DIY Exhaust Mod – Gain of 10+ HP!!!

[HDManny]

I drilled two holes (one per side) also but accidentally made them a little bigger then I intended and it sounds greats. As they mentioned on here previously, more noticeable when you go past 3000 rpms and it sounds louder not different.

[MN 986]

I started with 1/2"dia holes (one each side) on my 2002 2.7 and liked the extra sound. Eventually I wanted more, but could not find a larger diameter drill bit that was long enough to reach with the fixed exhaust tip. Then one day I ran across a 'stepped' drill bit and a drill bit extension, and slowly worked my way up to a 3/4"dia each side. I think it sounds even better. Definitely not too loud.

What have others tried?

[HDManny]

I used a 1/2" drill bit but as I said earlier, I got carried away then combined with the angle, I made my holes about the same size as yours. They are 1/2" by 1" so it should be the same, I like the sound and thought about going bigger.

[Alretired]

Does it matter if you drill almost straight back and not so much on the side? I assume you are still going into the same chamber of the muffler. I have the single tip (non-removable) and it is very hard to go at very much of an angle. Thanks.

[NWI Bill]

If you drill straight back, you'll drill through the back of the muffler and you don't want to do that. Drill to side like Crios instructed. I have a 98 Boxster with a single non-removable tip and didn't have any problem. Just use a long bit, 12" or so or use a drill bit extender. You can buy both at Sears. I just increased the diameter of the holes in mine to 1". I used a step bit to increase the size. I was getting a bit of "PFFHT" sound as I rev it. The increased diameter took care of that, the sound got a little deeper and no cabin drone.

Since we got into the low 30s here in Chicagoland today, I took the Box out for a drive to see how things sounded and rid myself of some cabin fever. :dance: