Exhaust Systems FAQ
The term exhaust gas system (also called "exhaust" or "exhaust system") is used to describe the component of an engine through which the exhaust gases are led into the open air. It consists of the downpipe or the Y-pipe with catalytic converters or diesel particle filters, mostly connections for lambda sensors, the pipe routing, the silencer, the brackets to attach the system to the vehicle and the tailpipe(s).
For cost and comfort reasons, exhaust systems are manufactured by the manufacturer in relatively small diameters and chamber silencers.
Our Bull-X development department is specialized in building exhaust systems which are in most cases approved for road use and have been significantly improved in sound and performance
A distinction is made between the "normal" Bull-X sports exhaust systems and the valved exhaust systems EGO-X:
Bull-X exhaust's exhaust systems are generally ECE-approved. In the case of the EGO-X systems, i.e. the flap exhaust systems from Bull-X exhaust, the systems only have ECE approval in combination with the Bull-X Tronic control unit.
You can find more information about approvals here: Approval FAQs
The silencers in an exhaust system are divided into two different body types, which have their advantages and disadvantages depending on the application: Chamber silencers and absorption silencers.
The types of exhaust systems are divided into chamber and absorption silencers.
With the chamber principle, the silencers of the exhaust system contain chambers through which the exhaust gases must flow. This dampens the noise of the exhaust system. Disadvantages of this principle, especially in turbo vehicles, are heat accumulation inside the silencers and a performance-retarding exhaust back pressure.
With the absorption principle, the silencers of the exhaust system pass through so-called absorption pipes. These are perforated and wrapped with steel wool. Due to the further construction of this type of silencer, consisting of glass fiber wool and insulating mat, the exhaust gases can flow more efficiently through the silencer, while still achieving a reduction in noise.
Bull-X (and the associated EGO-X) exhaust systems are manufactured exclusively using the absorption principle.
BACK PRESSURE
Exhaust back pressure is the dynamic pressure that moves within the exhaust side. With turbo engines, the exhaust system should have the largest possible pipe diameters and silencers without large constrictions in order to obtain more power, because the turbine lives on temperature gradients, which would be higher at the back pressure.
RESPONSE BEHAVIOUR
The response corresponds to a time progression of when and how the power is available. This is referred to when it comes to the power delivery of e.g. engine or turbocharger. The better the response behavior, the earlier and faster the component power is available.
In case of the turbocharger, it describes the acceleration behavior of the charger. The better the response behavior, the earlier and faster the boost pressure develops. In most cases, smaller turbochargers have a better response behavior compared to large turbochargers, since less exhaust gas or power is needed to set the compressor wheel or exhaust wheel in rotation.
An optimization of the response behavior can be achieved by specific improvement of the periphery. This includes an intake system including air filter, turbooutlet, pressure path , intercooler or downpipe.
DRONE & NOISE AMPLIFIER
With drones one means a disturbing noise inside the vehicle. This can be caused by missing mufflers, among other things. If one installs now still another Downpipe without flexible pipe, one can speak of a noise amplification, because thus still more volume reaches into the interior, which can work possibly disturbing.
Droning can be caused by the following: If customers order a replacement pipe or dummy in addition to their exhaust system.
- Alternative: middle silencer (MSD) to 63,5mm - the exhaust gas velocity increases and there is 50% less noise in the interior. Or a MoLi (=More Outside Less Inside) silencer, is absolutely silent in the interior, but has no approval. Nevertheless, the full exhaust sound reaches the outside, only in the interior you don't notice it.
