Plenum Spacer for LY7 engine by alm865

Last crawled date: 3 years, 1 month ago

Plenum Spacer for LY7 engine (Pontiac G8, Commodore VE SV6).
This is a model to CNC (or 3D Print) your own plenum spacer. Use polycarbonate plastic (lexan) as it has high resistance to heat, fuel and shattering. ABS may also work.
I saw all the plenum spacers on eBay and wanted to try one out but didn't want to spend $100 on one, so I made my own.
Mine is made out of 9.5mm polycarbonate. 9.5mm is the perfect length as the bolts are just long enough to still hold the plenum on.
For reference the standard plenum bolt lengths are:
2xM8 70mm Standard Pitch Thread
4xM8 160mm Standard Pitch Thread
Install instructions can be found here:https://www.maceengineering.com.au/WebRoot/ecshared01/Shops/mace/52F4/5BF9/8DFE/52CC/DE5C/AC10/0040/136E/VE_ALLOYTEC_Manifold_Insulator_Kit_Installation.pdf
One thing to note is that the port holes (the three air intake holes on each gasket) are about 2.5mm too big. I copied the design of a gasket which was obviously made bigger than the ports. Shouldn't be an issue however for best performance the port holes on this design should be shrunk about 2.5mm to match the ports better.
Warning: this didn't work for me. The engine check light came on and the car ran rough (felt like it lost power). Maybe it just needed a dyno tune, I don't know, but all I'm saying is make sure you have enough time and parts to reverse the mod in case you also have trouble.