Since you are located in the US, check out 42 Draft Designs

Audi Mk2 TTS 3" Downpipe

High performance parts made in the USA including exhaust systems, air intake systems, wheel spacers, wheel adapters, oil catch cans, and more.

www.42draftdesigns.com

 

I have the Unitronic on my A3 and have the CTS on my TT. No problems with either of them other than fit (which we'll get to). The CTS was obviously a lot cheaper and "YGWYPF" of course. The CTS is not bad per se, but it's not at the same level of quality as the Uni--it's to be expected though at the price differential. Also the Unitronic pipe is resonated, the CTS is not. So the CTS will drone at like 130-140km/h and above (80-85MPH +). It's not really a problem if you don't cruise at speeds that high, but in a lot of the US you might (as speed limits can be as high as 75 MPH and so driving at 85 MPH is not really anything unexpected).

The Unitronic also comes with v-band clamps with machined mating points, appropriately. The CTS just has standard exhaust clamps and fits together in "sleeved" fasion. Again something that is expected with the different price points. Both of them have their own fitment issues you kind of have to struggle and fool with a bit to get the most optimal placement/installation. Such is par for the course for downpipes from both my experience and the reports of many others that have had (mostly minor) fitment issues.

I can't comment on the Scorpion but I'd probably take the Uni over it, if we're talking about the same price. I think those are very Europe/UK-centric though too no? Not really seeing them for sale anywhere but in pounds or Euro, but perhaps I'm not looking in the right place.

Also if you're going with the CTS, I'd wait for a sale. It's kind of odd because usually CTS always has a "sale" lol. But surprisingly looks like right now they actually don't; but, their sales are definitely very frequent. I bought my CTS pipe for like $670 CAD (about $500 USD) on sale, but that was about 3yrs ago. I expect the [sale] price would be higher now (as everything is) but still cheaper than the $830 CAD list/reg. price.

The 42DD is another option of course. It says they use a 400-cell HF cat as well, where the others are all 200-cell I believe. The 42DD is interesting in that it has flanged mating surfaces but has the option of going v-band (but that costs another $200 USD). The thing about the flanged mating surfaces is that you can't really adjust the pipe much if you have fitment issues since there's really only one way it's going to go together. With the clamped style (either sleeve or v-band), you're free to rotate the pipe about to change how it fits. OTOH, that also gives the possibility you're not installing it in the intended orientation as there's no indication what that is--that becomes guess work and trial and error TBH. Also if you want to get a resonator on it, like the Uni, the price goes up another $90. So the 42DD is basically a "no frills" pipe, similar to the CTS in some ways, but can be "optioned out" to end up like the Uni pipe with v-band fittings and resonator. Kind of points out the YGWYPF theme here.

The Milltek honestly I don't see anything better there than the Uni pipe (?) and certainly nothing warranting a +$400 USD increase. My feeling is it's simply a case of "paying for the name", but that's just my take on it.

 

I have the Unitronic on my A3 and have the CTS on my TT. No problems with either of them other than fit (which we'll get to). The CTS was obviously a lot cheaper and "YGWYPF" of course. The CTS is not bad per se, but it's not at the same level of quality as the Uni--it's to be expected though at the price differential. Also the Unitronic pipe is resonated, the CTS is not. So the CTS will drone at like 130-140km/h and above (80-85MPH +). It's not really a problem if you don't cruise at speeds that high, but in a lot of the US you might (as speed limits can be as high as 75 MPH and so driving at 85 MPH is not really anything unexpected).

I can't comment on the Scorpion but I'd probably take the Uni over it, if we're talking about the same price. I think those are very Europe/UK-centric though too no? Not really seeing them for sale anywhere but in pounds or Euro, but perhaps I'm not looking in the right place.

The Milltek honestly I don't see anything better there than the Uni pipe (?) and certainly nothing warranting a +$400 USD increase. My feeling is it's simply a case of "paying for the name", but that's just my take on it.

Yeah driving at 85 mph (130km/h+) is pretty common for me so I had pretty much decided a while ago I did want it resonated. I don't want the car to sound obnoxious (it's not a civic), I want it to sound better. So I guess CTS is not the way to go unless they have a variation that's resonated (Which I don't think I saw one).

