RS3 downpipe advice needed

[Arelax]

Looking at getting a downpipe, main reason is I'm wanting a better sounding exhaust. I'm thinking this will give me what I want + a little power boost versus an expensive catback.

Currently DS1 tuned w/ all the supporting mods so I assume WG rattle wont be an issue

No emissions checks in my state

1) Benefits of Catted vs catless? (Aside from environment)

2) Which brands are preferred? currently looking at an APR catless

3) any other thoughts/advice/experience?

Thanks

[XLR8Performance]

Hey, I just wanted to introduce myself to help you modify your vehicle quickly and efficiently.

We have a few downpipes for you RS3 from 034MOTORSPORT, UNITRONIC, and Scorpion

Free feel to reach out with any questions. I will provide you with links below

https://xlr8performance.com/i-73639-...Rs3%2Bdownpipe

https://xlr8performance.com/i-73792-...Rs3%2Bdownpipe

https://xlr8performance.com/i-72232-...Rs3%2Bdownpipe

[o1turbo30v]

1) Benefits of Catted vs catless? (Aside from environment) - No, a few more hp with catless

2) Which brands are preferred? currently looking at an APR catless - no, they all do the same job

3) any other thoughts/advice/experience? - if you leave in your stock catted midpipes the smell wont be to bad if you go catless DP. Also get the DP ceramic coated before install

[Alex D]

My only complaint with going catless is the smell. If you just want a better sounding exhaust without having to do the downpipe and mid pipes, i recommend the Boost Logic Titanium exhaust. In my opinion, hands down the best sounding exhaust on the market for this platform.

[signde]

can you even find an APR downpipe for sale? APR discontinued stage 2 last year and my understanding is they were no longer making downpipes. i also seem to recall all remaining inventory sold out pretty fast after that.

[Brian@Unitronic]

I would highly recommend our downpipe! They should be back in stock towards the end of this month and I can assure you no other manufacturer has put as much engineering into a downpipe as we have.

With our downpipe you will have a deeper tone than stock and no "tinny" sound like you'd get from thin wall stainless downpipes.

https://www.getunitronic.com/parts/e...5tfsi-downpipe

Let me know if you have any questions

Brian

[ArrEssDrei]

As Brian said cast downpipes definitely have a richer/better sound to them at part throttle acceleration. Was quite noticeable hearing one on a friends car after running a milltek de-cat on my own for a year - which is not a bad sound, but is a bit high pitched under part throttle tip in acceleration. Waste gate rattle was horrific with my setup, so if a tune does not address that, it's well worth going cast and catted.

Not sure if I'd go de-catted if I had it to do again, sooty tailpipes, a bit of smell and not a lot of gains in power, plus relying on one shop to sneak me though inspections here. Though I do wonder if EGT (exhaust gas temperatures) are a factor to consider?

[Arelax]

As Brian said cast downpipes definitely have a richer/better sound to them at part throttle acceleration. Was quite noticeable hearing one on a friends car after running a milltek de-cat on my own for a year - which is not a bad sound, but is a bit high pitched under part throttle tip in acceleration. Waste gate rattle was horrific with my setup, so if a tune does not address that, it's well worth going cast and catted.

Not sure if I'd go de-catted if I had it to do again, sooty tailpipes, a bit of smell and not a lot of gains in power, plus relying on one shop to sneak me though inspections here. Though I do wonder if EGT (exhaust gas temperatures) are a factor to consider?

Thanks for the info, I'll def ensure its cast.
Thats what I like about the APR, you can get their high flow catted midpipes if the smell, soot, etc is too bad, or remove them and remain straight catless. Swapping a downpipe is not nearly as easy ofc.

can you even find an APR downpipe for sale? APR discontinued stage 2 last year and my understanding is they were no longer making downpipes. i also seem to recall all remaining inventory sold out pretty fast after that.

yes, you can get them used

I would highly recommend our downpipe! They should be back in stock towards the end of this month and I can assure you no other manufacturer has put as much engineering into a downpipe as we have.

With our downpipe you will have a deeper tone than stock and no "tinny" sound like you'd get from thin wall stainless downpipes.

https://www.getunitronic.com/parts/e...5tfsi-downpipe

Let me know if you have any questions

Brian

Thanks Brian, How does catless compare to catted in terms of sound?

[8STTRS]

Thanks Brian, How does catless compare to catted in terms of sound?

I'm not Brian, sorry but, in my experience, when you compare aftermarket headers or downpipes that are with and without cats, within the same brand, the difference is slightly more volume for a catless system. Of course, they are all significantly louder than the stock setup but, a high flow cat is not quiet by any means whatsoever.

[robotvoice]

I have a Redstar Exhaust downpipe on my TTRS and love it. I will be getting their downpipe for my RS3 once I am ready to swap it out. Fit and finish are awesome and they have great support.

https://redstarexhaustusa.com/audi/2...-downpipe.html

[jd_rs3]

I highly recommend e85 if going catless DP. The smell is horrible on 91/93. Your clothing and hair will smell like hydrocarbons until washed if you are anywhere near your car while it's running. It's at least tolerable with e85.

