Oct 21, 2010

Custom Boxster exhaust on a budget! ($450) DIY

Customized budget exhaust - total cost? About $450!
Porsche, trying to deliver some audible pleasure to its buyers, flagrantly positioned the Boxster's engine intake near the driver's head. This does a reasonable job of conveying the flat-6 soundtrack. 

Unfortunately Porsche decided to, in earlier models at least, completely mute the exhaust tone using bland tips and a bloated muffler. This is great for those who prefer their films the same way they prefer their cars (silent),  but a bit of a downer to those of us who want some more sound.

Unfortunately, most decent catback exhaust systems for the Boxster cost $800-$1000+.The cheapest I'd found was a $600 Chinese catback on eBay but I found the tips quite ugly and I was not about to pay $600 for the thing. Sure I wanted my car to sound good, but not so much that I'd spend over a grand on a muffler. 

So I decided to improvise, and modify a cheap, $300 exhaust to my liking. Read on!

I thought i was out of luck finding an exhaust for my Boxster until I looked on eBay one day and found that a seller was offering the Chinese catback brand new for $300 shipped. For that cheap, I couldn't even build a custom one, so I couldn't refuse! 

Here's an example of one, if the link expires just search 'boxster exhaust' on eBay:
Boxster Catback

This is what it looked like when it arrived (only snapped a quick phone pic):

Not bad, but I couldn't stand the exhaust tips. For some reason they left a thin tube inside the tip that makes the tips look like they're clamp on. Yuck. 

So, I went to Jegs and picked up these Magnaflow tips for $35/each = $70

They're 3.5" outlets with 2.25" inlets - uh oh! The Boxster's exhaust is ~2". So I searched and searched for stainless steel exhaust reducers (has to be SS to weld it to the catback) and finally found some on this site for ~$30:
Assured Automotive Reducers 

The site may be sloppy, but the service is great! Received my reducers quick with no problems.

So this is a mockup of the look I was picturing in my head:

Next I took the muffler, tips and adapters down to the local exhaust shop to get welded up. Cost ~$50:

The welds on the catback itself are of quite good quality:

So finally it's ready to install. I thought I'd shoot some comparison pics between the stock and this piece.

This was a while ago, so I've forgotten the exact measurements, but I remember the stock exhaust weighed around 35 lbs whereas the aftermarket one weighed around 15 lbs. That's 20 lbs of weight savings with one mod, not bad!

Now the exhaust rigged up in place:

Here is where I started to encounter some issues. Turns out, I don't think this catback was designed to fit on a Boxster S exhaust bracket at all but more likely designed to fit a base model. It mounts up to the piping just fine, but it is nowhere close to where it is supposed to mount on the bracket! If one bolts it to the bracket, the bumper cover won't go back on because the tips are up too high. The clearance issue is more than .25" (the amount by which these retrofitted tips would sit higher than the ones that came on the exhaust)

In fact, this is where the exhaust has to sit to clear the bumper cove, notice my butchery of the bracket on the catback in an attempt to mount it lower:

But now there's another issue:

Probably can't tell from there...

See it now?

Yeah, this looks far from appealing:

The tips stick out ridiculously far. The tip and adapter combination was only maybe 1/4" longer than the original tips on the exhaust. Again, I attribute this to the exhaust being designed for a base Boxster, not an S. Looks like a pair of...use your imagination...hanging off the back of the car.

Don't fret, because I came up with a way to fix this!

The only thing preventing me from shifting the exhaust back was the piping. However, I noticed the piece of pipe that attaches the muffler to the cats on the Boxster has a 90 deg bend on one side and a ~45 deg bend on the other. If I cut a little off of each end, it would shift the pipes closer to the middle of the car (due to trimming the 90 deg) and also farther back (due to trimming the 45 deg).

So I trimmed maybe 3/4" or so to start with:

Hey! That's a little bit of an improvement. But it definitely needs pushed back farther.

This is where the bracket is sitting now:

I needed to move the tips even farther back, but I couldn't hack any more off of the 90/45 pipe. So I turned to the cats and trimmed them a little:

As well as the inlets on the catback:


Wasn't too much cutting involved:

This is where the bracket sits now. Shoot, I need a way to secure it!

First I went about trimming away the unsightly, augmented holes:

Then, after a quick trip to the hardware store, I built a bracket that allows precise adjustment of the exhaust position  (both left and right as well as up and down) by turning the various bolts. I realize it's somewhat crude; I didn't have a workbench or any proper tools available at the time; I made it with an angle grinder and a drill only!

Reassemble and we have the final product!

Please see the accompanying review for my thoughts and impressions on the exhaust.


  1. Hello, good work! I want to install a catback exhaust like yours, but I want to know if you have any drone issue inside the car. I hear that some aftermarket catback have this issue. thanks.

  2. This one drones below 3000 RPM. I just purchased a set of CC Inserts to try and counteract the problem, I'll see what happens once I install them.

    1. What are the CC inserts you speak of? I have purchased the same exhaust for my 99.

  3. Awesome! This custom steel exhaust made the car look more sporty. Can you imagine the smoke coming out from there as the driver increases the speed of the car? It looks like it's ready for a race! :) -Kai Tiger

  4. Are the tail pipes 3.5" overall diameter or 4"...thanks

  5. Great work. I'm looking to replace the clamps that connect the muffler to the u-pipes. Are these clamps 2"? Thanks!

  6. Great looking set up. Here at Armytrix we have some exemplary set ups. https://www.armytrixuk.com/