Question on changing gears

[Dantera22B]

But the only way you'll get anywhere in an old Datsun is to rev the absolute nuts off of it. My car is slow as all hell below 4000rpm, as soon as it comes 'on cam' it comes alive and it needs to be revved hard due it only having a 1600cc.

[nota]

Is it that it's a waste of fuel and isn't necessary?

yes

Are basic family transport sort cars able to withstand that kind of abuse?

generally, no

Is it just adding extra wear to the engine?

yes

Think of this parable in regards to how you treat your engine .. a candle that burns half as bright burns twice as long

This is especially pertinent to high-mileage engines such as yours

Use lower revs when you require modest power (ie normal driving) and more revs only when you need more power (eg max acceleration)

[TVR IS KING]

Fair enough. I'll have to restrain myself.

[Bob]

Most efficient way to drive - Plenty of throttle and low revs. Opening the throttle more increases your volumetric efficiency, and lower revs means less energy lost to friction. Also, volumetric efficiency (compared to rpm) peaks well below redline on most engines. Lower revs also means less wear on the engine because the crank and valvetrain experience forces that increase very much with greater rotating speed.


Note: if your engine adds fuel and spark above a certain throttle threshhold and or changes air fuel ratio, then max throttle at minimum rpm isn't necessarily the best. What you're looking for is a point of maximum Volumetric efficiency at low rpm. I did a little bit of fuel map tuning on my car, and looking at engine speed vs. throttle position vs. volumetric efficiency is one of the best ways to find your engines most efficient range. if your interested in that stuff

[TVR IS KING]

Ooh. Driving my car as cheaply as possible sounds like my kind of thing. I could've bought a bigger Commodore, like everyone I know, but it's wasted space and fuel. I'm right into saving fuel in my car.
Low revs whenever I can help it then eh? Sounds good.

[NSXType-R]

Most efficient way to drive - Plenty of throttle and low revs. Opening the throttle more increases your volumetric efficiency, and lower revs means less energy lost to friction. Also, volumetric efficiency (compared to rpm) peaks well below redline on most engines. Lower revs also means less wear on the engine because the crank and valvetrain experience forces that increase very much with greater rotating speed.


Note: if your engine adds fuel and spark above a certain throttle threshhold and or changes air fuel ratio, then max throttle at minimum rpm isn't necessarily the best. What you're looking for is a point of maximum Volumetric efficiency at low rpm. I did a little bit of fuel map tuning on my car, and looking at engine speed vs. throttle position vs. volumetric efficiency is one of the best ways to find your engines most efficient range. if your interested in that stuff

VTEC kicked in yo!

Sorry, couldn't restrain myself from saying that.

[TVR IS KING]

Can any harm be done from being in a gear too high? I mean, provided the car isn't shaking or making strange noises. Like, if you're in 5th, and you have to climb a hill, but the revs sink pretty low so to keep your speed up you've gotta mash the accelerator to the floor. But you make it. Is that fine, as long as the car isn't making any strange sounds or anything? Or is it going to be stressing the engine/gearbox?

[Dantera22B]

Can any harm be done from being in a gear too high? I mean, provided the car isn't shaking or making strange noises. Like, if you're in 5th, and you have to climb a hill, but the revs sink pretty low so to keep your speed up you've gotta mash the accelerator to the floor. But you make it. Is that fine, as long as the car isn't making any strange sounds or anything? Or is it going to be stressing the engine/gearbox?

Change down. Your engine can get just as damaged that way as it can driving on the redline.

[drakkie]

Change down. Your engine can get just as damaged that way as it can driving on the redline.

After a campaign for efficient driving here (80km/h in 5th) many people damaged their cars on vacation. They went into the mountains, where they did the thing you describe. If they even managed to come up the hill, they broke down. IIRC it was 13.000 cases in a few weeks...

[Zytek_Fan]

yep ..... I don't rev the Matra's beyond 4500-5000 and the A610 used to be revved out to the red line --- but of course has now blown up twice So it'll be getting treated a wee bit better ( well for the first 2 weeks at least )

It's French, so it's cheap to repair

[TVR IS KING]

Okay, I'll take that advice on board too...

[IBrake4Rainbows]

The best thing you can do for you car is to respond to it's rev & gear requirements.

Listen, look, act

[fpv_gtho]

Can any harm be done from being in a gear too high? I mean, provided the car isn't shaking or making strange noises. Like, if you're in 5th, and you have to climb a hill, but the revs sink pretty low so to keep your speed up you've gotta mash the accelerator to the floor. But you make it. Is that fine, as long as the car isn't making any strange sounds or anything? Or is it going to be stressing the engine/gearbox?

Others have said already that damage can be caused, but from an economy point of view theres no point to it either. Labouring the engine just uses more fuel than allowing the engine to rev a bit and simply move itself. If youre still thinking of buying that Pulsar, theres no point letting it rev below 1500rpm before changing up. Above that will be fine unless youre in a bit more of a hurry or have the car loaded with people/cargo etc, then 2000rpm or even 2500rpm is more suitable.

[TVR IS KING]

Oh, I bought the Pulsar. Hard.
Fair enough then. There seems to be some merit to sitting in a higher gear. After all, that's the whole point of economizing with manuals isn't it? And the reason small cars may have a 6th gear for the highway?
But if there's risk of doing damage I won't push it beyond reason.

[fpv_gtho]

You'll soon be wishing you had a 6th gear when its buzzing at 4000rpm at 120km/h.