There's different rated versions from the same engine
model.
OM 447 h (fullly rated verson) is 250 BHP with earlier exhaust
emission standard.
Lower rated version is 220 BHP, presumably for the smaller O
402.
OM 447 hLA can also be 250 BHP but with later exhaust standard like
Euro 1.
OM 447 hLA (fully rated) 299 BHP which is usually used in the O 405
G instead.
Usually there's some 'trade-off' between power torque performance
& the stringentness of the exhaust emission standard required,
same engine you want higher performance then exhaust standard lower
& vice-versa.
On paper i'll consider the Volvo's 245 BHP & the O 405's 250
BHP as marginal difference only. Therefore, other factors like
choice of gearbox, gearbox & final drive gear ratios would
utimately affect the performance in acceleration & road
speed.
The O 405 being a citybus, is geared to have almost car-like
acceleration up to approx. 74 km/h max. speed so as not to hold up
car traffic on the busy roads in cities too much.
On the other hand there's supposely low end models like the OH 1318
with the OM 366 A only power 177 BHP yet these can be geared to
attain max. road speed up to 130 km/h instead. Drawback of course
is the snail or tortise-like acceleration like moving a heavy old
train !! This model widely used in Malaysia by operators like
Grassland, Sri Maju for mostly highway use. So you see, there's the
'trade-off' involved. Of course you want both acceleration &
top speed to be high, can be done. Then go for the latest
generation engines whereby they can output 400-500 BHP from just 12
liters capacity with Euro 3 exhaust standard like on the Travego
coach.
