B8 Ko4 owners follow up thread

[Spawne32]

Are you guys running upgraded brakes/rotors? On stage 1 my brakes already aren't enough. I find myself doing the light pumps a lot to slow me down faster.

I just have a feeling with with the stage 3 RS3 K04 I'm gonna get myself is some trouble. I'm E85 and even at just stage 1 it's off the chain.

I already blew by two cops this week over 60 mph, one was on the median on his cell phone and didn't have his radar (I was doing over 70 point blank) on since my Uniden didn't chirp at all, he didn't even look up. The other was parked directly perpendicular to my line so he couldn't get a reading on his dash mounted K band - just an FYI for those of you that didn't know.

Also considering the longevity factor.

BB has upgraded brakes, Trap has the 345mm Brembos, and I am swapping on the 356mm 2 piston calipers from the A6 soon as the snow clears in front of the garage.

[Iceman502]

This is an instance where VCDS may be better than the IE logger because I don't need so many parameters at one time, and get larger time steps. IE is down to the millisecond but doesn't actually print the value to that precision. When working with the numbers, I could have one-tenth of a second split into 14 values, or up to 19. The inconsistency makes it a bit more challenging.

I think I'm having this convo with myself BUT

VCDS is better for a mock draggy run because the time steps, while not consistent, are still very small (.05-.09 seconds) using Group UDS and Turbo mode, and the data itself is easily imported into MatLab with minimal post-processing.
To get around the time step issue is a simple for loop, and with this knowledge, I'm going to run a VCDS based quarter-mile, and see what I can produce. Assuming minimal wheel slip, it's going to be pretty accurate.

Logging parameters:
RPM - IDE00021
Air Mass - IDE00347
Lambda Voltage - IDE00558 (divide by 1.5 for lambda ratio)
Absolute Load - IDE00084
Boost Spec - IDE00190
Boost Actual - IDE00191
Boost Controller - IDE01900

[Nano909]

Can you hear an actuator rattle when you give it blip of throttle - close to a wall or any drive through?

No rattle, it might be the wastegate itself. My turbo is fairly new with low miles so I'm a little aggravated but whatever. Lol. Also I'm using 345mm Porsche Macan calipers. All my mods are listed in my sig.

[Perry01]

Are you guys running upgraded brakes/rotors? On stage 1 my brakes already aren't enough. I find myself doing the light pumps a lot to slow me down faster.

My Q5 came with factory Brembos and when combined with pads with a good friction rating (GG), they perform well enough.

[A4x]

This is exactly why some people like A4X have the prevailing theory that the K04 is a waste of time and money, because most of them barely crack 290 wheel unless they are more heavily invested in fueling mods and more aggressive tuning.

I never said it is a waste of time and money. It is certainly debatable whether it is worth it over stage 2. You are giving up peak torque with an "upgrade" to K04. Look at APRs published numbers (300 awtq K04 vs 326 awtq stage 2 stock turbo - 91 octane).

I just don't want any newcomers to get the false impression that they will spend thousands to upgrade to a larger turbo and not experience more turbo lag (maybe I should re-phrase this to lack of torque down low).

I'm going on 4 years of K04 power and I still love driving my car everyday. The linear power band of the K04 is one of the major advantages, even if you give up some down low off the line. Pulling hard to redline is fun.

I read everything you all have responded to me over the past few pages. Good discussion. Especially the part where Perry told me to look in the mirror and see bullshit

[A4x]

I run an OTS tune from IE with two very minor revisions. I'm talking controller gain, not map rewrites. With that in mind, tomorrow, I'm going to add my g/s airflow to BB's table for further data comparison. More air, more fuel, more power. If you can flow more air at any given point, you're going to make more power.

What's not bullshit, is that the compressor housings are the same volume. There is no additional lag created when swapping these turbos with regard to the frames themselves. The only quantifiable difference you could cite beyond airflow readings would be a manufacturer plot showing ramp-up speeds of pressure generation in a controlled environment. If you can find that, please share because I'd love to see one. They typically only provide compressor maps that don't show pressure derivatives.

