jktag

Does the cat bypass system require a tune to avoid error codes?

Thanks

Cm09578

I tried extended sensors in an attempt to avoid the check engine light, but I still got a code. Check engine light is normal with bypass pipes. Sam from By Design ran a custom tune for me and removed it.

Cm09578

Love the sound!

John D II

Yes, the newer Porsche ECU's are very sensitive, even most brands of full cats will throw a CEL, so with catless it's tough to fool the ECU.

Glad you are enjoying you new exhaust, Cody!

Scorpion006

Not sure if I missed it or not, but did you guys dyno the car before and after to know what your performance gains are?

I'm really interested to see that...

John D II

We did not, the owner of the development car specified no dyno...

MotoJB

Anyone out there have this catless x-pipe system on their 991tt or tts?

MotoJB

Just got back from overseas...to find a nice box waiting. Here's the system, can't wait to get it on this Thursday! Sound videos to come.

John D II

We had a 991 Turbo day today, finished and prepared 3 variants of our 991TT X-Pipe for shipping (pics below):
.

1. A Sound Level 2, 2.5 Catless "RACE" X-Pipe with 3.0 dual tips in ceramic black
2. A Sound Level 4 - MAX PERFORMANCE, 3.0 X-Pipe, 200 cell HJS cats with 3.0 dual tips in ceramic black
3. A Sound Level 4 - MAX PERFORMANCE, 3.0 X-Pipe, 100 cell HJS cats with 3.0 dual tips in brushed stainless finish

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John D II

Below is a video we shot at our exhaust testing facility, highlighting our newer 991 Turbo "valved" GT2 RS style exhaust. This particular version has a 3.0 X-Pipe at the core and utilizes 100 cell HJS catalysts. It can be alternatively optioned with a 2.5 X-Pipe. A simple push of a button opens the cat dump pipes for a much more aggressive tone, same as the OEM exhaust on the 991.2 GT2 RS. With the valves closed, it's our traditional 3.0 X-Pipe. Additionally, the valves can be programmed to open up at any user defined RPM. We have found 5,500 RPM to be a great spot to transition to open valves.

Users should enjoy this system's options. It's great to be able to toggle back and forth with the sound or set a driver defined RPM for the valves to open.
As an example, the system allows the operator to be in the open or loud mode on the open road and when approaching a busy area, gas station, etc. with a lot of people, simply select the closed valve mode and the system instantly becomes much quieter, very civilized and refined, unless you want to remain loud such as arriving to a car meet or car show where everything is typically louder.

Here are a few pictures from the development stage and a video to demonstrate the system.

Valve closed


Installed


Valved pipe directly off the catalyst, same as 991 GT2 RS (the inner tip is for gasses travelling through the X-Pipe when dump valve is closed, the outer pipe/tip dumps straight out from the catalysts when open)



3.0 X-Pipe w/ rolled edge tips (slash cut also available and pictured above)

You Tube

John D II

Here is a bench test video to demonstrate the valve action of this 991 turbo GT2 RS style valved exhaust system