Trap speed vs elapsed time in the 1/4 mile illustrated by M157 AMG's, one rear wheel drive and the other all wheel drive
By now you are well aware that Mercedes offers the 4Matic all wheel drive system for the facelifted CLS63 and E63 AMG models. So what happens when you put the pre-facelift rear wheel drive 63 AMG model up against the facelifted 4Matic all wheel drive model on the dragstrip? Even a casual automotive enthusiast would likely guess that the result would have the all wheel drive car showing the quicker ET (elapsed time) whereas the rear wheel drive car would have the higher trap speed.
That is usually the case although by no means an automotive law. It is what happens in the drag race below though and that is partially due to both cars wearing street rubber. Soft drag rubber is pretty much a necessity for a high torque rear wheel drive vehicle to get good traction off the line at the strip.
Now, this is not exactly apples to apples as the C218 CLS63 has an ECU tune. The W212 E63 AMG S is stock and an ECU tune makes a huge difference in power and torque. Combine an output increase as a result of ECU tuning for the CLS63 along with its roughly 200 pound lighter weight and it is no surprise it traps 128.72 miles per hour to the 4Matic E63 117.83.
A difference of almost 11 miles per hour is huge and using the old rule of thumb of 1 mile per hour being equal to 10 wheel horsepower without even seeing the dyno numbers of the two cars we know the CLS63 is putting out roughly 100 more horsepower at the wheels. A trap speed is often as good as a dynograph.
Even though the CLS63 is lighter and more powerful it still takes longer to cross the 1/4 mile mark at 12.190 seconds. The stock E63 AMS S 4Matic does it quicker with an 11.863.
It should be clear how these two important parts of a 1/4 mile run each have their own particular variables yet they relate to each other. It still is amazing how many people make basic errors when referring to which car is faster (trap speed) or quicker (elapsed time) when talking about a slip and the variables that influence the result.
This is about as simple and clear of an educational 1/4 mile run in relation to illustrating time and speed as there can be.