Overall, the Turbo wins – though it comes in for some criticism.
Lap time Nurbürgring Nordschleife (clear full lap without any of the interuption and missing bit that tourists have through using the toll set-up):
Turbo 8.34 min
Z4 8.32 min
Hockenheim:
Turbo 1.17.1 min
Z4 1.18.1 min
Accel/Braking 0 – 200km/h –0:
Turbo 28.0 sec (0 – 200 22.9 sec, 200 – 0 5.1 sec)
Z4 32.5 sec (0 – 200 27.5 sec, 200 – 0 5.0 sec)
Aerodynamic balance (closed roof):
Turbo frontal surface area (A) 1.61 sq.m, Drag (Cw) 0.38, A x Cw = 0.61
Z4 frontal surface area (A) 1.91 sq.m, Drag (Cw) 0.36, A x Cw = 0.69
Turbo front axle 23kg downforce, rear axle lift 19kg *
Z4 front axle 25kg lift, rear axle lift 43kg
* without roof, Turbo improves (downforce at front goes up from 221 Newton to 254 Newton, lift at rear reduced from 186 to 142 Newton) Does not say what effect open roof has on drag though... presumably increased, therefore better cornering, lower Vmax.
Maximum lateral forces in cornering*:
Turbo 1.2 g – criticised for understeering, skinny front tyres
Z4 1.2 g
* measured in the banked Sachs Curve – on normal corners circa 1.05–1.1 g
Slalom (36 metres) Vmax:
Turbo 129km/h – criticised for understeering, skinny front tyres
Z4 131 km/h
Avoidance Test (110 metres) Vmax:
Turbo 141 km/h
Z4 149 km/h
Final score (out of maximum of 70 points)
Turbo 47
Z4 43
Summary:
"The Turbo suffers from a conflict of interests between two worlds – the absolute purist (read minimalist) philosophy in the spirit of Lotus founder, Colin Chapman – and the attempt to make this more palatable for the masses. But, despite criticism, the car reaches its goal, as the final points show. It's surprisingly quick, has impressive driving dynamics and shows in its conception what a real sportscar should look like. However, considering the superb components, we had expected a little more from it."
Their main criticism is aimed at the skinny front tyres which "cause understeer not on turning in so much, as when the apex is reached and under load when accelerating out. With high changes in loading, as in lifting off suddenly, an abrupt oversteer is induced. Furthermore, even the light, precise steering which is so agile in everyday situations has to be criticised in such situations as the sharp reactions on the limit make it difficult to find the right amount of response. This leads to a very nervous behaviour at the limit because of the changes between over- and understeering result in erratic cornering lines."
They also complain that the ABS is coarsely regulated and causes snaking under braking. The one they tested did not have the optional cross-drilled discs and exhibited fading. They go on to say how the body leans considerably in cornering but the suspension has astounding comfort. They suggest that this "wobbley" cornering and snaking braking is mainly due to the standard suspension being inadequate.
So, basically what we already knew – needs 195's on 16" fronts and adjustable suspension.
Z4 didn't do so badly – still hideous though IMO
Edited by speedyK, 24 March 2004 - 07:14 PM.
Surprising how the Z4 got around the track quicker than the VXt.... Esp as it has substancial lift at 200kph 
Did they do the NA originally?? Have you a link to it?? 