Xlr8performance.com has scorpion products listed in USD and free shipping here in sunny Florida so I don't know where they're based but I definitely have easy access to their products. Scorpion popped up a few times in some other exhaust forums but again I had never heard of them til just the other day so wasn't too sure on them.

And then Milltek just left me scratching my head. I didn't see anything that really caught my eye on the specs so that price just seemed bizarre to me.
As always thanks for the response btw

 

We run 42 draft designs on all the cars. Our TT mk1 225 has had it on for 5 years never a issue b7 had it for 4 no issues. Can tell you they are not the same as cts. I just looked at a cts on a bt vw mk6 fit and finish not there. Also the 42 draft designs spacer works wonders had it another car with test pipe no check engine light etc. Actaully have 3 of them now. And 42 draft designs offers the vbands as a free upgrade now. Their builds are so good really a shame to put it on car. I am actaully getting one for the 2013 TT project.

 

Okay so it looks like maybe I should lean more into the 42DD over the Unitronic simply based off how much experience you've had with them already. Any opinion on the sound Over the Unitronic? The resonator on both look a little different so I'm sure it has to change the sound. Also, does the 400cell cat allow a slightly higher power output over stock from your experience?

 

Trackslag

I know you're in the US so it might price itself out of the equation, but the quality is second to none and you want 3.5" on the flange for best performance

 

Barr_end are we talking 3.5 at the pipe or flange? Yes 3.5 is better but there is a catch depends on the bend and if the gasket matches. if we are talking just the size of the flange as a hole ignore me.

 

Never had resonators. So cannot answer that. But if your keeping stock and just downpipe they growl when you get on it. Nothing crazy Im not a fan of loud exhaust. Remember he had makes them so will take 12 weeks for delivery

 

42DD uses Magnaflow cats and resonators.

A resonated downpipe / high-flow catalytic converter won't be much louder than stock. If you want more noise you'll need to replace your rear muffler / back box.

Removing the resonator won't make the car louder but will allow additional frequencies (drone) to be heard.

Note: If it matters to you, both 42DD & Magnaflow are made in the USA 🗽

 

Just to add some notes about noise... Personally I kind of hate "moar noise" so my TT is probably just about as loud as I want it to be (actually sometimes I wish it wasn't as loud). It's not what most ppl would consider "loud exhaust" TBH but personally I def. wouldn't want it any louder than it is at this point as I'm not a fan and don't like to be an ass clown that annoys people for no reason.

IME the CTS DP did make my S noticeably louder than stock, even with the stock muffler. The TT (with the stock S exhaust) was already louder than my A3 (also stock muffler) ever was but now the two cars are more like night/day with the exhaust difference.

The A3 with the factory DP, v. the resonated Uni DP. Next to no difference. It's slightly louder and has a very light burble from a cold start and high idle. Apart from that the car is straight up "quiet" and almost exactly the same as stock. Just the way I like it 😁

The TT, esp. when the valve opens was always louder as said--expected as it's a TT and an S model but also it's still a factory car, designed in the late 00s, so it's not crazy loud. But once I put the DP on there... Well it's not excessively loud but it's definitely a good lot different too. Even before the tune was put on it was an unmistakable difference. It's louder, all the time; and there's the drone at higher cruising speeds as unresonated. The drone is still not exactly terrible, it's not loud enough it drowns out the stereo or anything, but it is noticeable. I wish it was resonated but whatever it cost me less than $700 CAD shipped so I'm good with it

Also after the [IE] tune, it has definite burbles and stuff at low speeds, coming off the throttle. That part is kind of a nice effect--it's not loud or offensive in any way and makes it sound more a "sports car". But the other part that goes along with it is...above 4k RPM, coming off the throttle, it will straight up do the "pops and bangs". The funny part is this isn't supposed to be part of the IE tune. Their newer tunes (for EA888 Gen 3s, etc.) do have the option of turning this on and it is an advertised feature. The tune for the EA113 HO does not have this option nor does it mention it as a feature anywhere on their site. But you better be sure it does it! LOL. But, only at high RPM lifts, as mentioned, so it's not the "neighbourhood douchey guy" effect at least. Below 4K I just get the burbling effect at most. I'm unsure if this is due to a combination of the tune and my exact exhaust (CTS DP and stock muffler) or just an "undocumented feature" IE put in there but doesn't advertise, but yeah it def. does it either way.

