DIY Exhaust Mod – Gain of 10+ HP!!!

[Boxtaboy]

Originally Posted by particlewave

The internal bypass sounds great! It definitely added low end burble and is louder throughout the RPM range without being obnoxious. No drone.

Here is an iPhone video, but it really doesn't convey much without good headphones or speakers (sounds awful on my phone).
https://www.youtube.com/watch?v=ch0rsKOL5NQ

Neat trick you did there. I wonder if there's a way to get rid of the whine that you hear so prevalently on these early Boxsters as it's winding down from the up rev. In yours, you hear the whine as you rev up too. It's a feature I hear on pretty much every rev video of Boxster exhausts except a muffler delete like the one below, or a GHL muffler. My dansk exhaust exhibits very little of that whine, although I can still detect it a little. It must be the back pressure of the exhaust?

Muffler delete on Boxster:
https://www.youtube.com/watch?v=YbCwcWaJkGI