Coating an Intake Manifold on 4 Cyl. & Inline 6

The list of intake and exhaust manifold designs is endless. Every coating application will be unique to the vehicle and application it will be driven in. Here are just a few examples

1. Front or rear wheel drive.
2. Front wheel drives, is the intake at the front or rear.
3. Carbureted or Fuel injected.
4. Naturally aspirated turbo or super charged.
5. Street machine or track.
6. If track what type of track racing.
7. Confinement (How tight is the engine compartment).
8. How much air flow under the hood.

The reason we need to know this information, is to determine what your needs are.

For example let’s look at a stock TR4 Triumph. This vehicle has a confinement problem. The engine is so tight in the engine compartment that accessories get damaged from the heat from the engine. Carburetors percolate (boil gasoline) making the engine almost impossible to start after the engine is hot. The whole electrical system is affected -wiring, starter, generator etc. You must understand that the fuels of the 1960s produced much less heat then the fuel of today. Smaller thermostats and bigger radiators won’t reduce the radiant heat off the exhaust. This is where thermal management can really show off. By applying thermal barriers and dispersants the excess heat can be channeled away from accessories.

Carbureted styles of intake-exhaust manifolds that are connected directly together transferred heat from the exhaust directly into the intake manifold by conduction. During the winter, where temperatures are in the 30’s, this is good. However, in the summer, heat can cause problems.

1. Percolation (Boiling the fuel in carburetor). Hard hot starts.
2. Pre-heating air-fuel charge in the intake manifold.
   1. Loss of power
   2. Inducing detonation. (Air-fuel charge too hot).
   3. Damage to carburetor accessories that are temperature sensitive. Etc.

Intake-Exhaust manifolds of this type can benefit three ways. The use of thermal barrier on the exhaust manifold will reduce the radiant heat. Second by strategically placed a thermal barrier on the intake will reduce the radiated heat from the exhaust from being absorbed by the intake, and third a thermal dispersant strategically placed on the intake will allow the heat to dissipate quicker.

Intake manifolds cool in two ways: Firstly, the air flowing through the manifold and secondly, by dispersing the heat in the air stream that flows around the manifold. So by applying a thermal barrier and a thermal dispersant you will achieve a cooler manifold and engine compartment.