How to design and build a performance exhaust


Staff member
Deal, Kent UK
A3 1.4 TFSI 150 COD
Does anyone have experience of designing and building performance exhausts?

Do you have any tips to pass on to someone looking to improve the cars performance by making a custom exhaust? He'll probably get a pro in to build it but any pointers about materials, bends, joins and other tech info would be greatly appreciated.
n/a engines: never go bigger that an extra half inch dia piping.
turbo engines: go as big as you like.. (6inch pipe isnt practicle though)
keep the line as easy flow as possible, as in nice easy bends, no sharp bends and defo no miters!!!
dont straight pipe a n/a engine, shel be tara sore on petrol/diesel!
use a sports cat, itl keep the test men of your back and they dont hinder performance.
slip joints are a quick way of jointing the line together plus they leave you with some room for error.
use flanges on both sides of boxes so ur only replacing the box not the pipe aswell.
finally, go for a full stainless steel line. itl not cost alot more than the standard line ( if it does they're charging you to much). itl add value to your car in regards a lifetime guarentee on the exhaust.
Mandrel bent all the way from the manifold in 3-4 inch for turbo and surprisingly 3 inch is what the NA FN2 series race cars have fitted. No baffled mufflers only straight thru is also better.

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