manual says don't change until a certain speed, they probably know what they are talking about. If the car struggles in 2nd at a lower speed, that'll explain why the manual says what is says. So, your experience mirrors what the manual says - why then do you question what it says?
better to over rev a little than to lug it a little
for these situations, you do not worry about gas mileage....you don't want to hurt the engine
My car manual says not shift to 2nd gear until you reach 21km/h
but until reach 20km at least, i have to spin around 3k rpm in 1st gear.
if i change earlier i can feel lugging because between 1st and 2nd gear ratio there are too much change, almost big as twice.
on nsrrow street sometimes i have to drive and stay in 1st gear around 2500rpm
does it more economic drive to change to 2nd gear suddenly ?
my car is carbureted, maybe thats why manual says never drop below 1500rpm
