I need to queiten down my 7, for my early morning departures

What can i use ?
it needs to be fairly easily removable and not to bulky

Steve

Nothing will be more effective than a simple change of silencer. There is something called a decibel killer available on eBay but it would depend on your existing silencer. What setup have you got now?

Im using a custom chrome silencer, and its never been quiet
I do not want to change that !!

its the first pic in my photo archive

http://locostbuilders.co.uk/photos.php?action=showphoto&photo=a59976-Mullaney.jpg

Where were you thinking of attaching the additional silencer? Upstream or downstream of the existing one?

There's not much room downstream (I estimate from the photo), and an upstream add on, spliced in, probably won't be something you can quickly take off, e.g. when you reach a safe distance from the neighbours - if that's what you meant (?).

Otherwise perhaps you're limited to stuffing the aforementioned decibel killer up the tailpipe.

Personally, if I really wanted to keep the existing one, I'd add a permanent other one upstream and the get the engine retuned to match it. Anything temporary will stuff up the state of tune.

Would a permant fitted reducer affect power output ?

If i was to put a large washer in the end of the tailpipe, would that reduce the noise?
i have a couple of idea's on how to keep it there

If your silencer is re packable then my best advice would be to buy some Acousta-fil - brilliant stuff. I bought mine from one of the shows and it lasts a hell of a lot longer than the normal fibreglass variant - it also gives a mellow tone.

The pic shows a very small silencer and I'm afraid this is a classic case where size really does matter. A small silencer will always be loud and your suggestion of stuffing a washer in your tail pipe will only rob power and probably make it sound rather 'farty' .... but still loud

[Edited on 14-1-11 by RazMan]

I made a short one to replace the link pipe from the manifold to the main silencer. It was 5" long and reduced the noise by 5dB. Perfect for track days too.

From the pic your silencer does look quite small. As a comparison mine was 22" (plus the end caps) long and 6" diameter. Maybe even a bit over kill but it certainly worked and didn't restrict power on my supercharged 1.6, how does that compair to yours? Does add weight though unless you get it made in something other than stainles steel.

[Edited on 15-1-11 by bimbleuk]

Just a thought...

If the custom chrome silencer is an absorptive type, is there much (or any) wadding left in it?
How often do you refill it?

In my experience running a modified crossflow on carbs gives the silencer wadding a hard time. For example if the car is in daily use I refill my silencer every three months. Slight out of tune-ness causes erosion on an exponential curve, slow at first quicker as the erosion sets in and the change in the exhaust affects the state of tune. Major richness or leanness will see away even the best packed silencer fill very quickly.

I don't know about your engine of course but mine is a modified, sensitive, stressed-out creature, great when in tune, but hardly ever completely on-song no matter how well set up. It wanders in and out of tune with the weather and the erosion of the silencer wadding.

In fact unless I take extreme care filling the silencer the engine holds tune best once all the silencer material has gone! Just a bit anti-social A good baffled silencer would be great.



Probably not much help ... D

Sounds like you need Acousta-fil too

Thanks everyone

My exhaust does need repacking fairly often, and razmans link, looks promising

Steve

Yes, Razman, I agree with you - your link looks very interesting and I think I'll give them a call.

Thanks, I hadn't heard of that stuff before.


regards
D

In fact I won't call them - I can just buy it on ebay!

Don't trust the calculator they link to that tells you how much to buy, you'll end up with at least twice as much as you need. Still, at least I've got enough to re-pack it next time

You could install a turbo on your engine. The turbo is supposed to absorb some of the noise, also by the time the curtains twitch you will be long gone!