Nissan VG Engine Thread

[NarendZORCE]

http://en.wikipedia.org/wiki/Nissan_VG_engine

Nissan VG engine

The VG engine family consists of V6 piston engines designed and produced by Nissan for several vehicles in the Nissan lineup. The VG series started in 1983 becoming Japan's first mass produced V6 engine. VG engines displace between 2.0 L and 3.3 L and feature an iron block and aluminum head. The early VG30 featured SOHC, 12 valve heads. A Later revision featured a slightly different block, and DOHC, 24 valve heads with Nissan's own version of variable valve timing for increased high RPM efficiency. The block is a particularly strong design with a single piece main bearing cap, and is capable of reliably supporting more than 1000hp. The production blocks and production head castings were used successfully in the Nissan IMSA cars in the 80's and 90's.

The VG series engine found its way into thousands of Nissan vehicles, starting in 1984. The VG design was retired in 2004, as all models received the VQ series engine instead.

VG20E
The VG20E is a 2 L (1998 cc) engine produced from 1984 on. It produces 126 hp.
Applications:
* Nissan Gloria/Nissan Cedric
* Nissan Leopard
* Nissan Fairlady Z

VG20ET
The VG20ET is the same as the VG20E, but with turbocharger. The VG20ET produces 170 hp.
It was used in the following vehicles:
* Nissan 200Z (Z31)
* Nissan 200ZG (Z31)
* Nissan 200ZS (Z31)

VG20DET
The VG20DET is an 2,0L engine with DOHC and a turbocharger. It produces 210 hp.
It was used in the following vehicles:
* Nissan Leopard (F31)
* Nissan Gloria/Nissan Cedric (Y31)

VG20P
The VG20P is the autogas LPG (Liquified petroleum gas) version of the VG20. It produces 99 ps @5600 rpm and 149 nm @2400 rpm. It is an OHC 12 valve engine.
It is used in the following vehicles:
1987-1991 Nissan Cedric Y31


VG30i
The VG30i is a 3 L (2960 cc) engine produced from 1986 through 1989 and featured a throttle body fuel injection system. It has a long crank snout, a cylinder head temperature sensor positioned behind the timing belt cover, and a knock sensor in the cylinder valley.

Applications:
* 1986-1989 Hardbody Truck
* 1986-1989 Nissan Pathfinder


VG30E
The 3.0 L (2960 cc) VG30E produced 153 hp and 182 ft.lbf. Bore is 3.43 in (87 mm) and stroke is 3.27 in (83 mm). In 300ZX form, it produced 160hp and 174lb-ft. 1988 saw the 300ZX gain 5 more horses for a total of 165; however, torque ratings remained the same. In 1989, the Maxima received the 160hp rating, but also used a variable intake plenum that let it make 182lb-ft@3200rpm. Strangely, the 300ZX never received the variable intake plenum.

It was used in the following vehicles:
* 1984�1989 Nissan 300ZX/Nissan Fairlady Z
* 1987�1988 Nissan 200SX SE
* 1984�1994 Nissan Maxima
* 1990�1991 Infiniti M30/Nissan Leopard
* 1990�1996 Hardbody Truck
* 1990�1995 Nissan Pathfinder/Nissan Terrano
* 1992�1999 Nissan Gloria/Nissan Cedric (179 hp)
* 1992�1995 Nissan Quest/Mercury Villager (modified to become a non-interference design)


VG30ET
The 3.0 L (2960 cc) VG30ET was available in early production with a single Garrett T3 turbocharger and a 7.8:1 compression ratio. The USDM version produced 200 hp and 227 ft.lbf. In 1988 it changed to a single Garrett T25 turbocharger and an 8.3:1 compression ratio to reduce turbo lag, and was bumped to 205 hp and 227 ft.lbf. No VG30ET was ever factory equipped with an intercooler as they featured low boost pressure for fast response.

It was used in the following vehicles:
* 1984�1989 Nissan 300ZX Turbo
* 1984�1986 Nissan Fairlady Z
* Nissan Leopard
* Nissan Gloria/Nissan Cedric


VG30DE
The 3.0 L (2960 cc) VG30DE produces 222 hp and 198 ft.lbf. Bore is 3.43 in (87 mm) and stroke is 3.27 in (83 mm).

It is used in the following vehicles:
* 1990�1996 Nissan 300ZX
* 1987�1999 Nissan Fairlady Z
* 1988 Nissan 200zx (similar chassis to the 300zx, different panels
* 1993�1998 Infiniti J30 and Nissan Leopard J. Ferie
* 1992�1995 Nissan Gloria and Cedric
* 1989�1991 Nissan Cima


VG30DET
The VG30DET is the same as the VG30DE, but with a single ceramic turbo. It produces 255 hp. It was used in the Nissan Leopard (F31) As well as the Nissan Cima, Gloria, Cedric (y31) and 300ZR (z31) (same as the 300ZX , just the VG30DE and VG30DET instead of the VG30E and VG30ET )


VG30DETT
The 3.0 L (2960 cc) VG30DETT produces 280 hp and 283 ft.lbf when mated with a 4 speed automatic transmission. When used with a 5spd manual transmission, it was rated at 300hp and 283tq. It featured twin T25 turbochargers, twin intercoolers and variable valve timing.

