How to Install a Plenum Spacer in a 350Z

This is our very own, Emily’s, 350Z. She loves her car just as much as the next enthusiast. That’s why when deciding to upgrade and get more horsepower, she went with a Motordyne Plenum Spacer.  The new Iso Thermal system from Motor Dyne, decreases upper and lower temperatures throughout the plenum due to the combination of aluminum, and the administration of the Iso thermal controls. The cooler intake air increases the air’s density, in-turn, boosting engine power. Below is a step-by-step guide of how to install your new plenum spacer. The pictures can help guide you  through steps of what the installation should look like.

1. This is the engine bay and the car prepped for install
2. Remove strut brace across motor with a 14mm socket remove plastic engine cover with 10mm socket
3. Remove all (16)10mm head bolts and (2)10mm head nuts. Also remove the 2 guide pins in the lower plenum. For Iso Thermal gasket installation: Unbolt the upper and lower plenum to install the Iso Thermal gasket. Unbolt the lower collector. Then remove then discard the stock manifold gasket and place the thermal isolating gasket. Verify the gasket lines up before installing intake manifold then install the lower plenum assembly.
4. Lay the aluminum spacer on top of the plenum to find the correct orientation. Then lift the plenum enough to slide the spacer in. Thread washers onto every supplied bolt. Make sure the upper plenum rests against the lower plenum evenly and tightly.
5. Reattach the air intake to plenum
6. Reattach Place one strut bar spacer on each of the strut bar studs then place the strut bar on. Starting at one side, lift the strut bar bracket just enough to slide in the other three strut bar spacers. When you see the center of the of the spacer aligned under the bracket, drop in the bolts and screw them in finger tight. Repeat on the opposite sides strut bar bracket then tighten down all the bolts. For the two nuts 20 ft-lb; and for the six bolts 24 ft-lb.

If you’re looking for other, easy engine upgrades, check out our cylinder heads, mounts and bushings, or ourgaskets and seals to make your engine run at optimum levels. Use these steps to install and let us know how it goes. Send us pictures of your plenum spacer or post them on Facebook, Instagram or Twitter.