You have taken the time and effort to restore your car to top condition. With summer coming, you have been tweaking and tuning your AC system for optimal performance and to keep you cool while cruising. Your AC system is blowing cold air, your windows are tinted (or clear UV protected) and your weather stripping is keeping all the gaps closed tight.
But is there something else you could do?
Keeping cool means also keeping the heat out of the vehicle cabin. Your engine generates a lot of extra heat that can transfer to the firewall, heating the metal of the firewall itself which then increases the heat inside cabin. You sometimes feel that heat directly at your feet and legs, but that heat is also rising behind the dash and entering the cabin; defeating all your efforts to keep cool.
To prevent heat transfer, you need insulation.
Now, you may have put some foil on the firewall facing the engine, but you need something more significant for the interior side of the firewall. Carpet can help a bit, but carpet is not purpose-built as an insulator or barrier to effectively prevent heat transfer. You need insulation that is specific to automotive applications that can be applied directly to the vehicle or layered within the vehicle. In addition to materials added to the bottom of carpeted flooring, modern vehicles have insulation that is also applied directly to the vehicle's body to prevent heat intrusion into the cabin.
So, what are your options for insulation for your classic car? If you are in the middle of a restoration, a spray-on or directly applied insulator may be an effective solution. Products such as Lizard Skin have gained popularity over the past several years as a solution to blocking heat and are applied similar to paint, providing full coverage in difficult to reach places or complex shapes, where a laid-matting type solution may not be as effective. Another option is going the mat-applied route using materials such as Membrane to cover floorpans, firewalls and doors. The insulation mat can be cut in various shapes, usually peel and stick, and then can be rolled and massaged into place on the vehicle. The mat solution also allows you to do a section at a time so you don't miss out on any car shows.
Beyond insulating the cabin from heat and cold, insulation can serve as a sound deadener. This provides your vehicle with a quieter cabin by reducing road and suspension noise. So, when you are seeking to keep your car cooler than when it came from the factory, look at adding or replacing the insulation in your classic car, especially at the firewall.
Have you upgraded your insulation to keep your classic car cooler?