The high-tech blacksmith’s forge forms Cargraphic’s exhausts
posted on: Sep 8, 2009 on category: Parts

Cayenne Auspuff kl 1024x682 The high tech blacksmiths forge forms Cargraphics exhausts
“How do you make an exhaust?” “You take a hole and put a coat of metal sheet around!” Of course it isn’t as easy as it sounds in the classic joke. German expert tuners Cargraphic, from Landau in der Pfalz, know this all too well. “It is not a task for amateurs, because the design of a modern exhaust is a proper science and requires exact knowledge of air flow technology”, explains Thomas Schnarr, who leads the company together with his brother Michael.

“On the one hand the engine should breathe as free as possible and on the other hand you have to meet emissions and noise regulations, which is a difficult compromise.” That’s why the Performance Company, as the Landau firm likes to describe themselves, invested early and heavily in exhaust technology to hit their ambitious targets. Cargraphic doesn’t just deliver street-legal cars, but also competes in motorsport and develops its products for ultimate performance. Manufactured in Devon, England, Cargraphic’s exhausts shine not only through acoustic and optical brilliance, but also increase performance from the engine through reduced back pressure.

“Great Britain has always had excellent products and sports cars”, says Michael Schnarr, speaking from experience after many years working with British classics and modern machines like the Aston Martin. The English branch of Cargraphic was founded in 1996 and now has 30 experienced craftsmen and cutting edge machinery on its 1650 square metre floor. Precision, automated CNC machines bend the aerospace-grade stainless steel pipes to exact angles with the minimum force. This ensures that the exhaust system retains its power for many years, despite exposure to corrosive elements.The attention to detail and the deep engineering in the fabrication has to be seen to be believed. But the highlight is, without a doubt, the in-house research centre that allows Cargraphic to produce exhaust systems with precisely defined characteristics and to keep step with new developments in the engine section. That’s how Cargraphic remains on the front line on the rear of the car.

Optimising the central exhaust components:
The exhaust manifold: The path of the burnt gases starts directly behind the cylinderhead, which is connected to the cast iron or stainless steel manifold. Simple versions are often constructed as manifolds, while more powerful engines do generally have more complex shapes. Car tuners and motorsport companys like to use the so-called ‘flat manifolds’. Here the exhaust pipes are as close to equal length as possible, which improves performance and the torque-curve through the so-called Venturi effect: Inside the manifold a current of pressure is created during the ejection cycle, that sucks out the emissions out of the cylinder. The pistons do not face the same resistance and the engine can turn more freely.

The catalytic converter: This cleans emissions and is a can-shaped component with a hoop shape entrance and exit. It folds out through a block of ceramic combs that are coated with various precious metals, such as platinum. They serve to catalyse the chemical breakdown of the emissions. But from the sporting view the catalytic converter has a decided disadvantage: Thanks to high-flow resistance it strangles the efficiency of the exhaust. That’s why Cargraphic develops aggressive sports catalysers with an inner core made of stainless steel for all current vehicles in their product portfolio. It can take far harder knocks and higher emission temperatures than ceramic without breaking. That’s a recipe for trouble-free driving, even with race suspension and increased power.

Rear silencer: Depending on the design of the exhaust system, simple or a double version, there are one or two rear silencers. Inside it is separated into various compartments that are damped. The exhausts are forced to split into single airstreams, what helps the sound waves partially cancel each other out. Through cross sections and geometry the exhaust specialist Cargraphic can influence the engine power at this point, while varying the exhaust back-pressure. The lower that is, the less the pistons have to push, and that helps the engine maintain constant power and ultimate efficiency.

Acoustic fine tuning of the opening / port sound: As with an instrument, the tuning of an exhaust system is very complex and the spectrum can vary depending on a number of elements. Thankfully, Cargraphic has a number of tools at its disposal. An exhaust arm filter, also called Helmholz-Resonator, can be used to damp various frequency sections. It’s possible to use ‘rainwater pipes’, too, pipes with perforated walls that are cut laterally, either completely or partially. Reflection blinds can also be added. A fourth possibility are Venturi jets that constrict the exhaust pipe for faster airflow.

Exhaust Tip: For optical reasons the outlet is generally decorated with an attractive exhaust tip. Here there are various alternatives for the shape, as well as the single- or double versions. In addition there can be a special surface finish by chroming, polishing, painting or enamelling.

More information: Cargraphic

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