Berlingo 1.6 diesel engine, what teh rule of thumb for getting the best out of the engine and MPG?

Leave it parked in the drive.

rag its nuts off at 6,000rpm

I always thought short shifting the gears was pretty economical.

Smooth. Every time you touch those brakes* it means you havent thought ahead and burnt unnecessary fuel building up unnecessary speed. So a polar bear dies.

*except in an emergency.

My astra is listed as 55 mpg. It goes up and down the motorway for 65 miles each way at 55 ish mph and returns 63 mpg.

(edit) as above, forward planning and anticipation plays a massive part as well.

Buy a trilby/hat.

Buy a tartan rug and nodding dog for the parcel shelf.

Alternatively short shift and anticipate as far ahead as you can.

Give it some revs,preferably on an empty road, up past 3500rpm plus, in second and third, and watch all the crap come shooting out the back, James Bond and Q would be proud of the smoke screen, and it improves the mpg figure for some reason.

Avoid cheap supermarket fuel, go for shell or texaco.

Modern turbo diesels need accurate gear changes to get the most miles from a gallon.

They’ve got very narrow powerbands and the powerband (the area of max’ power and torque) is the engines most efficient operating zone. So select first and rev’ into the powerband slowly and smoothly and change up. Do this until you’re travelling as fast as you want then change into the highest gear and lift your right foot until the car ‘just’ maintains your chosen speed.

Avoid slowing down or speeding up as this consumes extra fuel or wastes energy (by braking). BE SMOOTH 😀

Look no further

Use the cruise control

Drive further, less often.

Try driving a 2t 2.5l diesel 40k a year Rob – I’m sure you’ll survive even if you thrash it’s nuts off.

Steady acceleration is the key with diesels though apparently – don’t floor it, gently squeeze, like a gun trigger.

Stay off boost?

Who gives a shit? Thrash it, be gentle with it. What’s the difference? About 5 mpg
Whoop friggin dee!!!

Fairly consistent advice seems to be accelerate briskly then cruise. But I drive mine incredibly inefficiently, because if you’ve only got 90 horses you might at least make sure they’re all doing something all the time 😉

Stay off boost?

Worst thing you can do, cos the engine is operating inefficiently when its off boost, if you floor the throttle from low revs in too high a gear, to accelerate up a hill say, you’ll burn more fuel but less power will be produced (and therefore it won’t accelerate as well) as if you changed down to get the engine into the turbo zone and hence nearer to the peak torque figure, where a much smaller throttle input will have a much more marked effect.

Key to driving diesels economically is of course planning ahead. NEVER EVER touch the brakes unless you absolutely have to, and accelerate briskly and keep the engine in the powerband, use as much as about 2/3 max revs (if your engine revs to 4500rpm change up about 3000rpm) but accelerate up to cruising speed pretty quickly, then chug along in top at minimal throttle input.

My astra is listed as 55 mpg. It goes up and down the motorway for 65 miles each way at 55 ish mph and returns 63 mpg.

That’s not surprising at all, but I’m sure if you do some town driving and a few stop start shorter journeys, you could bring that figure down under 40mpg easily. I had a 57 plate BMW 320D as a company car a couple of years ago, it had 177bhp from its 2 litre engine and 295lb/ft of torque, yet it also had astronomical gearing. If you gunned it, it was a pretty rapid car (0-60 in 8 seconds, 150mph top speed!) but of course you could get the consumption down into the low 20’s or even the teens if you tried hard enough. But stick it in 6th (37.5mph per 1000rpm in top), cruise control at 65mph on the motorway in the slow lane, and it would return 70mpg on a cruise!!!

A modern diesel will generally be calibrated to be most fuel efficient in the range of around 800-2500rev/min and up to around 50-75% torque. That ‘box’ is basically where the car runs in the NEDC cycle and so that is where it will be calibrated for (as this is where the official figures come from). Although the NEDC cycle is crap when it comes to simulating real world driving – it does still run in the same areas as most ‘normal’ driving do staying in the speed/load box above is a good start.

As others have mentioned, make sure the turbo is boosting as otherwise you’ll just have excess fuelling to get the torque up but not really doing a lot. I wouldnt’t totally agree on accelerating TOO briskly – its generally better to short shift and keep the revs down. Might also be worth even using the gear higher than you would usually – the torque is high enough and low down enough on most modern diesels to allow this. Other than that, as mentioned already, it’s really all about smooth driving and planning ahead.

most economical way is to get someone else to pay 🙂 Audi A3 company car so all mileage funded on allowance, depending on how its driven can vary between 28 and 65 MPG!!

just like riding – less comfort braking! Be safe

Highest gear isn’t always most economical…its the highest gear to easily maintain your speed that you need…ie at speeds flowing between 40-50 mph (I live in devon, its easily possible)….4th in my golf iv tdi…sees the economy up, whereas using 5th it stays fairly static…use the torque not just low revs high gear.

I almost always downshift into 4th when going up hill on the motorway.
It seems to get me an extra 20 miles or so from not trying to floor it to make up for the 15mph lost at a 2 deg incline. 😳

I, however, over rev the balls out of mine. just because I am impatient like that.

Who gives a shit? Thrash it, be gentle with it. What’s the difference? About 5 mpg
Whoop friggin dee!!!

A lot more than that, actually. More like 10-15mpg if you know what you’re doing. Maybe you can afford to waste fuel, but others can’t.

