Nissan’s V6 engine powered the most iconic cars we know today, and they make one of the best in that category. It is because the V6 configuration that allowed Nissan to achieve high-performance engines.
When VQ engines were introduced in 1994, the VG family was sidelined and retired in 2004. After years of sitting in the retirement chair, it is still a practical choice for economy and power range. This single turbo twin cam monster has scanty information about itself, but we will still discuss its engine design, applications, issues, tuning potential, reliability, and many more.
Join me as we tackle this highly reliable and durable engine, the VG30DET.
What are Nissan VG30DET engines?
The Nissan VG30DET is a turbocharged, 3.0 Liter, 24-valve, quad-cam V6 gasoline engine from the Nissan VG family of engines. It is equipped with the then-variable valve timing control VTC and a T3 four-bolt Garrett Turbo (Nissan N1 Type), running on 11.5 psi maximal boost pressure. The Nissan used the single-turbo machine from 1987 through 1995 in the Japanese market and the direct predecessor of the twin-turbo VG30DETT.
While VG30DE is considered similar to the VG30DE naturally-aspirated, it used a different intake manifold and heads. And contrary to what we know, VG30DET engines are not available in the Nissan 300ZR model – since the 300ZR only had the earlier version of the VG30DE.
There are some reports that Nissan developed the VG30DET engines with a heavier and stronger block so they could be allowed for use in GTP. It was an expensive suggestion and but they don’t have to produce a lot to make it legal, so Nissan only put them in Nissan’s high-end luxury cars.
The high-profit models helped to have a cushion in the cost of development. While the engine was on its way into production, Fédération Internationale de l’Automobile (FIA) changed the rules for GTP cars to allow the use of aftermarket blocks in alternative materials.
Nissan never used the VG30DET block in a P car; instead, they produced aluminum racing blocks, like other manufacturers.
It is equipped with a multi-point injection system (EGI), a mechanically timed electrical ignition system with one ignition coil, and a mechanical distributor.
Some of the technologies crafted for the VG30DE engine are also featured in the turbocharged version. They installed a cross-flow cooling system that utilizes a water gallery for the aluminum cylinder heads and block. In addition, it is integrated with an individual cylinder knocking control system, Electronic Concentrated Engine Control System (ECCS) by cylinder pressure sensors, Nissan Direct Ignition System (NDIS), Nissan Induction Control System (NCIS), and Nissan Valve Timing Control System (NVCS).
Nissan VG30DET features a cast-iron block and two aluminum heads with dual overhead camshafts design and acts four valves per cylinder.
Engine Specifications and Design:
- Production Run: 1987 – 1995
- Cylinder Block Material: Cast-iron
- Cylinder Head Material: Aluminum
- Configuration: V6
- Bore: 87 mm
- Stroke: 83 mm
- Valvetrain: DOHC with four valves per cylinder
- Displacement: 3.0 L (2960 cc)
- Compression Ratio: 8.3 and 8.5
- Weight: 532 lbs.
- Max HP: 255 HP
- Max Torque: 236 lb-ft
Two Types of VG30DET: Series 1 vs Series 2
Series 1 engines have red valve covers and black intake manifold; they don’t have knock sensors and circulation valves. Some of the turbos used in the VG30DE series 1 are either journal bearing or ball bearing, depending on the model. However, they are bigger than RB25 turbos and VG30ET turbos. These machines are presumed to make 230 HP at the crank. Most of these motors came in luxury Nissans in Japan and hard to come by.
Series 2 engine has a black intake manifold cover with an unpainted upper intake manifold and silver valve covers. It comes with knock sensors and recirculation valves, which series 1 lacks. These machines are presumed to produce 250 – 255 HP at the crank.
The series 1 and 2 engines also share the same cylinder heads as well as the upper and lower intake manifold. The VG30DET uses a top-side feed fuel rail setup like 1987 – 1989 Z31zxs naturally-aspirated and turbo. VG30DET runs on a 270/260 cc injectors stock.
All VG30DETs have bigger intake ports than the Z32 VG30DE from 1989 – 1999. VG30DETs has an unknown compression ratio that can be around 8.3 to 8.5 due to the power decline.
VG30DE and VG30DETT engine blocks are different from the VG30DET. VG30 twin-turbo and naturally-aspirated blocks have a casting of 30P, and the DET is a block casting F65.
VG30DET has a side-mounted starter just like the Z31s, and they also have the oil filter mounted like the Z31s as they have the motor mount setup like a turbo VG30ET.
The Nissan VG30DET has its engine architecture identical to those of the VG30DE engines. The cylinder block is made from cast iron supported with a system of four-bearing crankshaft. It has the same cylinder bore and stroke from the VG30DE, 87 mm and 83 mm, respectively.
The engine has one oil control ring and two compression rings. The connecting rod center distance is the same at 154.10 mm, and the crankpin diameter, 50 mm; the crankshaft main journal diameter, 62.9 mm, and the center distance of 41.5 mm.
