Aftermarket exhaust
 

Is there any significant benefit to installing aftermarket exhaust to stock 1999 Porsche Boxster? I installed one and the drone is terrible below 3000 rpm. Think I’ll go back to OEM.

It's a trade off that's about personal taste. An inexpensive exhaust from Ebay sounds, in my opinion, surprisingly good. But, yes, the drone from 2k to 3k is pretty annoying.

On the other hand, the OEM exhaust is boring, and in that respect, at least as annoying.

A higher dollar exhaust, like that from brombacher reportedly doesn't drone, but at over $1k, I'd rather have other mods.

To your original question: unless you've increased the volume of the intake (987 airbox & larger TB) any hp gains from exhaust upgrades will be negligible.

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http://986forum.com/forums/diy-project-guides/70112-internal-exhaust-mod.html

Sounds great, no drone and low cost. ;)

agree with maytag.
my cheap ebay exhaust (with headers) sounds great except for 2200-3000 rpm

I agree with particlewave. Sounds great, no drone and cheap :D

My $300 eBay muffler was also at least 1/2 the weight of the original one

so, in looking at the differences between those systems which report drone, and those which don't, the obvious difference that can be seen externally is the "crossover" pipe, right at the exhaust exit. (after the mufflers, before the tips).

So this begs the question: If I were to add a crossover tube, like that shown on the high-dollar items, will I eliminate the drone?

if you don't mind the cost. FVD Brombacher, no drone, sounds great, a bit pricey.

Cat bypass pipes will eliminate the 2-3k drone. It will also cause a Cel and the car is pretty loud from 4K up.

I'm already running catless mid pipes. no cell, plenty of drone

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ill Just report on the progression of my car. I bought the car with a modified intake. The stock intake tube was replace similar to the Pedro mod. The first thing I did was de-snorkel. That gave the intake more roar and you could not even hear the stock exhaust. I then bought the cheap $250 dollar eBay muffler. It was louder and sounded good except on the freeway it had a loud resonance around the 3k to 3.5k range. I later added both cat bypass pipes and a k and n filter and the car not is much quieter at 3k on the freeway but overall sounds great. I’m guessing if you still had resonance you still had the pre-cats in your headers. Again I’m just reporting my experience with my 98’ 2.5 boxster.

Mine is an '03 S (3.2).
Yes, I still running the stock manifold with the pre-cats. The secondaries are gone though.
My resonance is from around 2200 to 3k. But I live with it. ;-)

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The 986 muffler is restrictive as it uses tiny tubes internally. It's also a boat anchor at 33 lbs. I believe the Chinese muffler drone can be fixed by welding in a crossover pipe. I think someone on here did that. I built my own using pieces from a 987 muffler. Lost 16 lbs and flows much better. With aftermarket headers and no cats, it has just the right sound with no drone. The 987 muffler has the same internal size tubes as the 996 exhaust.

That sounds really interresting! Care to show & tell?

http://986forum.com/forums/show-tell-gallery/59449-woodys-build-thread-5.html
The exhaust modification starts with post 192

My car is at the muffler shop today to get this done!

You will love it.

The 'internal exhaust mod' was done yesterday on my car. I would say there is a very slight improvement in the sound. The car is still too civilized for my taste.

If that's the case, it wasn't done right.

It does sound tame from inside the car, but definitely not from the outside. Have you heard my video?
How many holes were made and what size?

Yes, I was expecting significantly more sound! One hole one each side, each 1 3/8".

That gives you a cross section of about 1.7", which is where I was when I said it needed more.

A 2" bypass, like the stock PSE, has a cross section of 3.14" (double what you have) so you really should have done two 1 3/8" per side. :(

Yeah the holes must not be big enough. Did they at least drill the holes all the way through the pipes? As you can see what I did in the internal bypass thread, two holes each side around 1 inch. Then I used a chisel to connect each hole. I can definitely hear the difference in the car with the windows up. With them open and the top down, big difference. Under a bridge or in a tunnel it is pure GT3 mode. My wife says she can hear me coming down the street at 30mph. If I get on it people always look. So I would say the mod works if done right.

Well. Darn. Yes, it sounds like the problem is not enough, or large enough, holes. I asked him to drill 1.5" through both sides of the pipe, on each side. When he had cut the 'window' to get in there, he thought that the pipe wasn't big enough to handle 1.5", so he went with 1 3/8".

http://986forum.com/forums/uploads02...1561739079.jpg

If he opens it back up drill 2 holes on each side, all the way though the pipe. I used a step bit, so I could only make the top of the hole full size. Both of the holes on the top of the pipe are 3/4 of an inch. The bottom holes are smaller. I put it back on the car with these size holes. I felt it needed to be louder. So I took the muffler back off and used a chisel to connect the holes. Basically I went through the pipes on the side of the muffler, placed a chisel in the hole closer to the end and hit it with a hammer until the holes connected.