[brobst]

Smell is an often overlooked part. Even driving behind a catless car is annoying. The hp difference doesn't add up till you get till like built motor territory. And at that point, you don't care as much.
As stated above they will sound different too. Like how the midpipes change the sound, the cat in the dp will have a similar effect

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[nate.co]

Here's some video - this is a Unitronic catted downpipe and midpipes. Stage 2 tune, 91 octane, IE intake and Unitronic intercooler. I highly highly highly recommend the catted setup, cars have catalytic converters for very good reasons. The car is fast as hell.

Microphone is mounted on the trunk, video is a GoPro suction cupped to the sunroof.

[Arelax]

Here's some video - this is a Unitronic catted downpipe and midpipes. Stage 2 tune, 91 octane, IE intake and Unitronic intercooler. I highly highly highly recommend the catted setup, cars have catalytic converters for very good reasons. The car is fast as hell.

Microphone is mounted on the trunk, video is a GoPro suction cupped to the sunroof.

thanks for that.
We have very similar radar/blackvue setups too. and i appreciate the tip on go pro mounting location. Is there an extension on the suction mount? and what microphone you using?

[WmRS3]

thanks for that.
We have very similar radar/blackvue setups too. and i appreciate the tip on go pro mounting location. Is there an extension on the suction mount? and what microphone you using?

I use same setup for all my street testing and races for years. I use go pro cup with a long red 8 in alum extension arm off ebay and an ebay mic with noise sock I mount it on outside of trunk with a little painters tape.

https://www.youtube.com/watch?v=BsycwqAXfGQ

[nate.co]

thanks for that.
We have very similar radar/blackvue setups too. and i appreciate the tip on go pro mounting location. Is there an extension on the suction mount? and what microphone you using?

Yeah, love that dashcam.

I just use a GoPro suction cup with an extension, can't remember where I got it, probably Amazon. Mic is a Rode Stereo VideoMic X (which is overkill here but a nice mic) on the same type suction cup with without the long extension.

[itr325]

I highly recommend e85 if going catless DP. The smell is horrible on 91/93. Your clothing and hair will smell like hydrocarbons until washed if you are anywhere near your car while it's running. It's at least tolerable with e85.

I’m catless and run E85 in summer and 93 in winter, I’ve never had my clothes smell. This is a bit of an exaggeration. That’s not to say there isn’t a little smell of un-burnt fuel, but it’s not awful.

[jd_rs3]

Agree to disagree then. 91 octane and catless DP is obnoxious if you stand near the car while running. And if you start the car in the garage, it will stink even worse.

Also never really understood the whole "I run 91 in the winter" argument but that's a different discussion.

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[brobst]

Agree to disagree then. 91 octane and catless DP is obnoxious if you stand near the car while running. And if you start the car in the garage, it will stink even worse.

Also never really understood the whole "I run 91 in the winter" argument but that's a different discussion.

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E85 has starting issues in colder weather. That and fuel blends end up being lower quality e85 like e60ish

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[tegxsi]

E85 has starting issues in colder weather. That and fuel blends end up being lower quality e85 like e60ish

Yeah, cold start on high E content can be a pain but can be done. Ethanol content is the same all year in California (+E80) according to Pearson and Propel fuels.
E60 is a breeze if tuned correctly...

I've tuned a few Subaru's and I've managed to them to start up in the winter...but these are California bay area winters lol
I'm fairly confident they will crank over without too much effort in freezing temps.

[brobst]

Just for reference. Also e85 absorbs moisture which is a bigger issue in the winter
afdc.energy.gov

Like gasoline and diesel fuel, E85 and other ethanol-gasoline blends are adjusted seasonally and geographically to ensure proper starting and performance. For example, E85 sold during colder months often contains lower levels of ethanol to produce the vapor pressure necessary for starting in cold temperatures. For this reason, fueling site operators offering ethanol blends typically cannot carry over summer-blend E85 into the winter months. They must instead "blend down" any remaining summer fuel to meet the ASTM specification's requirements for winter temperature conditions.

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[vincentc77]

I was in the same boat as you. Historically, I had a catless on my prior EVO X and it smelt terrible. Almost to the point where I was embarrassed. Im also in an area that does not do emission testing. Further more, I have heard feedback that many DPs have noisy wastegate rattle which is debatable with each persons opinion of "noisy" different. I had a difficult time paying an extra $1k for the Uni since my wife questions every car expenditure :( I have no intentions of ever going past a hybrid turbo and decided on the Uni. No regrets and it's been on for almost a year now. Very little rattle which is only barely noticeable when the windows are down and im near a barrier. Absolutely no smell and no worries of ever being fined for not having a cat.