Exhaust note/tone with Hiflow cats for TFSI 2.0T stage II ?

[doublespeeded]

Hi guys,

Apologies for starting this new thread as I have been doing some reading with regards to noise increase from Hiflow cats.

As I mentioned in another thread, I am preparing for a Stage II upgrade for my 2012 (facelift) 2.0T quattro TFSI ... which will include a tune, hiflow cat, DV, PCV & Catch can.

Im wondering, for those who have undergone this upgrade (and with hiflow cats), what impact or changes has it made to the exhaust tone?

The reason for my concern is that I also own a 2007' Mitsubishi Lancer Evolution IX with Stage III upgrades... it pretty much sits in the garage every day, as I am banned by my wife from driving it since, it causes "too much noise" starting/driving out of the garage early in the morning. Waking her up and the baby. (Jap car with camshafts + Larger turbo + canon muffler = Noise expected)

My Audi A4 B8.5 is my daily and also in the garage which is adjacent to the masterbedroom, its an elegant family sedan (saloon) that id like to keep it conservative and classy. Rather than something that sounds like a 'Boy-racer' or 'Rice Burner' our of Fast And Furious like my EVO.
So how much difference did the hiflow cat make with regards to noise?

from what I've read; Some people say it makes a big difference in sound which I highly doubt. In my experience in the evo, when I upgraded to a 100cell from a 200cell, I found it made no difference in noise nor any noticeable performance gain.

most people have mentioned that there is a slight increase in noise, but not by much as the cat isn't a noise resonating device such as a muffler or resonator... but due to more flow and less restriction, the car sounds a bit more aggressive in general, especially under WOT.

let me know your thoughts and opinion on this as im really keen.

Kind regards,

[Project Quattro]

It'll be fine. It does make it perceptibly louder if you're paying attention but it isn't a huge change nor is it objectively "loud," certainly not enough to get you in any trouble with the spouse. It's only noticeable basically if you're very used to a stock car and then jump right into one with a HFC. A downpipe would make it even louder, though, so you might want to stay away from that.


Sent from the Pedal Responce boardroom

[mecg]

I just got APR's new downpipe installed and the wife did notice that the exhaust was louder when I start the car, but not overly so. In fact, it's only when the car is first started and the revs stay above 1000 rpm's for the first minute or so. Once it goes down to about 800 rpm's the exhaust sounds the same as it did before the new downpipe. In your situation, you'll probably be just fine if you sit in the garage for that first minute and wait until the revs drop down to pull out. She probably won't hear a thing.

[Poodini]

^^
Ditto Project's and Mercg's thoughts. I'm currently running essentially what you listed, minus the catch can. The 2 things that you'll significantly notice in terms of noise are 1. Putting on an aftermarket HF intake and 2. Doing a muffler delete/straight piping or going all out with full downpipe.
If you peep the 'Exhaust note' thread, look for mine and Earhythmic's video clip. That'll give you an idea as far as what it'll sound like with the mods mentioned.
Hope that helps.
🏼️


Sent from my iPhone usingTapatalk

[hyperunion]

Exactly... I have the apr hfc dp as well... It did a great job reducing noise running it with the stock exaust.. it made the stock exaust actually sound pretty good at wide open throttle.. normal driving and high way cruise it was too quiet... A real way to get you in trouble, I barely noticed the speed with the apr stg2 tune.. it's scary quick, especially on e85...

Sent from my Nexus 7 using Tapatalk

[mecg]

Exactly... I have the apr hfc dp as well... It did a great job reducing noise running it with the stock exaust.. it made the stock exaust actually sound pretty good at wide open throttle.. normal driving and high way cruise it was too quiet... A real way to get you in trouble, I barely noticed the speed with the apr stg2 tune.. it's scary quick, especially on e85...

Sent from my Nexus 7 using Tapatalk

^^ This. Hope I don't jinx myself but I can't believe I haven't gotten a speeding ticket with this car, yet. My new favorite thing to do in my car now is to pass people. Takes like 3 seconds to get around slowpokes and back into my lane, and I'm always 90+ mph when I let off the gas. And, unless I'm using cruise control I'm pretty much ALWAYS speeding, no matter what the limit is at the time. Purely unintentional as there just isn't a sense of speed inside the car, until I look down at the speedo and say "Oh shit..."

