Quote:
Originally Posted by conmam
I totally agree with the efficiency. It is quite good. However, the very big downside is that the VVEL heads are not rebuildable since the VVEL ladders are not to be disassembled per Nissan and therefore if your intake valves clearance are out of specs and/or if you need to replace any of the intake valves components, you are out of luck since Nissan do not sell them separately from the heads. In this case, you must buy the entire head assembly, which is very expensive. Also, the VVEL actuator can be quite costly too.
For normally aspirated motors, it probably can squeeze more HP than any other non-VVEL heads, but really for forced induction, I would very much prefer either the VQ35HR or the VR38DETT heads since the difference is not worth the cost for cylinder head replacement. Also, if you wish to rev higher than 8000 rpm on a built motor, the VVEL system is a definite limiting factor. Just my opinion, that's all.
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Just to put it out there, the only reason these are considered a "Sealed part" from Nissan is they where not willing to give out measurements for inspection and reassembly.
With that said, we took the time to build jigs, and tools needed to measure and reassemble the entire VVEL system to factory specs, or modified. The goal was to be able to get a bucket of parts, and be able to re-assemble it to be a running, functioning head. We are at the point where we are able to do that.
Here is a post from another thread:
Quote:
Originally Posted by MAMotorsports
We put a good amount of time into sorting out these heads and how they work. As we feel that unless you fully understand how an entire engine works, you should not be taking customers money to build them.
With knowledge based on years of engine development (From VVL SR20s, to taking over and evolving Menards Spec VK56 CORR motors and VK45 based daytona prototype and indy lights engines), we developed tooling to inspect, measure, and re-build these heads back to factory spec or maxing out the available adjustment otherwise. The tolerances of all the VVEL components have to be set to a high degree of precision outside the scope of a hobbyist's feasible budget as far as specialized tooling goes. There are specialized fixtures to measure every single component. We have also determined exact wear tolerances for all of the associated components and have documented all of the manufacturing differences from nissan's evolution of the design.
With all that said, there are still some issues with making adjustments. While we have solutions for racing applications utilizing different engine control hardware, we aren't ready to invest into something that is likely unmarketable for a more street based consumer. Time will tell as more and more people have been contacting us for more high end engine builds not limiting themselves to just forced induction and leaving the heads alone.
The issue does not lie with figuring out the "magic screw" as we have that sorted out, the issues lie with the lack of being able to control the throttling of the engine with the throttle bodies. Using the VVEL to throttle the engine by controlling the lift as the OEM ECU does becomes an issue when you increase the minimum lift via the adjustment.
We are very excited about the future of these engines, and very excited about the development we have undergone here with the VVEL system in itself. As the future unfolds, we look forward to what projects present themselves to us as we always enjoy a good challenge!
-Daelen
Ma-Motorsports
Daelen@ma-motorsports.com
410.593.7080 |