We've seen cats melt at stock power levels. Is it rare? Yes.. but it can be catastrophic if the cat melting blocks your exhaust. Headers also provide good gains and change the tone a bit. Headers are typically our first go-to outside of a JLT intake/tune on these cars.
So it’s really the cats that are the issue, not the stock headers? Is there a way to install high-flow cats on a stock system?
This is absolutely correct. Kooks Green Cats (GESI G-sport cats) are higher cell count and can take the abuse far better than "normal" catalytic converters. I recommend taking a peak at their website as it has an abundance of information:
Yes it's the converters that don't like to get hot. I'm not familiar with anyone who makes a hi flow converter setup that would mate to the stock manis and resonator. Most people typically end up going the header route when they're building these things to be fast.
I hear ya, it just baffles me how expensive they are for such little gain compared to SW. What’s your impression of the Stainless Works catted headers?
So having been down this road bc SW is much cheaper option. SW and ARH make quality headers.... the issue being their cats are your basic 200 hi flow cat. So not going to last. Kooks green cats is where the big difference is and why the cost is greater.
personally if i were in your shoes and going with headers, id go catless, as you said that's an option for you in WV. as Lethal said the issue is the cats themselves being damaged. this was also explained to me by a tuner here in IL. he said if I ever go FI to consider ditching the cats. melting them or otherwise damaging them in such a way that causes them to give you a bad reading and changing how the engine runs can lead to serious engine issues that you dont want. so i think if you just go catless, go with whatever brand headers you want if you dont want to spend the extra on Kooks.
We're running the SW headers on our GT500 but the offroad track only version. I personally don't know many people who run their systems with cats to say how well they hold up. In general though cats and high boost/hp setups don't work real well together.
What is the best route to go for someone who wants to pulley it down to a 2.7 or 2.75 and still wants to road race the car? If I went headers I would probably get kicked off track for being too loud.
Hows the exhaust note and interior noise with catless version. This really peaks my interest. I'm assuming it throws a cel. I know Lund got hit by epa. Are they able to tune "offroad" set ups precisely or do they have to keep it dumbed down for emissions?
I road coursed our car stock and beat the snot out of it. Never had an issue. However the added heat from the pulley may put more strain on those stock cats. Maybe go with a catted header setup and stick with the stock resonator/stock catback. That way it's going to be as quiet as possible.
We have the 2" SW headers with offroad race leads on our car paired with a Corsa XX and Corsa sport/extreme catback. It's pretty loud from the outside under throttle but not overboard. It's also not wicked loud in the cabin. The only time I have to use the active exhaust valve in quiet or normal mode is when I'm on the phone. Otherwise that setup is by far the best sounding exhaust I've heard on a 2020+ GT500 by far. It's Ridic!!!
What did u guys do for tuning. I know my guy says no way they can dial in offroad set up appropriately bc of epa restrictions. But he is willing to install and get it as close as possible within the emissions restrictions.
We use Lund Racing on our Mustangs. They dialed it in perfectly!