Planet-9 Porsche Forum banner
  • Hello Everyone! Let us know what you would spend a $50 Amazon gift card on, HERE For a chance to win a $50 Amazon Gift Card!

1 - 13 of 13 Posts
717 Posts
Discussion Starter #1

Thank you to Rennlist member J.Ho for sending us his absolutely beautiful 991.2 Carrera C4S for development at Soul Performance Products! Seeing this car come off of the truck in Pennsylvania after traveling from South Carolina was VERY exciting for us! We are going to develop and test various components allowing us to provide a great product to the community that will be backed by third party dyno data and thorough video/photo comparisons. This thread will be updated as we progress. In the meantime between updates, we are eager to hear from members with any product recommendations, ideas and other thoughts.

We begin by evaluating and fixturing the stock components.

Stock catalysts: 15.85 lbs
Porsche Sport Exhaust (PSE): 22.90 lbs
OEM Tips: 3.2 lbs

Total OEM Exhaust (PSE Equipped) Weight: 41.95 lbs

The current plan is to develop and fabricate:
Tips for the OEM muffler in various styles (made in house!)
HJS HD 200 cell Sport Cats
Cat Bypass Pipes
Center Muffler Bypass X-Pipe
A track oriented straight pipe turboback exhaust - optional turn down tips

And for dessert - a GIAC ECU Flash to pair hardware and software together for maximum power gains.

In the future we hope to continue development on a proper valved center muffler as a PSE replacement. We will be updating this thread with the comparison between the Soul Performance Products offerings weights, photos, video comparisons and dynos vs. OEM so stay tuned!

717 Posts
Discussion Starter #2
The car was delivered to us with a custom made crossover center muffler delete made by a 19 year old friend of the owner. Our hats off for not only having the equipment to tackle that project, but to also complete it in a functional manner at such a young age. We have opted to develop our own Center Muffler Bypass X-pipe to pair with our catalyst replacement sections.

Speaking of catalytic converters - we evaluated the best way to design a replacement that is easy to install, provides an increase in performance and response while still maintaining emissions readiness with no CEL. HJS HD 200 cell large diameter catalytic converters allows us to deliver on the promise of emissions ready replacement Sport Cats that reduce restrictions after the turbos. This results in an increase in both engine and turbo sound, providing better spool time (not an increase in lag), and more horsepower and torque.

Using the best quality materials available however is only half of the battle. Having the experience and the knowledge on how to correctly fabricate the product to the quality that a 991.2 deserves is often overlooked. We utilize TIG welded joints with a 100% argon gas back purge to ensure that the penetrating weld is contaminate free leading to a stronger and longer lasting weld. Stainless steel is susceptible to contamination from oxygen, water vapor and other gases/vapors that can combine with the metal to form a compound that can compromise the integrity of the weld. When TIG welding stainless steel the outer portion of the weld is shielded by the flow of argon gas through the tip of the welder however the penetrating weld is not. We back purge the inside portion of the weld to ensure that it is thoroughly shielded from all angles and will not be contaminated.

Key points when back purging can be seen in the photo below. A key point when purging with Argon is that it is heavier than air. You start with the introduction of the Argon at the bottom or base of the product you are welding at a steady pressure. As the Argon fills the space at a steady pace it will replace the oxygen and continue to fill upwards towards the top of the piece. A small vent hole (seen in the painter's tape) allows the oxygen to escape and a pure and steady flow of argon to replace it. It is important to be sure that the piece you are welding is fully sealed with the exception of the small vent hole.

It is this knowledge an expertise that allow us to back our Sport Cats with a Lifetime Warranty - and industry leading 3 year coverage on the HJS catalysts themselves.

Back purging and welding a 991.2 Soul Performance Products Sport Catalytic Converter

We could not curb our curiosity of what a 991.2 C4S would sound like with a true straight pipe exhaust and we thought you would be equally as curious. Using 3” mandrel bent tubing straight out of the turbo to the rear of the car and fitting single wall turn downs, this exhaust system is radical, simple, and ferocious sounding.

