thats actually a nice idea...someone welded a "y pipe" and shut off the main route...pretty much exactly what your picture shows

 

exactly.. only this time I'll open the above site of the exhaust muffler.
the one with the heat shields on. make a hole from about 15 inch to 7 inch orso, and start remodding the inside, but fixing a Y pipe in is harder I think, so little room, but I'll think it over with a 6 pack or 2..

I guess buying an aftermarked exhaust would cost less effort, but than again, making it yourself is much more fun.. if it fails, I can always buy an other one..

 

this morning when I got home from work, en was not in the mood to get into my bed after a whole night driving the ambulance, I got in the garage and opened my exhaust .. again...

here the pics..

original hole..


hole after modification.


the hole across it.. well.. not anymore anyways..


the rear I left open , to function as a "bass-tube" for the sound. (and it's nice.)
and to avoid getting moist in there.. (I live in belguim, it's always moist and raining here.. )



welded the piece back together over the previous weld.



and mounted the whole thing again.


result after a quick test.
again, a little more bass at low RPM, a little more "grawl.." when on the throttle...
full power I have not been able to test yet, becorse traffic was a little to dense, and belgian roads are a mess.. .

I'll let you know how it goes..

 

for those wondering about the sound now...

http://www.youtube.com/watch?v=Knen9bXj8pQ

this was a quick movie with my friend's cellphone.. beter material is coming.

 

it sounds good. As for the gains? idk 10hp in either direction is nominal. That could be the difference between a cold engine vs a heat soaked one. Either way, great write up.

 

Nevermind! Did it on my RA and it's real easy...

 

Do you think it would make a big difference if you sealed the holes in the rear? Sound?

 

instead of a y-pipe why not just weld a flat peice of metal in the center chamber after the pipes that lead out to the tips, that would effectivly force the exhaust to go out only those two spots...

and for a "bass tube" just drill a few holes threw said metal peice and that way some gases would still bounce around in the back...

 

thanks for the DIY!

 

I know this is an old thread but I did this modified stock exhaust today and I removed the spring valve. Is it bd that I did that? Did I lose power?

 

The exhaust gas will follow the path of least resistance so the additonal task of closing the holes should be negligable for performance. It should keep a resonance (like a bass tube' and hopefully keep the standing wave that is out of cycle and dampens the sound (only - no performance degradation ).

I plan to do this mod soon.

I too am baffled (pardon tha' pun!) on what the 'flapper valve' is and what it's function is.

 

I have mine done with a 3'' mid-pipe, 3'' testpipe, and AMS Bellmouth. For anyone that's wondering, it's very quiet for cruising around. But, at WOT, it gives out a good tone. I can try to get a video if people are interested.