Gear Changes (In the interests of driving economically)

M

mattb10

Member
Hi all,

Just wondering something. Being a new Z4 owner, I'd like to ask about economical driving (Booooooo.... :thumbsdown:)

If you were trying to drive as economically as possible, how many revs are sufficient for changing up and down the gears? I'm not exactly going to be driving miss daisy, just curious! :driving:
 
I keep my revs under 3k when driving economically... I get 34mpg in a 2.2 around town... 42mpg motorway doing this.
 
mattb10 said:
Hi all,

Just wondering something. Being a new Z4 owner, I'd like to ask about economical driving (Booooooo.... :thumbsdown:)

If you were trying to drive as economically as possible, how many revs are sufficient for changing up and down the gears? I'm not exactly going to be driving miss daisy, just curious! :driving:
Click to expand...


I'd change up gears at 2.5-3k and keep my foot barely on the accelerator, just enough to keep it accelerating slowly then just enough to keep it going the speed I want at about 2k revs in whatever gear (unless your on the motorway and in which case 2k revs is like 50mph)

40 to 50mph in 6th gear = best mpg in my experience ( OBC displays crazy high mpg for 40 in 6th ...about 1.5k revs)

I of course rarely drive economically :evil: :driving:
 
just change gear as low as possible, enough to not make the car struggle or lose momentum...... or do what i do and ignore the mpg and just look at the miles in the tank. its less painful :)
 
Zeld4 said:
Which engine do you have?
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2.5

And thanks everyone. I'll bear that in mind. I can barely get out of 3rd gear near my house because of the bloody traffic and speedbumps! :( But once on the open road it's foot down all the way.
So yeah, screw you economy!
 
I don't care enough to do a study of this, but there is logic in getting into the highest gear as quickly as possible. The more time spent in low gears means poor fuel economy. A very light throttle may not be the best strategy. You certainly should shift up as soon as practical, but I'm thinking a moderate throttle may be the best strategy. Better than light throttle by reducing time in low gears. Better than heavy throttle because much more fuel is used with relatively little gain in the time in lower gears? Or is heavy throttle even better? Counter intuitive, but there is some logic to it.

I've no idea if there's anything to this theory, but it's something to ponder.
 
less then 3000rpm will do ! I believe 2500-3000 is the ideal range for economic driving! Driving like that I achieve around 38mpg in town (with low traffic) :driving:
 
7000 revs is the best, raises the heart beat and keeps you healthy. Healthy people make more money :D
 
Just drive it! Your in the wrong car if your looking for good fuel economy.

34 mpg in my 3.0 today driving in 40 miles of motorway, no idea if this is good or not. Didn't seem use a great deal of fuel.
 
bcworkz said:
I don't care enough to do a study of this, but there is logic in getting into the highest gear as quickly as possible. The more time spent in low gears means poor fuel economy. A very light throttle may not be the best strategy. You certainly should shift up as soon as practical, but I'm thinking a moderate throttle may be the best strategy. Better than light throttle by reducing time in low gears. Better than heavy throttle because much more fuel is used with relatively little gain in the time in lower gears? Or is heavy throttle even better? Counter intuitive, but there is some logic to it.

I've no idea if there's anything to this theory, but it's something to ponder.
Click to expand...

I've never driven for economy but your answer is the closest to correct.

The most economical method is to keep the revs between 2krpm and 2.5krpm where you floor the accelerator pedal (Wide Open Throttle = WOT) at 2krpm and then lift off at 2.5krpm and then change up and do the same in each gear until you are at the correct rpms for the required speed. Once you are at the correct cruising speed, you maintain your speed with pulses of acceleration at WOT. The engine can only consume the correct amount of fuel to the air that the engine can ingest at WOT, but you'll spend the least amount of time accelerating this way, which is where the fuel economy comes from.
 
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