Which? Rates Jazz #1

[Kremmen]

The latest Which? magazine just arrived and the annual car pullout has the MK4 Jazz at No1 in the small car section.

Which? testers got 91.1mpg around town.

[ndavey1]

91.1? How on earth did they manage that? 78 mpg is the most I got before the cold weather, and that was extremely careful driving with eco on.

[csp]

I have seen 90mpg on a couple of 8 mile trips but the route is mostly downhill. The overall mpg in the summer was about 67mpg but it has dropped to 60.8 now, most recent journeys have been short runs, the engine runs much more during the cold weather.

[peteo48]

Still a step change improvement over the previous models. I wonder if Jocko would manage 3 figures

[JazzMusic]

The car reacts extremly to speed and temp. My average is now nearly a woopy 5l/100 km. Once on a very cold day and the highway with 110 km/h the gearbox refused to shift up, so the engine remained at 3300 rpm. 6l/100 km on that trip. Interestingly, the hybrid battery did nearly nothing, not even charging or extremely slow.

It's a city car.

[Foksadure]

the gearbox refused to shift up

That's most likely the electronics driving the ICE, since there's no gearbox.
Pure software management, depending on the load, driving and environmental conditions.

[Westy36]

Good result for Honda.  I could live with 90+mpg.

[ndavey1]

the gearbox refused to shift up

That's most likely the electronics driving the ICE, since there's no gearbox.
Pure software management, depending on the load, driving and environmental conditions.

Speaking about software, I wonder if there will be any updates to improve or fine tune performance. 91.1 mpg isn’t good enough

[Downsizer]

The car reacts extremly to speed and temp. My average is now nearly a woopy 5l/100 km. Once on a very cold day and the highway with 110 km/h the gearbox refused to shift up, so the engine remained at 3300 rpm. 6l/100 km on that trip. Interestingly, the hybrid battery did nearly nothing, not even charging or extremely slow.

Using a wheel diameter of 59 cms and an engine to wheel gear ratio of 2.75:1 (are these figures right?) 3300 rpm would equate to about 133 km/hr (83 mph), so at 110 km/hr and 3300 rpm the engine was in generator mode, disconnected from the wheels.  Why was this?  I thought the direct drive is supposed to take over at around 95 km/hr.  Why does ambient temperature affect the change of mode?

[John Ratsey]

The car reacts extremly to speed and temp. My average is now nearly a woopy 5l/100 km. Once on a very cold day and the highway with 110 km/h the gearbox refused to shift up, so the engine remained at 3300 rpm. 6l/100 km on that trip. Interestingly, the hybrid battery did nearly nothing, not even charging or extremely slow.

It's a city car.

Which cars don't get badly affected by cold weather? That said, I've commented many times that Honda could have made the Mk 4 Jazz less susceptible to reduced economy in cold conditions (the underlying problem is that the standard vehicle economy testing doesn't include a very cold weather component). How were you reading the rpm? That engine speed is high for the vehicle speed unless you were climbing a modest hill.

The Jazz is too spacious to be a city car. Nonetheless, as it's a relatively high vehicle for its length which increases the drag factor and the drag losses increase with the square of the speed. The hybrid system gives the biggest benefit when in stop-start traffic (which often affects UK motorways in normal times) and provides little benefit when cruising.

[richardfrost]

The car reacts extremly to speed and temp. My average is now nearly a woopy 5l/100 km. Once on a very cold day and the highway with 110 km/h the gearbox refused to shift up, so the engine remained at 3300 rpm. 6l/100 km on that trip. Interestingly, the hybrid battery did nearly nothing, not even charging or extremely slow.

It's a city car.

Does it tell you the RPM? My hybrid doesn’t.

[guest9814]

The car reacts extremly to speed and temp. My average is now nearly a woopy 5l/100 km. Once on a very cold day and the highway with 110 km/h the gearbox refused to shift up, so the engine remained at 3300 rpm. 6l/100 km on that trip. Interestingly, the hybrid battery did nearly nothing, not even charging or extremely slow.

It's a city car.
This depends on how fast you whant to drive, In Israel we have at most 90km/h limits with Jazz MK4 i get at 90km/h  4.0l/100
I usualy try to drive slower and at 80km/l i seen 3.3l/100 and this with AC runing

Does it tell you the RPM? My hybrid doesn’t.

You can get RPM and not only RPM by connecting ELM327 to OBD2 Port and then use Car Scanner app on android tablet o smartphone

[Foksadure]

The hybrid system gives the biggest benefit when in stop-start traffic (which often affects UK motorways in normal times) and provides little benefit when cruising.

There's this new vid from the other thread that explains the e:HEV logic to the resellers. And emphasizes the fact that the powertrain' behavior is out of control of the driver on purpose to maintain efficiency.

(thanks to CoolRaoul)

I've switched back to the cinematics display on the dashboard lately.
It pretty much makes full sense now, including the gear (clutch) icon that pops up when the ICE is running the car. While charging the battery as well sometimes. Using the engine wasted heat to heat the cabin in winter also makes sense, since it's running at its optimal RPM anyway.

Combining B and ECON mode in short street road use, I was suprised by how many times the car actually charges the battery as soon as you lift the right foot enough, without loosing momentum unless you ask for brake/regen by lifting the pedal even more. No wonder Honda claims a 80% hybrid/EV usage in urban drive.

[Downsizer]

Until seeing this video I hadn’t understood that at very high speeds the direct drive clutch disconnects and the system reverts to hybrid mode, with high engine revs.  This explains JazzMusic’s experience described earlier in this thread.  However, this should never happen in the UK with a 70mph limit!

[Expatman]

Until seeing this video I hadn’t understood that at very high speeds the direct drive clutch disconnects and the system reverts to hybrid mode, with high engine revs.  This explains JazzMusic’s experience described earlier in this thread.  However, this should never happen in the UK with a 70mph limit!

Of course not!