Highest gear isn’t always most economical…its the highest gear to easily maintain your speed that you need…ie at speeds flowing between 40-50 mph (I live in devon, its easily possible)….4th in my golf iv tdi…sees the economy up, whereas using 5th it stays fairly static…use the torque not just low revs high gear.

Sorry, yeah, if I was able to write logical sentences then this is what I was aiming for. A highER gear is usually better than high revs but not THE highest gear.

Draft a lorry 😈 & remove all unnecessary weight, starting with the engine 😉

Don’t use 2nd and 4th, you can manage without them unless you are on a hill 🙂

Accelerate gently in 1st until you have a fair few revs on, maybe 2500-3000rpm depending on the gearing, then a slow change straight into 3rd, don’t rush as the clutch will scrub off a load of revs…it needs to be back down to almost idle. Then same again for 3rd to 5th. My car and works van drive fine this way, only my campervan that has long gearing struggles to do 1st to 3rd, which is a shame as 2nd is almost impossible to get when the gearbox is cold.

And play the ‘not going to use the brakes for roundabouts’ game although the rules allow brakes if you actually have to stop or are going downhill. Obviously changing down to use engine braking is not allowed either as that is still scrubbing off excess speed and wasting fuel.

Put it in neutral when going down a hill (only when safe obviously) using gravity not fuel.
Keep it below 3,000 rpm.
Don’t carry loads of crap in the boot.
Take any roof racks, boxes off.
Also don’t fill the tank to the top unless you are going on a long journey you will just be carrying extra weight around.
Correct tyre pressures.
Service it regularly.

You could also look at having the engine re-mapped This costs about £200 though.

Put it in neutral when going down a hill (only when safe obviously) using gravity not fuel.

Load of cobblers – you dont use any more fuel than tick-over if you are not on the throttle, even under engine braking.

are there any lorry drivers on this thread?
talking of drafting in the slipstream of lorries, does this annoy, i do it sometimes if im really skint and need to make it home on whats left in the tank. but i wonder if the driver of the lorry is getting angry with me.
this might be a stupid q but does it decrease the mpg of the vehicle im slipstreaming?

Load of cobblers – you dont use any more fuel than tick-over if you are not on the throttle, even under engine braking.

+1

In almost all cases you’ll use more fuel than you would if you were engine braking as the engine will be running at idle conditions rather than ‘zero fuelling’ overrun. Plus it isn’t the cleverest idea anyway in case for some reason you need to accelerate quickly.

talking of drafting in the slipstream of lorries, does this annoy, i do it sometimes if im really skint and need to make it home on whats left in the tank. but i wonder if the driver of the lorry is getting angry with me.
this might be a stupid q but does it decrease the mpg of the vehicle im slipstreaming?

If you are in a passenger car then no it wouldn’t have any effect on the lorry.

Load of cobblers – you dont use any more fuel than tick-over if you are not on the throttle, even under engine braking.

If my rpm drops from 2800 to 900 when I’m in neutral going down a hill, surely I’m saving fuel as the engine is working at a third of the rate.

Seems right to me, but happy to be corrected.

Edit: Seems to fool the car mpg readout as my trip mpg increases at a rapid rate during this long downhill.

im in a small sprinter but its only a 208. i stay with the lorries as pacemakers anyway, 55 is great on fuel, the sprinter gets away from you and before you know it your doing 80 down the fast lane 😯

Load of cobblers – you dont use any more fuel than tick-over if you are not on the throttle, even under engine braking.
If my rpm drops from 2800 to 900 when I’m in neutral going down a hill, surely I’m saving fuel as the engine is working at a third of the rate.

Seems right to me, but happy to be corrected.

Edit: Seems to fool the car mpg readout as my trip mpg increases at a rapid rate during this long downhill.

Wow, you guys are right. Just did a bit of Googling and it turns out I’m probably using more fuel idling downhill than keeping it in gear. Interesting.

Essentially, if you pop it in neutral down a hill then the engine needs to put in fuel to keep the engine turning over. If you leave it in gear and just let off the throttle then e engine almost reverses drive so that the wheels are driving the crankshaft round rather than the other way. This means you can put in zero to minimal fuel to keep the engine turning over.

“And play the ‘not going to use the brakes for roundabouts’ game although the rules allow brakes if you actually have to stop or are going downhill. Obviously changing down to use engine braking is not allowed either as that is still scrubbing off excess speed and wasting fuel.”

I would agree with this – it’s how I drive my own normally aspirated Berlingo but I also drive modern diesels as company pool cars and they don’t like it. If you don’t change down then they increase speed thinking a stall is coming up – they can fight quite hard against the brakes if you do this. Leave control with the driver say I.

Is it better to maintain a constant speed, or a constant throttle setting?

I let it settle at about 3200 rpm, which corresponds to a decent cruising speed. Then, if there’s an uphill bit, unless it’s very long, I let the car slow down, at the same throttle opening. Then, when I get to the top and start going down again, I just let the momentum build and gather speed, but still with the same throttle opening even if the revs do go up.

Is this a more economical way to drive than maintaining a constant ~80mph no matter what, or am I confused?

but I also drive modern diesels as company pool cars and they don’t like it. If you don’t change down then they increase speed thinking a stall is coming up – they can fight quite hard against the brakes if you do this

I will do 5th to 3rd (or 2nd) as the engine gets near idle and before it starts pulling, I just meant if you’ve stayed on the throttle a bit too long, there is no point using dropping additional gears to scrub off speed without the brakes 🙂