[hyperunion]

^^ This. Hope I don't jinx myself but I can't believe I haven't gotten a speeding ticket with this car, yet. My new favorite thing to do in my car now is to pass people. Takes like 3 seconds to get around slowpokes and back into my lane, and I'm always 90+ mph when I let off the gas. And, unless I'm using cruise control I'm pretty much ALWAYS speeding, no matter what the limit is at the time. Purely unintentional as there just isn't a sense of speed inside the car, until I look down at the speedo and say "Oh shit..."

Exactly... That's why the full exaust helps.. so you'll know you're above 95... Even cruise at 110 doesn't feel it...

Sent from my Nexus 7 using Tapatalk

[adamazing]

You're in luck.

Here is my video demonstrating those exact mods (except the DV).


And here is another video with a random drive from inside the cabin, with the ECS Kohlefaser Luft-Technik Intake System installed as well.


Hope those help answer all your questions.

[jcun]

You're in luck.

Here is my video demonstrating those exact mods (except the DV).


And here is another video with a random drive from inside the cabin, with the ECS Kohlefaser Luft-Technik Intake System installed as well.


Hope those help answer all your questions.

Ha I know exactly where you took that video up on the hill in mission valley off of friars! Nice sounding exhaust!

[hyperunion]

You're in luck.

Here is my video demonstrating those exact mods (except the DV).


And here is another video with a random drive from inside the cabin, with the ECS Kohlefaser Luft-Technik Intake System installed as well.


Hope those help answer all your questions.

Man my apr intake is so quiet compared to that ecs one!!.

Sent from my Nexus 7 using Tapatalk

[doublespeeded]

Hi guys,

thanks for your prompt overnight responses from across the globe. Your willingness to help really means a lot to me.


Further to the discussion:

It'll be fine. It does make it perceptibly louder if you're paying attention but it isn't a huge change nor is it objectively "loud," certainly not enough to get you in any trouble with the spouse. It's only noticeable basically if you're very used to a stock car and then jump right into one with a HFC. A downpipe would make it even louder, though, so you might want to stay away from that.

Well since you mentioned this, the tuner who will be working on my car for the stage 2 mentioned that it will only require a Hiflow cat upgrade and intake... im not sure if he mentioned the downpipe.
I hadn't noticed this, but does the stock/OEM downpipe have resonators?, I cant see why it would make it even louder.. since its only a larger diameter pipe?


Sent from the Pedal Responce boardroom

I just got APR's new downpipe installed and the wife did notice that the exhaust was louder when I start the car, but not overly so. In fact, it's only when the car is first started and the revs stay above 1000 rpm's for the first minute or so. Once it goes down to about 800 rpm's the exhaust sounds the same as it did before the new downpipe. In your situation, you'll probably be just fine if you sit in the garage for that first minute and wait until the revs drop down to pull out. She probably won't hear a thing.

yeah that's my main concern is the initial start up of the car, these modern houses... the walls are so thin... and not only is the bedroom adjacent but the bedpost is just behind the garage wall.
I normally don't wait around, I open the auto garage door, start the car, reverse out... close the garage door and drive off slowly. I generally don't see the 800rpm drop.

^^
Ditto Project's and Mercg's thoughts. I'm currently running essentially what you listed, minus the catch can. The 2 things that you'll significantly notice in terms of noise are 1. Putting on an aftermarket HF intake and 2. Doing a muffler delete/straight piping or going all out with full downpipe.
If you peep the 'Exhaust note' thread, look for mine and Earhythmic's video clip. That'll give you an idea as far as what it'll sound like with the mods mentioned.
Hope that helps.
��️

sorry I had a quick look but I couldn't find your post, would you mind posting a link?
Intake would only increase the induction noise right?... and not the exhaust note on idle & start up?

Sent from my iPhone usingTapatalk

Exactly... I have the apr hfc dp as well... It did a great job reducing noise running it with the stock exaust.. it made the stock exaust actually sound pretty good at wide open throttle.. normal driving and high way cruise it was too quiet... A real way to get you in trouble, I barely noticed the speed with the apr stg2 tune.. it's scary quick, especially on e85...

Sent from my Nexus 7 using Tapatalk

nah I wouldn't be going e85, we Australians aren't big users of Ethanol so far...my EVO is on e85 and I have to drive 20km to get a re-fill (since that is the only closest petrol station which sells it).
so your saying that the APR HFC + DP is a quiet system compared to others???

You're in luck.

Here is my video demonstrating those exact mods (except the DV).


And here is another video with a random drive from inside the cabin, with the ECS Kohlefaser Luft-Technik Intake System installed as well.

Hope those help answer all your questions.

