Why do cars have two exhaust pipes?
Content
The exhaust system is designed to remove exhaust gases from the engine cylinders. They are discharged into the atmosphere usually from the rear dimension of the car, excluding entry into the passenger compartment through leaks. But some cars have two, or even more, instead of one obligatory pipe.
Against the backdrop of global savings in everything in mass production, this looks illogical. Nevertheless, there is a reason for such a design step, and more than one.
Why did they use a forked muffler
Initially, the dual exhaust became a continuation of the design of multi-cylinder V-shaped engines.
Two rows of cylinders, two cylinder heads, two exhaust manifolds. Each emits its own exhaust, they are spaced apart in space, it makes little sense to reduce everything into one pipe.
If the engine is so complex and massive, then you can’t save much on a single-pipe system. Everything that follows was based on this scheme, but was not limited to it.
We can list this cause and its legacy:
- Dual exhaust of two-row engines, as the need to remove a large amount of gases without using large diameter pipes. The exhaust system is located under the bottom of the car, overall pipes will reduce ground clearance, cause layout difficulties. Two pipes of smaller diameter are easier to place, as are independent silencers for each channel. Meanwhile, it is impossible to reduce the cross section, this will lead to large pumping losses and a decrease in engine efficiency. Reduce power, increase consumption.
- A similar organization of the exhaust began to indicate the installation of a solid motor. Not everyone can afford to equip a car with a similar power unit, and many want to seem richer and sportier. Manufacturers began to help their customers by installing double pipes even on modest engines where they are not required. Often not even real, but decorative, clean dummies, but they look spectacular.
- The same can be said about the sound of the exhaust. The separation of the cylinder outlet along several lines allows you to more accurately tune the acoustics for low-frequency timbre coloring and the absence of unpleasant odd harmonics in the sound spectrum.
- A high degree of forcing, even in the case of small-cylinder engines of small volume without the use of supercharging (atmospheric), requires exhaust tuning. Neighboring cylinders interfere with each other, working on a common highway. That is, in gas pulsations, the removal of the next portion can stumble upon a high-pressure zone from another cylinder, the filling will drop sharply, and the return will decrease. The setting is reduced to the opposite effect, when the portion of gases coincides with the vacuum, so the cleaning is enhanced. But this is only possible with the use of multichannel collectors.
Parallel pipes and mufflers can be installed by the factory or workshops as part of the tuning.
Installation options
Exhaust channels can be diluted in different sections of the exhaust line.
The best solution is separate sections, starting from exhaust manifold, but it is also the most expensive in terms of mass, cost and dimensions.
Can be done bifurcation from the resonator, and to eliminate mutual influence in the manifold, use a tuned "spider" outlet.
A purely decorative solution - the installation of two end silencers with its pipes, working from a common pipe under the bottom, although it brings some benefit by reducing the dimensions of the outlet under the trunk floor.
A similar solution, but one muffler with two outlet pipes.
economy option, pipe imitation plastic diffusers, the real exhaust of a modest size is not visible at all under the bottom.
When choosing an option, you need to decide on the purpose of refinement - it can be external sports tuning or a real refinement of the motor.
Types of sports mufflers
Tuning mufflers are distinguished by a variety of shapes and tasks to be solved, but if we are talking about a dual exhaust, then these are usually the so-called T-shaped products that direct the total flow into one or two housings, respectively, at the outlet having a branch pipe for each or a pipe branch into two parallel channel.
Sportiness here is very conditional, mainly it concerns only appearance. The specific model is matched to the vehicle to avoid lower ride height and reduced performance.
How to make a bifurcated exhaust system
For self-production, it is necessary to have a lift or a viewing hole, a welding machine, a cutting machine and some skills in spatial design.
Measurements are taken of the space where the standard muffler used to be, a specific model of the T-shaped one is selected. Then a drawing is drawn up, according to which the work is completed with pipes and fasteners.
It must be remembered that the whole structure is very hot, the lines should not be carried close to the body elements, especially fuel and brakes.
The system is assembled in the form of a mock-up, seized by welding points, then adjusted in place and finally boiled to complete tightness. Elastic suspensions can be taken from any car model.
In most cases, it will be easier and cheaper to contact a specialized workshop for exhaust systems and tuning.
There are not only standard options, but also opportunities that are difficult to implement in a garage environment, for example, stainless steel welding.
It is important to get a guarantee that nothing will vibrate, knock on the body, create an unpleasant sound and smell in the cabin. A novice master is unlikely to succeed immediately.
