Efficacy of Heat Shields - AC White Paper

 

Heat Shields

Most of our air-cooled Porsches did not come equipped with heat shields. An oversight that we think wise to remedy. Race cars are always equipped with heat shields as well as almost all modern cars. Here are some reasons why it's a good idea.

Heat Shield Benefits

1. Protection of components: They protect sensitive engine components, electronics, and nearby parts from extreme heat generated by the engine, exhaust system, and other sources.

2. Performance optimization: By managing heat distribution, heat shields help maintain optimal operating temperatures for various engine components, which can improve performance and efficiency.

3. Driver safety: Heat shields help prevent excessive heat from entering the cockpit, improving driver comfort and safety during races.

4. Fire prevention: They act as a barrier to reduce the risk of fire by containing heat and preventing it from reaching flammable materials.

The materials used for heat shields are often lightweight and highly heat-resistant, such as aluminum, titanium, or advanced composites. The specific design and placement of heat shields can vary depending on the type of car.

 Heat Shield Performance Testing

There have been studies and tests conducted to measure the difference in engine temperatures with and without heat shields.

1. Engine bay temperature reduction: Tests often show that properly installed heat shields can significantly reduce overall engine bay temperatures, sometimes by 20°C (68°F) or more.

2. Component-specific temperature changes: Studies typically measure temperatures at various points in the engine bay. For example:
   - Intake air temperature reductions of 10-30°C (50-86°F) have been observed.
   - Fuel system components may see temperature reductions of 15-25°C (59-77°F).

3. Exhaust system impact: Heat shields around exhaust components can reduce surrounding temperatures by 50-100°C (122-212°F) or more, depending on the design and materials used.

4. Performance improvements: Some tests have shown that by maintaining cooler intake air temperatures, heat shields can contribute to modest power gains, sometimes in the range of 2-5 horsepower.

5. Materials comparison: Studies often compare different heat shield materials to determine their relative effectiveness. Titanium has high ratings but is one of the more expensive metals.

Titanium - The Ideal Metal for Heat Shields

1. High heat resistance
Titanium has a very high melting point (around 1,668°C or 3,034°F), making it extremely resistant to heat. This allows it to maintain its structural integrity even in the high-temperature environment of an engine compartment.

2. Low thermal conductivity
Titanium has relatively low thermal conductivity compared to many other metals. This property helps it to effectively insulate and reflect heat, rather than absorbing and transmitting it.

3. Excellent strength-to-weight ratio
Titanium is known for being very strong while also being lightweight. This is crucial in automotive applications where reducing weight can improve fuel efficiency and performance.

4. Corrosion resistance
Titanium naturally forms a stable, protective oxide layer on its surface, making it highly resistant to corrosion. This is beneficial in the harsh environment of an engine compartment, which can be exposed to various fluids and temperature fluctuations.

5. Durability
The combination of heat resistance, strength, and corrosion resistance makes titanium heat shields very durable, potentially lasting the lifetime of the vehicle with minimal maintenance.

6. Low thermal expansion

Titanium has a lower coefficient of thermal expansion compared to many other metals. This means it's less likely to warp or change shape significantly as it heats up and cools down repeatedly.

7. Reflectivity
When polished, titanium can be highly reflective, helping to bounce radiant heat away from sensitive components.

8. Aesthetics
In high-performance or luxury vehicles where the engine might be visible (like in some sports cars), titanium heat shields can provide an attractive, high-tech appearance.

AC Recommendation: Should You Install Heat Shields on Your Air-Cooled Porsche?

There's no real downside. Cost is low, installation is quick and easy, and benefits are real. We highly recommend titanium head shields as an upgrade.