Project: 997/991 GT3 exhaust on 911 3.2

[auchenberg]

Hi all,

Since discovering that it's possible to install a 997/991 GT3 exhaust on my 87 911 3.2, I've been searching for a solution and wanted to document the project here.

After searching the forums I've found many examples of custom headers build to match the GT3 muffler. After a bit of emailing with Brian from Rarelyl8 I learned that he was working on a set of active headers that's using a vacuum valve to switch between the primary and secondary input on the muffler. I was sold.

Below is the headers (with heat) from Brian, and a 991 GT3 muffler coated at PerformanceCoastings in their special "Porsche Grey" ceramic Chromex coating

A few photos:






The set is getting installed this week, and I'll be following up with more photos and videos.

/k

[Classic 911]

Nice


Sent from my iPhone using Tapatalk

[Bruce911_]

I was thinking about doing the same thing on me ‘88 Carrera. Just happen to have both 997 and 991 center mufflers. Do you know if they make it without heat too? Will be following to see how it comes out and your impressions.

[jpnovak]

very nice. Can't wait for a sound clip.

[GaryR]

Beautiful, how will you run the open/close solenoids (assuming thats' what they are)? Remote?

[ab1752]

This look awesome, let's hope Brian has plans for move those headers into production as that's exactly what I'm after for my 3.2. Can't wait for the updates, be interesting to see the differences in weight too.

[Cairo94507]

Beautiful exhaust. Can't wait to see it installed and hear a sound clip.

[ab1752]

Will the muffler require a modification to the rear valance too?

[ab1752]

Originally Posted by GaryR

Beautiful, how will you run the open/close solenoids (assuming thats' what they are)? Remote?

Being "active" im guessing you open and close the valve with your right foot.

[bkreigsr]

Whoa...
How much does that setup weigh ?

[mike sampsel]

Originally Posted by GaryR

Beautiful, how will you run the open/close solenoids (assuming thats' what they are)? Remote?

Well, mine opens with no vaccum, with vaccum they shut. As such mine is shut at idle and opens on acceleration (my vaccum connect to the front of the throttle body on my SC). No vaccum connection and the muffler bypass is open. I just have the active sport cat though.

Like it a lot.

[MIAdragon]

Looks heavy and complicated.

[RarlyL8]

We've had our long tube headers in production for about a year now and are finding new and creative applications for them all the time.
These 997GT3 back box conversions are neat systems, we've done several now. I really like active exhausts and have developed our own active mufflers for several applications. The 997GT3 muffler sounds a bit better than the 991 version. The titanium version is crazy light which is always a plus. The system as a whole is not overly heavy and it looks more complicated than it is. The valve system is simple, they open when the engine is under load. Electronic controls can be added of course.
Tailpipes do require a valance mod. We make fiberglass units for this purpose.

[SalazarS2K]

Wow that looks stunning. Any updates on this install? Looking forward to hearing some sound clips. What is the OD of the pipes and will this work for a 3.6?

[winders]

Originally Posted by RarlyL8

We've had our long tube headers in production for about a year now and are finding new and creative applications for them all the time.
These 997GT3 back box conversions are neat systems, we've done several now. I really like active exhausts and have developed our own active mufflers for several applications. The 997GT3 muffler sounds a bit better than the 991 version. The titanium version is crazy light which is always a plus. The system as a whole is not overly heavy and it looks more complicated than it is. The valve system is simple, they open when the engine is under load. Electronic controls can be added of course.
Tailpipes do require a valance mod. We make fiberglass units for this purpose.

Where are these headers made?

[speedster911]

Originally Posted by RarlyL8

We've had our long tube headers in production for about a year now and are finding new and creative applications for them all the time.
These 997GT3 back box conversions are neat systems, we've done several now. I really like active exhausts and have developed our own active mufflers for several applications. The 997GT3 muffler sounds a bit better than the 991 version. The titanium version is crazy light which is always a plus. The system as a whole is not overly heavy and it looks more complicated than it is. The valve system is simple, they open when the engine is under load. Electronic controls can be added of course.
Tailpipes do require a valance mod. We make fiberglass units for this purpose.

Brain, beautiful work as always from you!!

Curious, your headers with heat, can valves be adjusted without removal of headers?

Thank you, hope to purchase this setup from you late next year. Happy Holidays everyone

[RarlyL8]

Thank you!
It's not a bad idea to remove the 12 bolts and drop the headers when doing a valve adjustment to keep the nuts from seizing up over time and also take a peak inside the exhaust ports. The 1.5" version exchangers will clear the valve cover, the larger will not. I have re-designed the exchangers to be more form fitting, have max ground clearance and also to be serviceable like those on our RSR headers.
The 997 GT3 back box mod is pretty popular right now, I'm finishing up several at the moment trying to get out before Christmas. Also doing one for an Akrapovic version which should be interesting.

[jpnovak]

Do these wail like a modern GT3? I get that our engines do not have the rpm range to really get that scream. Just wondering if the firing pulse order, engine capacity, and flow rates give the same general sound.

I Have heard a few 997 mufflers (not GT3) and I like an early car sport muffler tone better.

Just curious about sound clips. I have not seen (heard) any.

[winders]

Originally Posted by RarlyL8

Thank you!
It's not a bad idea to remove the 12 bolts and drop the headers when doing a valve adjustment to keep the nuts from seizing up over time and also take a peak inside the exhaust ports. The 1.5" version exchangers will clear the valve cover, the larger will not. I have re-designed the exchangers to be more form fitting, have max ground clearance and also to be serviceable like those on our RSR headers.
The 997 GT3 back box mod is pretty popular right now, I'm finishing up several at the moment trying to get out before Christmas. Also doing one for an Akrapovic version which should be interesting.

Where are these headers made?

[RarlyL8]

http://forums.pelicanparts.com/porsche-911-technical-forum/1033382-m-k-tuned-headers-2-4l-3-0l-engines.html

They are my design and brand. Yes they do have some of the same visual cues as some other brands but that is to be expected. Design has been expanded from 1.5" & 1.63" to 1.75" and also step combinations. Heat exchangers have been revised on the larger primary systems. V-bands are used for the modular systems such as the 997GT3 back box and the Dynomax race muffler. Each set is configured per the application.