Adam, love your car man!... I thought you had the Caractere trunk lip spoiler?
Man, that is so quick... is that just automatic on E85?, the ESC was turned off and launched in this video right?


It appears in the video your car had a complete system with new muffler and quad dips... well Ill be retaining the stock mufflers and resonators, so it may differ to this.

Also, what may make a difference is that the Australian delivered 2.0T TFSI oddly has a one sided exhaust muffler and tip.... the US versions have dual.... im not sure how much difference that would make.

[Project Quattro]

I believe the OE downpipe is resonated, but regardless an aftermarket downpipe does make a significant noise difference. If you just do the HFC it'll stay quite quiet and you'll still get all of the performance gains.


Sent from the Pedal Responce boardroom

[hyperunion]

Yeah.. just using the apr hfc dp combo..with the stock exaust is very quiet... Very slight change to the factory exaust in a very good way...
Apr's dp does delete the factory midpipe resonator with a straight 3 inch pipe... And yes we have single side exaust for our cars as well... The dual is an awe exaust conversion..

Sent from my Nexus 7 using Tapatalk

[doublespeeded]

Yeah.. just using the apr hfc dp combo..with the stock exaust is very quiet... Very slight change to the factory exaust in a very good way...
Apr's dp does delete the factory midpipe resonator with a straight 3 inch pipe... And yes we have single side exaust for our cars as well... The dual is an awe exaust conversion..

Sent from my Nexus 7 using Tapatalk

I believe the OE downpipe is resonated, but regardless an aftermarket downpipe does make a significant noise difference. If you just do the HFC it'll stay quite quiet and you'll still get all of the performance gains.


Sent from the Pedal Responce boardroom

Ill try and find out what brand the tuner uses for the stage 2 upgrade... They are the suppliers of REVO chip...

checking if its an actual downpipe + Hiflow or just a hiflow alone....

I guess, worse comes to worse, if its irritatingly loud.... I can get my fabricator custom additional resonator in the system to reduce noise.

Im pretty pumped/excited for this stage 2 mod :)

believe me, im all for upgrades/customisation .. hence my 350wkw EVO IX (470whp)... but its just the wife being disturbed during sleep is my biggest issue and the Audi being an Elegant daily, can potentially end up sounding like a Cheap Rice-Box to a suit wearing Pen-pusher such as myself, is not ideal.


Thanks a bunch guys.

[inv3rtig0]

I'm gonna echo what everyone else already said... I'm running the 034 HFC + REVO Stage 2, stock exhaust - it is anything but loud. Don't sweat it, she won't even notice the difference.

[adamazing]

Ha I know exactly where you took that video up on the hill in mission valley off of friars! Nice sounding exhaust!

Haha, yup, good eye. A stroll around my hood.

Man my apr intake is so quiet compared to that ecs one!!.

Its definitely loud. I had a small complex about driving around with it for the first week or two after installing it. Simply because the sound was so noticeable.
But now I love it, and can;t imagine not having the sound there.

To be fair, the passenger window is also open in that video.

Adam, love your car man!... I thought you had the Caractere trunk lip spoiler?
Man, that is so quick... is that just automatic on E85?, the ESC was turned off and launched in this video right?


It appears in the video your car had a complete system with new muffler and quad dips... well Ill be retaining the stock mufflers and resonators, so it may differ to this.

Also, what may make a difference is that the Australian delivered 2.0T TFSI oddly has a one sided exhaust muffler and tip.... the US versions have dual.... im not sure how much difference that would make.

Thanks man! I do have a C-Style Lip, but that video is pretty old now. Long before I had a lot of the stuff I have now.
If I recall correctly, that was running E85 with ESC off.

I opted for the quad tip set-up and conversion kit from AWE. As other have mentioned above, in stock form, I only had the single sided OEM exhaust.

[doublespeeded]

Haha, yup, good eye. A stroll around my hood.




Its definitely loud. I had a small complex about driving around with it for the first week or two after installing it. Simply because the sound was so noticeable.
But now I love it, and can;t imagine not having the sound there.

To be fair, the passenger window is also open in that video.




Thanks man! I do have a C-Style Lip, but that video is pretty old now. Long before I had a lot of the stuff I have now.
If I recall correctly, that was running E85 with ESC off.

I opted for the quad tip set-up and conversion kit from AWE. As other have mentioned above, in stock form, I only had the single sided OEM exhaust.

