Homemade S1 exhaust (pictured) now fitted!

[YeS1tis]

Some time ago I did some research to find out what the original S1 exhaust consisted of and then set about making one from raw materials. I've fitted it at last but it sounds awful due to resonance in the front section. I think some reinforcement will stop that - the outer casing is just too flexible - I can see it vibrating! Just need some more time and I'll finish it. The sound at the tailpipes is good. Total cost so far is about £60.

[Alan461]

Good effort!
Is it stainless?
What is inside in the way of baffles etc?

[YeS1tis]

The front section is just a perforated tube round both pipes, so it is really just an expansion chamber, and the second section has a saw-tooth profile of perforated sheet separating the top part from the bottom with E-glass in the top. There are no baffles and it should be very free-flowing. It is stainless steel which is prone to resonance when compared with mild steel and as the bottom of the front section is almost flat it makes a perfect 'soundboard'! I have some thicker strip which I will weld on as a sacrificial rubbing strip and see what that does to dampen it. So far all I've tried is putting my hands on it which definitely worked but for obvious reasons is not a practical solution!

[S2Mike]

Looking good, hope you can solve the resonance issues. I had a stainless system, made up and fitted which was £490 more than you have spent so far, looks like you are gonna make a good saving, plus the pride in having made it yourself.

[AutoAndy]

looks good....a thought just occurred, why did TVR go to the effort of adding the non-symmetrical bendy bits around the diff area - I can see they are not necessarily for clearance, but was it to "tune" the pipes? (possibly only on the later Catted ones)? Did your research give any clues?

[YeS1tis]

I really don't know why they were made that way. I have used the tailpipes that were part of the dreadful system fitted to my car when I got it. The standard system is effectively a 2 into 1 into 2 as the gases and sounds from both banks mix in the box(es), so having two different tailpipes seems unlikely to make much difference to the overall sound. Although it is 2-1-2, gas flow is not restricted through the box(es) which are very free-flowing indeed unlike the system fitted when I got the car where the 2 downpipes were flowing into a single 2" pipe and a baffled silencer before branching out to twin tailpipes.