exhaust recommended for APR KO4. Is it needed?

[Nico]

Hi Guys,


I am thinking about getting the KO4 kit, but don't really want a loud exhaust note. APR states that the exhaust is recommended with their kit, but I remember that there was no performance gains achieved by adding an exhaust to a KO3 so the main reason people put it on their cars was for the sound.

Will there be performance gains when adding a exhaust to a KO4?

I will run a test pipe. Is this enough?


The only other issue i am concerned about are the exhaust gas temps. Will these be too high if I just run a test pipe?

Thanks in advance for you help.

[kristokes]

if you want an exhaust based on performance yet not too loud, get a milltek exhaust.

and yeah i recommend an exhaust especially if do a K04 upgrade.

http://www.audizine.com/forum/showthread.php?t=105668

check that out to compare exhaust notes

[SixthGear]

I say do it without the exhaust. If you're unhappy once the K04 is in, you can always buy one and probably have it installed the same day. You've got nothing to lose doing the K04 first in my opinion.

[MAlby7]

From what I understand the stock exhausts are not as restrictive as you think. Judging by the minimal increase in performance an aftermarket exhaust gives, I'd wait like sixthgear said.

[B7!]

i have the apr exhaust and test pipe with my k04 and its not load at all!! but if you get the test pipe that should be enough

[mrponline]

My concern with the stock exhaust is that it will restrict the K04. APR have designed the K04 programs to run with an TP and aftermarket exhaust.

It wouldnt hurt to run the stock exhaust but you probably wont get the maximum potential out of your K04.

As Simon suggested the APR exhaust (with K04 and TP) is not loud at all. I have an AWE which is much louder but it can be driven without bringing to much attention to the car.

[AAAA]

My concern with the stock exhaust is that it will restrict the K04. APR have designed the K04 programs to run with an TP and aftermarket exhaust.

It wouldnt hurt to run the stock exhaust but you probably wont get the maximum potential out of your K04.

As Simon suggested the APR exhaust (with K04 and TP) is not loud at all. I have an AWE which is much louder but it can be driven without bringing to much attention to the car.

it will restrict it. the reason the k04 kit for the b7 comes with the test pipe and the transverse kit doesn't is b/c the a4 exhaust is so much more restrictive. it's tiny in spots and that can restrict flow which will lose you horses if restricted enough

[swoardrider]

I too am searching for this answer. Only way to really know is to dyno a car with and without exhaust. I'm sure APR has done this, but I doubt I'll ever see the numbers from them.
Why?
My theory is because the gains of a bigger exhaust won't justify the extra $1k to some, thus shooting themselves in the foot. Better for them to say that the Ko4 kit is built to work with their exhaust and leave it at that.
For $1k, I want to see an extra 15 hp and 20 lbs of torque!

[Nico]

Hi Guy's,

Thanks for your responses.

I spoke to Guy and Derek previously (my local APR dealers) and they told me that the KO4 kit achieved its results 298hp etc... with just the kit not with exhaust and intake. So I am not concerned about loosing power by not adding these.

I am thus more concerned about safe running of the kit. I remember reading that if there is too much back pressure the hot air from the turbine cannot be removed from the turbine quickly enough therefore the turbo gets very hot and wears faster...or something like that. Is that correct?

swoardrider: I agree. I would prefer to save the extra cash if i can. I will try to do the dyno tests with and without exhaust, when I get the kit. Might be another month or so before i get it though.

AAAA: I hear what you're saying! But do you think the test pipe will "free it up" enough?

[lnferno]

I would highly recommend getting an after-market exhaust if you upgrade to the K04. The whole idea of a turbo upgrade is to push as much efficient air in and exhaust out of the system. Can you run the K04 without an intake and exhaust? Sure, but you're definitely not going to yield as much power without those complementing mods.

I also have the AWE exhaust. That, coupled with intake and the K04 kit (with test pipe) is LOUD when I get on it. If I drive conservatively, then it isn't too noticeable.

