Exhaust noise

[antelope]

My '91 SE makes an outrageous noise when accelerating hard under boost. It sounds like a really loud motorbike, through a megaphone. The car was modified before I bought it, so I'm not sure what exhaust is on it, but it's a 3 inch internal diameter at the end, and is one long, straight pipe from front to back, with a small box at the back. I was told it was a Pico when I bought the car...

Trouble is, it's embarassingly loud. I mean really..it would make a 17 year old chav blush. What's the best way of quietening it, without sacrificing performance [I presume the turbo has been ported otherwise the engine would keep cutting out - is this right?]. Do I simply replace the small box with a larger one?

[Monty]

Sounds like you have a Peco, on the tail pipe you have the oval pipe is there another round pipe inside? This was a known problem and IIRC the inner pipe needs cutting back as it was acting like a whistle. I`m sure there is a thread on here somewhere about this problem.

[steve matthews]

Antelope, I have a Peco or (Cybox) and agree it is noisy. Check Monty's response
first. Cybox (on the internet) offer an additional baffle that can be incorporated. If you have
emissions concerns putting back the main cat will baffle some with little 6 to 10 H.P.
reduction.
In my case the car is not a daily driver. I autocross, track and show with the occasional
wine and brew pub stop.
Steve -w- Peco (Cybox) exhaust with Fed. Down Pipe

[antelope]

Monty, the tail pipe [post silencer] is round, with a 75mm internal diameter at the point of exhaust gas exit. The lone silencer is about a foot long.

Reading on here, it looks as though I should replace it with a Piper, but that wold be a big cash hit for me. C'est la vie I suppose.

[Monty]

Monty, the tail pipe [post silencer] is round, with a 75mm internal diameter at the point of exhaust gas exit. The lone silencer is about a foot long.

Reading on here, it looks as though I should replace it with a Piper, but that wold be a big cash hit for me. C'est la vie I suppose.

does your silencer look like this?



When buying there was a choice, Oval tip on it`s own or the oval with the inner round tip, but the inner pipe caused a whistling/screammer sound. The inner pipe needs to be cut back.

Here`s the thread where the Peco started off
viewtopic.php?f=36&t=6510&p=73824&hilit=peco#p73824

[HJ2]

circumsizing the inner pipe gets rid of the mother-in law screech
I'm afraid on a dB level it won't get you lower though...

[antelope]

Hi Monty. No, it looks like this:

RIMG0010s.gif

Sorry, don't know how to get image to appear in body of message.

By the way, it's less of a whistle/scream than a guttural howl.

[rip]

I've a suspicion that is a Paul Matty system. I know Nobby had one although I believe he never fitted it. There must be more Elans out there with them fitted?

[antelope]

Paul Matty is a possibility. I bought the car from a guy in Worcestershire, where Paul Matty are based. Although he bought it from someone who'd had extensive work done on it by South West Lotus in Devon. I don't know who had the exhaust fitted.

[Monty]

Yep, not a Peco

You sure you haven`t got a Dump valve or maybe the sound is the turbo fluttering

[antelope]

Honest answer is that I don't know. I have much to learn, but without someone who knows what they're talking about, examining the car, it's rather hard to work things out. I know that the turbo was 'reconditioned' by SW Lotus as part of a major refurb..and I have reason to believe that it was ported [which I understand simply to mean that the 'exit' is enlarged]..but beyond that, I don't know. The exhaust burbles nicely when driving normally, but overtaking is something truly to be heard..imagine a deep toned 750cc motorbike at full blast, and double it.

What effect would a dump valve have?

The car doers backfire frequently on overun, if that indicates anything. [great fun actually..crackling and backfiring]

Perhaps I should pay Paul Matty a visit...[they're so expensive though]

[Monty]

Dump valve is a whooshhhhh sound so it`s not that, maybe there`s a leak in the exhaust or it could be just the way the exhaust is

You need someone close to you to take out for a spin and give advice, maybe Paul Matty could do that for free

Sorry i can`t be off more help

[antelope]

Thanks to all for help. I'll drive over to Matty this week. It is just a noisy exhaust. If it's theirs, they'll know how to quieten it.

[Gazza]

Looks very similar to a Janspeed exhaust I considered fitting to mine. Like the one fitted to an S2 not far from me.

Gazza

[rip]

The car doers backfire frequently on overun, if that indicates anything. [great fun actually..crackling and backfiring]

POSSIBLY that your timing needs advancing. Mine was terrible for popping until I experimented with my timing. Now I have advanced it a little I have much more power, less soot, hardly any popping & it the engine burbles to life rather than spluttering when I start it.

[antelope]

OK Rip. I've emailed admin to get a password in order to download the manual, so that I can attend to this. Thanks for the tip.

[Songbird]

Looks very similar to a Janspeed exhaust

[antelope]

Am I right in thinking that if it was a Janspeed, it would have the name embossed on it? Because I don't think it has...unless it's on top of the silencer and I can't see it.

[Gazza]

Don't think they do.

[DeeAitch]

Looks a bit like the 'sports' exhaust I bought from PM a few years ago - it was a 'Miltek' (Spelin?) and was crazy loud. Even the hairy bikers at work thought I'd lost it when it was first put on the car.
Didn't stay on for more than 1 hour (I did keep the front & centre tubes tho')
I seem to remember a Miltek logo on it somewhere - maybe even a welded on tag? For sure the centre has it.