Motorcycle Silencer for S4?

[jbeach]

Dear All,

In an effort to retain my S4's original silencer configuration, I purchased and installed a stainless dual "pea shooter" silencer from RDent. It's beautifully fabricated and sounds good, but, to be honest, is simply too loud for me, as least for my current usage.

So I want to replace my silencer with something a bit quieter (setting the SS unit aside for future use).

People say there's not solution because no space for intermediate silencer and insufficient space under S4 boot to install larger rear silencer. In essence, "this is about the lowest volume level you can accomplish, given the physical constraints."

Even so, I find myself driving around town seeing powerful sport bikes with mufflers about the same size as my SS pea shooter, cruising along in almost complete silence. These engines are very efficient, HP-per-liter, so I assume their muffler systems are similarly efficient.

So I'm asking you all: 1) Has anyone adapted a motorcycle silencer to their Elan and, if so, what type of silencer, how did you installed, other considerations, etc.? 2) Can you think of any reason not to explore this alternative and does anyone have any advice on how to proceed?

Very best,

John

[gus]

I can hear the rice rockets over a mile away on acceleration

putting around town, sure they are quiet.

Any straight thru muffler is going to be fairly loud.

My +2 came with a long bmw part, I think 2002 in the intermediate area, but I replaced it years ago with a full stainless exhaust. It fit but would scrape on occasion

[jbeach]

Thanks Gus,

Yeah, I've heard those rice rockets wailing away into the night. But I've also heard (and ridden) motorcycles with relatively high-performance engines - and silencers not significantly larger than mine - that are significantly quieter than mine, even at WOT. I don't know anything about muffler technology, but I'm assuming these are not straight thru mufflers, for what it's worth.

Best,

John

[Chancer]

I used motorcycle engine in 7's with the standard side exit exhaust and they were really really noisy, ones with bike silencers were even noisier.

Then I made up my own exhaust manifold for another project 7 by cutting up and rewelding the headers from a couple of the donor bike motors, I found that Inside the small expansion chambers where the two branches joined into one and also IIRC in the part where they siamesed into the single pipe there was a steel mesh material held into place by a welded plate of expanded metal,

Clearly a lot of design had gone into these acoustic dampers as their effect was to reduce the initial high frequencies, using the same silencers these engine were much much quieter and didnt blow the stuffing out of the silencer like the others did.

So my advice is to take the whole bike exhaust system, cut it apart and use the relevant pi?ces.

[elansprint]

Not had them on an Elan but have a pair on a 2002 TVR Tuscan they are just nice but the Tuscan has a transverse box the are fitted to and Cats of course
Ian

[elj221c]

I found that Inside the small expansion chambers where the two branches joined into one and also IIRC in the part where they siamesed into the single pipe there was a steel mesh material held into place by a welded plate of expanded metal,

I expect that was the catalytic converter that modern bikes have to have now.

We don't have to have one on our Elans, thank goodness!

[l10tus]

John,

I completely agree with you, my Sprint is louder than the farm tractors running past my neibourhood, both of which are totally unacceptable in today's society.

You may well of read my recent posts on 'Gearing', where I noted that the screaming high revs, coupled with the noise of the exhaust are just not good.

I too, would like to reduce the noise that my OEM (but Stainless Steel ) system produces.

At least then, I may be able to not hear my torturing of the engine because the overall gear ratio is too low.

There must be someone who can make a 'quiet' silencer, that's more socially acceptable in today's market ?

Regards,

Phil

[jbeach]

Phil,

You have summarized the entire issue very eloquently. It is the combination of revs and sound level. Plus, living in a neighborhood and, by necessity, driving in relatively populated areas. And, most importantly, wanting to really drive this wonderful car! If I wanted to putter around shifting at 2,500 rpms, this would not be a problem. But, then, why in the world would I go to the glorious trouble of owning an Elan?

Given current technology, there has to be a answer. I'm going to continue pursuing the motorcycle silencer route. If and when I make any progress, I'll post my results.

Best,

John

[elj221c]

Putting the motorcycle silencer to one side, it seems to be a fact that a stainless system will be noisier than the equivalent mild steel one.

It has been (is?) a problem at track days in the UK to meet local noise restrictions.

I always thought the standard system in steel I had on the S2 to be just right.

Characterful but not loud in the car and not offensive to outsiders.

Much quieter than the 'Rice Rockets'!

Haven't heard that terminology in aeons....

[Chancer]

The things were acoustic/harmonic dampers not a catastrophic convertor as the engine was a carburetted one, I alos did a couple of injection cars but never got my hands on any OE injected headers or the collector, the injected cars without the widgets were even noisier still.

I suspect that there were hours and hours of dyno time perfecting these tiny widgets because they made a tremendous difference to the sound levels.

[saildrive2001]

No doubt in my mind that the current stainless system I have on my S4 is much louder than the original mild steel one. If my radio, (which is the original MW, LW unit) could get many stations here in Canada, I would not be able to hear it with the current exhaust. I remember being able to hear it clearly years ago when I had the mild steel original system. I must say that it sounds great, but is a little tiresome after a period of time & quite loud with the top up.

[holywood3645]

I have a sprint SS back box I will swap you for the twin pipe S4. VGC
James

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