 

Just to add some notes about noise... Personally I kind of hate "moar noise" so my TT is probably just about as loud as I want it to be (actually sometimes I wish it wasn't as loud). It's not what most ppl would consider "loud exhaust" TBH but personally I def. wouldn't want it any louder than it is at this point as I'm not a fan and don't like to be an ass clown that annoys people for no reason.

IME the CTS DP did make my S noticeably louder than stock, even with the stock muffler. The TT (with the stock S exhaust) was already louder than my A3 (also stock muffler) ever was but now the two cars are more like night/day with the exhaust difference.

The TT, esp. when the valve opens was always louder as said--expected as it's a TT and an S model but also it's still a factory car, designed in the late 00s, so it's not crazy loud. But once I put the DP on there... Well it's not excessively loud but it's definitely a good lot different too. Even before the tune was put on it was an unmistakable difference. It's louder, all the time; and there's the drone at higher cruising speeds as unresonated. The drone is still not exactly terrible, it's not loud enough it drowns out the stereo or anything, but it is noticeable. I wish it was resonated but whatever it cost me less than $700 CAD shipped so I'm good with it

So, here is my train of thought; In Miami, we have ALOT of straight piped G36's, Civic's, Mustang's etc. so I've heard my fair share of redlines at 8 o'clock in the morning on a Thursday Not really my cup o' tea, I don't even like tea lol
Volume really isn't necessarily what I'm going for, so much as I am looking for that deeper tone with the burbles and the occasional pop. I already have an APR Stage 1 tune and want a more efficient flow of air in and out of the vehicle, not at the expense of others ears.

 

Volume really isn't necessarily what I'm going for, so much as I am looking for that deeper tone with the burbles and the occasional pop. I already have an APR Stage 1 tune and want a more efficient flow of air in and out of the vehicle, not at the expense of others ears.

Going with a Downpipe, high-flow cat & resonator sounds like what you are after.

Be advised however, the downpipe replaces your primary cat and you will get O2 sensor errors unless you correct for it. You might get lucky by adding a spacer to your O2 sensor (I did this for a short period w/ success but YMMV)

Most people just upgrade to Stage2 (which blocks the error) to take full advantage of having a downpipe.

 

Going with a Downpipe, high-flow cat & resonator sounds like what you are after.

Be advised however, the downpipe replaces your primary cat and you will get O2 sensor errors unless you correct for it. You might get lucky by adding a spacer to your O2 sensor (I did this for a short period w/ success but YMMV)

Most people just upgrade to Stage2 (which blocks the error) to take full advantage of having a downpipe.
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Didn't know about the spacer, will definitely have to look into that further. Does the stock downpipe use a spacer?
Also thanks for the imagery

 

Didn't know about the spacer, will definitely have to look into that further. Does the stock downpipe use a spacer?

You have two O2 sensors on your car. The primary sensor is mounted somewhere between your turbo's exhaust-side and the primary cat. It provides feedback as to how rich / lean your fuel mixture is based on the amount of unused oxygen / unburnt hydrocarbons found in your exhaust.

The secondary O2 sensor checks to see how well your primary catalytic converter is working.
The purpose of a catalytic converter is to convert nitrogen oxides (NOx), carbon monoxide (CO) and hydrocarbon (unburnt fuel) into less-harmful byproducts.

Since your downpipe replaces your primary cat, the secondary O2 sensor would report the cat as having zero efficiency resulting in a CEL / fault code. Adding a spacer can (sometimes) fool the secondary O2 sensor because it 'senses' something less (but more than nothing) when compared to what was measured by your primary O2 sensor.

The one pictured above came with multiple orifices that can be installed, giving you more leeway to find something that works. If you upgrade to Stage2 you don't need a spacer since the tuner knows you have a downpipe and will code out the error reporting for the secondary O2 sensor.

 

Since your downpipe replaces your primary cat, the secondary O2 sensor would report the cat as having zero efficiency resulting in a CEL / fault code. Adding a spacer can (sometimes) fool the secondary O2 sensor because it 'senses' something less (but more than nothing) when compared to what was measured by your primary O2 sensor.

