Lister Engine Forum

How to / DIY => Everything else => Topic started by: AdeV73 on August 25, 2009, 06:54:58 PM

Title: Silencing a CS
Post by: AdeV73 on August 25, 2009, 06:54:58 PM
As those who have read some of my previous gumph may recall, I have a couple of Aston Martin exhaust silencers (pattern parts, as it happens, not OEM). For ages, I've been running with one stuffed in the end of a 90-degree elbow. Today, as I'm bored, I welded the two silencers together, propped them on a bit of wood, & stuck it back in the elbow, thus:

(http://listerenginegallery.com/main.php?g2_view=core.DownloadItem&g2_itemId=3041&g2_serialNumber=2) (http://listerenginegallery.com/main.php?g2_itemId=3039) (http://listerenginegallery.com/main.php?g2_view=core.DownloadItem&g2_itemId=3044&g2_serialNumber=2) (http://listerenginegallery.com/main.php?g2_itemId=3042)

Each silencer is about 33" long, and approx 4" diameter; so with the tube in between & at each end there's about 6ft of exhaust pipe. Ignore the absolutely incorrect up-slope, this is a LONG way off being finished (I need a heatX in there as well).

Anyway, with that lashup in place, I cranked over the old girl... but she didn't seem to want to run. The flywheels went round, but I couldn't hear anything! It was spooky... and then I realised - she IS running, I just can't hear the exhaust any more!

Unfortunately, the whole thing is a bit unstable now, so I didn't dare walk away leaving the engine end unsupported, as it was bound to fall out... but even so, what an amazing difference.

So, I guess the moral of the story is: If you're having silencing difficulties, don't rule out pattern Aston Martin parts ;D  Any residual noise can be explained to your neighbours as a poorly DB6 that you're fixing up... ;)
Title: Re: Silencing a CS
Post by: jzeeff on August 26, 2009, 03:47:30 AM
So why are listers quieter than other diesels of similar HP?  RPM?  Size?  I'd like to understand the physics of it.