Author Topic: EXHAUSTS  (Read 374 times)

Ian Fletcher

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EXHAUSTS
« on: 04 May 22, 04:50 pm »
I picked up an exhaust pipe for a GX1160/GX200 off Marketplace over the weekend, which I will be fitting to my CK.
I have ordered a Stage 1 engine from GX tuning, but this comes with a de-baffled OEM exhaust, however I want a system that will pass the exhaust out through the body-side.
I will need a silencer to go on the end of the pipe, but was concerned with allowable noise levels, and wondered what noise restrictions various venue have?

I came across the following figures for GX200's on the internet:

EXHAUST TYPE   db@idle    db@ 4,000 rpm
OEM                       85             98
debaffled OEM         87            100
Pipe & silencer        92.5         104.5
Open pipe              100.5       111

I was looking to fit a RLV high flow muffler or RLV high flow muffler with additional baffles as sold by GX Tuning, but would like to hear (no pun intended) what others have found successful?  I would also consider making my own absorbtion type silencer as the pipe and silencer at 104.5 seems quite loud to me.

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Tinworm

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Re: EXHAUSTS
« Reply #1 on: 04 May 22, 05:09 pm »
don't know if this is relevant, but makeshift machinegun silencers can be made with washers and plumbers' olives interspersed in a tube! The things you pick up...
I don't want to bore you all with the details, here. But if you are interested, have a look at my blog https://peteskart.blogspot.com/

-Peter

Ian Fletcher

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Re: EXHAUSTS
« Reply #2 on: 04 May 22, 05:56 pm »
Thanks Tinworm  ;D

I have some exhaust wadding leftovers in my workshop, so happy to make my own.  It looks to me as the table above shows the pipe and muffler to be a bit on the limit, but then again it does not say at what distance the noise was measured, so looking to see what others have done and how successful their systems are.

StefanN

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Re: EXHAUSTS
« Reply #3 on: 04 May 22, 07:25 pm »
To get the hot exhaust out of the engine bay, you could add a pipe to the outlet of the OEM exhaust.  I think perhaps Chris’ ERA has something like that.

Ian Fletcher

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Re: EXHAUSTS
« Reply #4 on: 04 May 22, 07:55 pm »
Thanks Stefan, I might resort to that if the pipe and silencer is too loud.

Adrian

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Re: EXHAUSTS
« Reply #5 on: 04 May 22, 08:15 pm »
You could route the exhaust out through some flexible pipe.
I did wonder about using some high temp Silcone tubing for that but I have no knowledge of this at all.
:>)
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Adrian

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Re: EXHAUSTS
« Reply #6 on: 04 May 22, 08:25 pm »
Rhys has something on exhaust noise limits. I know I was well over it. I've got a muffler from GX Tuning now. 
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Ian Fletcher

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Re: EXHAUSTS
« Reply #7 on: 04 May 22, 08:37 pm »
Thanks Adrian, I would be interested to know which silencer you bought and how effective it is  :)

RhysN

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Re: EXHAUSTS
« Reply #8 on: 05 May 22, 05:59 am »
For circuits that are relevant to MSUK (and many kart circuits are) the limit is supposed to be 95dBa measured at 2/3 throttle with the meter 1 metre away from the exhaust, directly behind it with no sound reflecting or absorbing surface nearby other than the road (and supposedly hard surface). I only learned this on Tuesday when I asked a scrutineer.
Some places get away with noise at the boundary of the property, I wasn't able to get a number for that, it's individual councils.
We must avoid torturing our brains with false problems, it occupies but it can annoy. In jest!

jim

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Re: EXHAUSTS
« Reply #9 on: 05 May 22, 06:13 am »
It's a good job we're not part of the money grabbing, fun destroying, Hypocritical embarrassment to humanity that is the MSUK. A standard exhaust is louder than 95db so luckily we can never be part of such a circus.
If you can drive round corners, you're not going fast enough.

Ian Fletcher

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Re: EXHAUSTS
« Reply #10 on: 05 May 22, 08:15 am »
Thanks for all the info, I think I might have a go at making my own silencer.

RhysN

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Re: EXHAUSTS
« Reply #11 on: 05 May 22, 09:04 am »
It's a good job we're not part of the money grabbing, fun destroying, Hypocritical embarrassment to humanity that is the MSUK. A standard exhaust is louder than 95db so luckily we can never be part of such a circus.
According to the label on mine it's 85dB.
While we may criticise MSUK (and I do most days at work) they do licence many of the venues!
We must avoid torturing our brains with false problems, it occupies but it can annoy. In jest!

StefanN

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Re: EXHAUSTS
« Reply #12 on: 05 May 22, 09:41 am »
Thanks for all the info, I think I might have a go at making my own silencer.
I did - mine's not super quiet but OK.  The input side from the engine goes into a perforated tube with the end closed, then expands into the can itself and then output is also via a perforated tube.

It's worth (re)reading the thread on this before.   There's some numbers at the end which might be useful.
http://www.cyclekartsgb.com/tech-forum/noise/msg2809/#msg2809

Ian Fletcher

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Re: EXHAUSTS
« Reply #13 on: 06 May 22, 07:04 pm »
Thanks guys, good to hear some personal experience, will definately be making my own now.

RhysN

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Re: EXHAUSTS
« Reply #14 on: 11 May 22, 10:59 am »
We must avoid torturing our brains with false problems, it occupies but it can annoy. In jest!