exhaust mod question
 

so what would be the best way to mod the exhaust internally?
from this pic..
http://www.pcars.us/albums/7271.jpg

The best way performance wise,not so much noise wise,would be to gut it, install two pipes,one from each of the inlets and lead them out the 'butt'.
I have the dyno sheet of power gains,I don't remember the exact numbers off of the top of my head. If I can remember correctly;no loss in the powerband,+18lbs of torque at the wheels at 4.5k rpm though,that is nothing to overlook.

A guy on renntech posted that he used a dremel with a flex shaft and cutoff wheel to cut a couple slots inside the #1 pipe (on each side of the muffler). This basically does the same thing as the external bypass pipes - it sends a small portion of unmuffled exhaust straight to the tips.

Good job finding this picture! I've been searching for that for some time.

John V

Very interesting. I had no idea the stock exhaust was that complex. Someone did their homework (which likely explains why the stock exhaust has no resonance issues) on this!

I did not dyno my car when I swappex exhausts, but I will say that my car with the GHL Race exhaust definitly does feel more torquey. Throttle response improved as well somewhat.

Patrick

would you have any more pics, especially a side pic..

That's not my photo, but I did the internal mod. Do you see where the arrow is pointing from "3" towards the inlet pipe? That's where I cut my inlet pipes. I used a dremel with a flex shaft and a 1 3/4 inch cutting wheel. Following that, I used a chisel and a pry bar to open the holes to about 1". There are two holes in each pipe, and I bent the metal so it would direct flow out of the pipe into the chamber. The sound is perfect: deep and throaty under acceleration, noticable at idle, but NO resonance at highway cruising speeds. I also modified my secondary cats, which helped.
My car is a 2000S w/ an Evo intake.