The alignment was set to street specs of -2.0 degrees camber and 1/16-inch toe-in for the front and -1.8 degrees camber with OEM-spec toe-in for the rear. With the trick TCKR camber plates, it's now possible to change the front camber at the track to between -3.2 and -3.5 degrees, resulting in 1/8-inch toe-out.
This can be achieved on-site in about 15 minutes with a level surface, a floor jack, a 13-mm ratchet, a torque wrench, and a digital level (plus/minus 0.1 degrees). These settings were used for the lap testing described below. Adjustment of the independent rebound (damping) and compression (bump) of the V3s and zeroing in on the optimum setup is challenging, but will pay dividends for specific handling and ride requirements once the ideal arrangement is found.
KW provides a recommended initial setting for rebound and compression in the kit's installation instructions, which is a good starting point. On Project Z4M, I found that reducing the rear compression slightly (approximately half a turn) from KW's recommendation decreased stiffness, which softened the ride slightly and provided more rear-end grip at the limit for neutral handling when trackside.
On the street, the new suspension has a similar ride to the factory setup, thanks to the progressive springs. And this is with the shocks set to a track level of stiffness. Also, the new raked and lowered stance gives the car a mean and purposeful look. Because it's not ridiculously low, the larger tires don't rub on every driveway ramp.
At the last track outing, the average lap time was 93.1 seconds, with a fastest lap of 92.8. Testing with the new suspension components was kept as consistent as possible, with similar weather conditions, the same driver and no in-car lap time displays for motivation. The one exception was an alteration to the driving line for turn five, made necessary by track re-surfacing. This caused the recorded times through that corner on this particular test session to be about 0.5 to 0.75 seconds slower than before.
Regardless of this minor inconvenience, the addition of the new suspension goodies still resulted in faster lap times overall, the average time being 91.6 seconds, the fastest 91.3. The Traqmate data reveals higher speeds through almost every corner. Note the significantly reduced speed through turn five. To correct the new lap times to the previous (and future) lap testing, I have subtracted a conservative 0.5 seconds from the average and fastest lap times, resulting in 91.1 and 90.8 seconds respectively.
The readout also shows higher lateral-g measurements in most corners, with the highest-g corner-turn three-showing an average increase from 1.05 to 1.15 g. More grip from the new suspension components and their improved alignment capabilities allows more speed to be carried into and through a given corner.
Now handling and braking have been improved significantly, it's time to really have some fun. In the next installment, we'll see how easy it can be to add a bit more punch to this already powerful machine.