pbirkett, that was an entertaining read for a Friday afternoon.
I'm assuming 80% of the "bone-petrol head" responses on here are from people who've only ever experienced a diesel engine in a van, or a crane, or whatever other HGV you see wandering the streets of your nearest development.
The question in the thread.... Wait I can copy and paste it's right in front of me.
200bhp Petrol vs 200bhp Diesel
Now, bhp is simply an equation, as we should all hopefully know, for work done based on torque and engine speed.
So surely if you have a 200bhp NA petrol vs a 200bhp turbo petrol, they should accelerate in the same manner... Unfortunately most would think that, however as a few people have pointed out, 200bhp is simply the PEAK POWER.
As you're accelerating, you're not always at peak power, and more low down torque, means more low down power, so going back to the NA vs Turbo petrols, the turbo will naturally have more low down power (depending on boost) and thus accelerate faster than the 200bhp NA.
So surely, if two identical cars have the same 200bhp peak power, they should accelerate fairly similarly, that's true too, but as I've already covered, extra low down torque helps big time.
Generally speaking, a 200bhp diesel will have twice that in torque, whereas an NA petrol might have the same figure.
So whilst both cars are midway through the rev range, the diesel will be accelerating a hell of a lot faster than the petrol. There you go.
If you want the closest example I can think of at the moment, here you go.
BMW 320d vs 320i - Note that the diesel has a 13bhp benefit.
BMW 330d vs 330i - Note that the diesel has a 27bhp defecit.