Feature: exhausted all your options?
ALL YOUR OPTIONS?
Whether you want more noise or a bespoke exhaust system, let the experts build you a custom setup
THERE are many reasons why people choose a custom exhaust: the desire for more sound, a certain look (do you want your VW Golf GTI to ape the appearance of an R?), a performance enhancement or just because a standard system is too expensive or simply no longer available. Last mentioned was the case with the Mercedes-benz 560SEC parked on a lift at Powerflow Exhausts in Bellville when we visited (pictured above). Chris Daniels has 27 years of custom-exhaust experiences and took us through what is required to create a bespoke system.
OWNER REQUIREMENTS
The first job for an exhaust builder is to understand the needs of the client and translate those to the hardware. The MercedesBenz’s owner wanted a standard-sounding exhaust with slightly larger-than-stock twin outlets which would complement the vehicle’s classy demeanour. The original system was beyond repair and removed up to the flanges of the manifolds. These were still in good order and retained to save costs. According to Daniels, it’s important not to increase the diameter of the exhaust pipes on classic and vintage cars powered by naturally aspirated engines, as they perform better with normal back pressure.
THE MANUFACTURING PROCESS
It takes skill to construct a system from scratch. Powerflow uses only 409-series stainless steel with a 1,6 mm wall thickness, as it can easily last up to 10 years, where a mild steel system may remain blemish-free for only two. The pipe lengths, size of the mufflers (including location) and the routing of the exhaust are important factors. Sometimes it’s necessary to create a template to help achieve the perfect radius bend of a pipe at the bending machine. When pipes of 63 mm diameter and larger are curved, they are first filled with sand to avoid folds and creases on the skin. Standard mandrel bends are used for even larger diameter pipes, cut to size and welded in place.
It is a time-consuming process because the technician has to cut the pipes, bend them and fit the system in stages. Interestingly, all the welding is done underneath the car using the metal-inert-gas welding technique. This ensures the pipe runs exactly as planned and there is no interference with the vehicle’s underbody. Care is taken with the rubber mounting points to allow sufficient movement of the system in operation.
THE END RESULT
Three hours later, the exhaust on the Mercedes-benz is ready for its first test. This involves searching for leaks by letting the engine idle while the car is on the lift and running a piece of flexible pipe over each welded joint to listen for hissing noises. According to Daniels, this technique is failsafe and no leaks go undetected.
The last test is done by the owner, who drives the car and evaluates the soundtrack. This can then be adjusted by changing, adding or removing mufflers. Experienced customexhaust makers have a knack for getting the sound spot-on first time round.
Thanks to Powerflow Exhausts Bellville. For more info, call 021 930 7717 or visit powerflowexhausts.com/bellville