Rev's - when to change gear?

blue_haddock

if you change gear at 2k revs then you may well find your vehicle is labouring and not working at its most efficient.

scotsbob

Strider gave you the right answer

forgotmyname

If the pistons pop through the bonnet or at least leave a dent it was revved too high. If you start to do kangaroo impressions or stops as the gearbox falls out then its too low.

Every car is different. Each gear will be different. If i changed up at 2000rpm in 1st gear the revs will be below tickover speed in the next gear.

If i changed up from 5th to 6th gear at 2000rpm i would be doing 1500rpm. As 6th only drops 500revs.

Best economy is usually around peak torque. Where the least amount of throttle gives the most gain.

Change up too early and you will be below peak power and use more fuel getting back to that rpm, Too late and you have wasted some of those revs and will be partly passed the peak power.

You need to learn how your car performs, Take 20 cars off the production line and they may perform slightly differently.

KierNet

waynedance wrote: »

Change gear when I need to change gear, as said 2000rpm not good up a hill. I do not use the rev counter or speedo just know when to change.

Thats what I could never get my head around before I learnt to drive, sure its easy to know when to change gear up, but down gears confused the hell outta me! Now its second nature.

At a steady pace, mine changes gear around 1,500 (automatic), but when I put my foot down it will go to around 4,000/4,500. Put it in sport, and its up to 5,000/6,000, maybe higher...I've never really noticed...I'll try and look tomorrow!

Road_Hog

B'stard wrote: »

When do you change gear when driving, I change at 2,000 revs, to get the best speed/fuel economy?
If the revs are higher before you change will the fuel economy be worse.

Listen to the engine, gearbox and car. It will tell you when the time is right to change gear.

Nearly_Old

The diesel is automatic and generally changes up at around 2,500rpm.

The fun car is a straight 6 with a very flat torque curve and twin exhausts with the second one opening at around 3,000rpm. The change in the exhaust sound is the usual change up point and gives the best fuel economy.

In my wife's car if we're on a steady run then about 3,500 rpm seems to be best for fuel as the torque curve isn't so flat. But at 5:30am on nice June morning with a few like minded friends then it's 6,500rpm but economy is not an issue - just the fun factor.

If possible neither the fun car nor my wife's car are run at over 3,000rpm for the first 10 miles to make sure that everything is fully warmed up before higher revs are used.

NBLondon

The car tells me with a little green arrow on the dash :-)

I don't always obey it though - if I can read the road and see I'll be slowing in 5 seconds time I'll ease off instead, if I know I'm accelerating to join a dual carriageway I'll hold in 4th until I complete the join.

colino

It's an interesting question, and unfortunately there isn't a "right" answer as you and your car will be different from everyone else. Cars with powerful, big engines generally have bags of low down torque and can be put through the gears at surprisingly low engine and road speeds. Cars with smaller engines, even turbo'ed, like the revs as their power band is much different and they will really labour if put in too high a gear too early (never mind increased wear and tear on the transmission).
Style of driving is important too. A while ago some big manufacturers of volume cars started to have widespread engine problems, eventually pinned down to "valve gumming", though unusually this, despite same engines throughout europe, seemed largely restricted to the UK. Much work was done and talk of lower ambient temperatures was blamed (rubbish) but led to the development of the almost universal thinner, synthetic or semi-synthetic oils that we all tend to use that were originally restricted to high-end performance cars.
The real answer is our driving style. UK motorists due to economy, traffic or temperament tend to change up sooner and believe we are being more mechanically sympathetic with our cars. Couple this to the difference on how most cars run after, "an Italian tune-up" and you will see engines haven't really been designed to continuously plod around.
Best answer is to experiment and find out what you and the car are best suited to, but it certainly wont be a fixed point on the tachometer.

Strider590

colino wrote: »

A while ago some big manufacturers of volume cars started to have widespread engine problems, eventually pinned down to "valve gumming", though unusually this, despite same engines throughout europe, seemed largely restricted to the UK. Much work was done and talk of lower ambient temperatures was blamed (rubbish) but led to the development of the almost universal thinner, synthetic or semi-synthetic oils that we all tend to use that were originally restricted to high-end performance cars.
The real answer is our driving style. UK motorists due to economy, traffic or temperament tend to change up sooner and believe we are being more mechanically sympathetic with our cars.

UK drivers are crap, shock horror!!! :rotfl:

anotherbaldrick

colino wrote: »

It's an interesting question, and unfortunately there isn't a "right" answer as you and your car will be different from everyone else. Cars with powerful, big engines generally have bags of low down torque and can be put through the gears at surprisingly low engine and road speeds. Cars with smaller engines, even turbo'ed, like the revs as their power band is much different and they will really labour if put in too high a gear too early (never mind increased wear and tear on the transmission).
Style of driving is important too. A while ago some big manufacturers of volume cars started to have widespread engine problems, eventually pinned down to "valve gumming", though unusually this, despite same engines throughout europe, seemed largely restricted to the UK. Much work was done and talk of lower ambient temperatures was blamed (rubbish) but led to the development of the almost universal thinner, synthetic or semi-synthetic oils that we all tend to use that were originally restricted to high-end performance cars.
The real answer is our driving style. UK motorists due to economy, traffic or temperament tend to change up sooner and believe we are being more mechanically sympathetic with our cars. Couple this to the difference on how most cars run after, "an Italian tune-up" and you will see engines haven't really been designed to continuously plod around.
Best answer is to experiment and find out what you and the car are best suited to, but it certainly wont be a fixed point on the tachometer.

The VW group (VW,Audi Skoda Seat) cars running the 7 speed DSG semi-auto gearbox, all up changes are set at 2000 rpm . But then, what do the manufacturers know ?