How hot does an exhaust get? When we think of exhaust, images of billowing smoke and red-hot metal probably come to mind.
After all, the exhaust is the process by which waste gases are removed from an engine to prevent it from overheating. It’s no surprise, then, that exhaust is one of the hottest parts of a car.
However, just how hot does an exhaust get?
Under normal operating conditions, most passenger car exhausts measure somewhere between 200°C and 350°C (392°F and 662°F). Sometimes, when accelerating heavily or your car has a mechanical fault, the temperature can even go over 500°C (932°F).
Keep reading to explore how hot an exhaust gets in more detail and why it gets so hot in the first place.
How Does an Exhaust Get So Hot?
Many people believe that the exhaust from a car, truck, or motorcycle engine is hot because the fuel gets burned in the engine. However, this is not the case. The exhaust is hotter than the temperature of the combustion chamber.
The engine’s cooling system heats the exhaust gases. The coolant circulates through the engine and absorbs heat from the combustion chamber.
The hot coolant then flows through the radiator. The heat gets dissipated through the fins. The cooled coolant then flows back through the engine to absorb more heat.
The exhaust gases are also heated by the friction created as they flow through the engine’s exhaust system. This friction causes the exhaust gases to expand, which increases their temperature.
What Determines The Exhaust Temperature?
Your exhaust temperatures don’t always stay the same. They experience fluctuations depending on these factors:
The Engine’s RPM
Your engine’s RPM dictates the exhaust temperature. Running the engine at a lower RPM reduces the internal combustion rate, and the car produces less gaseous byproducts. The combustion rate increases as the RPM increases, and so does the exhaust temperature.
The engine’s RPM is lowest when the car is idling.
Length of the Exhaust Pipe
Exhaust pipes have different lengths and diverse designs. Some pipes are longer than others. Longer exhaust pipes generally get hotter than short ones.
The gases travel a longer distance, and the internal friction in the pipe is greater. The gases heat up as the particles collide with each other.
You should maintain your engine regularly. When your engine overheats, the exhaust gases get hotter than normal. Your exhaust temperatures rise if there are blockages in the outlet pipe.
Any objects in the pipe could damage the engine. A proper exhaust for a standard saloon car shouldn’t exceed 662℉.
How hot does an exhaust get? Exhaust temperatures reach anywhere between 392°F and 662°F. The temperature depends on the runtime, exhaust length, cooling efficiency, etc. Truck exhaust temperatures are generally higher at around 630℉ to 930℉.