GS-Riders International

Quoted from "prwatts"

Hi Peter, Please tell me if my understanding below is correct: It seems that those tests done by Motorrad were for aftermarket Cans/Silencers/Mufflers attached to the standard headers which included the catalysator.
Conclusion - to change the cans on their own makes little difference except maybe weight/size/looks. Am I correct?

Absolutely.

Quoted

So therefore the conclusion seems to be to not change the can (unless one is happy to spend quite a lot to save a few kg) but change the headers for one with no Cat. Is the test you show from SR Racing for a system with a Cat or no Cat? I assume they cannot easily sell a zorst in Germany with no Cat in it?

The SR full system has the cat in the can. It is not forbidden selling cat-less exhausts. What is forbidden is using them on public roads. The German GS-ers know from other Y-headers as well: The gain is not caused by simple removal of the cat, but by better internal header aerodynamics.

Quoted

I would like to know the results of a Header with no Cat and a stock Can.

See post 6, about 4 hp top end hp on a '04 GS, lesser on later models, with torque gain present on these, too. I have this data from German GS-ers.

Quoted

This is what I got from the Wunderlich Website:
Wunderlich Sport Exhaust Header System ... snip

The Wunderlich header is either a Zard or a Remus header. Either is fine, they are quite close to the SR header. Power gain of 4 hp is out of the box, no other adjustment or other parts are changed. Note, there is also a relevant change of torque. To me it seems a Y-header together with a modified stock exhaust (such as mentioned on UKGSer) would likely be close to the SR full system. Should you decide for doing this, I am hoping for your report incl. some pics.

BTW. You may consider investing the money saved for an aftermarket can into a Wunderlich Power Controller. To my opinion this makes more sense in conjunction with the better gas flowing header.