Help on exhausts

[hough]

Hi can anyone help, i am going to make my own exhaust system, but welding and fabricating the box is not a problem,

basically im amking my box out of 316 stainless, but can some one please tell me if the width of the box, the dia of the inlet / outlet tube makes any difference as i know that the longer the box the quieter it becomes....

please help

 

[lutonmatt]

think its all to do with the amount of stuffing (sound deading) you have in it and the way it flows around it
compaired to size

 

[hough]

so the dia or width of the box doesnt matter???

 

[HDi fun]

so the dia or width of the box doesnt matter???

Both are part relevant but the most important thing is gas flow.

 

[old-git]

One hell of a lot of design and experimentation has gone into the manufacture of modern performance exhaust boxes, so knocking one up on the bench is a tad hit and miss, in my opinion.

Good stainless boxes are not too expensive so I would suggest that you make the pipework but buy a box based on your power and noise requirements.

 

[hough]

hey but what is the fun in buying an off the shelf box, when you can make the box yourself and tune it yourself and how many companys can you name that make the box all out of 316 stainless.... and also i want to mirror polish my box

 

[old-git]

Agreed, much more fun to make it yourself, as long as you are not to bothered about maximising performance. If you have gas flow rigs etc, then fine, otherwise it will be very hit and miss. I have left this job to the professionals on my car.

 

[hough]

fair point i know im no expert in this field, but iv been looking into exhaust designs for a bit now, and having seen the in side of a few branded exhaust boxes some cheap and some not so cheap i thought id give it a go? im a tig welder by trade any way and used to build exhausts for tractors and lorries.... and with out beeing horrible to some of these exhaust companies iv known people that have used these places and they are not that great to say the least!!!

 

[old-git]

It sounds like you will have a better idea on what to do than some of the exhaust suppliers out there.

I am coming from the extreme end (IMO) of the performance envelope where exhaust design is critical, so I accept that I am being a little too 'high and mighty' wth regard to design

It's a shame you are so far away from Essex as another good TIG welder would be good to cultivate.

Let us see the fruits of your labour, especially the internal design. Are you thinking baffles or packing? If packing, I assume that you will make it re-fillable?

 

[hough]

sorry if i seem off, the only reason im making my own is the fact some of the boxes iv seen are poorly made, i am going for a refillable design like the one you get on motor bikes not baffles so i can go for a straight thought design, i will show you take some pictures and show you them when its finished if you like

 

[old-git]

You don't seem off to me.

As long as you get the pipe diameter correct, straight through systems are easier to make and less likely to cause back pressure. The tricks are getting the right number and size of holes along with the correct density of the packing material.

Looking forward to seeing the finished article.

 

[hough]

we i hope it works, as for the spec of the rear box i was going for 67mm in 71mm out with 71mm tail pipe, and the main box is going to be 360mm long 150mm dia but the tube in and out will be off set by 40mm off centre with 6mm perforated tube inside about 300mm long.... will take some pictures and show you what im doing

 

[T9 man]

we i hope it works, as for the spec of the rear box i was going for 67mm in 71mm out with 71mm tail pipe, and the main box is going to be 360mm long 150mm dia but the tube in and out will be off set by 40mm off centre with 6mm perforated tube inside about 300mm long.... will take some pictures and show you what im doing

Will look forward to seeing those pictures as well! I have a nice system made by Profusion near Heathrow but it's still not quite right.
So in February I shall be going to see the legendary Matt @ Simpson Race Exhausts

and have a special system made! they even make the boxes/mufflers to create the sound you want :amazed:

 

[jarrus]

Seeing the results will be interresting,

I have a system made by MIJ and I'm quite happy with it,
But truth be told there are a couple of things I don't like about it...

 

[hough]

jarrus - what is it that you dont like about the system????

 

[jarrus]

Some of the bends make the pipe diameter smaller, I mean not by much but it is anoying, and a section of the pipe hangs a little too low for my liking, I haven't put my new suspension on the car but when I do I think it might be a bit close to all the speed humps around here, a part from that it's a nice piece of kit, it sounds good (well as good as it can on my car) and the style of the tail pipe really suits the car, and the performance gain can be felt.

I think I would take it to custom chrome in burton (they make cherry bomb exhausts) if/when I need a larger diameter pipe.