Downpipe options

[JKWMD]

Hi,

I'm in the process of an upgrade to stage 2 on a 2018 RS3, and am now looking at down/mid pipe options. It would seem there are several choices, but reading through the posts, there doesn't seem to be any clear winner.

I'm looking for the pipes that make the best power, are of high quality, and have great sound; cost is not a high priority.

I'm not against going catless, but don't want anything overly loud, or smelly.

I was also wanting some advice on "wastegate rattle", and ways to eliminate/mitigate this, if possible.

Any advice would be most appreciated.

[Eat.Sleep.Race]

APR if you want catted, and great fitting. Although it is expensive if doing mid pipes. $1499

I went with STM, because the quality is TOP notch, its $950 w/5% off and in stock with quick shipping. I think it is the be choice, and sounds great.

[gokchen]

Hi,

I'm in the process of an upgrade to stage 2 on a 2018 RS3, and am now looking at down/mid pipe options. It would seem there are several choices, but reading through the posts, there doesn't seem to be any clear winner.

I'm looking for the pipes that make the best power, are of high quality, and have great sound; cost is not a high priority.

I'm not against going catless, but don't want anything overly loud, or smelly.

I was also wanting some advice on "wastegate rattle", and ways to eliminate/mitigate this, if possible.

Any advice would be most appreciated.

Intergrated engineering has a good downpipe with a removeable cat so you have an option. Unitronic is also going to be releasing a catted downpipe soon which apparently somewhat muffles the sound of the wastegate rattle more than other downpipes. From most feedback on this site it seems catless downpipes on a stock turbo have really bad wastegate rattle at lower rpm

Sent from my Pixel using Audizine mobile app

[javbomb]

IE catted has barely any rattle. Its built extremely well. 3.5" right through. Cheaper than APR, I would much rather give money to IE.

You can also easily just buy a 10.75" / 3.5" section of straight pipe too and decat it at your will.

[Brian@Unitronic]

We will be having a downpipe coming soon that sounds like it checks all of your boxes.

High Flow GESI cat that wont leave you with a smell
Large radius Cast piping that will allow you to make big power and have reduced wastegate rattle.
Will work with factory mid pipes as well as our high flow catless midpipes

[OE2]

We will be having a downpipe coming soon that sounds like it checks all of your boxes.

High Flow GESI cat that wont leave you with a smell
Large radius Cast piping that will allow you to make big power and have reduced wastegate rattle.
Will work with factory mid pipes as well as our high flow catless midpipes

price and availability?

[OD8]

Brian @ Unitronic, is there development happening for OPF/GPF 2019 engines on the hardware side?


Sent from my iPad using Audizine

[speeddemon69]

Unitronic or STM, i am waiting for the Unitronic as i want the least wastegate rattle as possible and also want a highflow cat.

[r26372]

It will rattle - period. Any catless a lot, catted less so, but all hi flow cats will sound about the same. They are simply using a lower cell cat to allow more flow, no getting away from wastgate rattle. Some have adjusted the play in the wastgate to reduce rattle, but this isn't a recommended solution by any tuner I've seen, just a few members that hated the sound enough to do it. If you put power above all else including bad sounding car, go stage 2. If you care a lot about sound, avoid. Something for everyone, depends on what you're trying to do.


Sent from my iPhone using Audizine

[MarcusDubya77]

What about avoiding CELs without having to use a spacer? Do the HFC ones do the job?

[BaltimoreCaesar]

I'm personally in the same boat as you and I'm waiting for the upcoming Unitronic DP. It also won't throw a CEL, which is a big deal for me.

[VargasTurboTech]

I am confused as to why people are associating wastegate rattle with a certain downpipe? We have dealt with wastegate rattle from factory vacuum-actuated turbos for going on 8 years. The reason people are associate more rattle with a downpipe is simply that you can hear it more clearly with the stock DP removed, the downpipe itself has nothing to do with wastegate rattle.

We make multiple pieces of hardware to address it. The BMW N54 is notorious for it. So bad BMW issued many many many updates to try to fix it.