You're talking about physics to back your argument, but physics isn't on your side at all in this one. Please, provide a counterpoint to Bb's chart showing more airflow with an IE OTS K04 tune, and an IE OTS Stage 2 tune. Since the K04 naturally flows more air, the boost ramp up at low rpm's is slower due to torque/safety limits on the rods, and the exhaust camshaft phase switch at 3000 rpm. Once you cross that threshold, 22 psi for days from OTS. The custom tune guys are trying to launch a piston to mars with the way they're tuning, and they know that. Their tune is not for the typical user who wants to maintain peak reliability (can I even say that when talking about an EA888 gen 2)?

First of all, MAF g/s is not a perfect comparison and does not tell a complete story. It is just one piece of the puzzle.

I am not referring to compressor housing size being responsible for the K04 having more lag. Start thinking about compressor wheel and turbine wheel geometry. Where does the compressor gets its energy from? What causes a K03 or IHI JH5 to run out of steam at high RPMs? Why can a K04 flow more air at these high rpms?

[Nano909]

My Q5 came with factory Brembos and when combined with pads with a good friction rating (GG), they perform well enough.

The 2.0t has the 330mm Brembos that are way better than our single piston junk.

[Nano909]

I never said it is a waste of time and money. It is certainly debatable whether it is worth it over stage 2. You are giving up peak torque with an "upgrade" to K04. Look at APRs published numbers (300 awtq K04 vs 326 awtq stage 2 stock turbo - 91 octane).

I just don't want any newcomers to get the false impression that they will spend thousands to upgrade to a larger turbo and not experience more turbo lag (maybe I should re-phrase this to lack of torque down low).

I'm going on 4 years of K04 power and I still love driving my car everyday. The linear power band of the K04 is one of the major advantages, even if you give up some down low off the line. Pulling hard to redline is fun.

I read everything you all have responded to me over the past few pages. Good discussion. Especially the part where Perry told me to look in the mirror and see bullshit

I promise you that my car has the same pull if not more than it did with stage 2 at lower rpm. I did feel the "lag" (lack of torque) with IE.

[Traptalk]

First of all, MAF g/s is not a perfect comparison and does not tell a complete story. It is just one piece of the puzzle.

I am not referring to compressor housing size being responsible for the K04 having more lag. Start thinking about compressor wheel and turbine wheel geometry. Where does the compressor gets its energy from? What causes a K03 or IHI JH5 to run out of steam at high RPMs? Why can a K04 flow more air at these high rpms?

The major differences are in the turbine housing

The stock turbo has a much shallower and smaller volume turbine housing

[Mars2]

The major differences are in the turbine housing

The stock turbo has a much shallower and smaller volume turbine housing

Are you 100% sure of that.
Some guy's measure it 4 or 5 year ago and says IHI JH5 has bigger Turbine AR.
I don't have a K04 to compare. but when I see picture it does not look much bigger.
Turbine wheel slightly bigger on IHI JH5 that K04-64. I'm just speaking of the size of turbine wheel not how it flow as nobody knows how IHI JH5 turbine flow VS K04 turbine.

[EvolutionArmory]

Are you 100% sure of that.
Some guy's measure it 4 or 5 year ago and says IHI JH5 has bigger Turbine AR.
I don't have a K04 to compare. but when I see picture it does not look much bigger.
Turbine wheel slightly bigger on IHI JH5 that K04-64. I'm just speaking of the size of turbine wheel not how it flow as nobody knows how IHI JH5 turbine flow VS K04 turbine.

How did they measure the AR of the housing? How they measured will change the results. Unless they sealed everything and checked with liquid or actually calculated the AR of the housings the proper way, what do their measurements actually mean? Do you know what I am saying?

It’s not like these factory turbos have a specified and known AR like an aftermarket turbo. You can compare the wheels easy enough but the housings are going to be much harder to measure.


Sent from my iPhone using Audizine

[Perry01]

The 2.0t has the 330mm Brembos that are way better than our single piston junk.

