Project 350Z – Finding More Power with MotorDyne Engineering

Project 350Z – Finding More Power with MotorDyne Engineering

by Mike Kojima

In looking for more low hanging horsepower fruit for Project 350Z, we decided to try an intake manifold plenum spacer from MotorDyne Engineering.  The 350Z's VQ35DE engine has a very thin intake manifold plenum that slopes toward the front of the engine to clear the low hood line.  Although this is good for styling, the engine would prefer more plenum volume and the flow to the front most cylinders is somewhat choked off due to the low overhanging plenum wall.

MotorDyne Engineering is the originator of the VQ plenum spacer.  Currently there are several on the market.  In testing spacers in the past we had had bad luck.  We tested a plenum spacer from a competing company and found that it actually lost power over the stock manifold.  We were kinda sketchy on the concept but Eric Hsu told us to give Motordyne Engineering a call as he had tested their spacer during his tenure at Cosworth with good results.

We talked to the folks at MotorDyne and they assured us that we should get no less than 6 whp from the spacer and many of their customers got much more.  We were still skeptical but the MotorDyne folks were confident so we ordered their 5/16″ thick Iso-Thermal plenum spacer kit.

MotorDyne Engineering makes a 1/2″ thick spacer that is claimed to make more power but it will not fit under the car's Strut Tower brace and since we like a stiff chassis and did not want to run without the brace, we opted to get the thinner spacer.

Want to read more about our Project 350Z?

The MotorDyne Engineering Iso-Thermal intake manifold plenum spacer kit is very complete.  It comes with all the gaskets, clamps, spacers and hardware needed for a straightforward and fairly simple installation.

The spacer itself is cut from 5/16″ thick aluminium.  The spacer comes with aramid gaskets bonded to it.  The plastic spacer and the gaskets do not conduct heat very well, helping keep the top of the plenum cool under use.  The spacer gives a pretty large increase in overall plenum volume.  We estimate around 15%.  It also gives more room around the ends of the intake runners for easier breathing.

You can see the spacer's thickness and construction here.  This simple device gives power!

The gasket between the upper and lower manifold parts provided by MotorDyne is made of heat insulating aramid fiber.  The gasket is designed to keep heat out of the plenum.  The other spacer that we tested did not have any of these features.  It was simply a plastic spacer with no gaskets.

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