It is used in the following vehicles:
* 1990�1996 Nissan 300ZX Twin Turbo
* 1990�1999 Nissan Fairlady Z Twin Turbo



VG33E
The VG33E is a 3.3 L (3275 cc) version built in Smyrna, TN. Bore is 91.5 mm and stroke is 83 mm. Output is 180 hp (134 kW) at 4800 RPM with 202 ft.lbf (274 Nm) of torque at 2800 RPM. It has a cast iron engine block and aluminum SOHC cylinder heads. It uses SFI fuel injection, has 2 valves per cylinder with roller followers and features forged steel connecting rods, a one-piece cast camshaft, and a cast aluminum intake manifold.

It is used in the following vehicles:
* 1996�1999 Nissan Pathfinder
* 2000�2004 Nissan Frontier
* 2000�2004 Nissan Xterra
* 1998�2004 Nissan Elgrand
* 1999�2002 Nissan Quest/Mercury Villager



VG33ER
The 3.3 L (3275 cc) VG33ER or VG33S is supercharged and produces 210 hp (157 kW) at 4800 RPM with 246 ft.lbf (334 Nm) of torque at 2800 RPM.

It is used in the following vehicles:
* 2000�2004 Nissan Frontier SC
* 2000�2004 Nissan Xterra SC
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[NarendZORCE]

http://www.autospeed.com/cms/A_1966/article.html

The Nissan VG30DETT

Inside its development.
By Julian Edgar

Designed in the late 1980s, Nissan's twin turbo, DOHC, 4-valves per cylinder powerhouse is one of the all-time classic turbo engines. Surprisingly sophisticated both for its time and cost, the engine was fitted to the 300ZX twin turbo sports car. Nissan engineers were aiming very high with the car - the background to the engine development makes this very clear.

In this article we'll cover the technical nitty gritty of the engine and its original development goals.

The Basic Anatomy



The VG30DETT is 2960cc in capacity, with an over-square bore/stroke relationship of 87 and 83mm, respectively. The combustion chambers are of a pent-roof design, with the spark plugs positioned close to the bore centre. The four valves per cylinder are operated by double-overhead cams working with zero-lash hydraulic tappets. The compression ratio of this twin turbo engine is 8.5:1 and the original specs show an SAE NET output of 300hp at 6400 rpm and a peak torque output (again SAE NET) of 283 ft-lb at 3600 rpm. Almost a cube in physical dimensions, the engine is 710mm long, 775mm wide and 695mm high.

While based on the much lower-powered VG30DE engine, major changes were made for the twin turbo engine. These weren't just limited to strengthening the engine and installing the twin turbos; instead the opportunity was used to design completely new intake and exhaust systems. The engineers made much of the fact that twin intercoolers, twin throttles, twin plenum chambers, twin turbos, twin exhausts, twin catalytic converters and twin mufflers were adopted.


Intake System

The intake system design had to balance two opposing outcomes:

��the smaller that the intake runner diameters were made, the greater the frictional losses (and so pressure drops)

��but the larger the intake runner diameters, the slower the airflow speed, resulting in a decrease in cylinder filling, especially at low rpm


In addition, simulation and testing showed that long intake runners resulted in better torque development at low engine revs - however, fitting long runners into an already crowded engine bay was going to be difficult. Runners that were 360mm long gave peak intake efficiency at 4400 rpm, while lengthening these to 480mm dropped the peak intake efficiency revs to 3600 rpm. Since one of the goals of the engineers was strong bottom-end torque, the longer runners became a requirement. Further testing showed that a runner diameter of 48mm worked well with the 480mm long design.

[It's interesting to note the major amount of development that occurred in tuning the intake system in this turbocharged engine. Many turbo engines - including Nissan's own RB26DETT Skyline GT-R engine - have no intake resonance tuning at all.]


Once 480mm (nearly 19 inch!) long intake runners had been decided upon, the next question was how they'd be fitted under the bonnet. The previous model VG30DE had placed the plenum chamber centrally on top of the V6, with relatively short but direct runners connecting the plenum to the intake valves. The measured pressure drop with this arrangement was 85 units.

[The units used are not completely clear - they may be mm of water at 4.4 cubic metres/minute flow.]

The first prototype VG30DETT intake system design placed a plenum chamber above each bank of cylinders, with the intake runners for that head connected to the plenum above it. This required that each runner go through nearly a U-turn, and so was called the 'U-turnport' design. The pressure drop of this design was, however, very high - being measured at 105 units, or nearly 24 per cent higher than the original VG30DE design with the centrally-located plenum chamber.

