Vauxhall Astra H estate - Driving technique for a small diesel?

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Mon 29 Mar 2010 22:42
Vauxhall Astra H estate - Driving technique for a small diesel? - Waino

Some weeks ago, I posted about my interest in retiring my old petrol Mondeo estate and replacing it with a 1.3 diesel Astra estate which had been run as a hire car by a good friend. Well, I took the plunge and the Astra is now mine - or at least, it will be when the documents come back from the DVLA.

I liked the idea of £90 ved and lower insurance ....... and the increased fuel economy and, frankly, we didn't need an estate quite as big as the Mondeo.

After 460 mixed miles which included a 250 trip on A road/motorway, a brim/brim calculation showed it had done 53 mpg - and I was rather disappointed.

On motorways and duelled roads, I found that 70mph was held with just a fraction over 2000rpm in 6th gear, the only snag being that if I hit an uphill slope, then the speed fell off (something that had never happened on the same run with the Mondeo). I just wonder if better economy could be achieved at 60mph in 5th gear, i.e. staying below the point when the turbo kicks in.

Has anyone got any tips for getting the best out, what I have to say, isn't a bad little car.

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Mon 29 Mar 2010 22:52
Vauxhall Astra H estate - Driving technique for a small diesel? - Herr Sandwichmann
Hi. I may be completely wrong, but 53mpg average doesn't seem too bad to me. I wonder if you had a larger engine in the car, it might even return better figures, through not having to work so hard on motorways, etc.

HS
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Tue 30 Mar 2010 08:56
Vauxhall Astra H estate - Driving technique for a small diesel? - piston power

Im lucky to get 32mpg out of a petrol 06 plate so stop moaning as for performance of course the mondy will be better it's a bigger engine you have a small diesel in a heavy car.

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Tue 30 Mar 2010 11:24
Vauxhall Astra H estate - Driving technique for a small diesel? - dieseldogg
Some Ex petrol converts to diesel take a while to realize that they can use the greater diesel torque and change up gears at much lower revs than in a petrol. ie revving the nuts off a diesel is counterproductive.
Hence excessive or higher than necessary fuel consumption.
jat
M
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Tue 30 Mar 2010 13:31
Vauxhall Astra H estate - Driving technique for a small diesel? - Waino

............ so stop moaning

I'm not moaning, just making an observation - you'll know when I'm moaning!

as for performance of course the mondy will be better it's a bigger engine you have a small diesel in a heavy car.

Yes, I suspected the the old Mondy would be more powerful - something to do with the 90/140 hp power ratio, I guess.

Do you have any helpful suggestions, bigtee, on the topic of 'Driving technique for a small diesel'?

Cheers, Waino

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Tue 30 Mar 2010 13:41
Vauxhall Astra H estate - Driving technique for a small diesel? - madf

We find:

don't labour engine in too low a gear.

Don't accelerate up hills.

Accelerate downhills.

Never over 3,000 rpm ..

Works for us.. 57mpg from a Yaris in mainly town driving. Motorways at 70? 68mpg

(driven HARD) Motorways at 75-80 (400 miles round trip last Monday to Basildon) 59mpg...

.

Edited by madf on 30/03/2010 at 13:42

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Tue 30 Mar 2010 14:41
Vauxhall Astra H estate - Driving technique for a small diesel? - oilrag

I have this engine in a Punto. it will likely be at it`s best and smoothest if you keep it at around 2,200 revs. 2,000 revs is fine as long as it`s not putting a vibration through the frame, when you floor it. Running at under 2,000 revs won`t save much and as it drops off the torque curve at around 1,800 revs there is no point ever letting it drop to that.

With it being a smaller capacity engine than, say, a 1.9, there will be much less torque from actual cylinder capacity when not on turbo boost.

Put simply, you need to drive it on boost.

It`s a great engine but i would not do Vauxhalls long service intervals on oil changes myself.

edit - try 60mph and 2,000 revs (or as near as possible) you could experiment with the onboard computer. It may not be totally accurate, but it will give you a good comparison.

Edited by oilrag on 30/03/2010 at 14:48

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Tue 30 Mar 2010 22:50
Vauxhall Astra H estate - Driving technique for a small diesel? - ed81

Best to just enjoy the car, I was obsessed with my mpg when I first got my Diesel Focus, couldn't take my eyes off them. But now 50mpg I am getting isn't too bad.

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Wed 31 Mar 2010 13:57
Vauxhall Astra H estate - Driving technique for a small diesel? - Sofa Spud

You don't need to rev diesels much if you're running light. Maybe if the car is fully laden and towing a caravan uphill you might need to use higher revs! However the same is true for a lot of petrol cars.

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Thu 1 Apr 2010 00:54
Vauxhall Astra H estate - Driving technique for a small diesel? - DP

We've had at least one turbodiesel in the household for the past 7 years or so, but I do remember the adjustment needed to drive them effectively after years of petrol power. The power delivery is completely different. Most diesels make peak torque somewhere around the 2000 RPM mark, and if you aim for this as a target in daily driving, you will find the engine pulls strongly when needed, and returns optimum economy. The simplistic answer is do everything a gear higher than you would in a petrol - so a third gear overtake would be done in 4th, and there is rarely a need to exceed 3000 RPM in daily driving.

Also, take advantage of the diesel's lack of engine braking. If you're cruising at, say 40-50 mph on an A-road or a busy motorway, select a high gear and you will find you can keep up barely touching the accelerator pedal, with "feet off" driving a realistic proposition as the car barely slows when you lift off. Our Golf will show 70-80mpg on the computer in these conditions. Of course, if you need to accelerate hard, you'll need to drop a gear or two, but it makes for economical cruising.

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