LIGHT WEIGHT VALVE MECHANISM – The cylinder head
arrangement and valve system are basically modular to
VQ30 engine which is fitted to Infiniti I30 and Nissan
Maxima Model. However new lightweight materials are
utilized in valve mechanism in order to reduce the valve
operating noise and friction of valve system.

Titanium intake and exhaust valves – Nissan has
experienced titanium valves for the use of racing engines
and VK45DE is the first application to mass production
engine with some modification for passenger vehicle.
Titanium alloy is adopted to both intake and exhaust
valves. Intake valve material is Ti-6Al-4V, and exhaust
valve material is Ti-6AL-2Sn-4Zr-2Mo, both are used with
no metallizing on valve face. Plasma carburing on the
valve stem and flame hardening at stem end are
processed in order to improve wear resistance in a long
life use which racing engine does not require. As a result
the intake valve is 48%, the exhaust valve is 57% lighter
than steel valves respectively. In addition, the titanium
intake valve shape was able to have more ideal shape for
air intake flow with no weight penalty. Table 3 and Fig.13
show the above advantage of titanium valves of VK45DE
engine.

Table 3. Valve Weight
-----------------Titanium/Steel
Intake Valve----31.3gr/60.7gr
Exhaust Valve--28.7gr/66.5gr

Aluminum valve spring retainer – In addition to Titanium
intake and exhaust valves, Aluminum valve spring
retainer is used to reduce the weight of valve mechanism.
The material is Al-Si and it is produced by cold forming
process. It is designed to keep the same stiffness as
usual iron’s one in order not to spoil valve movement as
high speed engine.
As the VK45DE utilizes aluminum valve lifter, same parts
as the VQ30DE, the weight as valve mechanism is
38%(intake),42%(exhaust) lighter than old VH41DE
engine (Fig14). By using such light weight valve system,
VK45DE shows not only less valve impact noise level
itself (Fig.15) but also better sound quality(Fig.16) for
luxury vehicle.Fig.15 shows the engine sound pressure
level at no load, 1800rpm measured by engine
dynamometer.

INTAKE MANIFOLD
Variable air induction system – Variable air induction
system shown in Fig.4 is adopted. Intake manifold
consists of two aluminum die cast pieces and upper
portion has variable induction air valves (power valves) .
Lower portion make the intake port to cylinder head and
intake surge tank is formed by upper and lower portion.
When engine speed is low, the power valves are closed
so that intake air can go through the A-passage( long
port), whereas at high engine speed the power valve is
open so that intake air goes through both B-passage and
A-passage which are designed to show maximum air flow
at the designed engine speed.



Low intake airflow resistance – Intake air flow resistance
was analyzed by both CAE and actual models. The
analysis was conducted from air induction duct to the
intake port of cylinder head and able to find out the
suitable shape to minimize the intake airflow resistance
that result in about 15% improvement from the VH41DE
(Fig.5). Our efforts are mainly dedicated to the selection
of the detail port shape of intake manifold and cylinder
head. Fig.6 shows an example of the analysis model of
intake manifold. The VK45DE adopted variable air
induction system which consists of dual intake port and
need to obtain compatible solution for both power valve
opened and closed conditions.

During the development, the importance of the airflow
around merging area of both intake port was recognized
and analysis was conducted to solve how to reduce the
separated region of airflow. Fig.7 shows an example of
the analysis of airflow at the power valve opened
condition. Fig 7(a) is the airflow streamline and stream
distribution before detail refinement, whereas Fig 7(b)
shows the final result of analysis by changing the
manifold shape which resulted in 2.2% increase of air
flow. This type of analysis were conducted for every
critical area in detail in order to accumulate the
improvement of air flow and finally the VK45DE engine
intake system could achieve about 15% improvement in
airflow resistance.

I wish there was some good vq 30 head jdm that would be direct bolt on. This would be great.

Or Im going to try to find someone who knows there **** when it comes to head work. Anyone have any thoughts on this?

So with the valves from the vk45 you believe that 8000 rpm all day long wont be a problem?

I would gladly put the VQ 35 head or nismo on but The intake manifold from the 3.0 wont work.

I read them and it didnt tell me a good place to get it done . Im not looking for a nascar head work and price . If I gained 10 hp for $600-800 Id be happier than a pig in sh$t.