You guys are all awesome!, thanks for the advice... ill be proceeding with the stage 2 HFC (DP if its included)...

understandably I know I've asked a difficult question to accurately answer, everyone interprets and tolerates noise/loudness...differently (for e.g My EVO with the Canon muffler is most likely over the legal AUS limit which is 92db....and for this particular car and to me, I still think it isn't loud enough and have even contemplated on whether I should remove the Hot-Dog resonator to give it a bit more of a Bark, which can also result in unfavourable cause drone).
But what I've gathered form everyone's response, it is likely to increase a bit of noise but very marginal, the extent its almost unnoticeable. which is what I kind of expected but I wanted to see what id be up against.

Ill keep you guys posted and my feedback once I get it done :)

thanks again.

[doublespeeded]

OK, So id like to know before I buy and attempt to either install HFC +/- Downpipe. Will it throw an engine code light since it disconnects the Co2 sensor?

The reason I ask is that either myself or my fabricator (who does a fantastic job customising exhausts) wont have an OBD or diagnostics tool to clear codes and faults.

Worse to worse if it does, then ill need to take it to the tuner to install.

thanks & regards,

[Poodini]

^^
You'll need an O2 spacer for your 2nd O2 sensor. This moves the sensor away from the exhaust path. You'll want your guy to put that on your new HFC.

I have this on my setup: http://www.uspmotorsports.com/Exhaus...er-SE-080.html

Have had it on for 8+ months and have yet to throw a code.
If you're planning on an APR stage 2 tune, part of the remapping also addresses that.
Either way, that should do the trick


Sent from my iPhone usingTapatalk

[doublespeeded]

^^
You'll need an O2 spacer for your 2nd O2 sensor. This moves the sensor away from the exhaust path. You'll want your guy to put that on your new HFC.

I have this on my setup: http://www.uspmotorsports.com/Exhaus...er-SE-080.html

Have had it on for 8+ months and have yet to throw a code.
If you're planning on an APR stage 2 tune, part of the remapping also addresses that.
Either way, that should do the trick


Sent from my iPhone usingTapatalk

Did you install a APR downpipe + HFC kit?

Im pretty sure my fabricator can custom fab that part up, so best I don't attempt it myself at home...

The reason I asked about the error code, in the past I disconnected the Air Bag sensor on my Mitsubishi Lancer Evolution IX as I was converting the halogen bulbs to HID... this required the removal of headlights to install the ballast, the Sensor from memory was in the way.
I forgot to disconnect the battery, so when I switched it on it had an error code.

[Poodini]

This is where VAG-COM/Ross Tech comes in so handy. Not only can you diagnostically scan for and clear error codes, but you can modify/unlock all sorts of cool features on our cars. If you don't own one, check locally if someone does and make friends! It's an invaluable tool!
As for downpipe, I opted to keep my exhaust OE up until I did the Magnaflow/straight pipe combo. Been loving it ever since!
Downpipe is fine, albeit somewhat pricey. But, if you don't live in California where the emissions laws here are so restrictive, then you're good to go.
🏼️


Sent from my iPhone usingTapatalk

[hyperunion]

Simple , if you run any sort of hfc.. you will get a cel code without a stg 2 tune that deletes the secondary readings..... Yes some, a few, run all different types of spacers and spacers with cats and do have luck with a test pipe not hfc without a tune... But the majority have gotten cel's regularly, with or without spacers... No tune or just want a stg1, stick with the stock hfc, and maybe try an aftermarket downpipe, post factory cat...

Sent from my Nexus 7 using Tapatalk

[Poodini]

^^
From my personal experience, when I upgraded the HFC, I had the O2 spacer installed at the same time. Possibly one of the reasons why it's been hit n miss with throwing a cel despite the spacer MAY have something to do with the OB recognizing the change in CO2 values. Just a theory.
Hyperunion is spot on regarding the Stage 2 tune. It all but eliminates that issue since it remaps threshold values for the exhaust output.

I've never run a test pipe. They have a penchant for producing more of that exhaust smell and is a little noisier on the back end than I like.
Plus, out here in Cali, it's a bit riskier esp. come SMOG time during the visual inspection.
Just my 2 cents


Sent from my iPhone usingTapatalk

[doublespeeded]

^^
From my personal experience, when I upgraded the HFC, I had the O2 spacer installed at the same time. Possibly one of the reasons why it's been hit n miss with throwing a cel despite the spacer MAY have something to do with the OB recognizing the change in CO2 values. Just a theory.
Hyperunion is spot on regarding the Stage 2 tune. It all but eliminates that issue since it remaps threshold values for the exhaust output.

