Project Nissan 240SX S13 Silvia Suspension - Nissan 300ZX Twin Turbo

1989 Nissan 240Sx S13 Suspension Parking Brake Line

The JIC FLT-A2 suspension features extensive adjustability that should allow us to dial in exceptional handling. The front struts and rear shocks are both high-pressure monotubes, a design that allows a larger piston diameter and therefore better low-speed damping compared to a twin-tube shock. Low-speed damping controls body motions like pitch, dive and roll, and results in better turn-in and a more responsive feel, usually at the expense of some ride quality. The FLT-A2 shocks are 15-way single adjustable, which basically means you get a 15-position knob to change rebound damping. Compression damping does change slightly as well, but you can't adjust it independently.

The biggest problem with Nissan suspensions of this era is limited compression travel. Lower any Sentra, Maxima or 240SX from the '90s and you'll get to know the bump stops. To work properly, a 240SX suspension will either have to sit at nearly the stock ride height, or have shorter shock bodies that allow more compression travel. The problem with shortened shock bodies, however, is the amount of compression travel you can actually use depends on the size of your tires. Suspension travel is useless if the tires just bottom out in the wheelwells.

This is where the JIC suspension stands out. In addition to a threaded spring perch that allows you to adjust ride height, the lower shock mount is also threaded, so you can adjust the position of the shock body. This allows you to position the shock so the bump stop stops the wheel just before the tire bottoms out, maximizing travel no matter what size tire you have.

The JIC coil-overs are remarkably complete, including all the factory-style mounting tabs for brake lines and ABS wires. The front struts also come with camber plates and the rear shocks come with precise spherical bearing upper mounts (pillow ball mounts, if you're from Japan). Front springs are 8 kg/mm (447 lb/in) and rears are 6 kg/mm (335 lb/in), though different rates are available in 1 kg/mm (56 lb/in) increments.

All the quality and craftsmanship in the world is worth nothing if the product doesn't work. Luckily, the JIC coil-overs work remarkably well. Despite the stiff springs, the suspension is exceptionally well damped, even on the softest setting. The generous low-speed damping and high spring rates make the car very responsive and help keep the suspension off the bump stops.

On the track, we never turned the adjusters past the 8th of their 15 positions, and found the car to be perfectly damped and balanced. With the stock anti-roll bars, we did find that body roll used up much of the front suspension travel, forcing us to raise the car about an inch compared to how we photographed it. We'll try stiffer bars and spending some quality time with the generous adjustability before the next installment.

Brakes
These brakes were half the reason for building this car in the first place. Last year we tested a freakishly fast Sentra that later came to be known as the Disco Potato for its groovy paint and tuboresque styling. Two aspects of that car's performance were so impressive they cried out for a rear-wheel-drive chassis to be housed in. First was the violently responsive 270-hp SR20DET. Second was the seatbelt-stretching performance of its Brembo brakes.

The Brembo Gran Turismo kit we used was designed for the Z32 300ZX, but any brakes that fit the Z or Skyline GT-R will fit the 240SX as well. The contrast in size and braking power compared to the stock brakes is laughable. Stock S13 brakes are frighteningly small 9.9 x 0.8-inch rotors with single-piston calipers. The Brembos are a massive 13.1 x 1.25 inches and use the same giant, four-piston calipers as the Ferrari F50.

The 300ZX parking brake cable is too short, but it will work if re-routed as shown in the top photo. At the front, we had to bolt the cable housing in place with a clamp. It looks hokey, but it beats not having a parking brake.
The 300ZX parking brake cable is too short, but it will work if re-routed as shown in the
The JIC front struts are an inverted high-pressure monotube, meaning the enormous shaft sliding up and down inside the spring isn't a shaft at all. It's actually the shock body. The shaft and bump stop are anchored inside the threaded housing.
The JIC front struts are an inverted high-pressure monotube, meaning the enormous shaft sl
In addition to an adjustable spring perch for ride height adjustments, the lower mount is also adjustable, allowing you to raise and lower the shock body. Also note the factory-style brackets for the brake line and ABS wire, and the large adjustment knob that makes shock adjustment easy with bare hands.
In addition to an adjustable spring perch for ride height adjustments, the lower mount is