The Nissan "VG30ET" V6 Turbo Engine
The fact is the VG30ET engine is more than capable of making big HP numbers on stock internals, and even more power with parts like aftermarket forged pistons.
Nissan has a very simple naming scheme:
V - V engine
G - Engine letter code
3 - first digit of displacement
0 - Second digit (indicating 3.0L)
E - Electronic fuel injection
T - Turbocharged
The VG30E was the most popular model, while the ET (turbo) and I (TBI) models were slightly less so. The VG got an early start on life with its 1982 announcement as powerplant of the Nissan Cedric and the first 1983 300ZX in Japan. By this time Nissan had already built more than 400 prototype engines and had subjected them to a combined total of well over 10,000 hours and over 1 million kilometers of sometimes brutal testing.
The 300ZX was introduced in the US market and around the world in late 1983 as a 1984 model. Its powerplant demonstrated to the world the higher power output, lighter weight, greater reliability, smoother and quieter operation, and numerous other improvements over the previously used L-series engines in earlier Z cars. The VG was soon praised by automotive reviews worldwide as being an engineering masterpeice. By late 1986, Nissan had produced over 500,000 VG powerplants and made the decision to conduct minor revisions for the coming years. For 4/1987 and up productions, many small engine revisions (such as full-floating piston wrist pins) were made to improve reliability and power output, this later model engine was dubbed the "w-series". By this time the VG30 had been slated for use in many other models."W" engines made their ways into a good portion of the nissan lineup, and other companies like ford. Nissan used the VG30 in the USDM models of Quest, Pathfinder, Maxima, 300ZX and 200SX SE V6. Even Ford Motors used the VG30 in certain years of the Mercury Villager. In the later years of its production life, the VG30 saw an evolution to a 3.3L and at this point was used exclusively in the Nissan Frontier, Xterra and Pathfinder. This 3.3L is called the VG33E and except for the larger bore and different accessory placement the engine itself is virtually identical to the 3.0L version; even the camshafts and cylinder heads exchange. The VG33 even saw a supercharged version dubbed the VG33ER. The VG33 series was discontinued at the end of 2004 in favor of the newer and more complicated VQ40DE engine. With millions of units produced in a wide array of vehicles over 21 years (from 1983 to 2004), VG's have depreciated to the point where they are easily affordable by any common gearhead. A good condition used longblock assemblycan nowbe found for under $400, boosted to over 400HP for under $2500 in midifications, and driven for years.
The VG30 is a time-tested engine that was overbuilt from the factory and is capable of making upwards of 500 crank horsepower on entirely stock internals. This very same engine was used in the Electramotive (later to become NPTI) GTP ZX-Turbo that dominated the IMSA GTP races in 1988 and 1989. This engine, with extensive race modification and arranged in qualifying trim (with no restrictor plates) it was able to produce upwards of 1000HP. Putting the other reasons for Electramotive’s sweeping victories aside, the fully homologated race engine VG30ET proved to be both robust and reliable at those power levels.
There has not been shown any measurable power capacity difference between the turbo and non-turbo engines. They are composed of almost entirely the same components, except for the piston's dish size which changes the compression ratio from 9:1 for non-turbo engines to 7.8 or 8.3 for the turbo engines. Because the non-turbo engines are more common and still have a relatively low compression ratio, they are becoming much more commonly turbocharged.
A stock USDM VG30 could come in one of a few arrangements, with the option of one of the most simplistic turbocharger systems available:
- VG30E 84-89+: Engine compression ratio of 9:1
- VG30ET 84-87: Single Garrett T3 turbocharger with a factory boost setting of 6.8PSI and an engine compression ratio of 7.8:1
- VG30ET 88-89+: Single Garrett T25 turbocharger with a factory boost setting of 4-5PSI and an engine compression ratio of 8.3:1
For the turbocharged version there is no stock intercooler at all. There is no compressor bypass valve or blow-off valve of any kind. The turbocharger uses an internal (integral) wastegate assembly to control boost, along with an external pop-off valve (not the same as a bypass valve), which on the front passenger side of the upper intake plenum. The air charge pipe (1) runs directly from the turbocharger to the throttle body; a little over a foot of total length.
Why is the system so simple? Well, simply put it was all they needed when the car was produced. A stock 300ZX Turbo, when it was released in Japan in 1983, became the car with the highest HP available in a Japanese standard production car. In addition, Nissan wanted minimal lag from their engine, instant power on demand at almost any usable RPM, and they got it by using a very small turbocharger, no intercooler (very short piping) and low boost pressure.
Fortunately, what this did is leave a lot of room for vast improvment resulting in large increases in horsepower. Unfortunately, a small turbo and severaly limited stock fuel system will only get you so far. Most people fail to upgrade these key components and never realize the true potiential of this engine when properly tuned!
The cast aluminum pistons and forged steel connecting rods drive an iron crank with 8 main bolts on 4 mains with a main cap "girdle" integrating all the caps into one solid cast unit. The cast-iron block was paired with aluminum heads using a whopping 13 head bolts each. Overhead camshafts driven by a timing belt control interference valves, so 50K mile timing belt changes are a must. 4/87+ engines had the advent of full floating wrist pins, which may have contributed to their additonal 5 rated HP.
USDM model VG engines are rated at different horsepower levels compared to other countries. With lots of cars, there is a lot of emphasis on getting a "j-spec" engine, but there is no difference in the Japanese VG30 engine, they are the same as the USDM engine from top to bottom. Euro/Aus engines got cams with longer durations resulting in an additional 10HP along with no catalytic converter (on the 83-86 cars) yielding the higher HP rating you will see on overseas cars.