Not true, for the A22s speed limited at 60kph, the engine runs
at higher revs at 60kph with Voiths as compared to ZF. This is
because the Voith only has 4 gears while the ZF has 6 gears, and
typically on the ZF the 6th gear kicks in at around 55 to 60 kph,
meaning that at 60kph, the engine will be running at lower speeds
(ie at the lower end of the tachometer).
Therefore, in the above case where the bus runs at the speed
limit of 60kph, the engine works harder with Voith as compared to
ZFs, I would expect the ZF to have a fuel economy advantage over
the Voith in this scenairo.
Fuel economy isnt that much either..Give a good gearbox tuning
la..So far i have tried various buses with different gearbox..The
drivers have to know when to decelerate when he feel that the 4th
gear is strained at 60..You just have to learn the bus
character..On paper is just a theory..Good drivers will know what
is hold gear system is.