The VQ35HR engine in the ’07-’08 350z just continues to impress us here at Z Car Garage.  This last generation of the VQ35 responds so well to bolt on modifications that the sky is the limit when it comes to producing normally aspirated horsepower.  Yesterday we bolted on another Injen intake system and an Unorthodox Racing pulley to accompany the Nismo exhaust that was already installed on this customer’s car.

The Injen intake now grabs air from in front of the radiator almost directly in the high pressure air stream.  The quality and appearance of the intake is top notch and fit and finish is up to the standards of a company that has been around as long as Injen.  The pulley from Unorthodox Racing is a high quality piece machined out of aluminum and is supposed to weigh around seven pounds less than the stock piece (8.25 vs 1.32lbs.)  We actually weighed both pieces and found the stock pulley on this HR to weigh only 4.8lbs, go figure.  Maybe they had two on the scale?  Anyways, the pulley is the stock diameter so all benefits come from reduced rotational mass rather than an under-drive system.

They dyno results were right were we expected them to be, but that doesn’t make them any less amazing!  While the main horsepower gain comes on the top-end, there are notable gains throughout the mid-rage on the torque side of the equation.  From looking at the graph you will also notice that the modifications cause the torque curve to not drop off as quickly past 5,500 rpm.  The car now makes twelve more foot-pounds of tourqe at peak horsepower, you will certainly feel that in your butt dyno!

Since the two modifications were carried out at the same time I can’t say for sure how much of a difference the crank pulley alone made, but if you look back at the first Injen intake we did on an HR you will see what the intakes did by themselves on that car.  I know, different day, different car,  but can be used as some sort of a comparison.

We are patiently waiting to see more aftermarket suppoort for the HR engines to see what sort of power we can extract.  I want to see cams, intakes, new headers, and more ideas that I’m going to save for our shop to make.  Hopefully more is on the horizon.