Efficient dynamics – does it really work?

[LeoSayer]

The theory sounds great and the fuel economy figures published by BMW look amazing – 40mpg urban and 50mpg combined. Not only that, but 258lb ft and 177bhp from the 2.0d is more than adequate for my purposes, even in a big heavy car like 5 series touring automatic.

Are these cars noticeably more powerful and economical than their predecessors? Is it worth spending a premium to get a newer efficient dynamics models, over say, a 2 year old 520d? Or is to just all good PR, based on the headline ‘lower CO2 emissions’ figures.

I am after an automatic family estate and I like the idea of spending less on fuel, paying less tax, even if it means I have to give more to BMW.

[MK4 Slowride]

It's a bit weird to begin with, you stop at the lights, neutral handbrake then the engine cuts out. People look at you as if you've stalled but no, foot on the clutch it starts up instantly. The diesel engine is brilliant but I'd got for manual to get that bit more from it as with auto your sacrificing economy & performance enough to make it slightly pointless where the 2.0d is concerned. Phone your local dealer & get them to post you all the booklets on Efficient Dynamics and read up on it yourself or go to www.bmw.co.uk you'll see the bit on Efficient Dynamics just to the end of model selection up top.

Edited by MK4 Slowride on Wednesday 23 April 10:27

[pgilc1]

Its worth noting that efficient dynamics isnt just about stop start. There are many more energy saving measures applied - weight reduction, regenerative technology, friction reduction, etc.

To put it in perspective, i had an LCI 535d - it overall was giving me around 4-5mpg more than an equivilent pre LCI / ED model. I drove it up through scotland with four adults and their luggage, and back down into glasgow for the day and home again and managedto get 39.9 mpg. 42mpg was acheivable on pure long runs. Thats some going in a car that can do 0-60 in 6.2 secs and with 420lb/ft torque.

Is it worth spending say £8000 more to buy a new one over a two year old? Probably not - the older car will still probably come with 10% of the new one. Is it worth buying the BMW over rivals because of ED? Yes - the 320d / 520d seem to be 10mpg more efficient than audis equivalent, though i hear audi will have equivalent or more efficient models within a year.

[pgilc1]

Lets put it another way, come trade in time of my x5 3.0d, i will go back to a 5 series. It wont be another 535d M sport- even given its huge strengths - it will be an ED 520d M Sport.

[steve-p]

My 330d only has 300 miles on the clock, but I just did a 40 mile round trip and got 54.3 mpg. I'm wondering what will be achievable once it's loosened up

[Welshbeef]

steve-p said:

My 330d only has 300 miles on the clock, but I just did a 40 mile round trip and got 54.3 mpg. I'm wondering what will be achievable once it's loosened up

Thats highly impressive.

When you did your 40 mile trip did you drive it with economy in mind (watching the mpg scale) or just normal driving?

[steve-p]

Welshbeef said:

steve-p said:

My 330d only has 300 miles on the clock, but I just did a 40 mile round trip and got 54.3 mpg. I'm wondering what will be achievable once it's loosened up

Thats highly impressive.

When you did your 40 mile trip did you drive it with economy in mind (watching the mpg scale) or just normal driving?

Yes a bit. It was about 20% urban with traffic lights and roundabouts etc and 80% rural A and B roads. The main concessions to economy were changing up whenever the car indicated to (which is very early with so much torque) and observing all the speed limits for a change On my normal 11 mile commute which includes some congestion and driven normally it only does 45 mpg, but that's still pretty good.

[Welshbeef]

Steve-p

So your BMW 330d is the 231bhp? Is it the ES/SE/M Sport?

Also at a constant 70mph what rpm are you doing in 6th?

[steve-p]

It's a manual 330d M Sport coupe, now a week old. It's doing 40 mph per 1,000 RPM in top gear, so 80 MPH is only 2,000 RPM and 70 must be 1750 RPM.

[Welshbeef]

steve-p said:

It's a manual 330d M Sport coupe, now a week old. It's doing 40 mph per 1,000 RPM in top gear, so 80 MPH is only 2,000 RPM and 70 must be 1750 RPM.

When your doing 70mph in 6th what is the instant mpg?

[welwynnick]

steve-p said:

It's a manual 330d M Sport coupe, now a week old. It's doing 40 mph per 1,000 RPM in top gear, so 80 MPH is only 2,000 RPM and 70 must be 1750 RPM.

That's hugely long-legged.

Does anyone know where to get mph/1000rpm figures for the current cars? I can't find them in brochures / websites any more?

Cheers, Nick

[Welshbeef]

welwynnick said:

steve-p said:

It's a manual 330d M Sport coupe, now a week old. It's doing 40 mph per 1,000 RPM in top gear, so 80 MPH is only 2,000 RPM and 70 must be 1750 RPM.

That's hugely long-legged.

Does anyone know where to get mph/1000rpm figures for the current cars? I can't find them in brochures / websites any more?