These vids are a pretty good representation of how load my car is on the K04, AWE exhaust, and Carbonio intake:

Random street passes (http://www.youtube.com/watch?v=aVAKNzWwwHo) At the very end of the clip, you can hear how loud it is.

Dyno Pull - rear exhaust shot (http://youtube.com/watch?v=9YgIbmVfRVk)

Dyno pull - front shot (http://www.youtube.com/watch?v=8WHEcdSwIGs)

Check the sticky at the top of the forum to see a comprehensive exhaust comparison.

[4-tified]

Hi Guy's,

Thanks for your responses.

I spoke to Guy and Derek previously (my local APR dealers) and they told me that the KO4 kit achieved its results 298hp etc... with just the kit not with exhaust and intake. So I am not concerned about loosing power by not adding these.

I am thus more concerned about safe running of the kit. I remember reading that if there is too much back pressure the hot air from the turbine cannot be removed from the turbine quickly enough therefore the turbo gets very hot and wears faster...or something like that. Is that correct?



Inferno is giving good advice.
If you want to achieve maximum air flow/pump potential with the higher capcity K04 then a solid mandrel bent exhaust will help you maximize the output.

The question is, how much "more" performance will be gained by going with a better flowing exhaust? That can only be answered by driving the car with stock and then with aftermarket exhaust and perhaps dyno both setups.

The theory is that more air in means more air out.
The engine is an air pump, so if you can force more air into it, you need to be able to move that air out to maximize efficiency and get the most out of the comprehensive package.

One thing to note is that larger exhausts tend to move the power band a bit up the rev band, thus upper rpm hp/torque is improved due to better/easier breathing, and the greater ability to move the exhaust air out faster. Sometimes, that can result in more lag at low rpm.
That is something you'll just have to test and tune.

If you want a quieter sound and still move the air, you could just have an exhaust shop custom build the pipes and mandrel bend them to keep the curves smooth and restriction free. You can use the stock mufflers and see if you like how that works for you.

The turbo engine I had was a Mits Eclipse. I installed a "16G" turbo, which had the capacity to flow twice the air of the stock unit. I modded the bleeder to up the pressure about 3psi. The performance gain was nice as I kept the stock system. However, in that car the stock systems were too small. Going larger helped a lot, and low rpm lag seemed actually less.
Again, it depends on what you start with.
The Audi exhaust is pretty nice. These days turbo engines are better designed and build to provide better performance from the factory.

There is another mod that can be used to help move hot air out the exhaust quicker. I haven't read about people using it on here though.
The idea is that the hotter the exhaust piping is the faster the hot gas will move through it. So, to speed up hot gas flow you can wrap the header and exhaust pipe with exhaust tape to keep things flowing nicely.

[swoardrider]

So here is a question for you dyno gurus. Can an exhaust free flow test be done the ghetto way by dynoing a car with stock exhaust, then doing another dyno run with the stock exhaust disconnected at the end of the downpipe?
It seems open pipes would be the ultimate test to see if the 2.0T would benefit from a free flowing exhaust.
Also seems like this would be the ultimate intake test. Why install a Carbino? Why not just take out the stock filter, run the car for a 1/4 day and see if there are any performance gains from a free flowing intake?

[lnferno]

So here is a question for you dyno gurus. Can an exhaust free flow test be done the ghetto way by dynoing a car with stock exhaust, then doing another dyno run with the stock exhaust disconnected at the end of the downpipe?
It seems open pipes would be the ultimate test to see if the 2.0T would benefit from a free flowing exhaust.
Also seems like this would be the ultimate intake test. Why install a Carbino? Why not just take out the stock filter, run the car for a 1/4 day and see if there are any performance gains from a free flowing intake?

I would think that if you dyno'd without anything coming out of the end of the downpipes, you could actually see less torque because there wouldn't be any back pressure to generate the torque. I could be wrong on that, but that's my educated guess.

As far as the intake goes, I'm sure you'd see more grams per second without any filter and probably a few more ponies, but that wouldn't be an accurate representation of how you'd run your car on a consistent basis.