The bottom line on wastegate rattle on a vacuum-actuated turbo is as follows. 1. The assembly itself can be about 20-25% of the problem. On the BMW's the design was terrible which caused some tendency to rattle. The Borg-Warner unit on the RS3 has a very well designed flapper with multiple strategies in place for the sole reason of eliminating rattle. For the Audi, I would say 0% of the problem is the flapper itself. For the BMW's the other 75-80% was simply the flapper position in relation to the turbine housing, which would be 100% on the Audi since the flapper itself is such a good design. If the DME is holding the flapper just off the housing on idle, decel, off-throttle etc. The high-speed exhaust is coming through there and causing vibration, and in return rattle. Think of a balloon when you squeeze the end and let the air out.

The remedy is extremely simple. In all of the BMW tunes, you have an adjustable default wastegate position or a simple rattle fix checkbox. This allows you to adjust your flapper position in relation to the housing, open it a little more rattle is gone as it has nothing to rattle against, close it more, and it's gone because if it's against the housing with some force it also cannot rattle.

Rattle can be easily fixed on this platform same as it was on the N54 but no hardware is even needed, just some minor adjustments to the wastegate position tables in the tune.


JB4 wastegate.jpgMHD Slider.jpg

[JKWMD]

It seems people are saying the IE pipe has little rattle, but what about the APR pipes?
I’d also like to know when the Uni pipes are expected.

Sent from my iPhone using Audizine

[JKWMD]

I am confused as to why people are associating wastegate rattle with a certain downpipe? We have dealt with wastegate rattle from factory vacuum-actuated turbos for going on 8 years. The reason people are associate more rattle with a downpipe is simply that you can hear it more clearly with the stock DP removed, the downpipe itself has nothing to do with wastegate rattle.

We make multiple pieces of hardware to address it. The BMW N54 is notorious for it. So bad BMW issued many many many updates to try to fix it.

The bottom line on wastegate rattle on a vacuum-actuated turbo is as follows. 1. The assembly itself can be about 20-25% of the problem. On the BMW's the design was terrible which caused some tendency to rattle. The Borg-Warner unit on the RS3 has a very well designed flapper with multiple strategies in place for the sole reason of eliminating rattle. For the Audi, I would say 0% of the problem is the flapper itself. For the BMW's the other 75-80% was simply the flapper position in relation to the turbine housing, which would be 100% on the Audi since the flapper itself is such a good design. If the DME is holding the flapper just off the housing on idle, decel, off-throttle etc. The high-speed exhaust is coming through there and causing vibration, and in return rattle. Think of a balloon when you squeeze the end and let the air out.

The remedy is extremely simple. In all of the BMW tunes, you have an adjustable default wastegate position or a simple rattle fix checkbox. This allows you to adjust your flapper position in relation to the housing, open it a little more rattle is gone as it has nothing to rattle against, close it more, and it's gone because if it's against the housing with some force it also cannot rattle.

Rattle can be easily fixed on this platform same as it was on the N54 but no hardware is even needed, just some minor adjustments to the wastegate positions tables in the tune.


JB4 wastegate.jpgMHD Slider.jpg

If it’s that easy, does IE or APR make the necessary adjustments on their stage 2 tunes?


Sent from my iPhone using Audizine

[VargasTurboTech]

If it’s that easy, does IE or APR make the necessary adjustments on their stage 2 tunes?


Sent from my iPhone using Audizine

That would be a question for APR or IE. But if people are dealing with rattle my guess would be most likely not. This platform is pretty new, it took a long time to figure out exactly how to deal with rattle on the N54, and even now if you do not have everything set up properly they can rattle. With how well the flapper is designed on these, it honestly should be a very simple fix in the tune to take care of it.

[JKWMD]

Would IE, APR, Unitronic, and others care to comment?


Sent from my iPhone using Audizine

[JKWMD]

That would be a question for APR or IE. But if people are dealing with rattle my guess would be most likely not. This platform is pretty new, it took a long time to figure out exactly how to deal with rattle on the N54, and even now if you do not have everything set up properly they can rattle. With how well the flapper is designed on these, it honestly should be a very simple fix in the tune to take care of it.

