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Z31 General Specifications

Here we will show general Z31 Specifications for the various models offered. These will include the 200z, 200zg, 200zs, 200zr, 300zx, and the 300zr models.

Engine

There were 5 engine types used in the Z31 Chassis throughout the years of production. They were as follows:

• VG20ET - 200Z, 200ZS, 200ZG
• VG30E - 300ZX
• VG30ET - 300ZX
• RB20DET - 200ZR
• VG30DE - 300ZR

VG20ET


The VG20ET offered in the Japanese 200Z, 200ZG, and 200ZS, was basically a VG30ET with the bore and stroke decreased. It came with a single Garret based TB250 turbocharger that had two different wastegate settings. At low speeds, the turbo's flap (wastegate) would stay closed improving the response at low RPMS. At high speeds, the flap would stay open, decreasing resistance and increasing exhaust flow. At its maximum flow, the flap would open at an angle of 27-degrees, while the A/R ranged from 0.21 ~ 0.77.

Though the intake and exhaust manifolds look similar to the VG30ET units, they do not interchange due to the smaller deck height of the VG20.

VG20ET Specifications:

Spec	Value
Displacement	1998cc (122 Cu. in)
Bore and Stroke	78.0 X 69.7
Compression Ratio	8.0:1
Horsepower	170 Hp at 6000 RPM
Torque	22.0 kg-m (159 Ft-Lbs) at 4000RPM

VG30E


The VG30E model engine was a Non-Turbo of the standard engine used in the 300ZX models found in the USDM and EURO markets as all 300ZX models in Japan were turbo models as they were the top of the lineup there.

Below you will find the engine specifications for the Non-Turbo version of the VG30.

Spec	Value	Note
Displacement	2960 cc (181 cu. in)
Bore and Stroke	87.0 X 83.0	Can be bored to 90mm safely. Break through occurs at 3.78" per defrag010 of Z31performance.com
Compression Ratio	9.0:1
Horsepower	160hp at 5200 rpm	165hp at 5200 rpm on late w-series models 1988-1989
Torque	24.0 kg-m (173ft-lbs) at 4000 rpm

VG30ET

The VG30ET is a Turbocharged version of the VG30E motor seen above. In order to maintain a super reliable power plant, Nissan decided to lower the compression for these models by installing Cast aluminum Dished pistons. This effectivly reduced the compression ratio from 9:1 on non turbo models to 7.8:1 for 84-87 and 8.3:1 on 88 and up models.

Specs for the Early 1984 to 5/1987 VG30ET USDM:

On the 1984-1987 turbo cars came with a Nissan made Garrett based T3 Turbocharger.

The engine was either a type A or type B sub-designation from 1984 to April 1987. These have Press fit wrist pins.

Spec	Value	Note
Displacement	2960 cc (181 cu. in)
Bore and Stroke	87.0 X 83.0
Compression Ratio	7.8:1	Pre W-series
Horsepower	200hp at 5200 rpm
Torque	1.4 kg-m (227ft-lbs) at 3600 rpm

Specs for the Late 5-87 to 1989 VG30ET USDM:

On the 1988 and later turbo cars came with a Nissan made Garrett based T25 Turbocharger.

The VG Engines were upgraded in April of 1987 to include new Steam passages in the block and heads as well as upgrading the pistons and rods to accept fully floating wrist pins. These pins were 21mm in size. These Engines were then designated as the W-series engines.

Spec	Value
Displacement	2960 cc (181 cu. in)
Bore and Stroke	87.0 X 83.0
Compression Ratio	8.3:1
Horsepower	205 hp at 5200 rpm
Torque	1.4 kg-m (227ft-lbs) at 3600 rpm

JDM Japanese Domestic Market VG30ET Specification

The VG30ET was the same as the USDM motors but made about 5 less horsepower due to emission standards.

Spec	Value
Displacement	2960 cc (181 cu. in)
Bore and Stroke	87.0 X 83.0
Compression Ratio	7.8:1
Horsepower	195 Hp at 5200RPM
Torque	31.5Kgm (227ft-lbs) at 3600 RPM

Euro VG30ET Specification

The European models made 230 hp (170 kW) in turbo form due to a better camshaft profile, also known outside of Europe as the Nismo camshafts. Some models were also equipped without catalytic converters.

VG30DE


The VG30DE was an early version of the motor used in the Later 90+ 300zx. It featured a slightly different block, Dual Overhead Cam Heads, and 24 valve with Nissan's own version of variable valve timing (NVCV) for increased high RPM efficiency. The production blocks and production head castings were used successfully in the Nissan GTP ZX-Turbo and NPT-90 race cars which won the IMSA GT Championship three years in a row.

The Z31 VG30DE engines differ from the Z32 and later model VG30DE engines in a few different ways. First the Crank snout is a different size, The Heads have round exhaust ports vs the Z32 and later oval ports. The Intake Manifold is a different bolt pattern. Also the Timing belt is a square tooth Part # 13028-16V25 or 13028-45P25 vs round tooth on the z32 part# 13028-45P86. The easiest way to spot a VG30DE block is there are only 8 head bolts vs the VG30E(T) having 13.

Spec	Value
Displacement	2960 cc (181 cu. in)
Bore and Stroke	87.0 X 83.0
Compression Ratio	10.0:1
Horsepower	190 Hp at 6000RPM
Torque	25.0Kgm (181 Ft. Lbs)at 4400 RPM

RB20DET Series Specifications


The 200ZR had the Last straight six offered in a Z it was the RB20DET. These early twin-cam RBs (identified by their red ribbed cam cover) run a relatively low 8.5:1 static compression ratio, 24 valve Dual Overhead Cam Head, and a ceramic wheeled turbocharger with an air-to-air intercooler which is fed by the 200ZR’s Hood scoop. It also used a NICS dual-stage twin-runner Ignition system, a hot-wire airflow meter and direct-fire ignition are also used.

The RB20DET has an cast iron block and aluminium head. All RB engines have belt-driven camshafts and all cam lobes move only one valve.

RB20DE Specification are as follows:

Spec	Value
Displacement	1998cc (122 Cu. in)
Bore and Stroke	78.0 X 69.7
Compression Ratio	8.5:1
Horsepower	180 Hp at 6400RPM
Torque	23.0Kgm (174 Ft. Lbs)at 3600 RPM

Fluid Capacities

[Insert fluid capacity tables here or reference external page as needed.]

Torque Specifications

VG30E(T)

Bolt Location/Nut Location	Torque Value Foot lbs (kg-m, Nm)
Oil Pan Bolts	3.6 - 5.1 Ft-lbs / 4.8-6.9 Nm / 0.49-0.70 kg-m
Oil Pump Regulator Valve	29 - 36 Ft-lbs / 39 - 49 Nm / 4 - 5 kg-m
Oil Pump Mounting Bolts	6 mm: 4.3 - 5.1 Ft-lbs / 5.8 - 6.9 Nm / 0.6 - 0.7 kg-m 8 mm: 9 - 12 Ft-lbs / 12.2 - 16.2 Nm / 1.24 - 1.65 Kg-m

Sources Used

• 1984-1988 Nissan 300ZX Factory Service Manual
• VG30DE Image is from RichZilla,

https://z31library.com/extras_archive/www.z31club.com/

• RB20DET information from 1986 JDM Dealer Brochure
• VG20ET information from 1984 JDM Dealer Brochure