Muffler modification...

[Peer]

I saw some increased HP numbers from a gutted (meaning cut open & rip out) muffler. I'm curious what exactly such muffler hack involves -- gut the entire thing, or perhaps just open up certain parts..? It would also be interesting to know how different the sound would be compared to the stock muff. So, has anyone here done this gut-out hack?

-- peer

[Stefan]

Typically people bypass one or more chambers by welding a bypass pipe externally. I have also seen stick a demel tool in the muffler input and make holes so as to let some of the incoming exhaust go directly into the second chamber.

The Porsche Sport Exhaust has a bypass tube that goes from the first chamber directly to the tailpipe. It is opened and closed via a vacuum flap that can be actuated automatically or via a switch on the dash.

[pk2]

Hi,

Do these mods give you any hp advantage? Or just sound. Does it require removing the exhaust system? Also, is “Porsche Sport Exhaust” a product, company, option, etc? Comprmise Ca. emmisions?

Thanks. PK

Edited September 22, 2007 by pk2

[chaudanova]

Hi,

Do these mods give you any hp advantage? Or just sound. Does it require removing the exhaust system? Also, is “Porsche Sport Exhaust” a product, company, option, etc? Comprmise Ca. emmisions?

Thanks. PK

Hey PK, the PSE "porsche sports exhaust" is the OEM Porsche Tequipment sport exhaust system, that uses a valve/switch, so you can set the flaps open to the full sport mode, or the quieter/more restrictive regular mode. I don't think this compromises ca emissions, as it is a factory option.

The muffler modifications, make the sound more agressive, and whether or not there is any hp advantage, from users that have done it, negligible if any, some report a slight increase, but I don't think anyone has dyno tested. Mostly done for sound.

Other aftermarket exhaust systems out there.... Most are louder, some louder than others. As far as power increase goes for these after market systems, some lose power, some don't really change it much, and a few out there do increase Hp.

Hope this helps...

- C

Edited September 22, 2007 by chaudanova

[Peer]

chaudanova wrote:

> The muffler modifications, make the sound more agressive, and whether or not

> there is any hp advantage, from users that have done it, negligible if any, some

> report a slight increase, but I don't think anyone has dyno tested.

Below you'll find a dyno chart for a hacked muffler. I'm just curious what they exactly did to it, since it's quite an improvement, especially the torque.

-- peer

[chaudanova]

chaudanova wrote:

> The muffler modifications, make the sound more agressive, and whether or not

> there is any hp advantage, from users that have done it, negligible if any, some

> report a slight increase, but I don't think anyone has dyno tested.

Below you'll find a dyno chart for a hacked muffler. I'm just curious what they exactly did to it, since it's quite an improvement, especially the torque.

-- peer

Oh wow, so someone did dyno test it... Sweet!

[pk2]

...Below you'll find a dyno chart for a hacked muffler. I'm just curious what they exactly did to it, since it's quite an improvement, especially the torque...

-- peer

That’s kina significant, this was with a hack? Wonder how it's done. I like the idea of a cut out so you don't always have to bum the neighbors out. Wonder how the PSE stacks up against it?

Good work’

PK

Edited September 24, 2007 by pk2

[pk2]

Hi,

Do these mods give you any hp advantage? Or just sound. Does it require removing the exhaust system? Also, is “Porsche Sport Exhaust” a product, company, option, etc? Comprmise Ca. emmisions?

Thanks. PK

Hey PK, the PSE "porsche sports exhaust" is the OEM Porsche Tequipment sport exhaust system, that uses a valve/switch, so you can set the flaps open to the full sport mode, or the quieter/more restrictive regular mode. I don't think this compromises ca emissions, as it is a factory option.

The muffler modifications, make the sound more agressive,...Most are louder, some louder than others. As far as power increase goes for these after market systems, some lose power, some don't really change it much, and a few out there do increase Hp.

Hope this helps...

- C

Thanks,

Do you think these after market jobs go back to stock decibels when the cut out is closed?

Thanks PK

[Stefan]

I would be very skeptical of a chart like this. It is essential to list the exact configuration that was tested as well as the ambient conditions in both tests. Additionally, a proper test is to take the median of a series of tests not to list the best looking single result obtained under optimal conditions.

Without this information these numbers are meaningless at best and misleading at worst.

The muffler is not the limiting factor on the stock 2.5L Boxster so replacing it will not increase horsepower or torque.

[Peer]

Stefan wrote:

> a proper test is to take the median of a series of tests not to list the best looking

> single result obtained under optimal conditions.

> The muffler is not the limiting factor on the stock 2.5L Boxster so replacing

> it will not increase horsepower or torque.

And how do you know this? Perhaps by doing the afore mentioned test of taking "the median of a series of tests"...?

-- peer

[weldon978]

I have the AWE tuning exhaust on my 05 987s. Love the sound. Not sure the HP gain as I dyno'd it after the mod. To be fair, the car has the EVO intake, and a GIAC chip reflash. You cen hear the mod on awe's website (awe-tuning.com). Go to the page that features the 987/cayman exhaust and look for the link to the video file.

weldon_boxster_awe_exh_giac_intake.pdf