Since you've gone Unitronic, have you talked to Paul/John about this?

I'd like to know if I purchase their upcoming downpipe, if there stage 2 tune will utilize your method of rattle mitigation.

[War]

I am confused as to why people are associating wastegate rattle with a certain downpipe? We have dealt with wastegate rattle from factory vacuum-actuated turbos for going on 8 years. The reason people are associate more rattle with a downpipe is simply that you can hear it more clearly with the stock DP removed, the downpipe itself has nothing to do with wastegate rattle.

We make multiple pieces of hardware to address it. The BMW N54 is notorious for it. So bad BMW issued many many many updates to try to fix it.

The bottom line on wastegate rattle on a vacuum-actuated turbo is as follows. 1. The assembly itself can be about 20-25% of the problem. On the BMW's the design was terrible which caused some tendency to rattle. The Borg-Warner unit on the RS3 has a very well designed flapper with multiple strategies in place for the sole reason of eliminating rattle. For the Audi, I would say 0% of the problem is the flapper itself. For the BMW's the other 75-80% was simply the flapper position in relation to the turbine housing, which would be 100% on the Audi since the flapper itself is such a good design. If the DME is holding the flapper just off the housing on idle, decel, off-throttle etc. The high-speed exhaust is coming through there and causing vibration, and in return rattle. Think of a balloon when you squeeze the end and let the air out.

The remedy is extremely simple. In all of the BMW tunes, you have an adjustable default wastegate position or a simple rattle fix checkbox. This allows you to adjust your flapper position in relation to the housing, open it a little more rattle is gone as it has nothing to rattle against, close it more, and it's gone because if it's against the housing with some force it also cannot rattle.

Rattle can be easily fixed on this platform same as it was on the N54 but no hardware is even needed, just some minor adjustments to the wastegate position tables in the tune.


JB4 wastegate.jpgMHD Slider.jpg

This post is gold and deserves it's own thread.

[r26372]

This post is gold and deserves it's own thread.

If it were so simple, why aren't the tuners doing this while releasing stage 2 tunes and why did it take BMW "many, many, many" updates to fix it?

The logic of the solution makes sense to me, but apparently BMW had issues getting it right and currently the few stage 2 tuners out haven't on our platform. Hope they do, as I'd be open to going Stage 2 if it didn't sound like garbage to my ears post stage upgrade.

[VargasTurboTech]

If it were so simple, why aren't the tuners doing this while releasing stage 2 tunes and why did it take BMW "many, many, many" updates to fix it?

The logic of the solution makes sense to me, but apparently BMW had issues getting it right and currently the few stage 2 tuners out haven't on our platform. Hope they do, as I'd be open to going Stage 2 if it didn't sound like garbage to my ears post stage upgrade.

BMW fixes included 4-5 different updates on the turbos themselves. I believe through the years they were offered the N54 turbocharger changed part numbers in the area of 10-12 times. The first versions have a tiny 6mm flapper arm, it wore out quickly, and rattled, the went to 8mm, helped but still wore out. They went to different materials, it helped but wore out. Then they started offering reflashes at the dealership to help fix the issue, IE moving the flapper around. Problem was, not every car needed to be in the same place to avoid the rattle. It took quite a while for aftermarket tunes to add the features as well, I would say in the past 3 years. Keep in mind the platform came out in 2007. So around 8-9 years to before it was understood what needed to be done to help eliminate the problem. The good news is, you just take the lessons learned on that platform, and apply it to others that have the same issues. Vacuum actuated systems have inherent rattle issues because the flapper default is open, not closed. If it's too close to the housing you will always get rattle

[War]