I've never run a test pipe. They have a penchant for producing more of that exhaust smell and is a little noisier on the back end than I like.
Plus, out here in Cali, it's a bit riskier esp. come SMOG time during the visual inspection.
Just my 2 cents


Sent from my iPhone usingTapatalk

Simple , if you run any sort of hfc.. you will get a cel code without a stg 2 tune that deletes the secondary readings..... Yes some, a few, run all different types of spacers and spacers with cats and do have luck with a test pipe not hfc without a tune... But the majority have gotten cel's regularly, with or without spacers... No tune or just want a stg1, stick with the stock hfc, and maybe try an aftermarket downpipe, post factory cat...

Sent from my Nexus 7 using Tapatalk

In Australia, the emission laws are equally as strict, but we do not have SMOG or any periodical tests. Officers issue defect notices if they catch you with something they believe to be too loud etc, they'll send you to an EPA testing station, where they would probably check everything. Euros are seldomly picked on over here… the cops seem to have a stigma against Jap cars here.

Well all this VAG, intermittent/reoccuring error codes with or without adaptors… sounds all too complicated and bothersome for me.
Ill ask my tuner what he thinks.

Well this is my plan for stage II, Ill take it to my fabricator FIRST, get him to install down pipe + HFC (I think i mentioned that this guy is amazing with his work..and id rather him do to the hardware install as he is better equipped than any tuner) If the set up ends up a bit noisy for my liking, ill get him to install an additional hotdog resonator to baffle it further (this is why a fabricator would be more handy).

Once he's done with that, even if it throws the code… ill take it to the tuner sort out the DV, catchcan + PCV and Stage II tune… hopefully he'll have an answer or will be capable for blocking the codes.

Thats what i hand in mind anyways.

[Poodini]

^^
Going to Stage 2 will eliminate throwing error codes. It's part of the software's remapping programs.
I'd still get an O2 spacer just to have a secondary backup.


Sent from my iPhone usingTapatalk

[doublespeeded]

^^
Going to Stage 2 will eliminate throwing error codes. It's part of the software's remapping programs.
I'd still get an O2 spacer just to have a secondary backup.


Sent from my iPhone usingTapatalk

Thanks, My last question, what happens when you drive around with a error code from HFC?

as I explained, ill have my fabricator install the HIflow cat + downpipe... (I also purchased a Turbo muffler delete too)... but the only thing the fabricator doesn't have is the OBD.

so after I leave his fabricating workshop.. it may be a week or two before I get the stage 2 software tune/chip... and I will likely have to drive the car to and from work in between.... whats the worse that can happen with an error code when driving?

thanks & regards,

[Poodini]

It won't affect your car. The error code is due to the 2nd O2 sensor not detecting enough particles from the HFC emissions. If it doesn't reach a certain threshold, it will trigger the error. That is where the 02 spacer comes in. The spacer creates more travel between the HFC and your sensor before it exists through the downpipe. That space allows for more particles to be detected by the sensor, thus tricking into thinking its within range of acceptability.
I ran my HFC for almost 2 months before I went to Stage 2 and never threw a code. I know that hasn't been the case for everyone. Some swear by straight spacers, some with an angled bend, some 90 degrees, there's no 1 spacer that works for all. Don't ask me why.


Sent from my iPhone using Tapatalk

[awdconnor]

Ill chime in..

i have a CTS HFC with a rear muffler delete, the only time you really hear the exhaust is when its around 2100-2400rpm.

[hyperunion]

Ill chime in..

i have a CTS HFC with a rear muffler delete, the only time you really hear the exhaust is when its around 2100-2400rpm.

I really can't see that!..lol... I really hear mine.. at various rpms

Sent from my Nexus 7 using Tapatalk

[awdconnor]

I really can't see that!..lol... I really hear mine.. at various rpms

Sent from my Nexus 7 using Tapatalk

i ment to say it drones around then

[hyperunion]

i ment to say it drones around then

Yeah.. those rpms are the difficult ones!!

Sent from my Nexus 7 using Tapatalk

[shonseb]

I would insulate the garage adjacent to the bedroom and go all out

[doublespeeded]

^^
Going to Stage 2 will eliminate throwing error codes. It's part of the software's remapping programs.
I'd still get an O2 spacer just to have a secondary backup.


Sent from my iPhone usingTapatalk

I would insulate the garage adjacent to the bedroom and go all out

Now that's one unique response!

lol

that be real tricky and costly.
Im not sure if that internal wall has insulation battss either.