Video to come tomorrow but in the meantime, what are your thoughts? We put a teaser clip on our Instagram @soulperformanceproducts so if you don't follow us there, stay tuned!

717 Posts
Discussion Starter #3
Love the sound of the Porsche Sport Exhaust but want to change the style of your exhaust tips? Soul Performance Products has an easy to install solution to increase aesthetics while retaining the stock PSE system!

Choose from a wide range of options: Single Wall Straight Cut, Single Wall Slash Cut, Deluxe Double Wall, and even Turn Down Tips for the track oriented car. Change the look of your car in minutes by simply removing the factory tips then tightening the t-bolt clamps on the Soul tips. We utilize t-bolt clamps to provide adequate clamping forces around the entire exhaust pipe. Each tip comes with an internal ring which allows for play so that you can line the tips up perfectly in the bumper. The PSE system allows for around half an inch of play in tip depth.

Slash Cut Single Wall Tips - $395 - 1.95 lbs / 3.5” L / 3.5” OD
Straight Cut Single Wall Tips - $395 - 2.3 lbs / 3.75” L / 3.5” OD
Deluxe Dual Wall Tips - $445 - 3.2 lbs / 3.75” L / 3.5” OD
Turn Down Tips - $195 - 1.85 lbs / 2.5” OD

REFINISHING: If you ever need your tips freshened up, we’ll clean and blast them back to (as close to) brand new as we can for a small fee.

CUSTOMIZATION: Interested in a custom logo at the end of your tips? We can do that! Want them longer or shorter? You got it.

All tips are currently available. 4” single wall variants will be available soon. If you’re interested in a set you can PM me or check out on our website on the product page, here.
717 Posts
Discussion Starter #4
Here's another look behind the scenes as we go through the development process. We like to experiment, and we like to craft new components. We removed the carbon fiber shells from a sample set of not-so-attractive sample tips that we had and built a set of custom double wall tips. It's our opinion that this design appears to be too small in the bumper outlets for the 991.2 application, but we can offer them none the less if anyone is interested. We're going to offer these tips by request for our other systems where the size is more fitting.

Stay tuned for more!
717 Posts
Discussion Starter #5
Jeff's 4S is back in his possession and we’re glad he’s happy! Prior to pickup we did a final road test and took a few pictures - every car we work on in house we're shooting for a customer car mural.

Jeff's car is now, indeed, a "bad jawn". Out back you'll notice our Single Wall Straight Cut Exhaust Tips.

We stopped at nearby Dinardo Foreign Motors - new school meets old school air cooled.

This Carrera sits a little lower than when it left the factory thanks to H&R Sport Springs - if you’d like to lower your own, give us a call! The ride is still quite comfortable and refined, zero complaints.

Tomorrow, we’ll dive into dyno data!
717 Posts
Discussion Starter #6
We approached AWE Tuning about testing our development car at their state of the R&D facility. Since AWE has been engineering precision Porsche performance parts for decades (not to mention the 991.2 Carrera platform) we knew we were in good hands.

The plan was to also incorporate a tune, but Jeff has decided to postpone and enjoy the car with hardware first. We look forward to hopefully getting Jeff tuned in the near future however, and providing further dyno results. Over the course of two days we made runs on several configurations, and here are the results fresh from the AWE Tuning dyno:

First up, Sport Catalytic Converters with HJS HD 200 cell catalytic converters and PSE:

From there we moved on to Cat Bypass Pipes and PSE:

Last, our straight through full 3" Trackback prototype:

We definitely anticipate much greater power gains when our freer flowing exhaust components are paired with a tune. Interested in getting dyno data for us? Let's chat!

Tomorrow we will be officially launching our Sport Catalytic Converters and Catbypass Pipes!
717 Posts
Discussion Starter #7 (Edited)
Available now - two high performance replacement options for the restrictive factory catalysts.

