Feedback on Gruppe-S Headers/OP & Catback Combo
 

Hello to everyone!

I’m new to the community so please bare with me.

I have just installed Gruppe-S Headers & a Gruppe-S OP with an Ultimate Racing cat back, and I am a little unsure of the results so I’d like to hear your thoughts. Check it out here (sorry for the poor quality): https://www.youtube.com/watch?v=4IIJudC4vhM

Note that I haven’t gotten my build flashed or tuned yet, but I plan to do so this week.

I was expecting a louder and more aggressive sound similar to a classic Subaru rumble, but I got a very raspy and metallic trombone-like tone when driving casually. I also experience quite a bit of drone at low and high speeds. This is a little weird since you wouldn’t expect this sort of tone from this combination.

This is by far the loudest car on the road when cruising lol, and again to be clear I am looking for a deeper rumble-like tone similar to classic Subaru rumble.

To be fair, I have done my fair part of research and very few have experienced similar notes with Gruppe-S Headers and certain cat back systems while numerous have gotten incredible tones from their build.

I’m thinking that I might have done a mistake during the install perhaps.

Now, I’m thinking of:

• Swapping/removing my Ultimate Racing cat back for Perrin 2.5/3, N1 or anything that has a little bit more restriction
• Flash my ECU in the hopes that my car runs smoother and maybe does something about the trombone-like tones at 2100-3600 RPMs.
• Weld resonators within my mufflers or simply swap mufflers altogether for now.

What do you guys think?

In any case, I wanted to share my experience with this sort of build! I hope this thread helps others :)

https://streamable.com/7jcst

I have The same headers, only other exhaust mod is a nameless single exit 5" muffled track pipe. Stock frontpipe and midpipe. No rasp at all with mine even at high revs, I am sure the stock midpipe and frontpipe help with that. Just adding my video for reference on another exhaust set up with the same headers.

Do not get the N1, that will also be raspy and terrible with catless UEL headers. You could look into the N2 or go with a nameless axleback like I did.

https://www.youtube.com/watch?v=5LqAASo306g here is a video of the N2, I think it sounds pretty good, theres other videos out there. I don't think the N2 has rasp.

Also you said you're thinking of flashing your ECU, did you tune your car when you installed the headers?

Tuning refined the sound so I would suggest you try that first.

The Resonator in your front pipe is gargbage when you change the header it does not do much to stop the rasp and weird sound frequency you get with switching to a aftermarket header.

i purchased a Vibrant resonator cut out the resonator in the front pipe and welded this in. Cleaned up the tone, no rasp and sounds great. You could also get the JDL ultra quiet front pipe but I don't know how good the resonator is, the Vibrant is well known for its quality. Just be aware it a tight fit so you might need to cut a section of your cat back and weld it.

https://www.youtube.com/watch?v=2MuBD10WzBI
https://www.amazon.com.au/Vibrant-11.../dp/B000E3VHWI

sounds cool, thanks for the video.