Yea, 4 pistons make a big difference and the 330mm rotors keep the rotational mass down. If I was tracking the thing I’d definitely go for larger rotors but I prefer the lighter weight 330mm rotors for daily driving. With good pads, they perform well.

[Traptalk]

Are you 100% sure of that.
Some guy's measure it 4 or 5 year ago and says IHI JH5 has bigger Turbine AR.
I don't have a K04 to compare. but when I see picture it does not look much bigger.
Turbine wheel slightly bigger on IHI JH5 that K04-64. I'm just speaking of the size of turbine wheel not how it flow as nobody knows how IHI JH5 turbine flow VS K04 turbine.

100% just held a stock turbo the other and was shocked how much more shallow the turbine housing is.

The turbine wheel is deeper inside the housing and the housing is more deep

My loba (Borg Warner)




Stock ihi




Now look at this gap on the stock turbo





And now look at the k04





I would estimate the k04 housing to be about 1” longer in that region

Edit : that’s not the volute tho so bot sure what effect it has on a/r

[Nano909]

Yea, 4 pistons make a big difference and the 330mm rotors keep the rotational mass down. If I was tracking the thing I’d definitely go for larger rotors but I prefer the lighter weight 330mm rotors for daily driving. With good pads, they perform well.

I had to upgrade mine. I do a lot of canyon driving and the stock calipers with EBC Reds would fade almost at the end of the pass I take. I didn't like that one bit. I didn't want to run a more aggressive pad like Yellows since I hear it takes them a long time to heat up for daily driving.

[Mars2]

100% just held a stock turbo the other and was shocked how much more shallow the turbine housing is.

The turbine wheel is deeper inside the housing and the housing is more deep

My loba (Borg Warner)




Stock ihi




Now look at this gap on the stock turbo





And now look at the k04





I would estimate the k04 housing to be about 1” longer in that region

Edit : that’s not the volute tho so bot sure what effect it has on a/r

That is bell mouth size that has nothing to do in the performance of the turbo that is already part of the "downpipe"
to my understanding what has influence to the turbo performance is:
- volume of exhaust manifold
- volume in the snail part of the turbine housing.

The part after the turbine is not so important one could extend it with a 3.5inch down pipe.
or did I got wrong what you try to tell me.

For those who don't know te size of K04 and JH5 turbine I put those here again:
- K04 Inducer 50mm exducer 44.5mm
- IHI JH5 Inducer 52mm exducer 44mm

Maybe those picture make me see it wrong but I see outside housing of IHI bigger but again I don't have both real in front of me


PS I can feel up with water a IHI JH5 turbine housing from the 4 hole head side to the exit of the turbine ( not counting the bell mouth) and tell you how much water can fit in their.

[EvolutionArmory]

Honestly, liquid is probably going to be the easiest way for us to measure as long as you can seal it up properly.

Unless of course people want to measure the AR properly. That might involve cutting the turbo in half though.

Don’t know for sure


Sent from my iPhone using Audizine

[Mars2]

like I say I can feel the hot side of the ihi that I have in the garage and tell you how much water.
I have plenty of Vaccum sealant tape from when a vacuum laminate Carbon. this thing stick on anything.
So can close the exit of turbine and seal waste gate and then feel up from the 4 holes.

https://www.westsystem.com/tools-sup...m-bag-sealant/

[Traptalk]

The part after the turbine is not so important one could extend it with a 3.5inch down pipe.
or did I got wrong what you try to tell me.

Like I said that is not the volute (the smaller area directly around the turbine)

But it is the most noticeable difference, and I feel it would be safe to assume that if there is subtle differences there, then there may be others as well

The way I understand it is that

A/r = area/radius

Area of the volute / radius of the turbine wheel hole

https://youtu.be/NUet-QO6DSQ

It’s possible getting the internal total volume will not tell the entire story

It’s possible they have similar internal volumes but the area of the volute at the tongue is pretty different although The wheel sizes are near identical


Edit: that lengthened “mouth” section would also throw off volume measurement

[bb-tt]

That is bell mouth size that has nothing to do in the performance of the turbo that is already part of the "downpipe"
to my understanding what has influence to the turbo performance is:
- volume of exhaust manifold
- volume in the snail part of the turbine housing.