991.2 Carrera (with PSE) SPORT CATALYTIC CONVERTERS ($2,395) and CAT BYPASS PIPES ($895)

+ The directional HJS HD 200 cell catalytic converters are appropriately sized for the power level of the 991.2 Carrera, well in the range of the greater advertised power gains that we’ve seen with tunes as well. The flow path is optimized to utilize the entirety of the catalysts for proper exhaust scrubbing, resulting in no check engine lights.

+ We felt it important to retain use of the factory heat shields as to not heat soak the components around the turbos.

+ During the fabrication process we back purge as many welds as possible for maximum durability and then hand apply our signature satin finish for a perfect, uniform look. Should you ever remove your components at any point and would like them refreshed, we’ll refinish them for a reasonable fee.

+ During testing we experienced no CEL with Cat Bypass Pipes, but cannot guarantee the same results on all cars as all cars are different and unique. Catted O2 Spacers are available to reduce any chances of triggering a CEL.

+ We designed our Cat Bypass Pipes to have a straight through exhaust path with valves open in pursuit of maximum exhaust flow and power - if you’re deleting catalysts that is surely your focus! We’ve positioned the secondary tube into the Porsche Sport Exhaust where it is to keep the valves closed tone civil and refined while still receiving ample exhaust flow.


Sound is subjective, but we’ll do our best to explain our experience so far. Both components accentuate the sound of the engine - you can expect more flat six growl. Love it or hate it, both components will also increase the presence of the turbos - with Cat Bypass Pipes allowing the turbos howl a bit more during deceleration and reach a more distinct wail on acceleration. The Sport Catalytic Converters are perfect for the daily driven car as there is no added drone and the volume level is refined.

Soul says:
Mike: “When we swapped back to Sport Cats I missed the extra sound the Cat Bypass Pipes added, but then again I like my cars as sporty as possible. If you like an aggressive exhaust tone - Cat Bypass Pipes are perfect. I enjoy the extra volume in the cabin and don’t mind it at any RPM, valves open or closed.

John: “I drive an hour to work every day and Sport Catalytic Converters would be on my car. I like the extra tone without the extra attention. My 944 is my race car.”

Don’t take our word it though, hear for yourself:

SOUL | 991.2 Carrera (with PSE) Sport Catalytic Converters

SOUL | 991.2 Carrera (with PSE) Cat Bypass Pipes


Sport Catalytic Converters and Cat Bypass Pipes are available now. Contact us to order, visit our 991.2 website section here, or let us help you find your nearest dealer / installer. Our Trackback turbo back exhaust will be available soon.
717 Posts
Discussion Starter #8 (Edited)
Unleash the full growl of the 3.0L flat six and hear the twin turbos sing in all their glory with a straight dual 3″ system from the turbos back - the Soul Performance Products Trackback Turbo Back Exhaust.

As mentioned earlier we experimented with a straight pipe system. Not only does it sound incredible, but it makes good power as well.

This setup weighs 27 lbs / 12.2 kg less than factory exhaust components (39 lbs vs 12 lbs) making it perfect for track days.

We've optimized the turbo heat shield bracket a bit further as seen below.

During testing we experienced no CEL, but cannot guarantee the same results on all cars as all cars are different and unique. Catted O2 Spacers are also available to reduce any chances of triggering a CEL.

We're locking in the mandrel bending profiles required for a once piece and design and should have sets ready to go next week! Available with any of our tip options:

That wraps up our development for the 991.2 with PSE. Next up - Base and S models without PSE. If you'd like to be involved in the development process, please get in touch!
717 Posts
Discussion Starter #10
Fabbing up another run of our Cat Bypass Pipes.

Two things to note:
Our heavy duty aluminum fixtures prevent warping, ensuring proper fitment every time.
We back purge our welds whenever possible to encourage full penetration of welds and longevity.

1 - 13 of 13 Posts