Anyone on here any good at welding stainless?

Originally Posted by ThEGr33k

I think the beowulf cans are a different shape to the blue flames. Could be worth asking at blue flame though. Might be a bitch slim chance, do you know of any dual output exhaust system with 70mm output to silencer?

dont you mean input? as the gasses are flowing in to the silencer

[yorkie_chris]

Originally Posted by ThEGr33k

I think the beowulf cans are a different shape to the blue flames. Could be worth asking at blue flame though. Might be a bitch slim chance, do you know of any dual output exhaust system with 70mm output to silencer?

They are, but they weld these endcaps up all the time so worth asking them. Guy there is proper sound, if he could do it and you took the bits in to him it would probably be a very reasonable price.

Where abouts are Beowulf based then? Got any contacts etc etc.

Originally Posted by barwel1992

dont you mean input? as the gasses are flowing in to the silencer

Kinda, I was referring to out of the system into the end can, asin the end can not being classed as part of the system



Other question is, where could I get some stainless that will be the right diameter? Is there any kinda shop I could pop to with my back section of system and say gimme something to fit this?

[yorkie_chris]

No, problem you will have buying stuff like that is you need to buy lengths of it. You need to talk to a stainless shop who deals with it all time and will have some around. General stockists will want you to buy lots.

There are also people who sell parts for making your own exhaust systems, have a google around. They will sell you your length of perf pipe by the meter

Let me know OD and thickness of your pipe, I will ask around.
What exactly do you need? Part to make flange with? Pipe to slip over link pipe? Be specific and detailed.

You could try ebay, lots of offcuts and random stuff on there.

Beowulf are near Halifax just up road from me.

Nice one Chris.

Right the plan!

The previous owner of the exhaust system I have took out the core of the exhaust cans which acted as a reverse cone mega, taking the 70mm into the muffler down to 45mm at the back of the muffler, he replaced it with a 45mm core pretty much all the way through... So I have the old core hanging around which I was planning to use to narrow down to the dual output on the blue flames.

So id take the back or maybe both ends of the blue flames off, take off the rear core (mesh things) and place the cone reducing one from origional system, then cutting out the back plate out and welding a pipe to connect over the 70mm exhaust output... Ill measure and see exactly what bore and thickness the pipe is and let you know.

As a rough picture of old (top) and what I want to do (bottom) look at my paint picture



I found this after a quick search. http://cgi.ebay.co.uk/2.75%22,-70mm-...b58085fe81304c

[yorkie_chris]

What's point of spending all that time and effort to produce a bottleneck in system? You any idea what that will do to the harmonics of it?

That is expensive on ebay, shop around, maybe you can find a full length for same price.

[andrewsmith]

Originally Posted by yorkie_chris

What's point of spending all that time and effort to produce a bottleneck in system? You any idea what that will do to the harmonics of it?

wet f4rt in a bathtub?

[timwilky]

that drawing looks horrendous. You are allowing the gases to expand, then compressing them. I never did any acoustic engineering, But I thought the idea was to allow the gas to expand through controlled flow gradually lowering pressures through a smooth a flow as possible. Yet to muffle the noise by restricting the rate at which expansion took place.

But then again I could be talking poo

[yorkie_chris]

Loads more going on than that, there will be a reflected pressure wave which needs to be right to allow proper cylinder scavenging.

I have no idea what that will do! Personally I'd try make it one smooth bore @70mm right through, then dyno it and see what happened!

[timwilky]

The scavenging requirement I understand well. but to me that was principally an engine design criteria dictated by valve timing and performance as opposed to using back pressure to reduce excess savaging. therefore a balance between performance and efficiency.

I know my favourite CFD system has an exhaust modelling function. But as not appropriate to our product. (Power stations) we do not have licences for the automotive modules. I would guess that some of the universities that do automotive may have the tools to model this.

But, without knowing the base requirements in terms of required header pressures & flow rates. I guess everything is "suck it and see".