We’re coming along with development of our 992 GT3 exhaust suite. This is part 2 of our deep dive on – see our first blog post in the series for information on the factory exhaust system.
If you live in the high rpms and are looking to maximize performance, shed a noticeable amount of weight, and realize the full sound potential that only a complete race system offers – this Race Exhaust System is for you. Removing the heavy and restrictive factory headers is central to the performance improvement. By pursuing a full system replacement we eliminated the restrictive cat assemblies, the “particulate filters”, and the giant 7 ⅝” connection point to the factory rear muffler assembly. A simple flange optimization to our previous generation GT3 Competition Headers allows us to get rid of the factory 991 gen connection point requiring costly OEM clamps and donut gaskets and utilize a more efficient v-band connection point. We’ve also designed a full 3” modular section that allows you to switch between catless and catted if you want to minimize the chance of CEL and reduce overall sound level at WOT. It is then finished off by a full 3” X-Pipe section for a smooth/high pitched sound with a tip plate that allows you to customize your tip selection. This system will knock your socks off in all aspects, and below are the more intricate details to the development.
Even a premier engineering masterpiece like the GT3 comes from Porsche fitted with exhaust manifolds restricted in terms of primary tubing length, runner diameter, and merge collection efficiency due to dense catalytic converters, mass production, emissions and sound restrictions. By refining the interface between the flange/primary tubes, using smooth radius large diameter bends, and implementing performance oriented collectors with merge spikes, we have been able to achieve increased flow, response, and performance with a more aggressive exhaust note to match. We focused on designing a high flow collector from CAD to CNC for a no compromise end result. This bespoke billet collector allows for maximized runner length and the elimination of several welds in the interest of durability. Our billet CNC head flanges allow for a more efficient transition from exhaust ports into the runners and adds extra strength in a high stress area preventing the chances for any cracking from repeated, hard use during track days.
REAR EXHAUST SECTION
The rear of the SOUL Race Exhaust System is optimized into a single, full 3″ flow. The design of the factory system includes very large catalytic converters terminating into a very heavy dual entry muffler with restrictive piping with variations throughout the flow path which hinder performance. Those seeking a race setup will appreciate the 25+lbs weight savings and concentration on increasing exhaust flow.
From there we dove into creating a header-back system to maintain maximum flow characteristics with a higher, smoother pitch and aggressiveness akin to an RSR race car. This full 3” diameter system is made from thick .065” wall T304L stainless steel and TIG welded with back purging to ensure it withstands hardcore track abuse. It’s also modular to allow interchanging between catless or high flow catted assemblies with minimal effect on exhaust velocity. Reduce the chance of CELs with 200 cell cats and tone down the exhaust if need be as the catless version is without a doubt the loudest and most aggressive system we have ever built. After the catted/catless section, the exhaust flows into an X section where we took care to minimize the diameter reduction while maximizing the blend of the exhaust to create that higher smoother pitch you hear in the videos. Finally a tip plate (same used on 991 GT3’s) allows one to switch between tip assemblies at their convenience.
The electronic valve actuators can not be simply removed from the valves or else the car will throw a CEL and put it into a reduced rev limiter to 6k rpm. Custom brackets hold the electronic valve actuators to simulate the same start/stop point of the valves in the factory exhaust system. This allows the car to run the non valved exhaust system without any CEL or reduced rev range. We can also turn the CEL off with ECU Tuning.
The sound experience of this system on the 992 GT3 is something to behold. The blending of the X gives the car a higher pitched sound befitting of a GT car with authoritative volume to match – on the extreme end for a street driven vehicle. Those seeking a Cup Car experience will be rewarded with an aggressive wail, and your face will hurt from the permanent smile. Choose the catted version and the overall sound level is reduced notably and gives you a better chance at a CEL free experience. Be warned, this system is not for the faint of heart! Pursue with caution or call us first if your driving experience is primarily on the street under 3k rpms, as we’ll discuss other options with you that may be better tailored for your individual driving experience.
Through a collaboration with Orbit Racing and Hydra Motor Works this 992 GT3 had independent dyno testing done stock, post exhaust install, and then with a Hydra Stage 2 ECU tune. Our Race Exhaust System by itself added peak gains of 23 whp and 19 ft-lbs of torque with excellent power added in the midrange and max RPM’s. Hydra’s Stage 2 ECU tune added massive additional power gains when paired with our exhaust, unleashing total peak gains of 60 whp and 26 ft-lbs of torque and max gains of 60+ whp and 70+ ft-lbs of torque – quite incredible to see on a naturally aspirated engine. The software is quite limited from the factory in the lower RPM range to due to the implementation of GPF filters in the headers and ever increasing emissions standards. By removing the GPFs and the other restrictions in the exhaust, this allows the ECU tune to unlock the true potential of the 4.0L.
Each component is assembled in the USA out of mandrel bent, thick wall .065″” T304L stainless steel. Our billet 304L stainless steel head flanges and merge collector are precision cut on a 5-axis CNC machine for the best possible exhaust flow and strength. Back purged TIG welding (with ARCAL™ Prime argon gas) ensures proper weld penetration and longevity – crucial for durability on the track. We fabricate the headers and system using thick gauge aluminum fixtures which act as a great heat sink during the welding process and prevent warping not only of our products, but the fixtures themselves to ensure perfect fitment. Enjoy your SOUL exhaust components with confidence on both the street and track as they are covered for life as part of our Lifetime Warranty!
HJS HD 200 CELL CATALYSTS
The highest quality catalytic converters available, known for their industry leading flow and durability. They are efficient enough to meet strict EURO 4 emission standards while still allowing for an increase in flow. The HD design uses premium triple foil winding for maximum strength. The brazing stripe is an extra feature in the interest of durability – it prevents the core from moving or experiencing any damage from sustained high horsepower abuse.
Questions? Comments? Let us know!