DIY Exhaust Mod – Gain of 10+ HP!!!

[chipmunk]

Update on my last post. I took my car for a long drive on Sunday and unfortunately, when under load on a slow incline, there is a drone. Certainly not as extreme as with the performance exhaust however a drone none the less.

My advice to anyone that is planning on doing this mod is stop at 15mm - possibly go to 18 or 20mm but 25mm is maybe too far.

Unfortunately in my enthusiasm I went from 15mm to 25mm without road testing so I can't say whether a middle point might have been better. What I can say is that I am now about to change my exhaust for the third time. Anyone passing through Kent this weekend is welcome to stop by and offer their moral support

[JAAY]

Really? Drone? What other exhausts have you had on the car? I have had many and yes there is a tone/sound (you can hear the exhaust) but not drone. I'm just curious as to what you are comparing it too.

[chipmunk]

well - I'm certainly not any expert on exhausts however my comparison is the Toyosport stainless system that I had on before. Currently, the exhaust sound is fine but at 2500 to 2800 it becomes more acute - what I would call a low grade drone. When the holes were 15mm this was hardly noticeable however now I have taken them to 25mm is has become annoying. Certainly not extreme like before however I guess it depends how fussy you are It may also vary between different cars / engines / models / etc.

[particlewave]

That's too bad, but at least we know that there is a limit. Someone had to find out the hard way
Thanks for all your hard work and dedication.

[JAAY]

I have 1" holes. You hear the exhaust but not drone in my case.

[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.

[Slate 01]

JDLMODELT, comments like yours have made me stop considering drilling anything into my exhaust. The exhaust sound is important to me, but in reality just a ego/notice me kind of thing, at least for me. I actually don't need the ego stroke to love my Porsche. To each his own. However if I come across a real nice exhaust system that is going cheap, then I will be stroking my ego immediately.

[chipmunk]

My observations in all of this are that Porsche must have designed a quiet exhaust for a reason - as JAAY has pointed out, all his previous after market exhausts have droned. Also, randomly drilling holes in things is generally not a good idea and once done there is no turning back.

[Niche]

So based on this thread I drilled my muffler. Sounds a little better, but will be returning to stock. There's a slight "hum/drone" that is a bit annoying. May be I drilled holes too big?

Here is stock:
https://www.youtube.com/watch?v=h03dShxx1Xk

Drilled:
https://www.youtube.com/watch?v=fah0Jx_BQ08

[chipmunk]

How big did you go?

[holtzy822]

ill just leave this here https://www.youtube.com/watch?v=wHRZ6_C6VZw

But in all seriousness I plan to do the mod when I pick up my car (a week -_-) I just hope it wont effect the ability to pass smog

[TeamOxford]

You can always tune your exhaust to your personal liking here:

https://www.youtube.com/watch?v=xjZeul6iuiM

Just sayin'.............

TO

[fab986]

Originally Posted by TeamOxford

You can always tune your exhaust to your personal liking here:

https://www.youtube.com/watch?v=xjZeul6iuiM

Just sayin'.............

TO

Haven't laughed that hard in a long time.... thanks for sharing, now I know what to do when I feel depressed

[JayG]

Originally Posted by holtzy822

ill just leave this here https://www.youtube.com/watch?v=wHRZ6_C6VZw

But in all seriousness I plan to do the mod when I pick up my car (a week -_-) I just hope it wont effect the ability to pass smog

as long as you are not injecting fresh air into the exhaust system to dilute the exhaust gases you should be OK. All this mod does is bypass part of the muffler

[Niche]

I did it, sounds better, but drone I got is making me look for other options.

[Niche]

Sounds better, but slight drone.