JLetson

I have a 2018 C4S Non-PSE Coupe. I just purchased the car and have had an APR tune done. Like others, I'm looking for a way to improve the exhaust sound a bit without spending insane money or creating an obnoxious sounding beast. Will sport cats alone help? Who makes direct bolt on replacement cats that will work with the OEM resonator? I really don't want to spend $6,000 for an entire system from Soul or Fabspeed, etc. Seems like there are more options for those cars that came with the PSE system. Any help will be appreciated.

A question about APR tune as well. Does the full horsepower and torque boost only kick in when the car is in sport mode? Does normal mode essentially remain as the stock power levels? I'm just trying to understand how that file modifies ECU. My car is a manual and I elected to get a reduced torque file installed and am not sure of the final performance numbers.

I appreciate any input I can receive.

Soul Performance

Thank you for considering our rear exhaust! Unfortunately the impact of modifying your catalytic converter sections will not be as great as a PSE car which has a straight shot flow path out with valves open. I will say that our Performance Exhaust System went through extensive testing to develop the anti-drone tubes to target the specific drone range inherent to the 991.2 - over a dozen variations were tested until we ended up with our optimized result. I wouldn't recommend running upgraded cat sections without some way to attenuate drone. If you're looking to do a package deal on everything, we're happy to work with anyone on the forum to get you the best results and best pricing. We're always here if you need us.

Most ECU tunes will allow the vehicle to operate under more aggressive timing, fueling, and cam phasing parameters among other things. You will notice some more grunt and a more immediate engine response from these changes and then a massive gain in power with the increased boost targets. We use Softronic as Scott has experience tuning factory Porsche race vehicles, you might want to give him a call to discuss.

-Mike

NHmacan

Call up John at Soul and tell him exactly what your goal is. They are supper nice guys and probably have the best customer service in the business. I actually spoke to John today .

Soul Performance

Sport cats alone is a subtle but notable change to overall sound level and turbo sound. Think of the factory cats as amplifiers to whatever you have downstream on the car, factory or otherwise. We do have a set of high flow cats that will work on your car with the factory rear system. However, your car has a very unique exhaust setup after the cats. Changing your factory muffler requires changing your OEM tips as they can't be reused. The factory tips also have a cast angle into them that no aftermarket tip has, so that angle has to be made up for with exhaust tubing over a longer area that interferes with the giant factory cat assemblies. To get the room to run an aftermarket tip you have to replace the factory cats with an aftermarket set to get the room to run the tip outlet tubing back further to make up for that angle, otherwise you take up room in the other direction and the tips will stick out like cannons behind the car. The other option is to buy a set of OEM Base Model Non PSE tips (either the oval or deluxe quad tips in Polished or Black Chrome) for about $900 from Porsche. These also have that unique casted angle to them, but unlike the S Non PSE tips they are not offset to the side which allows for compatibility with aftermarket exhaust systems built with an OEM Base model tip option. If you're up for it, feel free to give me a ring at 4848836197. We'll go down the rabbit hole and ensure we come up with the right path for you to go down

As for the APR software, I'd suggest giving APR a ring and reviewing that topic specifically with their team. Nobody here on the forums is going to answer your question better than the fellows that actually designed the tune you're using on the car, and from what I've heard they're friendly to chat with.

Why thank you for the kind words! Always a pleasure to chat with fellow petrolheads, we're lucky to be in this business : )

Regards,
John Gaydos