Randy Roth
1991 300ZX TT

My first Z was a White 1973 240Z automatic. Shortly after purchasing the car I installed a Crown Manufacturing Turbocharger long before most people even knew what a turbo charger was. I was running 9 pounds of boost and the car was a screamer. As a result, I destroyed the automatic transmission in less than a month. Pulled the auto and installed a used 4 speed. Proceeded to blow up the engine over 6 times as I continued to push the horsepower envelope on the car. Eventually had the car at an estimated 450RWHP running 13.5 sec @ 113.7MPH quarter miles with only 2.2 sec 60’ times! Anyway, all the fun ended when a lady rear ended me on I77 while she was dialing her cell phone and accelerated into me while I was stopped.

After being without a Z for several months, I wandered into the local Nissan dealer on my way back from the store and saw a used 1991 300ZXTT with 44,000 miles on it. I took it for a test drive, came back to the showroom, bought it and drove it home. It was a very nice car, A/C, nice stereo, cushy seats, great handling, etc. just one problem…after driving a 450 HP 240Z the thing was a sled. Found JWT and ordered the 365HP chip and POP charger. It was better but the NOS looked like fun, now it was getting somewhere but still less that stellar performance. So I decided to do the engine build thing, injectors, HKS 2530’s, intercoolers, pistons, rods, etc. Jim Thompson built the motor and took 2 ½ years to do it, I went nuts but he did a great job. It’s now a good street car with 604 RWHP @ 6,500RPM and @ 4,200RPM.

Webmaster's Note: The listing below has changed. The power numbers shown in this profile are no longer valid as Randy has had more work done to the car and will be somewhere in the neighborhood of 1000 RWHP when he finishes this round of modifications.

Specs:

Year: 1991
Color: Pearl White
Trim Level: Beyond stages
Engine: VG30DETT 3.0 Liter V6 Twin Turbo
Transmission: 5 Speed Manual
Horsepower: 604 RWHP @ 6,500 RPM (23 PSI Boost)
Torque: 622.1 Lb-Ft @ 4,200 RPM

Modifications

Engine
  • HKS GT2530 – Ball Bearing Turbos with .87 A/R exhaust housings
  • JWT - Turbo cam (Race#400, 262 deg .368” lift late sprocket + 4 deg adv on EX L/C
  • JWT - Z32T 87.25MM 8:1CR high silicon forged pistons (stock rings)
  • Nismo - 740cc injectors
  • JWT ECU Programming
    - High Octane circuit (more aggressive advance)
    - Nitrous is active at: full throttle, over 3000 RPMs, and less than 8 PSI boost
  • Greddy Profac Type S Boost controller

Clutch & Transmission
  • 4.10 Leader Gears
  • RPS Carbon/Carbon twin disc clutch
  • Stock 1997 5-Speed
  • PST 3 ¾” Carbon fiber driveshaft

Traction Control
  • RaceLogic – Traction Control
  • RaceLocic – Launch Control
  • RaceLogic – Speed Shift

Suspension
  • Stillen - Eibach Springs (front & rear)
  • JWT Tension/Compression Rod Bushings
  • JWT Steering Rack Bushings
  • JWT Front Control Arm Bushings
  • Stillen - Front Adjustable A Arm
  • JWT Front Hard Rubber Bushings
  • Stillen - Rear Adjustable A Arm
  • JWT Rear Hard Rubber Bushings
  • JWT Rear Hard Rubber Sub Frame Bushings

Intake & Exhaust
  • Ported & Polished Intake Manifold
  • JWT – Nitrous Spool-up Kit
  • Stillen – High Efficiency Intercoolers
  • Stillen – Hard Pipes
  • Intercooler duct opening for increased airflow
  • JWT - Dual POP charger
  • Custom 3” Stainless Steel Ceramic Coated Down Pipes w/separate Wastegate Pipe
  • Custom 3” Stainless Steel Exhaust (designed & built by NASCAR driver Jeff Green)
  • Random Technology 3” High Flow Cats
Interior
  • Boost Gauge – Pillar Mount
  • Nitrous Pressure Gauge
  • Nitrous Heater Switch
  • Nitrous Remote Bottle Valve Switch
  • B-Quiet Sound Damper
  • B-Quiet Composite Sound Absorber

Body
  • Removed Spare tire well for Nitrous Bottle and 5 gallon Fuel Cell (for racing fuel)
  • 25 lb Nitrous Bottle w/Remote open/close solenoid
  • Nitrous Bottle heater
  • 5 Gal racing fuel tank, electronically switched with 6 second time delay “return line” to keep from pumping street gas into race gas tank.
  • Dual Motor-Drive Fuel Solenoids
    - Pressure side: Dual input/output (increased flow)
    - Return side: Single and set for 8 second delay

Wheels, Tires and Brakes
  • Stock Wheels – Triple Chrome Plated
  • Rear Tires: Mickey Thompson ET Drag Radial 255/50R16
  • Front Tires: Goodrich GT 225/50R16
  • Stillen Cross Drilled Rotors
  • Porter GWR Break Pads
  • Line Lock


Planned Mods:
  • Quaife ATB Limited Slip Differential
  • Custom G-Force 5 Speed Transmission
  • Dual Fuel Pumps in race gas tank


Awards:
  • 2005 Battle of the Imports – First Place at Rockingham Dragway April 2005


Performance Numbers:

Best 1/4th Mile Time:
10.71 seconds (Rockingham Dragway - 10/22/2005)

Best 1/4th Mile Trap Speed:
131.00 MPH (Rockingham Dragway - 10/22/2005)

Best 1/8th Mile Time:
6.941 seconds (Rockingham Dragway - 10/22/2005)

Best 1/8th Mile Trap Speed:
107.07 MPH (Rockingham Dragway - 10/22/2005)




Photo credit: Jody Roth at ImagesByJody.com