Rolling on forever

[Gerrycan]

I have recently 'rescued' a 2003 Toyota Echo from my daughter's tender care as she now has a Mk5 VW Golf GTi (very nice).
So while I am performing remedial work on this manual 1.3 Echo I am driving it around town and part from the obvious differences the thing that surprises me the most is how much worse the Echo is at coasting.
I know the Octavia wagon weighs 450kg more but even in gear it still slows at a lesser rate than the Echo out of gear. I should say that despite its age the Echo is still returning consumption figures near Toyota's official figures so there are no obvious issues with it.
The Echo's old school port injected engine has the normal pumping losses and provides the engine braking I remember of old so I barely have to use the brakes at all even around town.
The Octavia by contrast with its direct injection (and reduced pumping losses) provides little or no engine braking, but used sensibly this characteristic provides lots of 'free', no fuel used, kilometres.

And it only takes the slightest decline for the Octavia (especially with clutch disengaged) to seem to roll forever.

[spud75]

All sorts of things going on here. Wheel bearings, low rolling resistance tires,in gear fly wheel mass, latent pressure on brakes, hand brake bit fully releasing, and the 450kg will provide huge difference in inertia. I am not going to work out the physics on the inertia of the mass of the car as working out the friction resistance of all the components is guess work.

[Gerrycan]

I'm probably overthinking it as usual. I'll just have to carry on being happy with the Octavia.

[Jondalar]

Hi Gerrycan,

Is you car DSG? If so I believe there is a setting to enable coasting mode, rather than the usual energy recuperation mode of the transmission. It's like putting my car into Eco mode where it will just disengage the clutch every time I lift off, rather than having engine braking, at least until the brakes are touched. Just thought it might be helpful.

Cheers,
Karl

[Gerrycan]

Hi Karl,
It's a manual so I choose the mode
My 1.4tsi (103kw) base spec version does not have any programmed modes or stop/start but that is my preference, less distraction and less to go wrong.
When I transitioned from my manual diesel mk2 to the current manual petrol it took me weeks to get used to the lack of engine braking and be able to efficiently utilise it. Driving a normally aspirated petrol engine again, albeit in a smaller car, has reminded me again how different this Octavia is to any previous car I have owned.
Our urban backstreets have a lot of mini roundabouts about 300 metres apart and 50 kph limits (some 40 kph) and when there is little or no other traffic I'll accelerate up to near the limit and just coast to the next roundabout either in or out of gear depending on distance and gradient.
It adds little or nothing to the travel time and minimises use of brakes and fuel.
The Echo does not coast anywhere near as well, in or out of gear, and has to be driven in a more conventional fashion, making it less economical in that situation.
Highway driving the Echo is about 0.5L/100 worse than the Octavia, for the same average speed which actually reflects quite well on both cars considering the Echo is pretty old now (and old tech) and the new but relatively large Octavia.

[hobbie2k]

I've noticed the same thing when comparing my Octavia (also a 1.4 TSI manual wagon) to my '96 Pulsar SSS manual.

Even though the Octavia is larger, the two cars are nearly identical in weight. The Pulsar's gearing is shorter, which increases engine braking some, but I think the bulk of the difference is in the Octavia's greater efficiency (mid 5s vs high 8s).

Coming down the SE Expressway into Adelaide there is a real noticeable difference as fourth gear (third if heavily loaded) is sufficient to maintain speed without braking in the Pulsar, but I need second (and 5k rpm) to hold the Octavia back.

[Gerrycan]

Second gear and the occasional brake dab as well for me down the SE Highway.
Air con on a hot day can make a noticeable difference, but even they are more operationally efficient these days so that the increased braking effect is intermittent at best.
Perhaps I should turn the headlights on, rear window heater and the radio up to full volume to increase dynamo drag.
I really don't like having to burn my brakes out unnecessarily (habit derived from all drum-braked car days)

Not complaining but it is during those times you can see some sense in a mild hybrid system.