[nadroj81]

You need an exhaust if you are running the k04. I have 99% confidence the claims for APR are based on exhaust. I would never run the car without a filter either...can you say engine damage?

You can pick up an AWE for 900 bucks, it is worth the investment. The stock exhaust is a POS. There are so many crimps in it which effectively reduce the exhaust size to half inch probably.

by not running an exhaust you are going to kill half the effect of the k04. With an exhaust you will allow the power band to continue into the higher rpms, with the stock exhaust you will be restricting it so much your power is going to die off just like with the k03.

[AAAA]

I would think that if you dyno'd without anything coming out of the end of the downpipes, you could actually see less torque because there wouldn't be any back pressure to generate the torque. I could be wrong on that, but that's my educated guess.

As far as the intake goes, I'm sure you'd see more grams per second without any filter and probably a few more ponies, but that wouldn't be an accurate representation of how you'd run your car on a consistent basis.

I think both of those are wrong in my opinion. you don't need backpressure for turbo cars. its the amount of pressure that the exhaust flows as to how fast it spools the exhaust side of the turbo to create boost. so if you have a bigger downpipe, its less pressure inside the housing so it takes longer to make the turbo spool, but no backpressure needed.

as far as intake, a free flowing intake would be beneficial, but also would soak up so much heat sitting there next to the turbo that its not worth it. i tried running just the inlet hose. no dice.

[rlopez]

Stytuned,

Good video very impressive and tempting... I've read articles that current exhaust systems are effective from cat on back and most gains can be had from a 'Test pipe'. However, i'm sure however small the gains are there are still some gains with a full on exhaust system. Have you any problems with K04? engine light? emissions test? I would like to upgrade to K04 but don't want any maintenance issues particularly with a 4 year warranty or 50K miles(full service by Audi). Who was your installer in Denver?

Thanks,



I would highly recommend getting an after-market exhaust if you upgrade to the K04. The whole idea of a turbo upgrade is to push as much efficient air in and exhaust out of the system. Can you run the K04 without an intake and exhaust? Sure, but you're definitely not going to yield as much power without those complementing mods.

I also have the AWE exhaust. That, coupled with intake and the K04 kit (with test pipe) is LOUD when I get on it. If I drive conservatively, then it isn't too noticeable.

These vids are a pretty good representation of how load my car is on the K04, AWE exhaust, and Carbonio intake:

Random street passes (http://www.youtube.com/watch?v=aVAKNzWwwHo) At the very end of the clip, you can hear how loud it is.

Dyno Pull - rear exhaust shot (http://youtube.com/watch?v=9YgIbmVfRVk)

Dyno pull - front shot (http://www.youtube.com/watch?v=8WHEcdSwIGs)

Check the sticky at the top of the forum to see a comprehensive exhaust comparison.

[lnferno]

I think both of those are wrong in my opinion. you don't need backpressure for turbo cars. its the amount of pressure that the exhaust flows as to how fast it spools the exhaust side of the turbo to create boost. so if you have a bigger downpipe, its less pressure inside the housing so it takes longer to make the turbo spool, but no backpressure needed.

as far as intake, a free flowing intake would be beneficial, but also would soak up so much heat sitting there next to the turbo that its not worth it. i tried running just the inlet hose. no dice.

Well, I can tell you based on factual evidence (data logging) that I actually spooled faster with a larger downpipe on my A4. What I cannot say with any certainty are what the results would be on our cars with no exhaust coming from the downpipe. I just haven't done it and don't have any plans to. In all actuality, would anyone really run this as their setup? Most likely not.

Back to the open air filter question. My response was assuming Carbonio setup just without the air filter, which again is not a practical setup and I can't imagine anyone doing in the first place.

[lnferno]

Rlopez -- the only problem that I've run into is that I had to replace the stock diverter valve. Although that's not uncommon even for cars that are just flashed. The stock DV is known to be one of the "weakest" links in our cars. Fortunately, it's only like a $60 part to replace. Can't wait for Forge to come out with their new DV!

[swoardrider]

You need an exhaust if you are running the k04. I have 99% confidence the claims for APR are based on exhaust. I would never run the car without a filter either...can you say engine damage?