BMW fixes included 4-5 different updates on the turbos themselves. I believe through the years they were offered the N54 turbocharger changed part numbers in the area of 10-12 times. The first versions have a tiny 6mm flapper arm, it wore out quickly, and rattled, the went to 8mm, helped but still wore out. They went to different materials, it helped but wore out. Then they started offering reflashes at the dealership to help fix the issue, IE moving the flapper around. Problem was, not every car needed to be in the same place to avoid the rattle. It took quite a while for aftermarket tunes to add the features as well, I would say in the past 3 years. Keep in mind the platform came out in 2007. So around 8-9 years to before it was understood what needed to be done to help eliminate the problem. The good news is, you just take the lessons learned on that platform, and apply it to others that have the same issues. Vacuum actuated systems have inherent rattle issues because the flapper default is open, not closed. If it's too close to the housing you will always get rattle

VargasTurboTech
Please start a new thread with a title along the lines of- Tune to fix flapper problem, or something of the sort. Along with reposting some of your wonderful posts in this thread. It may get some tuners thinking about these issues instead of being buried in this thread with a title that wont grab the attention of any tuners or people being tuned with this problem. Please and Thanks.

[Mansour]

It will rattle - period. Any catless a lot, catted less so, but all hi flow cats will sound about the same. They are simply using a lower cell cat to allow more flow, no getting away from wastgate rattle. Some have adjusted the play in the wastgate to reduce rattle, but this isn't a recommended solution by any tuner I've seen, just a few members that hated the sound enough to do it. If you put power above all else including bad sounding car, go stage 2. If you care a lot about sound, avoid. Something for everyone, depends on what you're trying to do.


Sent from my iPhone using Audizine

I've installed powervalve downpipe with 100 cell high flow cat, no existence of any wastgate rattle.

[Ross_T_Boss]

Some cars seem to rattle more than others, those messing with the actuator rod have found it possible to nip it up and reduce significantly, so I'd guess there is a little bit of variance.

As to the different downpipes - with IE it simply seems to be a combo of the thick, cast sections and 200-cell cat under the car. It's still there on mine but not as bad as I've heard on others, and those who have tried IE vs other non-cast options have confirmed it sits kinda in the middle to OEM.

That said except for cold-start I really had to listed for any rattle on mine when it was stock.

[LJS5]

I don't think mine rattled at all until i hit about 1000 miles.. since then its been every day.

[jd_rs3]

If the rattle is so easy to fix, why has no one been able to do it? I don't think it's just a simple fix, as mentioned here. Lot of big claims going on. Would love to see some results.

[Brian@Unitronic]

Since you've gone Unitronic, have you talked to Paul/John about this?

I'd like to know if I purchase their upcoming downpipe, if there stage 2 tune will utilize your method of rattle mitigation.

Our stage 2 software mitigates wastegate rattle as much as possible without effecting driveability

Our upcoming downpipe has thick cast stainless steel sections and a high flow cat, that when combined together with out software gets rid of almost all wastegate rattle.

Brian

[javbomb]

I am confused as to why people are associating wastegate rattle with a certain downpipe?

Because different downpipe materials resonate differently.

I had a stainless downpipe on my car for 5 weeks, the rattle was freaking insane. I put the Cast IE downpipe on, in catless form bypassing the 200cell, and the rattle is 80% less pronounced vs the stainless DP I had to the point where currently for me its a total non issue. Still there, but WAY lower in 'tinny' noise than with a 3" stainless downpipe...

https://www.dropbox.com/s/s65silqfxx...19.13.mp4?dl=0

Cast, vs stainless seems to make a huge difference. The 200CELL cat when I used it too had zero rattle whatsoever, but that, with the cast nature of the IE DP was overall too quiet for me.

Also, the rest of your post is spot on, Unitronic by the way, on Stage 1+ at least, if you start the car and it goes into cold start, you can stop the rattle dead in its tracks by cycling to Dynamic. Here watch, listen for the rattle in comfort vs dynamic, and that's not even moving. So you are right, there should definitely be a software thing to complete eradicate it under motion.

https://www.dropbox.com/s/nf7i6fvesq...14.43.mp4?dl=0

[r26372]

I've installed powervalve downpipe with 100 cell high flow cat, no existence of any wastgate rattle.

Not heard of anyone with a powwrvalve DP. Also if the cast options, with a 200 cell cat, and a tune attempting to mitigate the rattle have it, wouldn't make much sense your 100 Cell cat makes no noise.


