Product no.: MI603



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Exclusive to Mace Engineering, here we have our design-registered lower manifold insulators to suit the Holden VZ and VE series, fitted with an Alloytec 3.6L V6.


What are manifold insulators and what do they do?

Manifold insulators are a thermal insulating spacer that mount between your engine block and intake manifold. Made from a heat blocking composite, our manifold insulators will increase power from your engine by keeping the intake cooler and increase low end torque by increasing runner length. 



But how do manifold insulators keep the intake manifold cooler?

Given our manifold insulators are made from a composite material with a thermal conductivity of 0.29 W/m*K as opposed to aluminium, which has a thermal conductivity of 150 W/m*K; the difference works out to be that aluminium conducts heat 500 times higher than our composite material!

Also, with gaskets often made out of steel (thermal conductivity of 20 W/m-K) placed between the upper and lower manifolds being 0.5mm thick, replacing them with a manifold insulator will conduct up to an amazing 3,448 times less heat depending on the size chosen.

Our composite material also exhibits high stiffness and compressive strength, can withstand temperatures up to 150°C, and has a thermal expansion coefficient very similar to aluminium to increase sealing capabilities. In addition, the spacer can also withstand boosted conditions with ease.


Dyno Results:

The following test was conducted on a 2007 model Holden Statesman, with a standard Alloytec 6. Looking at the graph, we can see that power produced down low had increased by a staggering 10%! While power also increased virtually across the entire rev range. Please note that these results don't reflect the true nature of the on road gains given the lack of actual airflow, which further drop inlet temps.

Under normal driving conditions the plenum (upper manifold), with the insulator in place, becomes cool enough to comfortably touch. Unlike before, without the manifold insulator installed under the same driving conditions, making it very difficult to touch without getting burnt!




Key Benefits:

  • Design registered.
  • Reduces charge air temperature resulting in better power consistency and detonation prevention.
  • Power increase with no undesirable side effects.
  • Improved low end torque by increasing runner length.
  • Improved fuel economy.
  • Easy to install.
  • Can be used as a replacement gasket.
  • Reusable.
  • Proven gains at an affordable price.



  • 1 X Bolt pack (Not included in MI635)
  • 1 X Silicone gasket maker
  • 2 X Manifold insulator

Vehicle Fitment Guide



Parts Guide



Please select the part number you require from the drop down menu by utilising our vehicle fitment guide and parts guide.


Note: Our 25mm manifold insulator kit cannot be installed on MY09.5 vehicles due to obstruction of the water hose.

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