Skirrow
|
| posted on 13/9/16 at 10:25 AM |
|
|
Cheapest way to silence
My zetec installation into a Robin Hood 2B sounds far too noisy. I have a track day booked in Nov so need to address the exhaust noise before then.
I don't really want to spend a lot but I want it as quiet as I can reasonably get it without effecting performance if possible.
I especially don't mind if the silencer is big or ugly.
Should I just buy the fattest and longest cheapo silencer I can from eBay or will that not do the job?
|
|
|
|
|
coozer
|
| posted on 13/9/16 at 10:28 AM |
|
|
Is it just the exhaust? What about induction, that can raise the db level a lot!
1972 V8 Jago
1980 Z750
|
|
|
MikeR
|
| posted on 13/9/16 at 10:55 AM |
|
|
can't resist - turn off the engine 
Has the silencer ever been repacked? If not that's a starting point. There are also DB killers that fit up the exhaust - although you'll
need someone else to say how well they last on a track day. Can you rotate the exhaust to point down so the road takes some of the noise?
|
|
|
Skirrow
|
| posted on 13/9/16 at 11:04 AM |
|
|
It's been off the road in bits for a couple of years so now its running I won't be turning the engine off at any point soon!
Not thought about induction to be honest, exhaust is definitely loud though, if I can shut that up I'll look at induction if it's still
too loud.
Haven't repacked the exhaust so i'll have a look at that. I have 2 silencers, one carbon fibre thing that looks like a bike exhaust and
one, equally small, stainless one. Tried them both (not at the same time before anyone asks). Both sound really loud, loud enough for me to know just
by listening that they will be too loud for the track day.
Both point down-ish, but I'll try that. Might save another couple of dB
Not keen on the idea of a dB killer tbh. Not sure why, just seems like a bit of a bodge (although the rest of the car is one big bodge so don't
know why that's worrying me)
[Edited on 13/9/16 by Skirrow]
|
|
|
benchmark51
|
| posted on 13/9/16 at 11:11 AM |
|
|
On my locost I have 6 inch diameter silencer, 22 inches long, 2 inch diameter in and out and to be honest I'm not sure it would pass on a track
day test either. So I thought I would fit a short 45 degree pipe on the end with a second silencer which would go over the rear wheel arch and make a
bracket to attach it to the roll-bar. Should do the trick and be easy to fit and remove after the track day.
|
|
|
Skirrow
|
| posted on 13/9/16 at 11:49 AM |
|
|
Cheers, that's not a bad idea at all considering I already have the 2 silencers!
|
|
|
ian locostzx9rc2
|
| posted on 13/9/16 at 02:42 PM |
|
|
Cheapest and very effective if you can do it is a second silencer and better if it comes out the back for drive by as people spend a lot of money on
large repackable silencers on there cars .
|
|
|
HowardB
|
| posted on 13/9/16 at 04:05 PM |
|
|
Saw a neat track day solution. 2 silencers side by side.. into 1, 180 bend at the end and then the next silencer facing forward. Exit at the front.
Maybe that is an option as you have 2 cans.
Hth
Howard
Fisher Fury was 2000 Zetec - now a 1600 (it Lives again and goes zoom)
|
|
|
Skirrow
|
| posted on 13/9/16 at 04:10 PM |
|
|
Cheers, I'll see what bits of tubing I have and see what I can come up with
|
|
|
Dusty
|
| posted on 13/9/16 at 10:50 PM |
|
|
I found a great effect by putting a very small expansion chamber in front of the silencer. Made from an old custom chrome 5inch dia silencer but cut
and rewelded to be about 10 inches long.
[img]
 
Description
[/img]
|
|
|
ElmrPhD
|
| posted on 14/9/16 at 11:51 AM |
|
|
Dusty,
Any idea how much the heat wrap helps with dB reduction?
|
|
|
The Black Flash
|
| posted on 21/9/16 at 09:47 AM |
|
|
Heat wrap on the exhaust will increase noise, not decrease it. It causes the gas to hold heat for longer so it's got more energy when it
reaches the end of the pipe.
[Edited on 21/9/16 by The Black Flash]
|
|
|
MikeR
|
| posted on 21/9/16 at 11:23 AM |
|
|
I did somewhere a lot of research into exhausts and found the calculation for the expansion chamber.
New computer, 2 babies and a house move mean i've got no chance of finding it but i got it from googling ..... so it should be there.
If i recall its something like the size of two cylinders uncompressed volume * magic number + the inside leg measurement & ideally wants to be at
the point in the exhaust you want secondary reflections to maximise HP .... or you could just fit something and see what happens the idea is the
gasses suddenly slow down as the expand to fill the volume. Slower gasses = less noise.
Procomp did make a comment a long time ago about their exhausts that Stainless / Ali was louder than Stainless / Ali based on their experience.
(i also lost a lot of memory when the babies turned up due to sleep deprivation and neither the sleep or memory have returned)
|
|
|