You can pick up an AWE for 900 bucks, it is worth the investment. The stock exhaust is a POS. There are so many crimps in it which effectively reduce the exhaust size to half inch probably.

by not running an exhaust you are going to kill half the effect of the k04. With an exhaust you will allow the power band to continue into the higher rpms, with the stock exhaust you will be restricting it so much your power is going to die off just like with the k03.

If you leave the leaf screen in, running a 1/2 day without a paper filter is not going to hurt anything. It's not like we're 4 wheeling in the desert.

Yes stock exhaust is not built as nice as aftermarket. Compared to aftermarket, yes build quality is POS. Performance though is not. I refuse to spend $1k to sound like a fart can with no real performance gains. I'd rather spend that on another set of race tires. I will spend the money though, and deal with the noise if it means another 20 ponies.

The only true test is the dyno. Everything else is just speculation.

IMO the only things on this planet that sound good with exhausts are 2-strokes, motorcycles, and anything V-8 or larger!

[AAAA]

Well, I can tell you based on factual evidence (data logging) that I actually spooled faster with a larger downpipe on my A4. What I cannot say with any certainty are what the results would be on our cars with no exhaust coming from the downpipe. I just haven't done it and don't have any plans to. In all actuality, would anyone really run this as their setup? Most likely not.

Back to the open air filter question. My response was assuming Carbonio setup just without the air filter, which again is not a practical setup and I can't imagine anyone doing in the first place.

sorry, i mean comparing a large aftermarket dp to a larger aftermarket downpipe. certainly there are beneficial gains to getting a larger downpipe from the stock one, which is definitely too restrictive. that's what this discussion started out as. a good example would be exhaust for 1.8t. 2.5 was good on stock turbo, but 3 in caused lag b/c it was too big. hope that makes since

[swoardrider]

Well, I can tell you based on factual evidence (data logging) that I actually spooled faster with a larger downpipe on my A4. What I cannot say with any certainty are what the results would be on our cars with no exhaust coming from the downpipe. I just haven't done it and don't have any plans to. In all actuality, would anyone really run this as their setup? Most likely not.

Back to the open air filter question. My response was assuming Carbonio setup just without the air filter, which again is not a practical setup and I can't imagine anyone doing in the first place.

Correct, no one is going to run this all the time on the street. That's why it's called "ghetto" testing.

I figured this would be a cheap, quick, and easy way to see if this 2.0T motor responded to a free flowing intake and exhaust. My thinking, is that if there were no gains with the ghetto method, than how could putting on something like the Carbino be beneficial?

Same goes with exhaust. If an open exhaust hurts the power, than I would think this means the engine has to have some back pressure. If it remains the same, or gains are minimal, then it seams the engine is not benefiting from less back pressure, If it improves by say 5% or more, than it seams that less back pressure is a benefit. Then the magic lies in the design of the aftermarket exhaust system to see if they can harness this gain while still creating a tolerable sound level.

This is just a theory of mine. Again, not accurate testing, just ghetto general testing to see if certain mods are worth it without actually purchasing them. I have done this over a dozen times with 4 different cars, and my ghetto testing has so far been correct. The only benefits I've ever seen from intake and exhaust were on my motorcycles and jet skis. And every time, the carbs had to be tuned to the mods to see the benefits. And here, I think is where the secret lies. If intake and exhaust is indeed restrictive, and we could replace these items and tune each car individually for these mods, than we would see some real gains. And I think they have a words for that. It's called a race team!

[lnferno]

I see what you're saying and trying to do. For me personally, I live at 6000+ feet altitude and need all the help I can get with better air flow (hence my avatar), so even while the gains are minimal with intake, they do help! Same with Exhaust. My personal opinion is that each mod by itself probably won't make that much of an impact, but all of the mods working together promote a MUCH better breathing system, if you will, which at Colorado altitude is very important.

To echo your comments -- I would love to see further development and testing of new designs! I hope the aftermarket companies keep on raising the bar. The more competition, the better!

