Turbo Problems: Questions & Answers

Hi,

Do you have any additional information about the causes of...?
I'm sorry, but I cannot provide a translation for that text because it appears to be a URL. URLs are not typically translated, as they are meant to be used as web addresses.

For example, endangered loader models, assembly errors (e.g., oil supply?), damaging driving patterns, or similar issues?

Could the KKK turbocharger (KP39B) in my Polo also be affected?

ulf wrote:

... My Polo also has a KKK turbocharger (KP39B). ...

... Are you sure about that?

To my knowledge, the Borg Warner KP39 turbocharger was only used in the "smaller" TDIs (i.e., those with 74 + 77 kW).

If you really have a KP39 installed, then I understand why you're always complaining about performance issues.
The KP39 has a 39mm turbine, while the GT1749xx has a 43mm turbine, so there's a 4mm difference. I've driven both on my AXR (the stock one is a GT1749B), and the difference is like night and day. With the KP39, the engine feels constricted at higher RPMs, and the boost build-up takes a bit longer (although that was only visible in the logs).

Bertil wrote:

To my knowledge, the Borg Warner KP39 was only installed in the "smaller" TDIs (i.e., 74 + 77 kW).

Hi Bertil,

According to the label, I actually have a KP39B. I would need to research the VAG number to see if the same part is used in the AXR golfs.

If not, the "B" might indicate a counterpart to the Golf 4 ASZ turbocharger, model GT1749VA(?), with a correspondingly larger turbine.
(On the other hand: The KP 39 and a 39mm turbine diameter fit together so well that it's unlikely a larger turbine would be used in a B-version without changing the model designation.)

If so, that would probably be another reason to switch to a GT1749VB soon, in addition to my tuning.

Bertil wrote:

I have driven both on my AXR (the factory one is a GT1749B). . .

Oh dear, here we go again with the Garrett range
I only know off the top of my head about the 1749V (up to 115 hp?), VA (130 hp), and VB (150 hp) models. Do you know how your 1749B fits into that?

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With the KP39, the engine feels constricted in the upper RPM range, and the turbocharger build-up takes a little longer in the lower RPM range

. And is the KP39 an officially approved alternative tuning option for your engine?
If his turbine appears to be too small even for the exhaust volume flow of a 100 horsepower engine, then I can't really imagine that the same part would be attached to an ASZ.

Was was only noticeable during acceleration (i.e., a dynamic issue), or was there also a clear lack of top performance (maximum speed)?

Or was the LD (likely referring to a component or setting) so incorrectly adjusted in conjunction with the KP39 that it apparently only caused the pre-tax fuel consumption to not match the specifications for the turbocharger?

ulf wrote:

... According to the label, I actually have a KP39B. I would need to research the VAG number to see if the same part is used in the AXR golfs.

"I can tell you about the 'B' tonight. The charger is connected to the other motor again, and I can see that right away. I can give you the number for that right now."

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If not, the "B" might indicate a counterpart to the Golf 4 ASZ turbocharger, model GT1749VA(?), with a correspondingly larger turbine. (On the other hand: The KP 39 and a 39mm turbine diameter fit together so well that it's unlikely a larger turbine would be used in a B-version without changing the model designation.)

No, a KP39 always has a 39mm turbine, just like the GT1749xx always has a 1.7" (43mm) turbine (as far as I remember from the documentation). The maximum specified boost pressures are different.
Minor adjustments to the airflow are also possible to optimize the efficiency.

What's currently on my mind are the hybrid chargers. The compressor turbine was the same, but the exhaust turbine was different. However, I can't recall the specific designations for those components.

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If so, that would probably be another reason to switch to a GT1749VB soon, in addition to my tuning.

It definitely delivers much more than anything else.

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Bertil wrote: I have driven both on my AXR (the factory one is a GT1749B). . . Oh dear, here we go again with the Garrett range I only know off the top of my head about the 1749V (up to 115 hp?), VA (130 hp), and VB (150 hp) models. Do you know how your 1749B fits into that?

Thick fingers... I meant to type "V" instead of "B"... sorry.

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And is the KP 39 an official alternative configuration for your engine?

Yes, you can find the exact part numbers (MJ02/03) in the G4 AXR parts list. You can also see the different configurations there. It's not a lot, and it should fit without much effort.

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If his turbine appears to be too small even for the exhaust volume flow of a 100 horsepower engine, then I can't really imagine that the same part would be attached to an ASZ. Was was only noticeable during acceleration (i.e., a dynamic problem), or was there also a clear lack of top performance (maximum speed)?

