Most economical speed on W210 E200

[imbck666]

Yes, I know its a small engine and works hard...
but..

Whats the most eco speed for a W210 E200 5spd?

Ive heard that if you stick to 55-60 its very eco and between 70-75 most uneco.
is this true?

All ideas are highly appreciated

 

[Dieselman]

Top gear at about 1500-2000 Rpm on a light throttle will reveal the best economy.

 

[Bobby Dazzler]

The slowest you can go in top gear without labouring the engine (or teetering on down/up shifts) is a good guide for any car.

 

[Stratman]

The slower you go the less fuel you use.

If you're travelling at any given speed you open the throttle to go faster and close it to go slower. That should give you a clue.

 

[imbck666]

Being a commercial pilot I understand very well about piston and jet engines (studied for 4 years lol) but for example, in a Piston engine on a light aircraft, there is a ECO rpm we can set for optimum fuel range and it was like this :

Whilst cruising, 2000rpm is non eco,
2250 rpm slightly better
2300 economic
2500 - non eco again

So basically there was this mid range band where the engine has high rpm, but is still eco, thats why i asked the question.

But thanks for the answers anyway =)

 

[bogcaster]

The slowest you can go in top gear without labouring the engine (or teetering on down/up shifts) is a good guide for any car.

I'd agree with that. That definitely works for me. On the Viano 639, in top gear (5th auto) at about 1800 revs, 60mph I get 31mpg, but at 2100 around 75mph I get around 35mpg. Bizarelly, in commutting slow traffic churning along at a steady 50-55 can give a bonkers 45mpg. In all, not bad for a 2.25 ton 3l diesel vehicle shaped like a brick wall.

For my other cars, 60mph seems to be around the optimum, but not on the Viano. All of those are taken off the computer for long distance motorway driving, but that's if you believe them!

 

[Stratman]

..............
Whilst cruising, 2000rpm is non eco,
2250 rpm slightly better
2300 economic
2500 - non eco again
................)

Wouldn't flying at 2000 rpm require a higher angle of attack to maintain altitude, and thereby cause increased induced drag? Could this account for the increase in consumption?

Thinking about it, an aeroplane has two kinds of aerodynamic drag to cope with, induced and parasitic. A car (road, not racing) has only parasitic drag. Perhaps the airspeed given by 2300 rpm is where the graphs cross?

 

[mersum1es]

When you are at 'spot' of this kind of curve (first I found in g**gle), that's the best operation point. So engine speed and torque should be adjusted to that and it defines the vehicle speed:
http://www.engine-trade.com/uploadf...-Deutz-BF8L513C-Diesel-Engine-for-Vehicle.jpg

 

[Dieselman]

When you are at 'spot' of this kind of curve (first I found in g**gle), that's the best operation point. So engine speed and torque should be adjusted to that and it defines the vehicle speed:
http://www.engine-trade.com/uploadf...-Deutz-BF8L513C-Diesel-Engine-for-Vehicle.jpg

That one is for a diesel engine though.

In general terms, somewhere just below the maximum torque revs will give the best fuel usage return for the engine, but the wind resistance maybe higher, so going slower may work better.

 

[BTB 500]

Wouldn't flying at 2000 rpm require a higher angle of attack to maintain altitude, and thereby cause increased induced drag? Could this account for the increase in consumption?

Thinking about it, an aeroplane has two kinds of aerodynamic drag to cope with, induced and parasitic. A car (road, not racing) has only parasitic drag. Perhaps the airspeed given by 2300 rpm is where the graphs cross?

Light aircraft also typically have a fixed pitch prop, which further complicates things.

 

[imbck666]

2000rpm may not need a higher angle of attack as if you have different wind factors to compensate for it will change. if you have good headwind giving you optimum lift and nice cold air temperature, the engine will run a lot smoother, consume less fuel and will need a lower rpm to keep up a certain speed.

 

[imbck666]

Yes, and some light aircraft have variable pitch props, but it doesnt complicate things at all, if you have a fixed prop, you just decrease your throttle to compensate for wind factor/air resistance. Higher the headwind-more throttle to keep momentum

 

[BTB 500]

imbck666, out of interest ... what do you fly?

 

[imbck666]

PA-34 seneca

 

[martyz]

Commercial airline pilot was expecting to see something like;


but was surprised to find this little fellow;


PA34-Seneca

 

[imbck666]

Im licensed to fly anything like in the first picture, but until I find a job I can only afford to privately rent the little one every weekend
The little aircraft you posted, is actually a fair size, 12 seats can fly from london to spain no problem.

 

[D-18]

The little aircraft you posted, is actually a fair size...

Yep, I wouldn't mind something that hefty. You 'put on' my Jodel rather than climb into it....