The part after the turbine is not so important one could extend it with a 3.5inch down pipe.
or did I got wrong what you try to tell me.

For those who don't know te size of K04 and JH5 turbine I put those here again:
- K04 Inducer 50mm exducer 44.5mm
- IHI JH5 Inducer 52mm exducer 44mm

Maybe those picture make me see it wrong but I see outside housing of IHI bigger but again I don't have both real in front of me


PS I can feel up with water a IHI JH5 turbine housing from the 4 hole head side to the exit of the turbine ( not counting the bell mouth) and tell you how much water can fit in their.

so
k04 turbine Inducer 50.1mm / exducer 44.5mm trim 79
compressor inducer 45 / exducer 56.25 trim 64




IHI (courtesy of mars)
Turbine wheel of 52mm inducer / exducer 44mm (7 blade) trim 72
compressor of inducer 40.2/ exducer 52.5mm 6+6 Blade trim 58


lots of good info here https://www.homemadeturbo.com

on small to mid size turbos a larger exducer (compressor side) can reduce spool time due to tip speed being faster on the larger wheel (only to a certain point) "

generally speaking larger trim = more efficient, larger compressor exducer = quicker spool, larger compressor inducer = more flow

[Iceman502]

First of all, MAF g/s is not a perfect comparison and does not tell a complete story. It is just one piece of the puzzle.

I am not referring to compressor housing size being responsible for the K04 having more lag. Start thinking about compressor wheel and turbine wheel geometry. Where does the compressor gets its energy from? What causes a K03 or IHI JH5 to run out of steam at high RPMs? Why can a K04 flow more air at these high rpms?

You say 'first of all' and then list one point before quizzing me about the turbine wheel and its operational efficiency range....

MAF is not perfect for torque, but it is the only tool by which we can compare airflow, and we have been discussing lag. In this case and fortunately for us, both tunes reach the same boost pressure down low if I remember correctly. Your rephrase of 'less torque' has some truth to it, but the lag thing is debunked. Lag is lack of airflow and boost, right? We've quantitatively shown thats not the case.

[Mars2]

so
k04 turbine Inducer 50.1mm / exducer 44.5mm trim 79
compressor inducer 45 / exducer 56.25 trim 64




IHI (courtesy of mars)
Turbine wheel of 52mm inducer / exducer 44mm (7 blade) trim 72
compressor of inducer 40.2/ exducer 52.5mm 6+6 Blade trim 58


lots of good info here https://www.homemadeturbo.com

on small to mid size turbos a larger exducer (compressor side) can reduce spool time due to tip speed being faster on the larger wheel (only to a certain point) "

generally speaking larger trim = more efficient, larger compressor exducer = quicker spool, larger compressor inducer = more flow

that is 100% right

But don't forget that KO4 is 12 blade radial turbine and IHI is 7 blade Mixflow turbine so at our level of knowledge ( at least my level) we don't really know which one flow more.
On my hybrid I have proof that this IHI turbine when combine with a bigger compressor wheel ( RS6 for me) can bring that IHI to the level of Chinese K04. I flow about same as Trap but less than you BBtt with a genuine K04.
that said my RS6/RS7 compressor wheel inducer is slightly smaller than your K04. K04 is 46.36 on spec (45mm on your picture) my RS6/RS7 is 44.2mm
So I don't know where your 14G/s more come from? is it turbine or compressor? I guess a bit of both.
For sure the compressor side of K04 is way superior to genuine IHI JH5

To come back to the subject i think that a well setup KO4 ( good tune, right cracking pressure) will have very very similar spool than IHI in the power band we mostly use.
K04 has Bigger compressor exducer (help spool) and compressor billet compressor wheel vs cast for IHI so the weight should be pretty similar.
The only rpm where I can find my hybrid a but more lazy than IHI JH5 original is in the 1500rpm area as soon a hit 2000 my hybrid is superior.
But who drive's fast from 1500rpm??? 1500 rpm is when you are sleeping so you don't care your turbo is lazy at this rpm.