Somehow, it didn't feel as lively as with the Garrett when accelerating in the higher RPM range. It seemed like it was lacking peak power. But I didn't do any measurements with the KKK... just the butt-o-meter. The top speed was achieved with the KKK, but with the Garrett, you get a little more. You know... my value-added performance .
In the lower RPM range, the boost pressure only reached its maximum value gradually, as indicated in the log. The Garrett turbocharger tends to overshoot the target pressure more noticeably in that range.

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Or was the LD

incorrectly (performance-reducing) adjusted with the KP39, such that apparently "only" the pre-turbocharger https://community.dieselschrauber.org/en/viewtopic.php?t=8788&highlight=turbo+axr component didn't fit the turbocharger?
I've been wanting to figure out for a while now which ECUs (Engine Control Units) were installed with which loaders, and I've found that all combinations are possible (search the forum; we've discussed this before). Therefore, the mapping data shouldn't be different.

[EDIT] Link found: }

The person who stated that the turbo runs with both ECUs is actually named Ulf... does that sound familiar? }

Bertil wrote:

I can tell you about the "B" tonight. The charger is connected to the other motor again, and I can see that immediately. I can also give you the number right away.

Yes, that would be interesting.
Can you actually see the entire turbine if you just remove the coupling flange from the compressor? Then I might be able to measure my turbine if I can access all its parts...

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What's currently on my mind are the hybrid chargers. The compressor turbine was the same, but the exhaust turbine was different. However, I can't remember the specific designations.

Were hybrid chargers like these also manufactured by KKK as original equipment?

According to my records, my Polo doesn't have the same turbocharger as the AXR-G4.
G4 KKK: 038 253 016 N
Polo KKK: 038 253 016 S, later 038 253 014 C; the EU4-BLT only has the 014.

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Therefore, the characteristic curves should not differ.

Yes, but the actual pressure (and exhaust back pressure) that each type of turbocharger produces is, at least in detail, a different story...

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/viewtopic.php?t=8788&highlight=turbo+axr The person who stated that the turbo runs with both ECUs is actually named Ulf... does that sound familiar?

ulf wrote:

Quote: What's currently on my mind are the hybrid chargers. The compressor turbine was the same, but the exhaust turbine was different. However, I can't remember the specific designations. Were hybrid chargers like these also manufactured by KKK as original equipment?

No idea!

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According to my records, my Polo doesn't have the same turbocharger as the AXR-G4. G4 KKK: 038 253 016 N Polo KKK: 038 253 016 S, later 038 253 014 C; the EU4-BLT only has the 014.

I already suspected that... the G4 AXR leather is a KP39A.

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Quote: Therefore, the characteristic curves should not differ. Yes, but the actual pressure (and exhaust back pressure) that each type of turbocharger produces is, at least in detail, a different story...

I don't think we'll see a significant increase in power due to the boost pressure limit, but the driving experience is noticeably different. I can confirm that.

Okay, I just measured the chargers in my workshop (and was quite surprised).

GT1749VA: The inlet is 43mm and tapers down to just under 40mm at the compressor turbine.
GT1749V: Same here.
KP39A: Input 39mm ... I couldn't measure anything beyond that.

The KP39 engine is positioned so awkwardly in the corner that I can't fully access it. I couldn't determine whether there's a narrowing section leading to the turbine without completely removing the engine from the corner.
I would now confidently say that both turbochargers have almost the same size turbine. Therefore, only the air intake system of the turbocharger itself can account for the improvement in engine characteristics. It seems that the Garrett is better in this regard.


Okay, one more thing... The KKK turbocharger has an integrated manifold, while with the Garrett turbocharger, the manifold and turbocharger are two separate parts.

Bertil wrote:

I would now confidently state that both chargers have almost the same size turbine. Then, only the air intake system of the charger itself can account for the improvement in engine characteristics. It seems that the Garrett is better in that regard.

This would mean that it's not necessarily a turbine diameter of 39 mm or 1.7", as the model names suggest?

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The KKK turbocharger has an integrated manifold, while with the Garrett turbocharger, the manifold and turbocharger are two separate parts.

That's interesting: in the documents, the G4 AXR-Garrett is also listed as a one-piece "manifold with turbocharger".

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The engine with the KP39 is in such a awkward position in the corner that I can't fully access it.

Too bad. But if it ever needs to be moved, please let me know.

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The G4 AXR leather is a KP39A

. Is it also ball-bearing or needle-bearing mounted?
The rotational feel of my 39B on the compressor is so different (no radial play and extremely smooth compared to the sloppy VNT15 from the AFN), that I can only explain the difference in this way.

ulf wrote:

Bertil wrote: The G4 AXR leather is a KP39A . Is it also ball-bearing or needle-bearing mounted? The rotational feel of my 39B on the compressor is so different (no radial play and extremely smooth compared to the tranig-sluggish VNT15 from the AFN) that I can only explain the difference in this way.

