Project Viper GTS: Part 6 – Corsa Exhaust and Kooks Green Cats


Viper GTS ExhaustWith the exhaust removed, we can see the layout of the Viper’s exhaust path.

Kooks Custom Headers is doing their part for the environment by partnering with Global Emissions Systems Inc. (GESi) and staring the “Green Revolution” of EPA certified Catalytic convertors.  No longer do you have to choose between performance or environmental responsibility when their “Green Cats” do not rob power (are said to have less than a 5hp loss), work on NA and Forced Induction applications up to 800hp, at temperatures up to 1,500*F, will not set off a Check Engine Light, are OBD-2 compliant, and meets EPA Federal emission standards and are 49-state certified (due to the California Vehicle Code Section 27156 and 38391).

The GESi High Output Catalytic Converter features full stainless steel construction, including the substrate, outperforms stock converters, and provides a reliable solution to the most common catalytic converter problems.  The 300-cell per square inch stainless steel substrate is furnace braised to the mantle and uses a unique end-cap design lock for outstanding durability and rattle-free operation.  The cat can reach operating efficiency within 9 seconds of startup and is covered by a 5 year / 50,000 mile warranty on the shell and tube ends.

In order to achieve the necessary levels of pollution control, lower density cats need to be significantly lengthened, which reduces flow.  It’s possible to end up with a 100-cell converter that does not flow as well as a 300-cell model, and the short body of the Kooks “Green Cat” is designed for flow and efficiency.  According to Kooks, this is the only aftermarket racing cat that will pass emissions, not set CEL, and make a ton of hp.

“Only loses 1-2 HP going from off-road to catted.” 

About GESi®

GESi® is the brainchild of its co-founder and President/CEO, Eric Latino, a highly regarded Pro Mod drag racer a current holder of the Canadian class record. He co-developed the proprietary emissions reduction technology that sets GESi® catalytic converters apart from the competition. His goal was to offer a solution to owners of high performance vehicles who simply could not find catalytic converters capable of consistently surviving the conditions that those engines throw at them.

Kooks Green CatsThese Kooks Green Cats are a game-changer.  To be able to retain cats on your performance car, meet EPA emissions while losing little to no power over a straight pipe; this is a Win-Win and no-brainer in my book.

Now my day job might not be the most environmentally friendly of professions, (but I’m not a cattle rancher either, and cows put out far more emissions than automobiles, so the government probably has more improve on that front than to keep a short leash on our community) and as a car guy I like power and don’t really want to give it up at the expense of being good for the environment, especially when living in a state that does not check for emissions.  Now that Kooks has come up with a solution so you can have your cake and eat it too, I don’t mind giving up a handful of horsepower to be good for the environment, not have a check engine light, not have an increase in exhaust smell in a primarily street driven car, and knock down a little bit of sound compared to a straight pipe for the new Corsa exhaust.

Viper GTS Cat Comparison KooksThe Kooks “Green Cat” is roughly 1/3 the size of the factory catalytic convertor.  It’s amazing that this small package can be as effective as the monster it replaces. 

Stock Viper GTS Cat SubstrateKooks Green Cat Substrate

The original factory cat (LEFT) has a ceramic substrate with power-robbing dense fins which increase the exhaust’s backpressure, further increasing exhaust temperatures, and can eventually cause the ceramic to fail and plug up the cat.  This is very common for any supercharged car and is especially an issue with the Viper.  The Kooks “Green Cat” (RIGHT) has a stainless steel housing and a less restrictive stainless steel substrate.  Most ‘metal’ cats don’t use stainless steel substrates, and while they are far better than ceramic cats for forced induction applications, the stronger Kooks stainless substrate will ensure even greater durability and longevity.

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