Anyone on here any good at welding stainless?

[yorkie_chris]

Originally Posted by timwilky

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

I don't think there is enough data to even make a meaningful model, or anywhere close.

Suck it and see

yeah scavenging and back pressure are a valid requirement if his falco has turned into a 2 stroke

otherwise i wouldnt bother too much, unless your tuning the engine to F1 Standards

[yorkie_chris]

Originally Posted by amarko5

yeah scavenging and back pressure are a valid requirement if his falco has turned into a 2 stroke

Lol, it still matters on 4 strokes too.

You are right, I guess it is a bad design in terms of perfect exhaust efficiency. Best would be to just take the mufflers off... but then anyone living within a mile of my route to work might not appreciate that. These blue flames are well rated for performance in exhaust head to heads so I figured I could use them. Maybe if I can get this done I might experiment with 70mm bores with the set of end cant im using atm, I can imagine them being a little on the loud side though.


By the by, reverse cone mega's, they are supposed to be good for performance right? From what I understand they get larger then smaller at the actual exhaust, surely the muffler in my design is similar no?

Originally Posted by yorkie_chris

I don't think there is enough data to even make a meaningful model, or anywhere close.

Suck it and see

Id imagine most standard exhaust are no where near good for engine performance! Most are an afterthought at best and at worst used to meet emissions and noise regulations.

Been doing a little reading about exhaust design. Sounds like no one really knows for certain what works best but... I'm wondering if the increase in diameter (from about 50mm to 70km before the mufflers) towards the end of the exhaust would slow the exhaust gas speed down a little too much and causing reflection and power loss?

Originally Posted by ThEGr33k

Id imagine most standard exhaust are no where near good for engine performance! Most are an afterthought at best and at worst used to meet emissions and noise regulations.

Quite the oposite Nick,
The exhaust for the new Multistrada took a year and a half of the development time

Modern standard exhausts are a wonder of engineering and design. They produce all but the same power as the best aftermarket exhasust which are louder and nowhere near as stringent on design criteria!

Imagine having to reverse engineer a standard exhaust! Someone gives you a superbike with a full Akrapovic or Arrows system on it and you now have to come up with a system that produces over 98% of the power but has to meet all of the Euro three regulations, sound as quiet as they do, works on reflective sound damping instead of absorbtion damping, look good and contains noise and power valve and a catalytic converter!

I think standard exhausts are a wonder of modern engineering. And thats probably why the full exhaust system on a GSXR 1000 is now £5008 (no, thats not a mistake!)

C

Your probably right there Berlin. I was mostly meaning my own to be honest, the standard exhaust was silly, poor joins and other things. Another that is pretty poor is the sv1000, soooo mental kinks and stuff.


don't suppose anyone knows a good read on v twin exhaust design?

[yorkie_chris]

Originally Posted by Berlin

I think standard exhausts are a wonder of modern engineering. And thats probably why the full exhaust system on a GSXR 1000 is now £5008 (no, thats not a mistake!)

C

The design is, then they weld them up out of sh*te stainless using a pidgeon.

They are £5008 just because they can take the p*ss with parts prices... not because it costs owt like that to make them!

Granted and no one would actually pay that for one when there exists such a beast as Ebay. Or aftermarket exhausts

A three year old bike needing a new exhaust from Suzuki, would be written off by the insurance as not economically repairable. How ridiculous is that?!

Originally Posted by 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!

Im willing to try and make a 70mm straight through exhaust muffler, or convert these to that. It will involve dismantling the current setup, so if like id imagine it is silly loud then I maybe stuck with it for a short time... Guess I can get some inserts made so I can quiet it that way should I need to.