Which (if any) Garrett turbochargers actually use ball bearings or needle bearings ?

ulf wrote:

...This would therefore no longer (necessarily) mean a turbine diameter of 39 mm or 1.7", as the model names suggest?

Yes, the inlet diameter is specified.

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Quote: The KKK turbocharger has an integrated manifold, while with the Garrett turbocharger, the manifold and turbocharger are two separate parts. That's interesting: in the documents, the G4 AXR-Garrett is also listed as a one-piece "manifold with turbocharger".

Take a closer look. There should be a Garrett turbocharger with and without a manifold in the G4 series (not necessarily the AXR model). I have two of them, even though AKTE claims otherwise.

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Quote: The engine with the KP39 is in such a awkward position in the corner that I can't fully access it. Too bad. But if it ever needs to be moved, please let me know.

If the Jetta has received a new engine (the engine is still in front), the snow blower is no longer needed (after all, it's winter), and the trailer, which is also still in front, needs to be moved again... ... The Lupo is probably the smallest problem.

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Quote: The G4 AXR leather is a KP39A . Is it also ball-bearing or needle-bearing mounted? The rotational feel of my 39B on the compressor is so different (no radial play and extremely smooth compared to the tranig-sluggish VNT15 from the AFN) that I can only explain the difference in this way.

So difficult to turn as the GT1749VA is, I would say it has plain bearings. Is it sloppy? Well, after 110,000 km, the VA hasn't worn down that much. There's hardly any play... it's just that the VTG is stuck . That's why I could also get it at a good price.
I have no idea if the KKK is ball-bearing. I'm not very familiar with KKK products. Let me see if I can find some information about that.

http://www.turbos.bwauto.com/en/products/passenger_diesel.asp

[EDIT] As far as I can tell from what I'm reading here, the 3K Borg Warner also "only" uses plain bearings.
http://www.turbos.bwauto.com/en/products/design_bearing.asp
... is also available in German: http://www.turbos.bwauto.com/de/products/design_bearing.asp

Bertil wrote:

ulf wrote: ...So, this wouldn't necessarily mean a turbine diameter of 39 mm or 1.7", as the model names suggest? Yes, the input diameter is specified. Yesterday: So, I just measured the chargers in my workshop (and was in for a big surprise): GT1749VA: The 43mm inlet tapers down to just under 40mm at the compressor turbine. GT1749V: Same here. KP39A: Input 39mm ... I couldn't measure anything more.

Ah, oh... a misunderstanding?
"For me, 'turbine' always refers to the exhaust side, and 'compressor' refers to the intake side."
So, with all these differences, were you only referring to the compressor side?
I could easily measure that on my loader as well.
However, I'm quite sure (since I've removed the intake manifold before) that the inlet also tapers conically towards the compressor; the transition to the last cylindrical section before the compressor impeller is not rounded, but rather you can feel a "notch" which, in my opinion, is likely to be unfavorable for airflow.

Perhaps the loader could be improved by smoothing out that sharp "kick" sound.

Your perceived difference between the KKK and Garrett might be due to the fact that the KKK inlet tapers the cross-sectional area from the upstream rubber hose reducer in a stepped manner to 39 mm, creating corresponding vortices, while the GT1749 creates a less vortex-prone conical transition -> then, it might be possible to tune your KP39A by conically machining the inlet to achieve a similar effect .

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Considering how stiff the GT1749VA is, I would say it has plain bearings. Is it sloppy? Well, after 110,000 km, the VA wasn't sloppy. There's hardly any play...

I meant "sloppy" in comparison to the VNT15, which had an estimated radial clearance of about 1 mm without oil pressure on the compressor. How does the rotational feel compare on your KP39A?

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Take a closer look. There should be a Garrett turbocharger with and without a manifold in the G4 series (not necessarily AXR). I have two of them, even though AKTE claims the opposite.

I'll have time for that later, also for the BW links (thank you ). I'll get back to you.

ulf wrote:

So, with all these differences, were you only referring to the compressor side?

Yes... I don't consider the exhaust side to be that important.

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But I'm quite sure (since I've taken the intake manifold apart before) that the opening also tapers conically towards the compressor; the transition to the last cylindrical section before the compressor impeller isn't rounded, but rather you can feel a "notch" which, in my opinion, is likely to be unfavorable for airflow.

Ah yes... the GT1749VA is as smooth as a baby's bottom all the way up to the turbine. It only tapers conically.

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Perhaps the loader could be improved by smoothing out that sharp "kick" sound.