[EvolutionArmory]

To sum up what has been said, the K04 doesn’t lag

If it does, it isn’t the turbo’s fault. There’s no reason why a K04 shouldn’t be making full boost by 3K or even sooner. If it isn’t doing that, it isn’t set up right or the tune is delaying boost onset. Maybe both.

I mean, if you have your turbo set up to 5-6 PSI and have a shit tune, it will boost like this. 🤣



Attachment 221109

Get your turbo dialed in right and with a good tune, boost can move 1000+ RPM’s sooner like this
Attachment 221111

Show me one tuned IHI or K03 stock turbo making 20 PSI at 2600 RPM. K04’s aren’t more laggy.


Sent from my iPhone using Audizine

[JLAllroad]

To sum up what has been said, the K04 doesn’t lag

If it does, it isn’t the turbo’s fault. There’s no reason why a K04 shouldn’t be making full boost by 3K or even sooner. If it isn’t doing that, it isn’t set up right or the tune is delaying boost onset. Maybe both.

I mean, if you have your turbo set up to 5-6 PSI and have a shit tune, it will boost like this. 🤣



Attachment 221109

Get your turbo dialed in right and with a good tune, boost can move 1000+ RPM’s sooner like this
Attachment 221111

Show me one tuned IHI or K03 stock turbo making 20 PSI at 2600 RPM. K04’s aren’t more laggy.


Sent from my iPhone using Audizine

To your point the K03 would have to be set up right and run the proper tune, just like the K04 or any other turbo, at that point a valid comparison can be made.


Sent from my iPhone using Audizine

[EvolutionArmory]

To your point the K03 would have to be set up right and run the proper tune, just like the K04 or any other turbo, at that point a valid comparison can be made.


Sent from my iPhone using Audizine

Valid.


Sent from my iPhone using Audizine

[Mars2]

I'm over 20 psi by 2600rpm with my IHI.

[Nano909]

I'm over 20 psi by 2600rpm with my IHI.

How's your K03 running?

[Mars2]

I don't have a K03 🤣🤣🤣 Because I don't have a B7. K03 was on B7

[EvolutionArmory]

I'm over 20 psi by 2600rpm with my IHI.

No, you’re over 20 PSI at 2600 with your hybrid.


Sent from my iPhone using Audizine

[A4x]

To your point the K03 would have to be set up right and run the proper tune, just like the K04 or any other turbo, at that point a valid comparison can be made.

I'm gonna assume that APR gets their turbos setup right before publishing dyno numbers.

Here are the APR published numbers for stage 2 stock turbo vs K04. You can see everywhere below 3800 rpm, the stock turbo makes more power. This is the best apples to apples comparison we can get. There is a reason APR has finalized their tunes like this. Maybe I am using the wrong terminology but this sure looks like a bigger turbo has more turbo lag

I could do this same analysis for the other tuners that offer a stage 2 and K04 tune. I'm sure we would see the same trend...

[Nano909]

I'm gonna assume that APR gets their turbos setup right before publishing dyno numbers.

Here are the APR published numbers for stage 2 stock turbo vs K04. You can see everywhere below 3800 rpm, the stock turbo makes more power. This is the best apples to apples comparison we can get. There is a reason APR has finalized their tunes like this. Maybe I am using the wrong terminology but this sure looks like a bigger turbo has more turbo lag

I could do this same analysis for the other tuners that offer a stage 2 and K04 tune. I'm sure we would see the same trend...

The only way to compare would be to take two cars with each turbo to a custom tuner and see what happens. We can't take really use an OTS shop that makes tunes more on the conservative side for longevity.

[Mars2]

the guy that has a stage 2 with JB4 ( forgot his name) could set up his JB4 to have super early spool and Max it out to see what boost he get at low rpm.

But to be honest I think to get the max of IHI you would also need to increase cracking pressure on it, or you will always be limited by the 4.5psi cracking pressure.
So to compare you would need both IHI and K04 to be at same cracking pressure.

