Collector covers can help...
Collector covers can help provide a layer of protection to the driver.
Level 1: Exhaust Pipe Coating
The best way to slow exhaust heat travelling to the rest of the car is to keep the heat in the exhaust pipe itself. Most often, the way to do this is through the use of coatings. One coating is called Emisshield, which makes use of the properties of emissivity, the ability to absorb and reradiate energy (in this case, heat). This coating is applied to the inside or outside of the exhaust pipes. The key is that it must have a "load" to reradiate toward. With the Emisshield applied, the heat energy is absorbed by the coating and reradiated back into the exhaust gasses as opposed to heat transferring through the metal pipe. Through dyno testing, the Emisshield has shown to maintain a higher exhaust gas temperature and a lower header pipe surface temperature when compared to an uncoated header pipe. The benefits of the Emisshield may be two-fold-protection for the rest of the car from the exhaust heat and its ability to maintain exhaust gas temperature, therefore sustaining exhaust velocity through the primaries.
Working with the emissivity principle (absorb and reradiate), Emisshield would not work the best in all situations. As an insulator from a heat source without any airflow to carry off the heat, the Emisshield would have limited places to reradiate the heat.
The heat-resistant boards...
The heat-resistant boards can help in thermal shielding, especially in short races and lower-heat areas.
Level 2: Exhaust Pipe Shields
The next level after keeping the heat inside the pipe is to mount insulation materials to the exhaust pipe itself. A few years ago, fiberglass header wrap was outlawed by many sanctioning bodies because of its tendency to absorb oils and gasoline during an accident or engine failure. It would then continue to burn and fill the vehicle with smoke. In response to that rule, exhaust-mounted insulations were made by incasing the insulation inside metal such as stainless steel.
A few companies offer these stainless steel exhaust shields. These are made with ceramic and silica insulations. The stainless steel containers have grommets for attachment. They are attached to the exhaust using safety wire or stainless steel tie straps.
As an alternative to the stainless steel shields, 3M came out with an industrial fabric and insulation shield. This ceramic textile is used in place of the stainless steel as the outer shell material. The attachment uses the same methods as the stainless shields. These shields, although built of a high-tech textile, cause concern of absorbing the oil from a blown engine and smoking on the hot exhaust. However, if they do get normal oil drips on them, they can be cleaned.
Tunnel Shield is a composite...
Tunnel Shield is a composite material for insulating the floor or the firewall.
Level 3: Under Floor and FireWall (Tunnel Shield and reflective fabric shielding)
At times, it is impractical to mount insulation onto the exhaust itself. In that case, the next best location for the insulation is on the floor and firewall. There are a few options, including reflective silicone foam, adhesive gold foil, and ceramic insulations. But the product that has taken off the most in the last few years is a composite material called Tunnel Shield. This material consists of an embossed aluminum face backed up with fiber insulation and an aggressive high-temperature adhesive on the mounting surface. This material can be cut and molded to fit any shape underneath the car. The adhesive has been shown to hold to 450 degrees F, but it is recommended that a few safety rivets be used if a large piece is being installed.
Level 4: Floor Coating
Once the heat has reached the sheetmetal floor, it has many paths from which to transfer into the vehicle. It is important to look at the interior sheetmetal as a place to continue to slow the transfer of heat.