Or so we thought. Somehow, somebody at Stoptech heard about our plans and decided they were up to the challenge. All other work came to a halt as they started bombarding Nissan with questions. With persistent interrogation, they learned the Brembo brakes available on the Track Package are the exact same brakes offered on the R34 Skyline GT-R. Perfect. If R34 brakes bolt to the Z, then Stoptech's 13- and 14-inch upgrades for the Skyline would fit as well.
Then they learned we were using 17-inch wheels, which were too small for either of their massive brake upgrades. Undaunted, they took the mounting dimensions of the Skyline, and designed new caliper brackets to use with their smaller 332mm rotors.
With the rotor and caliper mounted, selecting piston sizes was the next challenge. Stoptech can build its calipers with eight different piston sizes ranging from 28mm to 44mm. Piston size directly affects caliper clamping force and pedal feel. With 1,000 psi of brake fluid pressure, for example, a four-piston caliper with 28mm pistons will exert 3,820 lbs of clamping force. (That's 3.82 square inches, times 1,000 lbs per square inch.)Bigger pistons mean more surface area and more force. However, more fluid is needed to fill the space behind the pistons, so the master cylinder has to travel farther to deliver all that fluid. Make the pistons too big and that extra travel is felt as mushy brakes.
Stoptech's 332mm rotor is quite a bit smaller than the 355 and 380mm GT-R brakes it offers
Somebody at Stoptech must know something about somebody at Nissan. The 350Z on these pages hit U.S. soil in a FedEx plane just four days before these pictures were taken. Somewhere between the airport and our camera, though, Stoptech engineers had their big, throbbing heads in the wheel wells measuring caliper sizes, pad dimensions and backing plate clearance.
Based on the stock brake dimensions, they initially chose a 96 percent brake torque reaction. This means that, at the same pressure, the Stoptech brakes would exert only 96 percent of the braking torque of the stock front brakes. This puts more braking force to the rear to compensate for most manufacturers' tendency to use too much front brake bias. This also means you have to push slightly harder to get the same braking force. Coupled with braided steel brake lines that don't expand with the higher fluid pressures, and Stoptech's rigid caliper design, the end result is firm, hard pedal feel.
Surprisingly, though, the result was not shorter stopping distances. The stock 350Z was able to drop anchor from 60 mph in 113 feet, and our newly modified car was doing it in 119 feet. Curious, we temporarily disabled the ABS and the traction control by unplugging an electrical connector on the rear diff for the rear wheel speed sensors. Stopping au natural, the brakes turned out to be frighteningly rear-biased.
Undaunted, Stoptech's Steve Ruiz whipped another pair of calipers from the back of his truck, this one sized for 100 percent of the stock brake torque, and swapped them on the spot. Theoretically, of course, ABS should compensate for the rear bias on a full maximum-effort stop like this. Theory turns out to match reality in this case.
So how in the world can big, sticky, R-compound tires and giant brakes add up to longer stopping distances? One word: camber. When we lowered the car, we ended up with several degrees of camber front and rear.
That camber did wonders for our handling, ensuring that with body roll and tire carcass flex, the entire contact patch would be put to good use. In a straight line, though, the tilted tire simply meant that only the inner half of the tread was touching the ground. We proved this with our big, smoky burnouts. After six or seven monster displays of our collective manhood, the inner tread blocks were gone, with a scant few molecular layers of rubber protecting steel belts from our prying eyes. The outer tread blocks, on the other hand, were literally untouched. The front tires were tilted in exactly the same way.
-
Stoptech's prototype kit included finished production-quality brackets, braided steel brak
-
Because the Z caliper is mounted so far from vertical, air bubbles can be easily trapped i
-