thek

You know driving it in a gear (or two) too high. Like if I am coming up to a roundabout in 4th but im just cruisin, so instead of taking it in second (like I should) I just keep it in 4 th. Takes the motor awhile to get back up to speed after but when the speed limit is 50 thats no biggie at all (especially if you take the roundabout at 40 lol). Just seems a waste of effort when you will be back in 4th 5 seconds after the roundabout anyway.

My main questions are:

Is it bad to do this for the gearbox? Or motor perhaps?

Is it bad or good or the same for fuel economy?

Its just the way my manual driving style has developed so I want to find out if its good or bad.

Thanks.

XD 351 Ute

Depends on the car and conditions really.
I let my XF ute lope around in top gear a fair bit, and she pulls from about 900 rpm with no worries.
However, I don't floor the the trottle expecting her to get up and go, it is usually just a light load or throttle.
If I had her full of gear in the back, or towing a trailer, then I wouldn't allow it to lug at all.
It's much better for the engine to have a few rev's on board while allowing the torque to do it's work.
You're just asking for trouble doing that under reasonable load, and there's always a good chance of stalling the engine and looking like a fruitcake!!
Not to mention the loss of vehicle control, braking and steering etc....

Ed :)

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My XF 3 on the tree ute is ALWAYS stuck in third......

blueraven

Yeah, I'm not sure about the phyiscal implications on the running gear on the car, however it does effect vehicle control, braking, steering, etc... However, I imagine it can be that hard on the car as long as you don't try flooring it to get up to speed again.

dave_au

It good for fuel economy using a higher gear, however if you let the rpm slip below the idle rate it can damage the engine.

Pik0

Low RPM doesnt always mean better fuel economy, if im to believe the BMW thing that they have with the instantenious ecomony meter (under the tacho) you can be in 2nd at 4000rpm and as long as your not pushing the accelerator hard your not going to be using much fuel at all...
Also if your in top gear at 500rpm the engine has to work hard to get the car moving so uses more power to move it along, thats how i think anyway...

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Steffo

I'd be more worried about the engine in your scenario.. not the gearbox.

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deankdx

40 kays i forth ??? maybe yo should include revs at 40 kmh in 4th also, my 351 clevo with gas cam ages ago made power lower in ev range than std cam and didn't mind going 1000rpm in top(4th for this car) my crossflow six doesn't like it as much but i reckon economy is better if you maintain 1500rpm ish motor is "on the cam"and has sufficient torque at light throttle, if you had 4.11 diff ratio 4th gear at 40 kmh would be ok IMO

WBT56

If you are not at 100km/h or at 2000rpm, you are in the wrong gear. In my car I just skip third around town, and go up and down from second to fourth. Fourth is 2000rpm at 60km/h. Fuel economy is more based on throttle position than engine rpm.

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If you're not driving a manual you're really just steering.

Rodderz

Your better off not putting unnecessary load on the engine, as with some smaller cars where you hear the tappets going like crazy if in a high gear at low revs

As others said depends on the gearing and power of your car, but the gears there are for changing, thats why I always drive manuals!

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thek

Thanks for the replies guys. The car is my gf's 1988 Astra 1.8 ohc. It feels like its got a pretty (numerically) high diff ratio but Im not sure what it is. Probably 3.7:1 or thereabouts.

I dont drive it too often so Im not too worried about what will happen to it. But in the future I will have a manual cortina (most likely 5-6 speed, ohc 2.0 litre pinto or 4.1 crossflow, both turbo).

I know the characteristics of these engines couldnt be more different. Not to mention the diff ratios I will use.

So I would imagine the torque monster 4.1 could be lugged much more than the 2.0. Although the 2.0 will have a 3.7:1 diff or maybe even higher (numerically) so maybe not. Might just have to wait and see.

Thanks again.