BruceBanner wrote:adsgreen wrote:Don't see why people are surprised...
Sure, the AMG has more power but nothing dramatically more and it's heavier resulting in a similar power to weight ratio.
I would imagine the auto clutch on the amg is locking but they are generally far from instantaneous when changing.
I've dug out my old spreadsheet and put in the stats for the c63 based on some info.
http://mbworld.org/forums/c63-amg-w204/ ... urves.html
(Interesting how the peak falls off so even though there is a bucket of torque when you are accelerating to full power you end up using much less. Gear changes appear to be between 5krpm to 7k rpm and the average torque here is about 310 at the wheels). The extra massive torque advantage is only there low down not in the main engine zone. Be good to see if it really does change at 7k rpm under full power.
Anyway, the results are yes the c63 is fractionally quicker until it hits 4th gear and it's noticably longer and the rs claws back.
But we're talking tenths here and a couple feet there.
As you said I thought the superior torque would rule, but it never transpired. Also it struggled for traction off the line.....no such probs for me
This is the problem when comparing torque in that it doesn't take into account gearing. With everything the same (mass, gearing, tyres etc) and assuming no wheelspin, the higher torque car will always accelerate more. That isn't in dispute. The problem is that the torque drops off in the "happy" range where the engine lives between shifts at full throttle... coupled with the extra weight, traction limits and automatic transmission losses (ok, reduced a degree by the locking torque converter) the gap is nowhere as clear cut as you'd think.
However if you both accelerated from say 20mph in 2nd the AMG would simply dissappear as it has buckets more torque at that point of the engine curve and the RS4 needs revs being smaller displacement. AMG will feel feaster as it's much easier to go quickly.
Interesting to see (with a pinch of salt) that the B7 is pretty evenly matched against the Merc... Some tracks the merc wins but interesting that the ring time is much slower (15 seconds) than the audi.
http://www.fastestlaps.com/comparisons/ ... 3_amg.html
Edit: In fact I think this shows how torque is not as critical to performance driving as first is thought.
C63 AMG
Weight: 3924lb (1783 kgs)
BHP: 451 = 252/ton
Torque: 443 = 248 /ton
B7 RS4 Saloon
Weight: 3638lbs (1653 kgs)
BHP: 414 = 250/ton
Torque: 317 = 191/ton
So the power to weight is virtually identical but the torque to weight is considerably different (The RS4 is approx only 75% that of the Mercedes) and yet track times are broadly similar.
