Well it probably isn't my original crazy idea, but if anyone knows how a tuned header works by using rarefaction (sp?) to impart some energy into the exhuast to help scavenge the cylinder. Then you know that whenever you have a change in pipe diameter this creates a shockwave the travels back to the exhaust valve and if timed correctly, bounces off the valve back into the header creating some suction as it travels back down. In a regular header this happens when the primaries exit into the collector and if they are open, it occurs again when the wave exits the collector. Om a stepped header, it occurs each time you have a change in primary pipe diameter and if you have a change in collector diameter (to those in the know, I'm sorry of this is a rather incomplete picture, but I just wanted to give a little background for my idea).

Well anyway, it occurred to me (especially when I was fiddling with an Engine Analyzer Pro demo) that when you take, say a header with a 3" collector and mate it with a 3" exhaust system, you effectively extend the collector by a significant amount (until you reach something like a cat or merge the exhaust with an H or X pipe). This effects the shockwave introduced by the collector and mutes its effect as well. This led me to thinking about putting the collector into some sort of chamber where it would allow the collector to function, but still exit into a full exhaust system. It seemed to me that you could weld some reducer cones (or venturi reducers in Flowmaster speak) together and place the collector down into the area where reducer flares into the larger area, like this



Then using the other side of the reducer to transition down into the proper exhaust pipe with a minimum of turbulence (and hopefully with only a minimal reduction in flow.

Discuss????

 

completely over my head? would doing this net any HP gains? or is this for sound?

 

performance, if it was for sound then there would really be no point to this because it would be like adding a cat before a cat which would kill the sound

 

Tru'dat, the idea is to basically trick the collector into thinking it is running uncorked - if thats an easier way of describing it. I don't think it would alter sound to much, if any, because its simply a hollow chamber that slips over the collector creating a step in the exhaust system near the collector.