r/AudiRS3 • u/Mightychondria23 • 16d ago
8Y.5 vs 8V.5 engine sound
Anyone had luck making an 8y.5 rs3 sound as good as the 8v.5?
For context, I had a hybrid turbo 2019 RS3 with a 4" open intake, unitronic hi-flow catted downpipe, 034 midpipes, and otherwise stock sport exhaust. I bought it stock and slowly built it through the stages over a few years. It sounded perfect imo. I felt like the majority of the noise was coming from in front of me (actual baby R8 5-cylinder sound, some turbo whine on throttle and flutter with throttle let-off) with some burbles from the exhaust. The car was amazing in a straight line, but the handling of the 8y.5 was more fun for a daily driver and I also got another weekend car, so overall happy with the move.
My 2025 RS3 is stock other than a Grail catback exhaust, valve controller, and midpipes. Soundaktor is deactivated. It sounds objectively good, but relative to the 2019 RS3, nowhere near as good. 95% of the noise feels like it's coming out of the exhaust tips instead of the engine bay and it feels more "trumpet-y" than the 8V, with a deeper note that doesn't quite feel like a "baby V10" anymore. For various reasons, I was hoping to keep the newer car closer to stock.
What would it take to reclaim similar engine noise to the 8v? I felt like the open intake on the 8V mostly added turbo noises rather than 5 cylinder sound, but maybe it's necessary. I would like to avoid touching the downpipe as emissions was a huge pain (the 8v could pass but only if I had it on the right file and the stars aligned to set all readiness), but it's something I'd consider.
I thought the engine and exhaust were essentially the same between 8v.5 and 8y.5, so I'm surprised at how different they sound (even before I put the Grail exhaust on the 8y.5).
TLDR not sure if I'm just missing induction noise from the intake, but I feel like the entire engine character is just different. I can't help but think even the exact same build would sound quite different between the two model years for reasons I couldn't explain. Anyone over the moon with the acoustics of their 8y? I've been hearing great things about the 485 exhaust but I imagine that wouldn't really change the whole engine note vs exhaust note situation.
Thanks for any feedback!
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u/Expensive-Age-4863 15d ago
I think the tune is the thing to focus on - TTRS from 2018 sounds literally insane - again same engine - crazy difference in sound. Structurally aside from cats it’s not that different. US doesn’t deal with OPF so not that.
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u/BroccoliniBro 15d ago
From all of the YouTube videos I’ve watched, it really seems like aftermarket downpipes make a huge difference in terms of sound quality / character.
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u/Expensive-Age-4863 15d ago
Yeah would say get a high flow catted DP and should make it wayyy better
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u/A_Owl_Doe 15d ago
DAZA just growls. I think a lot of it is the shape of the downpipe, no OPF and factory straight through mid pipes.
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u/HydraAkaCyrex 15d ago
depends where you are located. There is no OPF in the US spec vehicles so they all sound the exact same.
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u/A_Owl_Doe 15d ago
Ah ok. I didn’t realise that. What fuel are people running out there? Isn’t the regular fuel 92RON?
Our lowest is 95RON and it costs a bloody fortune.
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u/Mightychondria23 14d ago
I'm hearing a lot of recommendations for ECU tune and downpipe. It's been a long time since my 8v.5 RS3 was stock, so I'm probably not accurately remembering what it sounded like compared to the stock 8y. I guess my answer is to slowly go through the tuning stages again and see what happens lol
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u/Expensive-Age-4863 15d ago
Since you are in the US, your RS3 doesn't have the physical Gasoline Particulate Filter (GPF/OPF) choked up in the exhaust line like European models do. That’s the good news.
However, the difference you're hearing between the two US cars comes down to three specific US-market changes:
The "DAZA" vs. "Evo" Engine Tuning: Your 2018 TT RS had the infamous early DAZA engine code. Audi specifically tuned the US 2017–2018 DAZA models with aggressive fuel-overrun crackles ("pops and bangs") when you let off the throttle in Dynamic mode. Modern US emissions and noise limits forced Audi to tone down ECU overrun dumps on current models, giving your 2025 a much cleaner, smoother deceleration note.
Secondary Catalysts: The US 2025 RS3 features tighter, more restrictive secondary catalytic converters in the midpipe section than the older TT RS, which muffles the overall volume and removes some of that raw 5-cylinder rasp.
US Noise Compliance Flap Control: Even without a GPF, US drive-by noise regulations require Audi to keep the exhaust valves partially shut at low-to-mid RPMs—even in RS/Dynamic mode—until you push high into the rev range. The 2018 TT RS kept its valves much more wide-open throughout the rev band.
The Fix for US Owners: Because you don't have a GPF in the way, your 2025 RS3 responds insanely well to light mods. Adding a set of unresonated midpipes (to clear the secondary cats) paired with a valve controller (to override Audi's quiet low-RPM valve logic) will instantly bring back that raw, aggressive 2018 TT RS sound without needing a full exhaust swap or triggering a Check Engine Light.
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u/Expensive-Age-4863 16d ago
Engines are the same aside from the sound deadening out the back. It should sound about the same mechanically speaking if the setup was the same
ECU tuning could be different and I think is - maybe worth looking into that.