Diesel engines are more efficient than gasoline (petrol) engines of the same power, resulting in lower fuel consumption. A common margin is 40% more miles per gallon for an efficient turbodiesel; for example, the current model Skoda Octavia, using Volkswagen engines, has a combined Euro mpg of 38.2 mpg for the 102 bhp petrol engine and 53.3 mpg for the 105 bhp ? and heavier ? diesel engine. The higher compression ratio is helpful in raising efficiency, but diesel fuel also contains approximately 10-20% more energy per unit volume than gasoline. Diesel engines are also much more economical than gasoline (petrol) engines when at low or idling engine speeds, when they use very little fuel due to the precision nature of the injector system. Unlike the petrol engine, diesels lack a butterfly valve (choke) in the inlet system, which closes at idle. This creates parasitic drag on the incoming air, reducing the efficency of petrol/gasoline engines at idle. Due to their lower heat losses, diesel engines rarely run the risk of gradually overheating if left idling for a long period of time providing the cooling system is in good order. In many applications, such as marine, agriculture and railways, diesel-engined vehicles are left idling unattended for many hours or sometimes days. These advantages are especially attractive in locomotives.

pinched from rudolph diesels web site. i think it shows that diesel engines generaly run cooler than petrol, as was my point.
regards
david.

 

Which everyone can feel when they drive with their diesels in the cold environment - the diesel engine doesn't produce so much heat for warming up the inside of the car. Many of the manufacturers install electrical heaters into the air condition system to improve the heating. And many drivers install additional engine heaters or fuel heaters.

 

your right there mikka

 

Actually, I thought the point was that modern diesel engines run cool enough that the turbochargers no longer need a cool-down period before shutdown after having worked. No one is arguing about diesel versus gas turbochargers, the issue is whether diesel tc's should be cooled down either via gentle driving for a few miles before shutdown, or by idling for 30-60 seconds after having arrived. As I said, do as you like with your diesel and its oil-cooled turbocharger. But I have diesels, with pyrometers installed, and if I am about to shutdown after significant engine load, I will protect that tc by allowing a modest cooldown. The thermocouples clearly indicate as high as 1100-1300 degrees F pre-turbo (about 200 deg less post-turbo) when having just exercised, and under more moderate loads generally in the 800-900's pre-tc. That is well above the coking point of lubricant oils, so a cool-down period will help prevent the tc's internal channels from narrowing over time. Again, this is for me, you do as you see fit.

Cal

 

i do hear what your saying cal, and i agree with you, its far better to treat your turbo with respect and allow it to cool down so as not to run dry (due to heat which will dry out the barings).
but i still dont think that this is nessacery with an E60
the design of the M57 engine and materials used, would not allow "under normal driving" to warrent any cooling off period after driving.
the same could not be said for a petrol engine such as the subaru boxer turbo, which definatly requires a 30-60 second cooling off period in order to maintain baring life

modern diesel turbos do not require such "care" (although you can if you want to be pedantic)
hence no such warnings being given by the manufactures.

but as you rightly say, its each to there own.

 

Thanks guys - It's good to know that they are solid - no swirl flaps and a reliable turbo should mean years of happy motoring!!!!

The ED Start/Stop works on Manuals only currently, and you have to stop, go into Neutral, apply the handbrake for shut down/stop. Then when you press the clutch the engine is fired by a heavy duty Alternator/Battery and NOT a starter motor. There is no cranking - it just purrs into life like a hybrid...

The ED Auto Trannnies have the new "toggle" like joy stick controller, so are partly ready. The Alternator techniology is missing but under development as far as I know...probably for the F10!!

 

OMG...when is it going to end....

 

You don't need to apply the handbrake for stop start to work. At least i didnt when I had a 118d loaner the other week.

 

Hi all!

Long time no see.

I have now about 100k on odo and some hard driving on track and autobahns, but so far I have not payed much attension about cooling of engine/turbo. I think that more important it is to let engine heat up before pushed!

Like if you come out of The Ring, there is quite lot of time before one can find place to park, so that 30-60 sec "cooling" comes automatically.

And no! No any turbo problems and I have not heard so many in e60's. Couple though: one because valve went broken and through turbo and other because lack of oil due broken filter. Hardly no typical!

Skaffa