A 'crossport' design was then built, where the plenum chamber feeds the opposite cylinder bank. This design allowed the retention of the long intake runners but gave a measured pressure drop of only 80 units - better than the VG30DE design, despite the use of intake runners nearly twice as long. The change from a U-turnport to a crossport design resulted in a 5 per cent increase in peak power.

The intake system ahead of the intake manifold was also extensively developed. The airfilter housing used two filtering elements to provide sufficient filtering area within the tight confines of the engine bay. Only a single airflow meter was used, but the junction where the duct splits to feed each turbo was extensively developed. The final design used a very long radius inner bend reducing measured pressure drop by 77 per cent over some of the designs trialled. Together with the use of a bellmouth at the entrance to the airflow meter, these flow improvements increased peak power by 2 per cent.

Twin Turbos


Since the VG30DETT was launched, we have become used to high performance engines being fitted with twin turbos. However, at that time, it was daring move. In terms of the cost penalty alone, doubling the number of turbos must have been prohibitive.

The engineers justified the use of twin turbos with some careful study. To avoid the response penalty of fitting a single large turbo with a commensurately large rotating inertia, the engineers used two hybrid turbos, each with a Garret T25 compressor and a Garret T2 turbine. Using these hybrids reduced rotating inertia by 20 per cent over conventional T2 turbos. And then of course there was the use of two smaller turbos, rather than a single large one. Compared with a single turbo of equivalent flow performance, the use of twin turbos reduced the rotational inertia by 30 per cent.

However, the Nissan engineers suggested that the use of twin turbos only became advantageous at peak power outputs of over 250hp.

Variable Inlet Valve Timing

NVCS (Nissan Valve Timing Control System) is used to vary the timing of the inlet camshaft by 20 degrees.


This table shows the inlet cam timing:

NVCS on
Inlet Valve Opens 19 degrees BTDC
Inlet Valve Closes 49 degrees ABDC

NVCS off
Inlet Valve Opens -1 degree BTDC (ie 1 degree after ATDC)
Inlet Valve Closes 69 degrees ABDC



The timing of the exhaust valves is fixed, with opening occurring at 59 degrees BBDC and closing at 9 degrees ATDC.


At idle and low loads the NVCS is off, while at medium to high level loads at less than 6100 rpm the NVCS is on. At all loads above 6100 rpm, NVCS is off. The action of NVCS makes a substantial difference at engine speeds below 6100 rpm, adding as much as 30ft-lbs to the torque output.

The 28 degrees of overlap when NVCS is on is high compared with what would be used without having variable valve timing. The similar era Nissan RB30ET SOHC turbo in-line six (as fitted to the Holden VL Turbo) can be compared - it has a cam overlap of only 18 degrees. Note that the graph shows that more torque is obtained everywhere under 6100 rpm with the NVCS 'on' valve timing; however the 8 degree overlap that occurs with the NVCS off helps give a very smooth idle.

Engine Internals

Upgrades made to the VG30DETT over the VG30DE include the use of pistons with fully floating gudgeon pins, piston oil squirters and pistons equipped with cooling channels, "autothermatic" pistons with insert steel struts, and better conrod big-end bearing materials.

The exhaust manifold was cast from Ni-resist D5S material rather than conventional high silicon cast iron, giving an improvement in tensile strength from 3 kg/square mm to 9 kg/square mm at an expected maximum exhaust temperature of 900 degrees C.

The con-rods were also made from an upgraded material - micro-alloyed steel. This also enabled a reduction in conrod mass of 93 grams. The crankshaft was also made from micro-alloyed steel, strengthened at the webs. The VG30DETT crank is 10 per cent stiffer than that fitted to the VG30DE.

The sump was also reconfigured, with an oil guiding plate designed to return oil scooped up by the crankshaft counterweights back to the deep section of the pan.

Conclusion



While the RB26DETT engine of the GT-R Skyline is usually awarded kudos when Nissan's turbo engine line-up over the years is considered, the VG30DETT - with its variable valve timing and carefully tuned intake manifold system - is the more sophisticated of the two engines. (But isn't it amazing to consider that the one company developed - at the same time - two such brilliant twin turbo six cylinder engines?)

At the end of the development the engineers said: "We are confident that this engine has achieved the utmost in power output together with high torque and high response worthy of a new generation sportscar."

And lots of modifiers over the years have agreed with them...
_________________
Drags, Circuit, Solodex, Rally, Karting, the Shows, the Girls, the Car you drive...
ZORCERs done know... the speed lifestyle magazine in the Islands, ZORCE
Click to hear it >> http://www.zorce.com/fortheforums/Zorce15NEW.mp3
Download & SEE iT! >> http://www.zorce.com/fortheforums/Zorce-15.mp4
...........................................................
Oh Yeah! Feel the Rush, it's like... WOW!
May the (Mass x Acceleration)-F+Z be with you...