Cheers, Nick

The mk4 Golf GT TDI 115 was geared to 36-37mph in 6th hence it was pretty easy to get it into the 60+mpg range on most runs. However at full tilt in 6th you'd be doing just shy of 130mph however doing a mere 3,500rpm.... with a red line starting at 4250rpm.... 6th was very much the over drive.

Love the sound of the 1750rpm in 6trh of the 330d - also as per the brochure that is smack on peak torque so you have 500Nm to play with on your right toe... nice.

[steve-p]

Welshbeef said:

When your doing 70mph in 6th what is the instant mpg?

I had to go out so I took the long way round to try it. It's not hilly round here but neither is the M4 completely flat so to get a more representative figure I set the cruise control to 70, reset the fuel consumption and drove for 5 miles. It averaged 58.8 mpg.

[Welshbeef]

steve-p said:

Welshbeef said:

When your doing 70mph in 6th what is the instant mpg?

I had to go out so I took the long way round to try it. It's not hilly round here but neither is the M4 completely flat so to get a more representative figure I set the cruise control to 70, reset the fuel consumption and drove for 5 miles. It averaged 58.8 mpg.

Thats very impressive. The 123d SE 5 door I tested with 3000miles only managed 56.5mpg From Newbury junction to J11 M4 so maybe a bit hilly in the not beneficial way, however I would have expected the 330d to be much less than that.

5th Gear on their website have a long review of the 330d SE 231bhp and they do state it really is the best car in the real world more than enough power and even when really pushing on they averaged a good 42/43mpg.

It certainly is a car I aspire to/could afford now but kind of reluctant as I realy hate depreciation (but will have to get a new car sorted before Aug08).

[steve-p]

I would have gone for the 335d but it's auto-only. Not that I have anything against autos, I've had loads, but I fancied a manual for a change and it's a nice gearbox. The petrol 3 series are supposed to be pretty economical too. The 330d is a great package though and I'm looking forward to seeing what it can do when it's fully loosened up.

[Welshbeef]

steve-p said:

I would have gone for the 335d but it's auto-only. Not that I have anything against autos, I've had loads, but I fancied a manual for a change and it's a nice gearbox. The petrol 3 series are supposed to be pretty economical too. The 330d is a great package though and I'm looking forward to seeing what it can do when it's fully loosened up.

Looking at your car history there seems to be a significant number of fast cars in there - so far how does the 330d 231bhp compare?

I have read that if you really go for economy you can get 750miles from the tank - thats running dry mind (55mpg average).

[steve-p]

I'm still running it in so it's hard to say, although it has masses of torque which makes it very relaxing to drive. I expected it would seem quite a bit slower than I'm used to, but on the other hand still plenty fast enough for most purposes in the real world, and cheap to run. It seems like a good compromise as the rumours begin of £1.50 a litre by the end of the year

[MitchT]

MK4 Slowride said:

It's a bit weird to begin with, you stop at the lights, neutral handbrake then the engine cuts out. People look at you as if you've stalled but no, foot on the clutch it starts up instantly.

I was under the impression that it took about ten minutes of driving to regain the battery charge lost from one engine start, so surely in a situation where you're starting and stopping a lot you'll end up with a flat battery?

[Welshbeef]

MitchT said:

MK4 Slowride said:

It's a bit weird to begin with, you stop at the lights, neutral handbrake then the engine cuts out. People look at you as if you've stalled but no, foot on the clutch it starts up instantly.

I was under the impression that it took about ten minutes of driving to regain the battery charge lost from one engine start, so surely in a situation where you're starting and stopping a lot you'll end up with a flat battery?

Have you seen the siza of the batteries on the 120d alone??? Id say size wise its near on a 1/3 or more bigger than the equivalent Golf sized one using Bosh as an example.

With the set up it will stop allowing you to do stop start if it knows the charge is too low and keeps the engine running. When braking ti charges up the engine. Also until the engine is yup to operating temp it doesnt cut it out.

[Welshbeef]

steve-p said:

I'm still running it in so it's hard to say, although it has masses of torque which makes it very relaxing to drive. I expected it would seem quite a bit slower than I'm used to, but on the other hand still plenty fast enough for most purposes in the real world, and cheap to run. It seems like a good compromise as the rumours begin of £1.50 a litre by the end of the year

500Nm @ 1750rpm really is something special.

With 6th gear at what speed can you realistically use it from? As you have said 40mph per 1000rpm so Im guessing that 40mph or less then its 5th gear or lower. Is 6th

Going from the speed ratio for 6th you quoted then

40mph = 1000rpm
50mph = 1250rpm
60mph = 1,500rpm
70mph = 1,750rpm
80mph = 2,000rpm
110mph = 2,750rpm
130mph = 3,250rpm
160mph = 4,000rpm
Red line is 4,500rpm?? = 180mph theoretical top gearing speed. (althouh you could rev out to the govenor 5000rpm = 200mph.