Mike Kojima posted on May 25, 2009 09:19
 |
| Here is a sectioned VQ35DE head out of a 350Z. Note the sharp edge and abrupt transition of the short side radius to the valve seat on the intake and exhaust valves. These sharp edges produce flow inhibiting turbulence. Also note the metal around the base of the spark plug tube. This hampers cooling and can result in a hot spot and detonation |
 |
| The 370Z's VQ37VHR head has a much smoother short side radius transition for better flow. Note how improved the water flow around the spark plug tube is. Cooling is much better in this area allowing 11:1 compression safely on pump gas. |
The second are changes to the combustion chamber to safely allow a high 11:1 compression ratio on pump gas. The cylinder head cooling on the VQ37VHR is greatly improved over all previous variants of the VQ engine. The overall thickness of the aluminum around the combustion chamber is reduced and the volume of the water jacket behind the combustion chamber has been increased to improve cooling of the combustion chamber. Most importantly the metal around the spark plug hole has been really thinned out close to the combustion chamber. This is because the VQ37VHR uses a smaller diameter spark plug. This allows a lot more water around the hot spark plug itself. These cooling improvements eliminate hot spots that can cause engine damaging detonation.
This also means that forced induction might be feasible even with the high compression ratio and that if the compression ratio is reduced, a lot of boost on pump gas without detonation will be possible.
Does the new 370Z’s engine a sophisticated world class high performance engine? Hell, yes with its
 |
| Here is the VQ35DE head from the combustion chamber view, you can see how the port directly under the valve is rough with sharp transitions. Note the large diameter spark plug hole. The chamber is deeper and has a larger volume for lower compression |
 |
| The 370Z's VQ37VHR's ports are much smoother right under the valve with smoother transitions into the ports. This flows much better. Note the smaller diameter spark plug which allows for better cooling in this part of the head. The chamber is shallower with less volume for more compression |
excellent cooling, high compression, infinitely variable cam timing and high flowing heads, the VQ37VHR kicks ass. So is the VQ37VHR engines VVEL system complicated and hard to modify? Yes very much so. Does it have any potential for modification for more power? Yes, it is very different and it will take the aftermarket some time to get it figured out but it is possible. Jim Wolf Technology is actively working on potential mods for the valvetrain right now. GTM is also about to release a turbo kit for the 370Z as well. Technosquare is deep into the ECU.
The future for the modded 370Z is bright. Stay tuned.
Sources
Jim Wolf Technology http://www.jimwolftechnology.com/
Technosquare http://www.technosquareinc.com/
GT Motorsports http://www.gtmotorsports.com/