I am involved in a discussion in another forum about the new R8 diesel.

Anyway, there was some contention as to whether it is power or torque that creates acceleration. I've done a little research on the BMW website and came up with following analysis.

It seems that if you want to go fast, get a petrol, but if you want to go fast in the wrong gear, get a diesel.

 

Interesting conclusions

The gearing comes into play, of course bhp and torque are intrinsically related.

Interesting to see how the pull from 50-75 in the diesels, esp 335d.

 

Net forward force creates acceleration.

 

Spot on. But it's an argument that the d*esel brigade just don't want to accept.

They can harp on about their 50-75 in 4th times all they want, but if we leave the 4th gear alone and do it from 2nd or 3rd in a comparitive petrol variant we immediately remove d*esel's advantage, and in many cases crush it.

 

Area under the torque curve is what's important.

That's why an NSX feels so much faster than an S2000. The absolute values are much closer, once the NSX's greater mass is factored in.

So you want a car with a table-top torque curve and a long rev band.

Not a jerky diesel with a 16-speed gearbox.

 

but even within the petrol world you have different ways to achieve a particular number.. all with their individual pro and con...

large CC's (US model)
turbo's (European model)
high RPM (Japan model)

 

I tell you one thing, the 335d overtaking - 50-90mph is fecking awesome. No messing around waiting for VTEC (i.e. that hard 2nd gear to high revs or 3rd gear too low revs), it is awesome.

Shall be very interested to compare the missus car with the 350Z when I get it.

I expect the 350Z to obviously be quicker with 309bhp in a 1515kg car versus 286bhp in a 1645kg car, but the 'on the road' stats are probably quite similar.

From driving both cars, I know the 350Z is very quick 100mph plus, but after all that hairing around the 335d still gets 30mpg +++ and my new Zed won't get much higher than 15mpg after a good beating

 

Try sorting your list by 0-60 times and look at the power to weight ratios and it will tell you all you need to know.

As has been stated power , torque and rpm are linearly related.

My new motorcycle is a Triumph Street Triple which a 675cc engine that has a torque curve pretty much flat from 3k to 12k rpm and makes IIRC about 7Nm more than my outgoing ZX6R. However theZX6R would rev 2k rpm higher. So the Triumph *feels* quicker than the ZX6R because it makes good torque everywhere whereas the ZX6R feels like it can't pull the skin off a rice pudding until it makes 8-9k rpm.

However they both make the same power and the performance stats is pretty much the same, because the ZX6R can use it revs to take advantage of gearing resulting in torque at the wheel the same as the Triumph.

 

[QUOTE=smnasn,Jan 14 2008, 09:36 PM] Try sorting your list by 0-60 times and look at the power to weight ratios and it will tell you all you need to know.

As has been stated power , torque and rpm are linearly related.

My new motorcycle is a Triumph Street Triple which a 675cc engine that has a torque curve pretty much flat from 3k to 12k rpm and makes IIRC about 7Nm more than my outgoing ZX6R.

 

It's a fantastic bike, has totally rekindled my love of motorcycling.

The ownership experience is great too.

The motor is interesting, as in Daytona guise it's pushing the technology limits to the max (i.e same power/revs as Jap 4 cylinder engines in a 3 cylinder engine = ballistic cylinder speeds).

Build quality is up there too.

In short, I love it.