I believe the OP was referring to top speed, not acceleration.
Power & drag are the two primary factors to top speed
I believe the OP was referring to top speed, not acceleration.
Though it is always nice to read the figures and do the math, it misses the very real world point. As soon as you want to have a bit of fun on a good road, you natrualy head straight for the engines sweet stop and try and keep it there as you change cogs. Point being no body drives at 2750 rpm when they are having fun. Handy on the commute to work. Worth noubt once your on it, then it's all about power.ph001 wrote: ↑Fri Nov 08, 2019 10:17 amAssuming similar gearing, the 'seat of the pants' acceleration force comes down to the torque to weight ratio. I did a few stats on this in another thread which showed very interesting results:
Peak torque to weight ratio (higher is better)
3.0Si - 0.181 lbft/kg
Z4M - 0.186 lbft/kg
E46 M3 - 0.167 lbft/kg
You can see how close the N52 and S54 are. But perhaps also as important is at what rpm peak torque is:
S54 - 4900 rpm
N52 - 2750 rpm
What really stands out here is how low down in the rev range the N52 makes peak torque, in fact that is truly exceptional for a normally aspirated engine and I doubt there is another na engine in the world that makes peak torque so low down. Looking specifically at that point in the rev range:
S54 @ 2750rpm = 220lbft / 115bhp
N52 @ 2750rpm = 232lbft / 121bhp
...but also remember that M is at least 50Kg heavier and the difference becomes even more pronounced - the N52 is the clear winner.
As mentioned above, all the S54 gains are after the second vanos changeover point around 4500rpm. Fundamentally it only really makes more power because it revs higher, but I agree it's all the more exciting for it!
Sounds like you may already have tried that Idea out in the wet.
I don’t think there’s a MR or MC owner that hasn’t
You are actually defining what ”power” is: torque x revs.ph001 wrote: ↑Fri Nov 08, 2019 1:57 pmYou are being over-simplistic. The only reason diesel cars tend to be slower to 60 is that they cannot maintain the high torque over a very wide rev range. In terms of acceleration force (or G-force if you like) from 2000 - 4000 rpm they tend to wipe the floor compared to na petrol engines. Like I said earlier, you have to look at the whole power curve to determine which will be quicker to a particular speed.
That is a really bad analogy of the point I think you are trying to get across. ph001 is quite correct in what he says.
Good advice , a listen to the S54 start from cold & ticking over can often tell a good one from bad.