JWT’s Mike Smith attaches the rig that measures the valve lift so the flow for each designated valve lift point can be done accurately.
Now the head flow can be done and data recorded for each measuring point and graphed.
Our head flowed pretty decently, showing the the Newan contouring of the valve seat, port and chamber works really well.
With the VVEL system, the valve stem tip heights are very critical so we had JWT set that up for us. The tip height is achieved by facing off the valve tip height precisely.
JWT set up our heads with their standard springs on the exhaust side and beehive springs on the intake side. Beehive springs have a wider natural frequency range. This is the reason behind using them as opposed to regular springs on the VVEL intake side of the engine which is constantly seeing dynamic changes of the valve motion.
The nose of VQ cams tends to crack at high rpm and JWT solves this by drilling the cam sprocket bolt holes deeper and using longer bolts shown here.
JWT also selected the proper thickness of OEM Nissan DLC coated valve buckets for the heads intake side. The VVEL system depends on the DLC coating to survive due to its back and forth sweeping motion which puts a lot of contact stress on the followers. Especially high contact stress is created when the follower hits zero velocity at the beginning and ends of the sweep.
9 comments
Replacing with upgraded oil gear only is sufficient versus full upgrade of oil pump assembly and cover? Always pondered the value in doing so or maybe there’s a horsepower threshold so any insight is appreciated.
Basically the pump capacity is ok, the problem is the gears break at high RPM.
Kojima-san, thank you for sharing your insight so I decided to purchase the full assembly including the billet cover from Boundary. I also opted for their MartenWear for convenience since they also offer this service although there are other things I may reach out to you separately regarding WPC. Stay well.
Other than the bizaro heads the block looks similar to the VR38 and drag racers are pushing around 1100hp out of the stock block, 1700hp with sleeves, and up to 3000 on a billet block.
The VELL is trick but it locks you out of a lot of otherwise simple modifications.
It is pretty close to the VR. With tuning the VVEL system can give you a bunch of power.
What are the benefits from using the larger valves from a titan truck ? Was there any modifications done to make them fit ?
more flow. The seats must be cut for the larger valve.
Hi,
In the build you used the Titan valve is sodium filled for better cooling and is 1 mm larger for better flow. As the VQ35HR is similar will the same valves fit as was done on the VQ37VHR if so what is the OEM part number so that I can purchase them.
Thanks for your many articles on Nissans
Regards
Jim
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