DIY Exhaust Mod – Gain of 10+ HP!!!

[Ian c]

Originally Posted by particlewave

Here you can see the center chamber and baffle pipe more clearly. That pipe connects chambers 2 and 4 and diffuses into chamber 3.

I'll try to dig out a photo I took whilst cutting Into a 2003 .
They're different .
I modified mine into a "permanently open Pse" inside the muffler , then welded it closed again .

[chipmunk]

I have a 2003 so definitely interested in any photos you have. Drilled sounds so much better but you need to be prepared for a small amount of drone.

[Ian c]

I thinki Drilled mine as well in case it was needed later ....
I'll have a look later , but I think I remember drilling a pilot around 1/4" while it was easy and off the car with the tips removed
But basically on a 2003 the chamber layout and gas flow is different ...

My idea was to follow what porsche did with the Pse which to all intents was a modded stock muffler , as they all ready took care of engineering out the drone

[holtzy822]

yes yes i know this is an old thread but Im considering drilling the holes in my 97 base. I live in California so does anyone know if this would effect the smog at all? I'm thinking i want to go with 3/4" holes to avoid the drone but still have a noticeable difference. If its still too quiet ill drill it out some more. I'm sure it cant drone worse than my 87 944.

[chipmunk]

I'd go half inch and then increase from there. 1 inch provided a nice deep tone but there is a little drone (more noticeable on steep inclines). It is also noisy inside when driving at speed. I have just put a std box back on and it's nice to be able to hear my music again without turning it right up.