How to silence a muffler/exhaust temporarily?

[Tripsss]

Hey guys,

Im nearing the end of an engine conversion and the current exhaust on the car is 3" which will need to be replaced with something alot quieter and smaller. At the moment the car is not registered and I'm trying to find an alternative/temporary way to quieten the exhaust until i get it on the road.

My first thoughts would be to make up a gasket from galvanized sheet metal, drill a dozen holes in it and fit it after the cat. In theory this would work but will it melt?

Other thoughts would be great!

[GTSBoy]

Well, don't use galv. Use 3mm thick steel and you'll be fine. Make the holes equivalent area to about a 1" - 1.5" diameter single hole (or just put a single hole in it about 1" and if it is too quiet/slow just add a couple extra smaller ones) and you'll be sweet.

[Tripsss]

Yeah, so in theory that sound be fine as long as the hole isnt too restrictive.

Now all i need to do is find some 3mm steel...........

[GTSBoy]

Even 1.5 or 2mm will be better than galv.

[Jim]

I'd be more inclined to fill the rear muffler with stainless scouring pads from Bi-Lo and pull them out with a wire hook later.

[Tripsss]

Another interesting idea.....how long do you think they will last with the heat though? I dont fancy the idea of the roadworthy guy watching my car burn.

Also considering the muffler is welded to about 1.5m on exhaust fishing them out later would be near impossible.

[Sicarius123]

I'd be more inclined to fill the rear muffler with stainless scouring pads from Bi-Lo and pull them out with a wire hook later.
I know people who've been done for that just because the exhaust gasses have pushed the scouring pads out enough to be visible.

The restricter plate is a better idea.

[Tripper]

Chicken wire shoved up the exhaust.

[-rod-]

I had a custom made exhaust silencer made this afternoon. Fits so perfectly and they only charged me $20 for it. I would recommend the shop to you but its a bit far away. Fat Pipes at Kallangur.
Don't know if it would suit your situation though. I will upload pics over the weekend.

[curmudgeon]

I know this works cos I've done it before. Get a short piece of pipe about 1/2 the exhaust pipe diameter (or a bit bigger) and about 300mm or so long. Blank one end off and fit the other with a flange so that it can be sandwiched into a convenient spot eg. collector. Drill about 20 x 7 or 8mm holes along its length. Works well as a temporary quietener.

[Tripsss]

great suggestion.

I spent the weekend making a restrictor plate with 3m plate with 5 10mm holes drilled in it. Unfortuantly it didnt work as well as I hoped so i will drop into the exhaust shop and see if they can make one as you suggested curmudgeon.

[jzx83]

Or, use your restrictor plate to hold the scourer pads in place. Or better still, go to a hardware shop and get some steel wool from their abrasives section. It is also used for 'sanding' stuff in place of sandpaper. Would likely have more bulk than the scourer pads, and might just be cheaper to. The bit I am not too sure about is that there are different grades of steel wool - stretching the memory here but I think the finest was 000 then 00, 0 1 and maybe 2. I suspect that the go would be to start with the coarsest steel wool as that would be the least restrictive.

[Jim]

how about getting a temporary exhaust fitted with a stock muffler or 2. for all the fucking around you're doing it would take less time and cost the same.

[Tripsss]

I popped into the exhaust shop and he's making up a silencer as described above. Im a little worried with what he will come up with though...even with the sketch i gave him......time will tell.

Jim - I've considered that as an option but I would be throwing away more money to then get it redone to fit the car.

I'll post a pic once I get it.