The one pictured above came with multiple orifices that can be installed, giving you more leeway to find something that works. If you upgrade to Stage2 you don't need a spacer since the tuner knows you have a downpipe and will code out the error reporting for the secondary O2 sensor.
View attachment 512548

Glad you mentioned this because my goal is to reach 325hp and it's my understanding I'll need to get Stage 2 but it will de done later on down the line. So I can better prepare for it.

 

FNChaos you are correct you will need spacer but coding out the error is not true. All they do is stop it from having a CEL the emissions side will always be failed. So if you live in a fucked state like I do. You will have to find a way with spacer to fool the ecu. I did this with 42DDs like I said before have 3 of them and never recieved the CEL. Best way to use a spacer is make it flush to the pipe from the inside.
In NY you can only have 1 failed emissions error 2 and your a no go.

 

FNChaos you are correct you will need spacer but coding out the error is not true. All they do is stop it from having a CEL the emissions side will always be failed.

Yes, I was referring to blocking the CEL warning for the driver not a solution designed to fool an inspector.

As it is, installing a downpipe on a street-driven vehicle is illegal in all 50 states under the Clean Air Act. One's ability to get away with it depends on how your state conducts its inspections.

 

That is the hard choice I am dealing with now. I really wanted to keep the stock exhaust. I am going custom tune now to see what we can get out of the stock exhaust I would think that we could push it alittle more hp wise without upgrading. But then we have the issue when I upgrade to bigger turbo. When talking to APR couple weeks ago they said they had a tune for the stock downpipe/exhaust for their KO4 upgrade. Hard to believe. Already had my issues with IE but thats another story. I never was a fan of any upgraded downpipes and exhaust. and anything past the downpipe is just noise. No gains been proven time and again. Plus the 4 bangers just sound bad. We have a VW R32 and the sound that makes is awsome. No mods just stock exhaust.

 

Hate to quote stages. But at 'stage 2+' on a KO4 EA113, there is a more than noticeable difference in peak figures & area under the curves advantage from cars only running a downpipe, to those running a full exhaust system.
At this point if you are looking for everything the stock turbo can give now fuel isn't issue with uprated HPFP & raised rail pressure valve (RS4)- a full turbo back exhaust is worth while, more than just noise.

Downpipe with a cat or a resonator is definitely needed not to have a silly amount of noise and keep a nicer exhuast tone, otherwise EA113 ends up sounding as you said, poor 4 banger with plenty of rasp

 

do not agree at all. How do you get anything after downpipe which runs almost the full length to the box more power. Explain or show me data. Dyno data would be better. Test pipe will always out perform HFC. but a muffler is not going to restrict flow at the end. Who is telling you this?
Yes going to push the stock Turbo but one of the Hybrids are in the future. And yes fueling is a issue. Maybe not at the 350 range but the plan is 400whp now. Guys with the EA888s gen 1 and gen2 in other forums are pushing the cars way beyond what is being done here. Check out facebook EA888 big turbo forum. Some or them are reacheing 450whp on stock internals but all upgraded fueling injectors etc.

 

Literally hundreds of posts that could be sampled in TFSI Tuning Page or direct on R-tech Performance page
EA113, Stock catback, on a stock KO4 turbo is restrictive in getting full figures from 'stage 2+' - it has been shown plenty
I'm not just posting a personal opinion and asking to be proven wrong, there is plenty of data out there to show that statement as what it is - observation fact

Engine internals wasn't something referenced and is completely different subject, but full frame turbo regardless of engine EA113 or EA888 will run less boost, less heat and less stress to achieve the same power figure from a hybrid stock style turbo, always better way to go if that can be afforded along with everything else needed.
& it is indeed well proven the EA888 (at least the Gen 3 variant) is far stronger engine in terms of the peak power figures that can be ran on an un-opened/stock engine.

 

Ok wait are you saying stock downpipe and mid section. You are correct yes thats the bottle neck. I was referrring to after market downpipe and mid section. the rear muffler on any aftermarket exhaust doesnt do shit other than noise. I am sorry misread.
ignore the last part I was on a rant I did edit it 9am this morning but didnt update.