Did anyone think that was a good idea?

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Your perceived difference between the KKK and Garrett turbochargers might be due to the fact that the KKK inlet gradually reduces the cross-sectional area to 39 mm, creating corresponding turbulence, while the GT1749 creates a less turbulent conical transition.

Yes, it could be. Hopefully, this step isn't intentional.

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-> Then, it might be possible to fine-tune your KP39A by adjusting the conical shape of the inlet.

In principle, yes (see above).

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How does the feel of the trigger pull compare on your KP39A?

No significant difference. I feel like the KP39 is a bit smoother.
The KP39 has only been in use for 11,500 km, while the GT1749VA has already been used for 110,000 km. My GT1749V also has 105,000 km on it, which could make a direct comparison less accurate. Both Garrett turbochargers have a very similar feel when it comes to spool-up.
All the bearings in the loaders have very little play (estimated at ~0.5mm).

I'm always surprised by how difficult it is to operate the loaders without oil pressure.

Bertil wrote:

Quote: Your perceived difference between the KKK and Garrett might be due to the fact that the KKK inlet gradually reduces the cross-sectional area from the upstream rubber hose to 39 mm, creating corresponding vortices, while the GT1749 creates a less vortex-prone conical transition . Yes, it could be. Hopefully, this step is not intentional.

I can hardly imagine any benefit... why would one intentionally slow down the uncompressed air at the narrowest point before the compressor, i.e., where it flows at its maximum velocity, by creating vortices?

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With the KP39, I have the feeling that it doesn't feel as stiff.

I'm always amazed at how stiff the loaders are without oil pressure.

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From my memory, I would say that my cold KP39B, after being "started," has the shaft rotating freely for several seconds with just two fingers, which seems absolutely unthinkable for the VNT15. And the KP39B bearing also has absolutely no noticeable play, even with "very careful" manipulation... both seem to me to be ball or roller bearings, even though your links don't mention that.

Take a closer look. There should be a Garrett turbocharger with and without a manifold in the G4 series (not necessarily AXR). I have two of them, although AKTE claims the opposite. I've gone through all the production years of the G4. The only turbocharger without a manifold attached belongs to the AGR, with part numbers 038 145 701 A (Garrett) or D (KKK).
Can you identify the VAG number on your Garrett turbocharger? If so, we can use TVN to find out which vehicle it's originally intended for.

(It's amazing how far off-topic we've gotten - it would be nice if vagtuning could still respond to the original topic }).

ulf wrote:

...why would one intentionally slow down the uncompressed air at the narrowest point before the compressor, i.e., where it flows at its maximum velocity, by creating turbulence?

Okay, I'm not going to commit to that. Aerodynamics is a tricky thing.

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I have gone through all the production years of the G4. The only charger without a manifold attached belongs to the AGR, with part number 038 145 701 A (Garrett) or D (KKK). Can you identify the VAG number on your Garrett turbocharger? If so, we can use TVN to find out which vehicle it's originally intended for.

038 145 702 G, GT1749VA (originally from a 130 HP PD Passat).
038 145 702? The GT1749V turbocharger for the AXR engine (the letter is no longer legible).

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(It's amazing how far we've gotten in the OT...

Sorry, my fault.

Sorry, I didn't see it, as I've been busy dealing with seats the last few days.

It seems that Golf 5 and first-generation A3 models are affected, but so far I haven't heard or seen anything about this issue with other engines.

vagtuning wrote:

Also es scheinen Golf 5 und A3s der ersten Baureihen betroffen zu sein...

Naja, immerhin haben deren Lader nicht die gleiche VAG-ET-Nummer wie meiner . . . Thank you .

Bertil wrote:

038 145 702 ? The GT1749V in the AXR (the letter is no longer recognizable)

Oh dear, how mean... it's the letter that makes the identification .
Is there absolutely nothing left to identify, or at least some remnant that leaves at least three possibilities open, of which (with a bit of luck) two are not even documented in the records?
I'd also be interested to know what kind of "external charger" is connected to your AXR.

Hello Ulf,

While this is quite off-topic and won't help solve your problem, the BorgWarner link provided by Bertil contains an interesting note...



next to

<--click on the images

can be found there (Baden-Württemberg):

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Maximum capacity. The maximum volumetric flow rate of a radial compressor is typically limited by the cross-sectional area at the compressor inlet. If the air reaches the speed of sound at the impeller inlet, further increases in flow rate are no longer possible. In the compressor characteristic curves, the choking limit is indicated by the sharply decreasing speed lines on the right edge of the characteristic curve.

Greetings, Cryonix.

I have to go on stage now to replace a rotten rear trailing arm .