Drilling Exhaust

[fragdude]

I know a bunch of people have drilled holes in the exhaust pipes and welded pipes leading to the exhaust tip. I was wondering if one could just drill he holes and leave it be? it sounds really shoddy, but I honestly can't hear my engine often with the radio on. Has anyone done this?

[Cloudsurfer]

I would think you would get exactly the same kind of sound one gets with an exhaust leak, which is to say, not sexy at all.

Patrick

[Blkboxster]

yep thats a stupid idea

[fragdude]

I thought so, just had my fingers crossed hoping it wasn't

[Kirk]

I've heard of something along these lines. The idea is to stick a drill bit as far inside the muffler inlet opening and drill some holes through the pipe INSIDE the muffler. If you look at a cross sectional picture of the muffler you'll see that there are a couple resonance chambers the exhaust has to travel through. By drilling holes inside the inlet pipe you allow some exhaust gas to bypass one of the resonance chambers inside the muffler and thus increase the noise level. This is just something I read about, I have no first hand experience hearing the results of this mod so I make no claim as to how well it works...

[j.fro]

I've done the "inside the muffler" hack. The sound is much improved. PM me and I'll give you all the details for doing it.

[Wret]

There are already some holes just inside the inlets. I assume they were put there to "tune" the exhaust note. If you can enlarge those holes, as mentioned, you bypass some chambers and baffles and allow more sound through.

[j.fro]

That's exactly it!

[fragdude]

hmmm, sounds quite appealing.....How hard would you guys say this is? and what would I need to do this. Unfortunately I don't really have a lift ( I do have some ramps, but I don't like using them) and my only friend that has one has left for europe..

[nola911]

Originally Posted by j.fro

I've done the "inside the muffler" hack. The sound is much improved. PM me and I'll give you all the details for doing it.

Since this thread is about this very topic, why not share it to the masses of interested followers?

[vipola]

I passed trough all this with my speedbike, changing exhaust for straight pipe, drilling hole, emptying muffler padding.. to get that lound sound.. usually at detriment of performance, even if peoples think there engine is more powerfull when there is more noise, removing backpressure usually make engine less performant.

I think a porsche should be nice and gracious.. not have that hell-loud-mad-straight-pipe-noise..

I like my bike to be the loudest on the road, but I like my porsche to be sexy and gracious.

There is no point of deteriorating a such nice car to make it sound like a F1 (or a corolla with no muffler)..

that's my 2 cent..

[RobZ]

Originally Posted by maxferran

Since this thread is about this very topic, why not share it to the masses of interested followers?

+1. I agree.

[Kirk]

Originally Posted by Wret

There are already some holes just inside the inlets. I assume they were put there to "tune" the exhaust note. If you can enlarge those holes, as mentioned, you bypass some chambers and baffles and allow more sound through.

I'm not sure that all Boxster exhausts have those holes. Here's a picture of one without them. So your mileage may vary... Still you're making holes or making the existing ones bigger, so it shouldn't really matter.

No you don't need a lift to do this. I imagine that if you're flexible you could even do it with the muffler still on the car! Check for instructions on muffler removal though as I believe there are some on this site. You'll need to remove a U-shaped pipe just before the muffler inlet. Again, with that totally removed or at least moved out of the way, I believe you might be able to fit a drill up under there to do this. If not, you certainly could do it with a 90 degree attachment.

Kirk

[RandallNeighbour]

Originally Posted by Wret

There are already some holes just inside the inlets. I assume they were put there to "tune" the exhaust note. If you can enlarge those holes, as mentioned, you bypass some chambers and baffles and allow more sound through.

My buddy and I have tried this. We cut a 1 inch x 2 inch hole just inside the muffler and after two hours work IT DID NOTHING TO IMPROVE SOUND OR MAKE THE MUFFLER LOUDER.

One actually has to tear apart the muffler and remove a lot of metal to get the sound to change, then weld it back.

The bypass system seems to be far more effective. We didn't try that and I haven't heard it on anyone's car as of yet, but everyone who does it says it sounds better.

Personally, I see no reason why you couldn't drill a one inch hole on both sides of the inlets where you would then weld the pipes to the center at a later point. An exhaust leak would sound different as it would be pre-cat near the headers. All the pipes do is route the hot gasses to the center of the car to be sent through the existing tip.

The only issue I see with drilling the holes and not putting bypass pipes in would be heat buildup. Lots of hot gasses building up under the bumper might melt something if you're stuck in traffic. It gets the trunk HOT HOT HOT now, and I'd hate to see what could be worse than what it is with unmodified OEM muffler.

[angman]

Just FYI I had installed one of those cheap chinese headers yesterday (ones sold on ebay) that I picked up from 986speedster (thanks!). My shop didn't tighten the screws that cover the O2 sensors properly (my 97 doesn't need them) so they fell off after a few blocks of driving. My friend that was with me thought the rusty van beside me was trying to race me. I knew that it was the bolts that fell off which left two small holes in the headers. My car sounded worse than an old Corolla with a hole in its exhaust. It was so embarassing to drive a Porsche around that sounds worse than a horribly modified cheap asian rice rocket. I will gladly go back to my old integra with a straight pipe any day.

Oh and the cheap chinese headers (once installed properly) sound great. It comliements my Dansk exhaust and seems to have gotten rid of some of the resonance that I had in the lower RPMS. The quality of the stainless is very good quality. if you try hard enough you can even see them behind the rear wheels. I feel that I lost a bit of low end torque though.

[jmatta]

I highly recommend the bypass pipes on the muffler. I have one installed on my S and it sounds great. It sounds even better now that I've added secondary cat bypass pipes. Everyone wants to know how I get such a wonderful sound out of my car.

[Gubu986]

Does the bypass pipes weld to the inlet pipe entering the muffler?

[jmatta]

Yes, the bypass pipes are welded to the inlets per the picture. You just need to be careful that you don't insert the U-pipe to deep or you'll cover up those holes!

[Gubu986]

Originally Posted by jmatta

Yes, the bypass pipes are welded to the inlets per the picture. You just need to be careful that you don't insert the U-pipe to deep or you'll cover up those holes!

Thanks, Jmatta!

[Christian H]

Originally Posted by jmatta

I highly recommend the bypass pipes on the muffler. I have one installed on my S and it sounds great. It sounds even better now that I've added secondary cat bypass pipes. Everyone wants to know how I get such a wonderful sound out of my car.

Do you know if the diameter of the bypass pipes are critical ?
Yours look to be about an inch or so,would larger/smaller diameter pipes give a different tone or just be louder/quieter?
I have gas and mig welding experience so this looks like quite a straightforward mod unless I'm missing something !