Superbike Exhaust Dreamers

[Soldier74]

Here's the deal: One of my good friends and I are going to attempt and start our own custom superbike exhaust line (you know, like Yoshimura, Arata, Muzzy, etc). We are both currently full time Mechanical Engineers and race amateur just for fun. World Superbike/Moto GP is our passion. I have about 1 year's worth of snowmobile exhaust design work under my belt, but other than that, our careers are non-related. Can anyone give us some help on attaining design software? Perhaps some professional advice? Anything at this point would be greatly appreciated. Thank you.

 

[BrianPetersen]

Rules-of-thumb for primary header pipe length and diameter on 4-stroke engines can be found pretty easily. I built my own 4-into-2-into-1 exhaust header for my FZR400 race bike (due to lack of availability except for one manufacturer known for making lots of noise but poor tuning ...) and I got the diameters and lengths the old fashioned reverse-engineering way ... I measured up a couple of exhaust systems on other 4 cylinder engines that are known to be well engineered and then proportioned them to my application, with the estimation that the cross-sectional areas should be in proportion to the horsepower (i.e. gas flow) and the lengths in inverse proportion to the RPM at which peak power is desiged. It worked out okay.

The right way to do this is to use engine simulation software. You can download a free demo (limited to a single cylinder engine)

http://www.lesoft.co.uk/index1.html

- click on "Downloads" then "Freeware". I had problems with the user interface of that one, but got it to work. There are a number of others out there.

I suspect most exhaust system manufacturers are still doing the old cut-and-try method. No aftermarket exhaust system for my little FZR had pipe diameters *small* enough ...

 

[Soldier74]

Any recommended software or pipe bending/welding techniques? What about packing types?

 

[facty]

Exhaust manufacturers still do the cut and try method at the latter stages of the development process, but up to this point they use one of the more robust 1D engine simulation codes to optimise designs:

GT-Power from Gamma Technologies
Wave from Ricardo
Boost from AVL
Virtual Engines from Optimum-Power Technology

Each of these softwares has their own pros and cons and people who will argue for one over the others, but I know directly of exhaust companies using each of them.

 

[SomptingGuy]

facty is correct. Indeed there aren't many (any?) serious tier-1 exhaust or intake suppliers that don't run one or more of these codes. None is cheap though.

The codes are much less prevalent in the aftermarket and low volume world though, where the goals are different (sound level and quality is not an issue).


- Steve

 

[thundair]

You might try Pipe max although it was written for automotive, I am sure the data you require is the same.

http://www.maxracesoftware.com/pipemax36xp2.htm

As the pros on this sight will tell you every thing changes with cam, valve, stroke, bore size and rod ratio...So what ever you come up with for a commercial pipe will be a compromise for these variables..

Cheers

I don't know anything but the people that do.

 

[Soldier74]

Thanks for the help guys.