Completely off topic, but I'm jealous of the nice road courses you guys have access to in Cali. hehe

[swoardrider]

Completely off topic, but I'm jealous of the nice road courses you guys have access to in Cali. hehe

Yes we truely are blessed. For me especially. Living in Sata Cruz, I have the luxury of being in the middle of Cal, so I can easily run the tracks in Nor Cal or So Cal. Plus how many people can say Laguna Seca is their home track!

Funny, it just hit me from your post how demographics really influence our mods!

I just did "The Streets" track of Willow Springs Raceway on Friday, so when my friend sends me the pics, I will post them up.

[Slo.Mo.Shun.]

I think both of those are wrong in my opinion. you don't need backpressure for turbo cars. its the amount of pressure that the exhaust flows as to how fast it spools the exhaust side of the turbo to create boost. so if you have a bigger downpipe, its less pressure inside the housing so it takes longer to make the turbo spool, but no backpressure needed.

Well give it a try disconect you exhaust from the dp and try to boost more than 12.

I tried one time just for the hell of it, and all i got is super quick spool but super low boost. Now with the Milltek and all my valves working properly 20-23 is the norm

[Nico]

I definitely don't doubt that a carbonio intake is beneficial because I have seen the numbers.

http://www.mjbmotorsport.com/id82.html

Although from looking at the carbonio especially the OEM part that is used it doesn't seem much bigger!

And I understand that a freer flow of air is beneficial in an exhaust in theory. Adding a test pipe will increase air flow especially close to turbo where it counts. Therefore a freer flow.

Sorry everyone I'm just a skeptic especially since everyone used to claim big gains from exhaust and then the test was done and there was no benefit on chipped KO3 at all.

http://www.mjbmotorsport.com/id80.html

[Nico]

Anyone know anything about exhaust gas temps?

[PannikAttk]

if you want an exhaust based on performance yet not too loud, get a milltek exhaust.

and yeah i recommend an exhaust especially if do a K04 upgrade.

http://www.audizine.com/forum/showthread.php?t=105668

check that out to compare exhaust notes

I second the Milltek...Excellent gains (12 hp to the wheels on my 1.8T, which already had a 3"DP). It's also barely louder than stock.

The only way I can describe the sound is classy and subtle but with enough grunt to know you're not stock. It was even quieter than my brother's stock SRT-4 exhaust.

[Slo.Mo.Shun.]

I second the Milltek...Excellent gains (12 hp to the wheels on my 1.8T, which already had a 3"DP). It's also barely louder than stock.

The only way I can describe the sound is classy and subtle but with enough grunt to know you're not stock. It was even quieter than my brother's stock SRT-4 exhaust.

I third the Milltek, sound levels are close to stock, but it is has a much richer and deep tone.

[AAAA]

Sorry everyone I'm just a skeptic especially since everyone used to claim big gains from exhaust and then the test was done and there was no benefit on chipped KO3 at all.

http://www.mjbmotorsport.com/id80.html


if you're talking about 1.8T k03's, you're completely wrong. people used to see anywhere from 8-20hp depending on their other mods from 2.5in and 3in dp/exhaust.

what about exhaust gas temps?

[Nico]

if you're talking about 1.8T k03's, you're completely wrong. people used to see anywhere from 8-20hp depending on their other mods from 2.5in and 3in dp/exhaust.

Did you look at th link I posted? This was a 2.0T with chip and high flow cats and neuspeed exhaust....... Before and after dynos actually show a loss of power! only a few hp so probably not significant but at the end of the day THERE WERE NO GAINs.... I am sceptical about huge gains on the 1.8T also but I don't know much about it so I will take you word for it.

This doesn't mean there won't be gains on the KO4 as it flows more air esp at higher RPM's. I was just hoping someone had done the tests.

[4-tified]

Did you look at th link I posted? This was a 2.0T with chip and high flow cats and neuspeed exhaust....... Before and after dynos actually show a loss of power! only a few hp so probably not significant but at the end of the day THERE WERE NO GAINs.... I am sceptical about huge gains on the 1.8T also but I don't know much about it so I will take you word for it.