Sent from my iPhone using Audizine

[MarcusDubya77]

Our stage 2 software mitigates wastegate rattle as much as possible without effecting driveability

Our upcoming downpipe has thick cast stainless steel sections and a high flow cat, that when combined together with out software gets rid of almost all wastegate rattle.

Brian

Will it trigger a CEL because of the O2? Or is it programmed out with the tune?

[Mansour]

Not heard of anyone with a powwrvalve DP. Also if the cast options, with a 200 cell cat, and a tune attempting to mitigate the rattle have it, wouldn't make much sense your 100 Cell cat makes no noise.


Sent from my iPhone using Audizine

Probably folks in the US have not heard of powervalve, but it has been in existence for a while

As for wastgate rattle noise, I confirm again it does not exist, btw my car is a stage 2 custom tuned by MRC

[Acerxz]

We will be having a downpipe coming soon that sounds like it checks all of your boxes.

High Flow GESI cat that wont leave you with a smell
Large radius Cast piping that will allow you to make big power and have reduced wastegate rattle.
Will work with factory mid pipes as well as our high flow catless midpipes

Saw this at waterfest today. Wish all the parts were available. I'm ready to buy it all. Everything looked great.

[brad65ford]

Probably folks in the US have not heard of powervalve, but it has been in existence for a while

As for wastgate rattle noise, I confirm again it does not exist, btw my car is a stage 2 custom tuned by MRC

Always thought that a case dp with heat wrap would greatly help with rattle.

[Potshot]

Will it trigger a CEL because of the O2? Or is it programmed out with the tune?

As far as I'm aware all the tunes eliminate the cel warning.

Hoping uni drops theirs soon. I want to hear it before considering. Rattle must vary from car to car as some report no significant rattle and some report they cant stand it and remove the d.p., even with the same brand of dp.

[RowdyaudiRS3]

It seems people are saying the IE pipe has little rattle, but what about the APR pipes?
I’d also like to know when the Uni pipes are expected.

Sent from my iPhone using Audizine

does anyone have these on their car and can confirm neither rattle (or lower the rattle)? looking for a DP as well but a catted one. Videos would be cool to see haha

[Aramze]

does anyone have these on their car and can confirm neither rattle (or lower the rattle)? looking for a DP as well but a catted one. Videos would be cool to see haha

I have the APR down pipe on my car. I honestly don’t think the WG rattle is that bad. Never really bothered me, but I don’t have much to compare it too. Hit me up on Instagram (Aramze30) and I’ll try to share some videos.

[seanix9]

Probably folks in the US have not heard of powervalve, but it has been in existence for a while

As for wastgate rattle noise, I confirm again it does not exist, btw my car is a stage 2 custom tuned by MRC

I also have the BCS (Powervalve) 4" DP and with the 100cel cat the rattle is almost non existent. But running the cat delete pipe, the rattle is really bad.

[RowdyaudiRS3]

i was thinking of running a regular catless downpipe with the factory catted mids that came with my car (stop smell and some say keep rattle to a minimum).

is anyone running a setup similar to this & does this make sense/ good or bad idea? *note, im not tracking my car religiously so not worried too much about 1/10th of a second off my 1/4 mile lol just want it to be fast and functional.

I will be on stage 2 uni tune with inlet/intercooler/intake and an AWE switchpath exhaust (currently have the awe performance mids with stock DP installed, no rattle and no smell)

[Potshot]

I can't find a price for the BCS (Powervalve) anywhere. Can you use stick midpipes with the BCS (Powervalve)? Any additional info appreciated.

[Banny]

I can't find a price for the BCS (Powervalve) anywhere. Can you use stick midpipes with the BCS (Powervalve)? Any additional info appreciated.

https://www.akstuning.co.uk/bcs-powe...3-8v-2017.html

[seanix9]

I can't find a price for the BCS (Powervalve) anywhere. Can you use stick midpipes with the BCS (Powervalve)? Any additional info appreciated.

That won't be possible. Its a single piece DP as per the link attached above. To use the stock mid pipes, the APR unit may work as its the same design as oem essentially.