What is the effect of air leakage in the exhaust pipe?

See where the exhaust pipe leaks, and it doesn't matter if the tail leaks. If the front part leaks air, the exhaust back pressure will be reduced, and the torque will be reduced at low speed, which will lead to weak starting and indirectly increase fuel consumption. But at high speed, because the exhaust is smoother, the power will increase.

What effect does the exhaust pipe leak have? It depends on where the exhaust pipe leaks, and it has no effect if it leaks at the tail section. If the front part leaks air, the exhaust back pressure will be reduced, and the torque will be reduced at low speed, which will lead to weak starting and indirectly increase fuel consumption. But at high speed, because the exhaust is smoother, the power will increase. The leakage of exhaust pipe has a great influence on supercharged vehicles, but has a little influence on naturally aspirated engines.

If there is only a small hole in the exhaust pipe, it will not lead to a serious increase in vehicle fuel consumption. Theoretically, if the exhaust pipe is completely removed, the exhaust resistance will disappear completely, which will lead to the increase of engine power and fuel consumption. There is no silencer in the exhaust pipe of racing cars (including motorcycles) just to reduce exhaust resistance, but the noise is huge.

What if the exhaust pipe leaks?

1, you can try to replace the interface pad first, because the air leakage may be caused by the aging of the interface pad. However, when several interface pads are changed and they don't work, you need to check them carefully.

2. It is found that the interface of the front exhaust pipe (exhaust manifold) has been deformed and some convex and concave pits have appeared. If the whole exhaust manifold is replaced, not only the maintenance cost is high and the delay time is long, but also the intake and exhaust manifold pads need to be replaced. In order to save money for the owner and solve the problem as soon as possible, the method of winding copper wire at the interface can be used to plug the leak of the exhaust pipe and eliminate the abnormal noise when the engine is running. Cut a copper wire from the old cable and wrap it around the interface pad, just like the hand-woven straw hat in the past. The inner ring is more important, and the outer ring is bigger and thicker than the interface pad. After installation, tighten the exhaust bolt when the car is hot, and the abnormal noise of the exhaust pipe will be completely eliminated.

3. Copper wire can be used to connect the interface pad, and the bolt of the exhaust pipe interface pad can be tightened at high temperature when the car is hot, which makes up for the leakage of the exhaust manifold, enriches the gap of the exhaust manifold and greatly improves the sealing performance of the interface. In order to improve the sealing performance, there are many ways to connect other items and seals like this. For example, in order to prevent oil seal from leaking, cotton thread or adhesive is wrapped around the joint; In order to prevent the air conditioner from leaking fluorine, an elastic adhesive tape is wound at the end of the interface nut; In order to prevent the valve cover from leaking oil, the upper end of the cylinder head is covered with a film.

Causes of exhaust pipe blockage

1, the car can't accelerate. If the engine is idling unsteadily in the middle of long-distance driving, the car will feel suffocated if it can't refuel. When troubleshooting the engine, it is necessary to consider whether the exhaust pipe is blocked, because poor exhaust leads to less air intake and lower engine power.

2. The automatic transmission is forced to downshift frequently, and the blocked exhaust pipe will inevitably reduce the engine power. At this time, in order to accelerate, the driver must step on the accelerator deeply and let the accelerator fully open. Therefore, the computer will control the automatic transmission to downshift forcibly according to the opening state of the throttle.

3. There will be slight backfire when the engine refuels. When the engine exhaust is not smooth, part of the exhaust gas will stay in the cylinder, diluting the mixed steam and slowing down the combustion speed.

(Photo/Text/Photo: Pacific Auto Network Q&A called Beast)