[JLAllroad]

The only way to compare would be to take two cars with each turbo to a custom tuner and see what happens. We can't take really use an OTS shop that makes tunes more on the conservative side for longevity.

There is a reason AUDI chose the k03 for their non performance models.

There is a reason APR is showing it out performing their K04 to a certain level ( a kit and software that they want to sell).

The K04 is a very well rounded turbo but if you truly believe that a K04 will respond faster than a K03....we can’t be friends.


Sent from my iPhone using Audizine

[Nano909]

There is a reason AUDI chose the k03 for their non performance models.

There is a reason APR is showing it out performing their K04 to a certain level ( a kit and software that they want to sell).

The K04 is a very well rounded turbo but if you truly believe that a K04 will respond faster than a K03....we can’t be friends.


Sent from my iPhone using Audizine

I didn't say the K04 responds faster. Only that according to all the data posted here, the lag is so minimal that you won't even notice it.

[EvolutionArmory]

There’s multiple examples of K04 cars reaching 20-22 PSI or higher at or before 3K. What the heck is turbo lag? 🤷

If your K04 car has more turbo lag than a stock turbo, you’re doing it wrong.




Sent from my iPhone using Audizine

[JLAllroad]

There’s multiple examples of K04 cars reaching 20-22 PSI or higher at or before 3K. What the heck is turbo lag? 🤷

If your K04 car has more turbo lag than a stock turbo, you’re doing it wrong.




Sent from my iPhone using Audizine

Then under comparatively even circumstances everyone will be doing it wrong.


Sent from my iPhone using Audizine

[Nano909]

Then under comparatively even circumstances everyone will be doing it wrong.


Sent from my iPhone using Audizine

That's why I said we shouldn't take the word of an OTS tune and look at the data on hand. We need someone with a K03 to get custom tuned. Lol

[JLAllroad]

That's why I said we shouldn't take the word of an OTS tune and look at the data on hand. We need someone with a K03 to get custom tuned. Lol

Then that’s tune vs tune.

And you need to find someone with a K03 that isn’t WG compromised.

The APR example is actually quite good as they stand to lose money with an over performing K03.


Sent from my iPhone using Audizine

[bb-tt]

I'm gonna assume that APR gets their turbos setup right before publishing dyno numbers.

Here are the APR published numbers for stage 2 stock turbo vs K04. You can see everywhere below 3800 rpm, the stock turbo makes more power. This is the best apples to apples comparison we can get. There is a reason APR has finalized their tunes like this. Maybe I am using the wrong terminology but this sure looks like a bigger turbo has more turbo lag

I could do this same analysis for the other tuners that offer a stage 2 and K04 tune. I'm sure we would see the same trend...

And i am going to assume APR's Numbers are not accurate as not a single person that posted their dyno sheets for stg 2 here, audiworld or vw vortex was even close to the #s APR posted on their website

[A4x]

And i am going to assume APR's Numbers are not accurate as not a single person that posted their dyno sheets for stg 2 here, audiworld or vw vortex was even close to the #s APR posted on their website

Well not just APR, but every other tuner with published dyno curves for stage 2 and K04 will show a similar trend.

No doubt you guys on custom tunes can squeeze out more power below the 3800 rpm crossover point of the APR numbers, but I'm pretty confident that between 2000-3000 rpm the smaller turbo wins.

For people saying we don't spend much time at these RPMs, I agree. My main concern is 1st gear from a stop when I'm next to someone I want to beat to the next light.

[Nano909]

Well not just APR, but every other tuner with published dyno curves for stage 2 and K04 will show a similar trend.

No doubt you guys on custom tunes can squeeze out more power below the 3800 rpm crossover point of the APR numbers, but I'm pretty confident that between 2000-3000 rpm the smaller turbo wins.

For people saying we don't spend much time at these RPMs, I agree. My main concern is 1st gear from a stop when I'm next to someone I want to beat to the next light.

Some of us are hitting full or over requested boost between 2000-3000.