DIY Exhaust Mod – Gain of 10+ HP!!!

[Slate 01]

Okay you have all convinced me, NOT! Since I have been having trouble getting the bit to bite anyway and now I am hearing conflict on drone, nothing special in sound (from the sound bites I seen posted, I can't really hear much of a difference, maybe none at all), I'm leaving it stock and going to enjoy it as it was engineered by Porsche. Thanks for the thoughts and guidance but I'm standing pat, if I want more sound or different sound I'll put in a Borla or Magnaflo or something like that.

[chipmunk]

It's always difficult with something like this as the definition of what is or isn't a drone is often a matter of opinion. Also, my car will make any increased noise at the 2500-2800 range more noticeable as it's a tiptronic and likes to keep the revs there when doing 50mph (the speed limit on a lot of our roads). As I have said, the drone is fairly marginal (certainly not like before) so quite possibly what I hear as a drone JAAY may think is just increased exhaust noise. You really need to experience it yourself.

What I can say though is that there is a significant increased volume from the exhaust overall - the video clips don't show this as I think the camera has automatically adjusted the volume. With the smaller holes I could only hear the increased exhaust note at idle but now I can hear it reflecting off buildings as I drive through town, so a big improvement there. The sound is also much better in that it's not a raspy sound (a bit like a hole in your silencer - which of course is what it is ) but a deep sporty sound. I just think (for me) I should have stopped a little sooner however others may think it's absolutely fine - especially if you drive a manual and don't spend much time in the 2500 - 2800 range.

While this doesn't help anyone in the US, anyone close by to Kent in the UK is welcome to stop by and hear what it sounds like. A second opinion might be useful.

[JAAY]

The automatic would definitely make a difference and also I have hight flow cats, headers and a totally different motor. None the less great job documenting all of this!

[chipmunk]

Changing the manifolds does make a difference. I remember EDC saying that the drone decreased appreciably when he installed free flow manifolds.

Just curious - with that configuration, would a high end performance exhaust not be better than modifying the std muffler? Or do all performance exhausts suffer from the same drone problem?

[JAAY]

I have had many exhausts and they all had drone that was deafening. The stock muffler had made the most power in conjunction with some cheap headers and good high flow catalytic converters.

[chipmunk]

Interesting - I did wonder about that. I originally thought that the drone was related to the design of the exhaust system and the materials it's made from. I have now come to the conclusion that the car - location of the engine, seating compartment, etc are susceptible to reverberation from the exhaust sound i.e. it doesn't matter what system you use - when the exhaust noise reaches a certain level you get the drone. This seems to be in line with your experience as well. Maybe this is why the Boxster exhaust is so quiet in std form...

[JAAY]

My thoughts exactly. It is what it is and there is nothing we can do about it.