exhaust mod question

[djomlas]

so what would be the best way to mod the exhaust internally?
from this pic..

[blinkwatt]

Originally Posted by djomlas

so what would be the best way to mod the exhaust internally?

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.

[John V]

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

[Cloudsurfer]

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..

[j.fro]

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.