making my own exhaust, few questions before i begin

[fitero7]

hello eveyone, so here is my project. i am somewhat of a cheap bastard mainly because im broke most of the time...so this is why i have elected to build me own exhaust system. my idea and jump in and give me your opinion about this is to use the stock headers all the way down to where they go from 4-2 and cut off from there (cats go bye bye) and fabricate my own 2-1 for a slip on yoshimira exhaust that i currently have on there. i would weld a new o2 bung on it. so with this having stock headers to to 4-2-1 using the yoshimira slip on that i already have on there, would this be a viable idea in creating my own cool ass exhaust? would i have to get it tuned? if so i have more questions. let me know what you think everyone!! also i am a welder machinist and have access to all materials and a tig welder...so it free lol

 

[Blackmax]

Stock head pipe is the part you need to change,as that is where all the HP is lost

 

[nosbig]

I would think that you will have to get it tuned as soon as you tell the cats (bye bye).

 

[fallenarch]

Exhaust pipes are deceptively complicated. The headers are tuned so that there is a pulse of exhaust through them. This pulse actually helps allow the filling and emptying of the cylinders. Very hard to do properly without some real R&D. Not saying it's impossible but I think there will be some real compromises without the design technology to do it properly.

 

[fitero7]

I can do some r&d, build and test them in solidworks and see what that tells me. Or I can just copy and fine tune the shape of other exhaust systems. I'd hoped there was someone out there that could give me a few pointers. And maybe someone that can tune near Tulsa Oklahoma

 

[1busa]

Maybe on like a chopper or rat rod bike it would be fine 2 fabricate up an exhaust but on a sport bike like this I think you and your busa would be much better off just saving some $$$ and buying a used exhaust off a forum member on here or possibly ebay. Like Fallen said there is a lot of time, money, and science that goes in2 making exhausts for these machines. If it was that easy to just weld up an exhaust with some spare pipe etc. Lying around then these exhaust companies would've been put outta business or dramatically slashed the prices on their pipes.

Not saying you can't do it but it will take time and $$$ to do it right. A whole lot more money than a used pipe ready 2 bolt on no muss no fuss would. Don't know about where your from but dyno time around here ain't cheap and a session or 2 would pay for the pipe you need and provide more HP. But in the end if you just wanna be different 4 the sake of being different and don't care about HP and just wanna make a bunch of noise then Have @ it!

 

[fallenarch]

Well I know the diameter of the headers is critical so that the hot gases pass through at the right speed. Also the length of the headers should be the same for all cylinders. The configuration (4 into 1 or 4 into 2) changes the character of the engine from torquey to screamer - but I don't remember which is which. Maybe some of the tuner guys can chime in and help you out. I must say by the time you get good material (high quality stainless steel or titanium) and all the equipment you need to fab this up I don't see this being very cheap to do properly. I think theV&H header is only about $400, I would think this project would easily cost that much. On the other hand people do the impossible in their garages all the time!

If you remove the cats and then use the stock header I suspect you are not going to get the top end and the low end will be a bit difficult to smooth out when you get it tuned. If you are messing with the exhaust to this extent you really need to get it on a dyno to be sure you are not doing damage to the engine.

Edit: Oh yeah, remember you gotta get the filter out!

 

[bikerboy2182]

i gutted my cats but when u do make sure u weld the pieces back in that keep it 2 seperate chambers. not going to help performance but it will help sound and heat build up at ur feet. then i took 3/4 of the wrap out of my two bros slip ons and had my ecu flashed. runs really smooth and much better then before. its a great low budget setup

 

[kml]

Exhaust System Technology: Science and Implementation of High Performance Exhaust Systems