This doesn't mean there won't be gains on the KO4 as it flows more air esp at higher RPM's. I was just hoping someone had done the tests.

I'm hear ya. Too many people take the traditional "tuning" items, done mostly for marketing that any real testing, as fact.
Exhaust do NOT always make more power, and sometimes they might make more peak power at the loss of power across the rev band.
So, it's all speculative at best unless one actually does the tuning and TESTING. It's one thing to see the power on the dyno but it's another to see any added benefit at the track.
Just because the dyno might show a 20hp peak gain, that might not result in any faster track times. If that happens is the mod really worth it?
It might be if you're only going for bragging rights.

You asked about heat wrap and it could be a viable option, but again, it depends on the testing done. There is a LOT of info on the web if you search for 'exhaust heat wrap or wrapping'. Motorcycle racers use it, it seems, more often. But, it has automobile applications as well.
There are even specially made turbo "jackets"/wraps that go around the turbo itself. The makers claim that keeping the turbo heated actually helps it's efficiency. You'll have to check them out to see if you agree.

Let us know what comes of your testing and tuning. [up][:)]

[AAAA]

Did you look at th link I posted? This was a 2.0T with chip and high flow cats and neuspeed exhaust....... Before and after dynos actually show a loss of power! only a few hp so probably not significant but at the end of the day THERE WERE NO GAINs.... I am sceptical about huge gains on the 1.8T also but I don't know much about it so I will take you word for it.

This doesn't mean there won't be gains on the KO4 as it flows more air esp at higher RPM's. I was just hoping someone had done the tests.

were those 2 dynos done on the same day, right before and after exhaust install? if not, then they cannot be that useful b/c conditions can be different. but i agree, it probably shouldn't have dropped. but keep in mind, a transverse 2.0t comes with a 2.5in exhaust, so maybe 2.75in and up starts to be non beneficial.

[nadroj81]

Did you look at th link I posted? This was a 2.0T with chip and high flow cats and neuspeed exhaust....... Before and after dynos actually show a loss of power! only a few hp so probably not significant but at the end of the day THERE WERE NO GAINs.... I am sceptical about huge gains on the 1.8T also but I don't know much about it so I will take you word for it.

This doesn't mean there won't be gains on the KO4 as it flows more air esp at higher RPM's. I was just hoping someone had done the tests.

they were also done on different days. Environmental factors can easily +/- 10hp&torque.
The best thing to do is test with stock exhaust, Reset the fuel trims, install new exhaust, put a quick 100 hard miles on the car, dyno the same day. preferable like 10/11am and then 5/6pm when the temp is about the same

[lokeh]

The real question asked was not about better performance but more of longetivity of the kit and/or wear and tear on engine with a stock exhaust.

Personally, I would ask one of the main APR gurus since it is there K04 and hopefully they should know the answer without trying to be a salesman. :)

[swoardrider]

I'm hear ya. Too many people take the traditional "tuning" items, done mostly for marketing that any real testing, as fact.
Exhaust do NOT always make more power, and sometimes they might make more peak power at the loss of power across the rev band.
So, it's all speculative at best unless one actually does the tuning and TESTING. It's one thing to see the power on the dyno but it's another to see any added benefit at the track.
Just because the dyno might show a 20hp peak gain, that might not result in any faster track times. If that happens is the mod really worth it?[up][:)]

I couldn't agree more. That is why I too am sceptical in this thread. I don't care about "mandrel bent", or "all the crimps on a stock exhaust". I want to see real tests. On the last 3 cars I owned, I've spent at least $1k each, or more on exhaust and seen 0 gains!

One of them was my E30 M3. I knew it though even before the purchase of a B&B Tri-Flow system, but being young, I wanted the sound. This car is a perfect example of how the stock system can't be beat, even if it looks like shit. The B&B engineers told me that it took them 3 prototypes just to find a combination that didn't lose power over stock! Then It took them another 3 prototypes just to make a 3 hp gain!

My point is that I don't want to throw away a perfectly good and quiet stock exhaust unless it is really needed.