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      07-19-2008, 07:44 AM   #1
mixja
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Drives: 2011 E90 DCT Silverstone
Join Date: Jun 2008
Location: Beverly Hils, CA

iTrader: (1)

M3 vs Competition - factoring in Torque, Weight and Gearing

Following on from some of the information posted in this thread (see http://www.m3post.com/forums/showpos...3&postcount=50), I decided to capture some of the dyno test data from Rototest Research Institute (http://www.rri.se/) and compare the performance of the M3 with its competitors, taking into account not only dyno performance but also gearing and weight.

All performance data is based upon the "at the hubs" measurements from RRI. Weight is based upon the kerb weight measurement performed by RRI, plus 75kg for the driver. These results don't incorporate other factors such as drag, which obviously becomes more of a factor at higher speeds and favours cars with more power, regardless of weight.

The vertical axis in each comparison represents torque @ wheels per tonne (derived by taking the actual torque @ wheels in each gear and dividing by weight in metric tonnes). The horizontal axis represents vehicle speed in km/h. Each graph shows the weight scaled torque output for a number of gears, and gives a good indication of how the cars would perform against each other.

The results are quite interesting...

Round 1: M3 Manual vs M3 DCT

Test Data:
M3 MT Weight - 1686kg
M3 DCT Kerb Weight - 1711kg (added 25kg to MT weight)
Redline - 8250RPM (used for both cars)
Dyno Data - http://www.rri.se/popup/performanceg...p?ChartsID=793 (used for both cars)

Comparison:
Interestingly the manual transmission has shorter gearing for 1st gear, which in theory should see it launch quicker off the line if executed correctly. 2nd gear is very even between the two, but once the DCT hits third gear it has a clear advantage. The DCT has the MT in 3rd and 4th gears - the MT has a brief period of respite between 155km/h and 170km/h, but otherwise between 115km/h and 195km/h, the DCT has a clear advantage due to its shorter gearing. Past 195km/h it is pretty close, the MT has a slight advantage with its taller gearing, but I suspect the effect of the instantaneous changes of the DCT have a much greater impact here, where losing a few km/h in speed between gear changes be much more noticeable in terms of a performance comparison.

BMW state the DCT is faster than the manual, and apart from the initial launch off the line, the figures tend to back up factory claim.

DCT wins Round 1.




Round 2: M3 Manual vs C63

Test Data:
M3 MT Weight - 1686kg
M3 Redline - 8250RPM
M3 Dyno Data - http://www.rri.se/popup/performanceg...p?ChartsID=793

C63 Weight - 1903kg (much higher than the factory quoted EC weight of 1730kg!)
C63 Redline - 7000RPM
C63 Dyno Data - http://www.rri.se/popup/performanceg...p?ChartsID=795

Comparison:
The lighter weight and short 1st gear of the M3 MT effectively negates any advantage the more powerful C63 engine has initially off the line. The C63 however has a much stronger 2nd gear, the huge mid range torque should help the C63 to a quicker 0-100km/h time. The C63 still has an advantage in 3rd gear which will see it quicker through the 1/4 mile with a faster trap speed, but the high RPM power of the M3 is starting to take effect. By 4th gear, the M3 should actually be quicker, however a steadily increasing amount of drag will work in the C63's favour with its stronger power output.

The C63's torque advantage is too much for the M3 manual to overcome, C63 takes Round 2.




Round 3: M3 DCT vs C63

Test Data:
M3 DCT Weight - 1711kg
M3 Redline - 8250RPM
M3 Dyno Data - http://www.rri.se/popup/performanceg...p?ChartsID=793

C63 Weight - 1903kg (much higher that the factory quoted EC weight of 1730kg!)
C63 Redline - 7000RPM
C63 Dyno Data - http://www.rri.se/popup/performanceg...p?ChartsID=795

Comparison:
This is the comparison we are all waiting for in real life. The taller 1st gear of the DCT (as compared with the manual) means the C63 should get off the line a bit quicker assuming traction is controlled appropriately, and even with a shorter 2nd gear, the DCT will not be able to match the C63 to 100km/h. Once passed 90km/h though, the DCT is on top of the C63 thanks to its shorter gearing, which should see it match the C63 down the quarter mile.

This comparison is pretty tight, but the faster gear changes of the DCT might just give it the edge.

Round 3 is a points decision to the DCT!




Round 4: M3 DCT vs RS4

Test Data:
M3 DCT Weight - 1711kg
M3 Redline - 8250RPM
M3 Dyno Data - http://www.rri.se/popup/performanceg...p?ChartsID=793

RS4 Weight - 1811kg
RS4 Redline - 8000RPM
RS4 Dyno Data - http://www.rri.se/popup/performanceg...p?ChartsID=281

Comparison:
So the M3 DCT has just managed to see of the stiff competition from AMG, so what about its Audi competitors?

First up it's the aging RS4. Unfortunately for the RS4, it looks like its age really has caught up with it and it has no chance whatsoever against the M3 DCT. The RS4 only has a low RPM torque advantage, but where it counts it falls well behind.

Round 4 is a KO win to the DCT!




Round 5: M3 DCT vs R8

Test Data:
M3 DCT Weight - 1711kg
M3 Redline - 8250RPM
M3 Dyno Data - http://www.rri.se/popup/performanceg...p?ChartsID=793

R8 Weight - 1703kg
R8 Redline - 8000RPM
R8 Dyno Data - http://www.rri.se/popup/performanceg...p?ChartsID=778

Comparison:
The M3 DCT has trounced the RS4, but what about the much revered R8? The R8 is over 100kg lighter than the RS4, and performs better in both the mid-range and high-RPM than its RS4 sibling, despite sharing the same powerplant. Combine this with slight shorter gearing, and the R8 is fares much better against M3 DCT.

The R8 has a clear advantage off the line, with stronger 1st and 2nd gears. Combine this with its Quattro AWD transmission, and the R8 should be able to lay down considerably quicker 0-100km/h times than the M3 DCT. 3rd gear is much closer, but the R8 still has a slight advantage, which should see it run a quicker quarter mile than the M3 DCT.

Round 5 goes to the R8, and so it should given the price tag on the R8




Round 6: M3 DCT vs M5 SMG

Test Data:
M3 DCT Weight - 1711kg
M3 Redline - 8250RPM
M3 Dyno Data - http://www.rri.se/popup/performanceg...p?ChartsID=793

M5 Weight - 1919kg
M5 Redline - 8000RPM
M5 Dyno Data - http://www.rri.se/popup/performanceg...p?ChartsID=153

Comparison:
So the M3 DCT has seen off its main current rival the C63, and even given the R8 a good go. Things are looking good for the M3 DCT, so how will it fare against big brother M5 with the more antiquated SMG transmission.

Well as good as the M3 DCT is, the M5's peaky 500HP engine is just too much for the M3 DCT (and all of the other cars discussed here) in a drag race. Although the M3's power band looks much nicer for daily driving, once that M5 engine gets spinning, it is all over.

Round 6 is a KO to big brother M5.