Robispec’s Street Class Time Attack Nissan 370Z, Simple is Better?

Robispec's 370z uses Cobra steering wheel gasket mounts (seats) with Schroth 6 point harnesses.  The seats give great lateral support, mount the passengers lower and shave about 80 lbs off of the cars weight.

The Robispec 370Z’s interior remains mostly stock except for a Cobra race seats with Robispec brackets that dump the seats as low as possible. The driver (steering wheel gasket) is one of the heaviest single components to a car nowadays and mounting it lower can help reduce the height of the center of gravity nearly as effectively as running a drysump! Robi also fabricated a big beefy harness bar that serves double duty as a chassis stiffener that bolts solidly to the chassis ring module. This brace really makes a feelable difference in stiffening the already stiff 370Z’s structure. A Schroth 6 point harness helps retain the steering wheel gasket in high G maneuvers.

Robispec's harness mount is big and beefy for a reason.  It serves as a chassis brace which significantly stiffens the chassis.  The brace bolts solidly to the cars fortified ring module.

In the front relatively soft 8kg springs are used with Robispec’s pillow ball top mounts. Robi’s top mounts make sure that every bit of travel is controlled by the KW damper and frees up an additional 2" of bump travel. In the rear 10 kg springs are used, with the rear springs staying in the stock off-the-shock location. The front swaybar was replaced with Whiteline’s brand new 27mm diameter 3-way adjustable front bar, polyurethane bushings and spherical bearing end links. The front bar is set on full soft. The rear swaybar is completely removed. Other than corner weighting and an alignment to Robi’s specifications, that’s it! No hard bushings, no spherical bearings, no relocated pivot points, just a sold, basic suspension system, full of smooth riding, squeak and rattle free fun.

For street class, a tire with a UTOG rating of 140 or higher must be used, this eliminates all of the DOT legal super strictly race tires and makes tire choice critical. Robi chose a tire which we feel is one of the best in its class for this use, the Nitto NT05 ultra high performance street radial. The NT05 is a good blend of daily driving durability and trackable stick. Look for more of these tires on MotoIQ project cars in the near future.

In case you were wondering why the Enkei NT03+M wheels have two sets of valve stems, its because one set is for adding dry nitrogen gas for more consistent pressure and the other set is to purge out air.  This feature is handy when you are running nitrogen.

Fat 285/35-18 NT05’s are used on all 4 corners on Enkei NT03+M 18x10.5 wheels. Longer studs with 25mm rear spacers arte used. This allows a 30mm offset on all 4 wheels, easing rotation of the tires for even wear. The Enkei NT03+M uses Enkei's proprietary MAT process, a spin forming operation that roll forms the cast wheels rim section over a mandrel while it is spun on a fixture.　 This strengthens the wheels rim section through grain refinement caused by cold working the　metal during forming.  The metallurgical changes to the rim seen in MAT are very similar to those of forging.  MAT helps a cast wheel get much of the lightness and strength associated with forged wheels making the NT03+M a good choice for this fast and hard driven car.

Robispec's 370Z big brake kit uses Brakeman 4 piston calipers, a lightweight two piece hat and slotted rotors

Since the car started as a base model Z without the trick stock brakes, Robi worked with Brakeman to develop an inexpensive but effective 4 wheel upgrade using Brakemans forged 4-piston F4 front calipers with smaller forged F3 rear calipers. The Robispec brake system also comes with unique 2-piece floating wave rotors; slotted in the front and drilled in the rear. The wave rotors reduce mass and allow for the ultimate in boundary layer evacuation of spent pad material under hard braking. Soft street pads are used for daily driving and Brakeman Race #3 compound pads are used for track duty. Brakeman braided steel brake lines and Motul RBF 660 round out the brake system.

Robispec's rear 370Z brake upgrade uses Brakeman 4 piston calipers and unusual wave type drilled two piece rotors.