Quote:
Originally Posted by KoenG
Ha... thanks for this... In a previous reply I argued that in real life (not in a race, but in daily traffic) you can't directly compare in gear accelerations since it's the speed/rpm range that dominate the experience.
With your figures I would compare the 50-70 in 6th in a M135i with the same speed range in 5th in a 330d. Why? Since the rpm range they evolve through is comparable then. Then the 330d needs 3,5 seconds versus 4,4 for the M135i.
Maybe you say this is not a fair comparison and you have a point, but on the other hand, why would "comparable rpm range" be less fair than "same gear"? I guess the latter is of NO relevance at all when you think it over. The mere fact I had to change gears 4 or 5 times to get me at 50mph is entirely irrelevant.
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You wrongly assume both gearboxes are mapped the same and both cars have a similar width speed range in each gear.
In reality the ZF box in the diesel changes up early even with medium throttle inputs, with similar throttle inputs in the petrol the gears are held longer. Why? Because after 2750rpm the torque on the 330d is dropping away quickly, by 3500rpm it has less than the M135i. Unless you are on a very light throttle you'd probably find the petrol is in the same gear or even one less than the diesel. Driving in comfort mode briskly the ZF will happily keep the revs 3k-4krpm on the petrol. That's the petrols mid-range, still having another 1000rpm ceiling of maximum torque and 3000rpm below the red line.
And on the motorway with both cars in 8th the 330d only has a maximum of a 4% advantage (Before weight) and at the legal limit it's actually below it's peak torque figure, it doesn't reach that until 80mph. In 8th in the M135i the car has maximum torque available from 45mph to 155mph.
You can play these figures all day but the petrol cars shift down well before kickdown is operated and a lower gear is just 200 milliseconds away. We all know the result then.
Cheers
Lee