The VG30DET’s cylinder head also has a good cooling efficiency due to its light and strong aluminum alloy material. It has a dual camshaft design for each head and acts in four valves per cylinder. The camshafts are driven via a single timing belt and equipped with Variable Valve timing VTC on the intake cams.
The VG30DET is equipped with hydraulic valve lifters.
Applications of the Nissan VG30DET Engine:
- 1991 – 1994 Nissan Cedric Y32
- 1988 – 1995 Nissan Cima FY31 and FY32
- Nissan Gloria
- Nissan Leopard
- Autech Zagato Stelvio (based on the F31 Leopard)
Engine Tuning, Upgrades, and Modifications
Nissan VG30DET engine, like its brother, VG30DE, which is a naturally-aspirated one, is not hard to tune because it is internally balanced. Even its internal components are already strong enough to withstand aggressive boosts, so it is a good platform for upgrades that can produce higher horsepower even without changing the internals.
This is a turbocharged engine already, so you don’t have to worry about turbo installation if you want to replace the stock one.
If you want to tune the VG30DET engine, you can start by changing its cam profile design. Changing the cam profile puts a lot of difference on your machine, and it plays a crucial role in increasing the power by altering the duration of the intake and exhaust camshafts. Most of the substantial torque gains are the effects of a better cam profile.
You have two options for cam profile – fast road and motorsport cams. Fast road cams are suitable for high-end RPM power, but it pulls a bit low-end HP. Motorsports cams, however, boost the higher-end RPM band, which compromises the lower-end power, and the car will not idle smoothly.
As per the VG30DET, it is recommended to use the fast-road cam for sustainability between low to mid-high power demands. VG30DETs are good in lower-end powers, so integrating it with a higher-end RPM power creates a good balance.
Remapping the ECU also helps reach the maximum potential of all the modifications you’ve made. And as a turbocharged engine, it is essential to tune the ECU properly. However, some stock ECUs are locked and cannot be flashed, so buying an aftermarket ECU is the only option. This upgrade gives an additional 30%, at maximum, boost on your turbocharged engine.
You can also modify your engine in three different stages.
The first modding stage includes remapping, intake headers, panel air filters, drilled and smoothed airbox, fast-road camshaft, and performance exhaust manifold.
The second stage is fast road cam, high-performance or high-flow fuel injectors, induction kit, fuel pump upgrades, ported and polished head, performance catalytic converters, and exhaust manifold.
The last stage requires more effort because of engine balancing and blueprinting; others want to add another turbo, but Nissan released a twin-turbo version of the VG30DE. Crank and piston upgrades to alter the compression ratio, head flow ports, and bigger valves.
Problems Surrounding VG30DET Engines
The Nissan VG30DET, like its engine basis VG30DE, is highly reliable and durable. The internal components and turbocharged version can attest to that attribute. However, some shortcomings and issues might arise especially considering the age of this engine. With those being said, we want to give you some additional information regarding its problems and weaknesses in the long run of its use.
If you religiously follow the schedule recommended for an oil replacement, timing belt, and other components, this least worries you. Furthermore, it is equally vital to maintenance is readiness.
The first issue is the engine’s timing belt. Timing belts are a standard maintenance item across all the machines, and through time they deteriorate due to changing temperatures and external damages. It is recommended to change the belts when they reached the 60,000-mile mark and check it regularly after that. Failure to replace the belts, especially when it is already damaged, is considered a done deal for your engine. So, you better make it timely when changing the belts.
To add to that, some VG30DET engines have issues regarding fuel injectors. This problem also affects its naturally-aspirated counterpart. Also, as part of its aging reputation, crashing and corroding connecting rods affect the engine. It takes tremendous effort to bring those to pristine condition, and they are commonly irreversible.
VG30DETs have no issues with engine overheating and oil leakage.
The turbocharged version of the VG30DE, the VG30DET, took a lot of its architecture from the previous release. It is also equipped with the technology and systems that are used in the VG30DE. It has stronger internals, new cylinder heads, and intake manifold, making a good pair for a turbocharged engine. This engine is designed for high-performance applications as well as its successor, the twin-turbo VG30DETT engine.
It is equally, if not better, reliable as the VG30DE engine, even in its stock form, as it can withstand higher power output without changing its internals. To add to that, it possesses a quick engine response, low noise and vibrations, and a low level of maintenance. Nissan kept it that way throughout their VG30DE versions. It is best used for high output and high range engine RPM. It sits at the center of speed and economy.
Though it has some issues and problems related to its age, those are negligible if you took care of the engine correctly. VG30DET machines can easily top 200,000 miles with the proper maintenance and use of quality engine oil.
I hope that this simple discussion helped you understand the VG30DET’s engine design, applications, tuning potential, weaknesses, reliability, and overall impact on the automotive industry and community.