Quote:
Originally Posted by clarence
Diesel engined cars have longer gearing not because of choice but because of the rev range of the engine. For example, the d redlines at abt 5000rpm whereas the i redlines at 7000rpm, so if u have the same gearing then the d will run out of breath very quickly. U don't change gears at the same revs when driving a petrol engined car vs a diesel engined car, for example if u change gear in a diesel car at 2000rpm then for a petrol car u change gear at 2500rpm. U just need to compare the normal shifting points of the 8AT for both engines - it's more or less in the same gear at the same speeds despite the d shifting up earlier than the i.
Acceleration from standstill is not only abt top end power, it is also abt low end torque, that's why the 20d is not quicker to 100 than 20i (brochure figs:7.3s vs 7.5s). Don't forget at initial step-off (i.e. 1000rpm) the 20d have only got 175Nm of torque to play with, & it takes 750rpm more to reach peak torque of 380Nm. The 20i has peak torque of 270Nm at 1250rpm, & if u extrapolate the power/torque graph of the 20d u'll get 270Nm at around 1300rpm, so at initial step-off the 20d doesn't have an advantage over 20i (there's no comparison with the 28i as it has over 225Nm at 1000rpm, not to mention much higher power output thruout the rev range). Don't say hard acceleration from standstill is no use, u'll need all the speed u have at busy junctions or roundabouts. Fyi, according to Auto Zeitung, the 520i does 0-40, 0-80, 0-100 & 0-120 @ 2.2s, 5.3s, 7.3s & 10.1s respectively. The 320d does it in 1.9s, 5.2s, 7.6s & 11s. Don't forget the 520i is 180kgs heavier than the 320d. U can see the 20i is no slouch compared to the 20d, the difference will be apparent if u drive a manual with lots of constant speed cruising & u like to overtake without changing down. The difference between the 2 is less if it's an automatic as it'll kickdown if u floor the throttle during overtaking.
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I guess we say the same
What you experience and appreciate is determined on how and where you drive it. To me, the d is extremely well balanced for real traffic: very frugal, iron fist in lower rpm the cost is a grumpy sound. Of course the i is also magnificent, but you'll appreciate it better when you have the opportunity to let the beast go but it is never so efficient and the fist is a bit smaller at lower rpm (although available a bit faster like you state).