Exhaust system

[cadwell]

Nearing the end of my S4 rebuild, I have just fitted a set of headers from Classic Lotus, presumably the Paul Matty ones. They are a beautiful piece of work and fit with plenty of clearance to the chassis.
Problem is what Centre pipe and silencer to use.
The Y piece exit is 42.5mm which fits the standard Centre pipe and transverse silencer. However the standard tailpipe is only 41.3mm dia which may or may not be adequate but cosmetically looks very small.
I prefer the transverse silencer as it can be fitted to be less obtrusive than the straight version.
Given that the gasses will be cooler at the tailpipe, all could be well with this set up.

As far as I can see the only alternative is the TTR 2” Centre pipe and silencer, which seems to be a bit over the top.
Being a larger diameter than the Y piece exit.

The engine will hopefully give around 130bhp so I am uncertain what to go for, or indeed

Does anyone have any thoughts on this?

Peter

[gjz30075]

You may not be able to fit a transverse system due to the shape of the undersides, ie, not having the
'cavity' for the silencer. There are short adapter exhaust pieces to accommodate different size mating pipes,
usually sold in the auto parts stores.

If you have to go 'straight through', can you fit one of these adapter pieces instead?

[cadwell]

Greg
I really don’t want to state the obvious but of course I have checked to see if the transverse silencer will fit.

Mine must be an early S4 with the rear moulding as an S3.

Peter

[Craven]

I used the standard centre pipe and changed dia at the input side of a TT big bore silencer, nice piece of kit.

[gjz30075]

Ah, ok. I wasn't sure when the changeover to the straight through configuration happened. Or if there's
a difference between a Federal car vs non.

I 'assume' then the car came from the factory with the transverse system so an adapter piece would
be the easiest way to go. I don't think a 2" pipe is over the top. Anything to help breathing on
modded engines is good.

[cadwell]

Craven,
That’s what I was thinking of doing.

You have confirmed that it fits ok, but what about the noise level, is that reasonable?

Peter

[Craven]

Hi
Yes fitted to the car I applied some stick on thermal heat shield to well, it’s a bit tight, its quite a bit noisier than standard sounds lovely on acceleration but I would say a bit much for long journeys my car S3 DHC

[cadwell]

Looks good Craven, I won’t be doing any long journeys so it might be the way to go.
Peter