How important is backpressure in exhaust?
However, a little back pressure is a good thing. In fact, it helps. The right size pipe is large enough to breathe well but small enough to create a high exhaust flow. Steps in the exhaust system also create negative pressure waves that travel back to the cylinder and help empty the cylinder of those gases.
Is backpressure good or bad?
As it turns out, backpressure is simply bad for power output. Basically, when people claim that a certain amount of backpressure is beneficial, they’re mixing up backpressure and scavenging.
How is exhaust backpressure measured?
To measure exhaust backpressure, you need a pressure gauge with a scale that reads zero to 15 psi, or zero to 100 kPa or higher (note: 1 psi equals 6.89 kPa, and 1 kPa equals 0.145 psi). If you don’t have a low pressure gauge, you can buy a basic exhaust backpressure test kit for around $60.
What should the back pressure be in an exhaust system?
Mufflers generally result in maximum back pressures in the range of 6 kPa. In exhaust systems with a DPF, the back pressure can rise to significantly higher levels—especially if the filter is heavily loaded with soot.
Which is an example of backpressure in an engine?
A common example of backpressure is that caused by the exhaust system (consisting of the exhaust manifold, catalytic converter, muffler and connecting pipes) of an automotive four-stroke engine, which has a negative effect on engine efficiency, resulting in a decrease of power output that must be compensated by increasing fuel consumption .
Why is back pressure a myth in exhaust theory?
Back pressure: The myth and why it’s wrong. One of the most misunderstood concepts in exhaust theory is backpressure. People love to talk about backpressure on message boards with no real understanding of what it is and what it’s consequences are.
Why is backpressure in a car a bad thing?
Each cylinder gets its own exhaust pipe, which, at roughly three feet long, only serves to steer the exhaust flow up and away from the engine—in the process, using the force of the exhaust to create a little extra downforce to boost traction. But there’s a conflicting theory that you’ll hear: Too little backpressure is a bad thing.
What causes back pressure in an exhaust system?
Jason takes to his whiteboard to break it all down. As he often does, his graphical presentation does an excellent and relatively concise job of illustrating what causes back pressure, what back pressure really is, and why back pressure has negative and positive effects on an exhaust system.
A common example of backpressure is that caused by the exhaust system (consisting of the exhaust manifold, catalytic converter, muffler and connecting pipes) of an automotive four-stroke engine, which has a negative effect on engine efficiency, resulting in a decrease of power output that must be compensated by increasing fuel consumption .
What do I need to measure exhaust backpressure?
The first thing you need is a pressure gauge that can read up to about 20psi. They sell these at auto parts stores and many can read vacuum as well. For exhaust back pressure, I prefer mechanical gauges because they’re generally cheaper to replace and less delicate.
Each cylinder gets its own exhaust pipe, which, at roughly three feet long, only serves to steer the exhaust flow up and away from the engine—in the process, using the force of the exhaust to create a little extra downforce to boost traction. But there’s a conflicting theory that you’ll hear: Too little backpressure is a bad thing.