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I am sure that some of the more capable aftermarket companies with actual engineering departments like Cosworth, Tomei and Jim Wolf Technology could come up with a performance solution for the intake side of the valvetrain but will it make economic sense to do so?  I would not want to be the engineer tasked to design a cam, or is that an eccentric for this motor?  In the meantime, we are eager to see if the aftermarket can rise to the occasion to be able to offer tuning parts beyond basic bolt-ons and mild forced induction kits for this engine.

Perhaps a compromise solution might be ECU tuning of the VVEL system to bias its mapping toward performance instead of being compromised by emissions and fuel economy issues.  Perhaps more aggressive ECU tuning of the intake valve events with stiffer valve springs coupled with a different exhaust cams may be the way to go.  We'll see what the aftermarket can cook up.  The Nissan ECU is a tough nut to crack but aftermarket standalones are becoming more sophisticated every year.  Motec and Pectal may come out with plug and play solutions for the valve control dilemma.  Jim Wolf Technology and Technosquare will also work on cracking the code and learning to tune the 370Z's ECU as well. In the meanwhile, due to the difficulty in modifying the valvetrain, forced induction will probably be the easiest way for the tuning community to extract larger amounts of power from this engine.

The engines bottom end is stout stuff.  The engine is oversquare with a 95.5mm bore and a 86mm stroke.  Oversquare engines favor high revs and the VQ37VHR delivers with a 7500 rpm redline. The rods are strong and beefy as is the forged crankshaft.  The crank has plenty of main and rod bearing area to support high loads without failure.  The block uses a bed plate style main bearing cap.  Instead of having individual caps to contain the main bearings, the main caps are integrated into a beefy extension of the block which is bolted to the main body of the block in many places.  Real racing specific designed engines and motorcycle engines use this sort of solid support for the crankshaft.  A bedplate gives the engines bottom end unparalleled strength and stiffness.  This helps reduce unwanted noise and vibration (NVH) as well as improve bearing and crank life.  Oil jets fed by the main oil galley help keep the pistons cool and improve cylinder oiling. We feel that the VQ37VHR bottom end can be built to easily sustain over 1000 hp without problems.


Instead of having individual main bearing caps like a typical block and the old VQ35, the VQ37VHR has what is called a bedplate.  Basically a bedplate is an extension of the block that includes the main bearing supports. A bedplate is an order of magnitude stiffer and stronger than the traditional open main caps.  There are now 4 bolts per main bearing journal vs. two and each journal ties into all the others and the stiff, thickwalled cast oil pan.  With a bedplate there is no main cap shifting or fretting and no bearing problems, even with 1000+ hp going through it.  The bedplate is a feature usually found in purpose built racing engines.  Another advantage of a bedplate is that it partitions the interior of the block and reduces windage and pumping losses due to turbulance in the crankcase.


Since the bore remains the same throughout the bigger VQ family and the VQ37VHR shares the tall deck version of the VQ engine first found in the VQ35HR and the VQ40 engines, with only the stoke changing, it will probably be reasonably easy to build bigger versions of the engine by interchanging the VQ40 truck crank or Skyline GTR's VR38DETT crank.  Imagine 4 plus liter engines in the Z chassis!

The top of the block features an open deck which helps control top cylinder temperatures for improved ring seal, less bore distortion and reduced hydrocarbon pollution.  What is somewhat controversial is if this is ideal for forced induction.  Conventional wisdom says that a closed deck supports the cylinders better and helps the head gasket seal better when boosted.  The VR38DETT found in the Skyline GTR is closed deck to support that premise.  Boosted examples of the earlier versions of the VQ motor had the open deck hold up fine to over 700 whp of boost.  When the power reaches quadruple digit levels, the aftermarket has buttressed sleeves that will help solve any issue that might arise.

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# chanito
Friday, February 06, 2009 7:06 PM
The sad part is that there is no serviceable part except the DC motor on that valve train, if the valve gap is out of adjusment, you will need to replace the head. also using the wrong weight on the oil can make it very noisey, however it work wonderful, is very tough and can take abuse

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