Perforated tube

topcatcustom · Post by **topcatcustom** » Tue Dec 01, 2009 10:37 pm

I found that Demon Tweeks stock 1m lengths od perforated tube, if I bought a length and used it for 2 short mufflers would I be ok using say 5" OD cans and would stainless steel wool be the best option for packing? The cheapest decent mufflers I have found off the shelf are about £50 each, and would prefer straight thoughs which seem to be more expensive even though they must be easier to make!!!

Alley Kat · Post by **Alley Kat** » Tue Dec 01, 2009 10:43 pm

Here's another place that does exh bits TC, http://www.pjengineering.co.uk/products.asp?cat=11

Stainless steel wool round the tube, then glass packing. Steel apparently stops the fibreglass being blown out so quick. I made bike ones without it and after a year it was noticeablya bit louder - praps steel wool would've helped... only found out the idea later though...

topcatcustom · Post by **topcatcustom** » Wed Dec 02, 2009 7:53 am

Cheers, though when packing from one end is it really possible to pack 2 layers like that?

Alley Kat · Post by **Alley Kat** » Wed Dec 02, 2009 8:36 am

Could do it at some stage before welding bits makes it hard to get in, doesn't have to go right end to end I guess. Wire a layer of s/steel around the perf tube as a sort of liner just to give the glass wool an easier life. Like I say, not done it, heard of the idea too late... but seems sound theory (doh! no pun intended)

Ian Anderson · Post by **Ian Anderson** » Wed Dec 02, 2009 9:07 am

Instead of a straight through put a bend in the perf tube so it snakes through the silencer - at low revs / throttle it will help deaden the sound but once hard on it still allows a fairly clear passage

Ian

Alley Kat · Post by **Alley Kat** » Wed Dec 02, 2009 9:17 am

Where did you get bendy perf tube? Not seen it listed anywhere.

topcatcustom · Post by **topcatcustom** » Wed Dec 02, 2009 10:24 am

You could always try the sand filling before bending techique

Alley Kat · Post by **Alley Kat** » Wed Dec 02, 2009 10:32 am

tbh can't see the point, normal running's fine, its when giving it some rice the farces of law & order might take an interest. e.g. my bike had 6" of "canister" with wool, not tightly packed. At normal riding it was absolutely fine. But give it some, twas pretty loud.
Home made perf tube, lot of drilling! (but damn cheap!)
Victor was the same, had cheap Turbo mufflers on, nice and quiet in normal drive but stomp = much noise.

topcatcustom · Post by **topcatcustom** » Wed Dec 02, 2009 10:57 am

Were the turbo mufflers straight through or S type ones? I did briefly consider drilling them myself.... I do have some perforated sheet in the rack but cant roll it tightly very well. Where is best to get the fibreglass packing and stainless wire wool from? I'm also assuming that the outer diameter being bigger means to an extent that it would be quieter? 2 1/2" straight through would want a good 5" outer dia? Got loads of space for a big diameter can, may even go 6"...

Alley Kat · Post by **Alley Kat** » Wed Dec 02, 2009 11:40 am

The turbo muff's were straight-through if I remember right - 99% sure though. No idea about stainless wool, my glass packing came from NF Auto but there might be other/cheaper places.
Reckon it's a bit of a guess on packing and sizing, when i did the bike I figured it'll cost £0 as everything was there, so if it fails no loss. Or cut open and repack.
Was about to mod some more bike ones recently, was going to tack them together and road trial before final weld. Just in case they were too loud, or too quiet

and needed a change in amount of wool packed in.

Ian Anderson · Post by **Ian Anderson** » Wed Dec 02, 2009 1:11 pm

Melin Motorsport for the Glass packing and steel wool
http://www.merlinmotorsport.co.uk/EXHAU ... index.html

Ian

Post by **katanaman** » Wed Dec 02, 2009 1:42 pm

Last time I tried to use steel wool it glowed bright red and caught fire. No harm was done and it looked spectacular but it was gone after that. Course it all depends how close you are to the engine whether it will do that or not. Mine was a bike so pretty close.

topcatcustom · Post by **topcatcustom** » Wed Dec 02, 2009 10:36 pm

Might stick some copper nails in for a green flame!!!

Not sure about making them up now, 2 sheets of fibreglass and a roll of wire wool, with the bit of perf tube will set me back about £90-£100, I can get some turbo mufflers from real steel for just over half that! Is a real pity but I guess buying materials like that there are just too many middle men involved!

Alley Kat · Post by **Alley Kat** » Wed Dec 02, 2009 10:51 pm

Reckon gets bits cheap as poss - offcuts of tube from a local place maybe? + drill it. Sniffed the bay of e, there's some much cheaper s/s wool there. Could maybe use 'glass roof insulation type gear, it's only fibreglass (I guess?). Mine cost me about a tenner or so for the fibreglass, rest was lying around.
But turbos or whatever are less faff... and pretty cheap.
Interesting(ish) that the Merlin page says the s/s not needed for fibreglass, but is for the other gear they have.

topcatcustom · Post by **topcatcustom** » Thu Dec 03, 2009 12:43 pm

Yea the stainless wire wool is about half the price on

bay, do you have to use fibreglass too or would just wool be ok? Could probably get a better price on a bigger pile of wool, and maybe I will drill my own tubes- then I can drill a section of a length which means less welding and joints involved, what size holes did you use and what sort of spacing?