Silencer box suitable for 3.1/2 Derby specials?

David Cocking

My 1935 3.1/2 exhaust is getting a a little tired. Just the one box on it, basically just a small "cherry bomb", creates a great note but perhaps a little TOO loud. Any suggestions for suitable replacements?

Nicholas Simons · Posted: Mon May 11, 2020 8:24 am Post subject:

Talk to Servicentre

http://www.rrexhausts.co.uk/

http://www.rrexhausts.co.uk/3_4_litre.htm

David Cocking · Posted: Mon May 18, 2020 8:46 am Post subject:

Thank you Nicholas, they certainly appear to be a good option for a standard Derby exhaust. As my exhaust is already far from standard, as an option I'm also wondering if any of the MkVI or Derby Special builders have used other non-marque exhaust specialists with good results for a custom design. Possibly also at a significantly lower cost than the Bentley specialists?

John Murch · Posted: Mon May 18, 2020 2:59 pm Post subject:

Torque Technique
Address:The Avenue Postcode/City:SP2 0BT Wilton County:Wiltshire England
Phone: 01722 744747

I have heard good reports of the above.

David Cocking · Posted: Mon May 18, 2020 7:23 pm Post subject:

Many thanks John. They're just up the road, will give them a bell.

DavidThompson · Posted: Sat May 23, 2020 1:23 pm Post subject:

Hello David
Merlin Motorsport at Castle Combe have lots of exhaust bits, as well as silencers.
What diameter do you need?
I have a few silencers loitering in my garage that might fit.

David Cocking · Posted: Thu May 28, 2020 7:56 pm Post subject:

Thanks all. It looks like Torque Technique have unfortunately closed down - number unrecognised and website gone. Thanks for the offer of bits David, although I'm not really sure (I have no idea!) what I actually need. I was hoping to find some guru who could design around the notes I'm looking for while mooching, while cruising and while giving it some. Through another friend I may have found another local outfit that know what they're doing - I'll give Merlin and them a call and will let you know how I get on...

John Murch · Posted: Fri May 29, 2020 5:17 am Post subject:

Another suggestion is:
Dave Tyler t/as Len Hartley Developments, Unit 2, Wootton Fields Farm, Marlborough Road, Wootton Bassett, Swindon, Wilts. SN4 7SA

01793 849430

He made up a Silencer for the 3ltr a year or so ago and does one off pipework.

I don’t think he has a website.

David Cocking · Posted: Sun May 31, 2020 7:52 pm Post subject:

Thank you John, sounds like another good lead to follow.

David Cocking · Posted: Mon Jun 29, 2020 7:48 pm Post subject:

OK, here's the outcome - probably not one for the purists! I was about to follow up on the above leads that had kindly been suggested when I mentioned the issue to a petrolhead pal of mine over a (socially distant) cuppa one sunny afternoon. Ah! says he, you need more of a growl than the current bark eh? - what you need is a wodge of scrunched up wire mesh inside the pipe, as far back as you can get it. Disturbs the uniform airflow that can lead to the annoying resonance as it exits the pipe. He has done this before apparently, retaining the mesh with a simple split pin through a couple of small holes drilled across the pipe diameter. So, I rummaged through my odds and sods and came across a roll of steel wool which I felt may achieve the same thing, I simply wrapped the wool with a bit of wire to keep it together, lightly packed, and tied it inside the fishtail on my exhaust with a bit more wire. Bingo! Gone is the harsh bark, replaced by a much more agreeable growl. No more need for earplugs on long runs. Time taken - a few minutes, total cost - nowt! Not sure how long it will last but I think the concept is proven and replacement will be a doddle. Performance? It may just be that my grin is even bigger but I have been out a fair bit since and, if anything, it feels to be going even more like the clappers than it did before!