DIY Exhaust Mod – Gain of 10+ HP!!!

[tommy583]

https://www.youtube.com/watch?v=PO9l-X4eUOk This guy made a great how / before and after video. He even gives a shout out to Particlewave

[particlewave]

Originally Posted by tommy583

https://www.youtube.com/watch?v=PO9l-X4eUOk This guy made a great how / before and after video. He even gives a shout out to Particlewave

Ha! That's funny

I did this mod at the same time that I de-snorkeled and I thought the increased sound was nice, though mild. I'm now convinced that the muffler mod did little or nothing at all, as others have reported on the 2.5, and the increased sound was primarily from the intake.

I can confirm that the 2.5 muffler on my '99 is full of sound deadening material, rendering this mod virtually pointless.
I might crack it open some day to see what can be done.

[geetee]

2ndary cat delete and 2x 1 inch holes. No drone but still too quiet. I might go 2x 1.5 inches or maybe 2 additional holes....

[particlewave]

Or maybe all of the pictures of opened mufflers have just had that material removed before the picture? Can anyone who has opened one confirm or deny?

Edit: I went ahead and enlarged the holes from 1/4" to 3/4" and it did increase low end rumble, though not as dramatically as I'd hoped.

[heymanwatchthis]

Wonder what Crios mod is like if you add the Pedro Sport Exhaust mod?

[tommy583]

Originally Posted by heymanwatchthis

Wonder what Crios mod is like if you add the Pedro Sport Exhaust mod?

I sold a crios modded muffler to a buddy who sent it to Fister. They do a mod similar to the Pedro exhaust. I don't know if they closed the crios holes back up or not, but it sounds pretty awesome now.

[geetee]

I'm finally happy with sec. cat delete. 2 holes each pipe. 1.5 inch and 1 inch holes on each side. No drone and decently loud. 03 2.7

[particlewave]

I'm going to go right through the top of the muffler and into the inlet pipe with one or two 1" holes.

Originally Posted by fridsten

I'm considering opening up my muffler, enlarging the holes where the pipes enter, thus making what could pretty much be called an internal Pedro mod.


Drilling by the red arrows would allow the exhausts to follow the blue arrows into the outlet.

Would that work? It would be a fairly easy mod to make, provided you're able to weld or get someone to do it for you. It would also look completely stock from the outside.

[The Radium King]

Originally Posted by particlewave

I'm going to go right through the top of the muffler and into the inlet pipe with one or two 1" holes.

i wonder if you could go in via the entrance pipe to drill the holes - similar to the crios mod?

if you do as you say, perhaps a couple of 3/4" knockout plugs to fill the hole - no welding required, do it while the muffler is in the car?

[particlewave]

Originally Posted by More

Thread needs more pics for us 97 to 99 Boxsters. I need to see where exactly to drill the holes.

I'm not completely convinced that it does anything on the earlier mufflers because of the sound deadening material inside.

Originally Posted by The Radium King

i wonder if you could go in via the entrance pipe to drill the holes - similar to the crios mod?

if you do as you say, perhaps a couple of 3/4" knockout plugs to fill the hole - no welding required, do it while the muffler is in the car?

I will definitely look into this. It will be after the 1st of the year before I get to it. If I can't get at it from the inlet, I'll go through the top (don't want the plugged holes to be visible from the bottom).

[More]

Any 98ers on here that have made this modification?

Does it work?

[particlewave]

Originally Posted by fridsten

I'm considering opening up my muffler, enlarging the holes where the pipes enter, thus making what could pretty much be called an internal Pedro mod.


Drilling by the red arrows would allow the exhausts to follow the blue arrows into the outlet.

Would that work? It would be a fairly easy mod to make, provided you're able to weld or get someone to do it for you. It would also look completely stock from the outside.

Originally Posted by particlewave

I'm going to go right through the top of the muffler and into the inlet pipe with one or two 1" holes.

Internal muffler bypass that does the same as bypass pipes or the Porsche Sport Exhaust.

1" hole drilled in shell and pilot hole drilled into inlet pipe.


Inlet pipe hole widened to 7/8"


I punched through both the top and bottom of the inlet pipes and widened each to 1", so two 1" holes in each.

The cross sectional area of a 1.5" bypass pipe is 1.77".
The cross sectional area of a 1" hole is 0.79", so I have a total of 1.58" per side...very close to the 1.5" bypass pipe.

I'm going to get the shell holes closed up tomorrow and muffler reinstalled, then I'll test it out on Wednesday, so I'll report back then with results.

[fridsten]

Originally Posted by particlewave

I'm going to get the shell holes closed up tomorrow and muffler reinstalled, then I'll test it out on Wednesday, so I'll report back then with results.

Excellent!

[particlewave]

It's "voilà", lol (parlez-vous français?)

Only $1000?
Glad you like it, but that's crazy expensive. You could have had bypass pipes bought and installed for less than $200.

[jintwert]

Originally Posted by particlewave

It's "voilà", lol (parlez-vous français?)

Only $1000?
Glad you like it, but that's crazy expensive. You could have had bypass pipes bought and installed for less than $200.

No, you are mis understanding me. I got rid of the 986 headers for 2006 Cayman headers and installed 987 mufflers with sec cat deletes. So I have the less restricted headers and 987 mufflers. So doesn't sound like a heat score through straight pipes!

[jintwert]

Originally Posted by particlewave

It's "voilà", lol (parlez-vous français?)

Only $1000?
Glad you like it, but that's crazy expensive. You could have had bypass pipes bought and installed for less than $200.

Why would you pay 200 just for bypass pipes off them crappy 986 manifolds? and still small pipe? With a 74mm TBI and plenum upgrade and the softronics chip, it came together well. And it all looks OEM. Im not the kind of guy to pay somebody like Fxxxxxxd money for just stainless pipe...whats that get you?

[particlewave]

Plenty do it and are more than happy.
No, I get it. I just don't get the amount of money some people are willing to spend on some piping.

The bypass pipes I mentioned are for the muffler.
I can see how the headers might have cost a bit, but surely there are other, more reasonable options for those with secondary cats...I'm glad I only have one set, so only have to deal with the muffler.
This thread is about modding the stock muffler.

As long as you're happy.

[jintwert]

Originally Posted by particlewave

No, I get it. I just don't get the amount of money some people are willing to spend on some piping.

I can see how the headers might have cost a bit, but surely there are other, more reasonable options for those with secondary cats...I'm glad I only have one set, so only have to deal with the muffler.

As long as you're happy.

Its only money...LOL. Have not seen a Brinks truck follow a hearst to a funeral yet...
And the sound is wicked...nice low toned growl, no drone at any rpm, and 5500 on is wild. Also put on a Chinese made xpipe tip so it looks like a Cayman tip also.

[particlewave]

Originally Posted by jintwert

Its only money...LOL. Have not seen a Brinks truck follow a hearst to a funeral yet...
And the sound is wicked...nice low toned growl, no drone at any rpm, and 5500 on is wild. Also put on a Chinese made xpipe tip so it looks like a Cayman tip also.

No, the Brinks trucks drive to the homes of the descendants.

Anyway, back to the topic of modding the stock muffler.

[jintwert]

Originally Posted by particlewave

No, the Brinks trucks drive to the homes of the descendants.

Anyway, back to the topic of modding the stock muffler.

OK