DOES still lots of people have k03/k16 hybrid turbo issue? or is it tollay gone cuz they changed
09-15-2005, 06:58 PM
#12
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Both are for the hot side. They both involve increasing the clearance between the turbine and the
housing. They both reduce turbine efficiency, but allow more flow up top. I'm pretty much quoting Imolavirus's post below.<ul><li><a href="https://forums.audiworld.com/s4/msgs/2112280.phtml">https://forums.audiworld.com/s4/msgs/2112280.phtml</a</li></ul>
09-15-2005, 07:48 PM
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The K03 turbine and the K04 compressors are more closely matched rpm-wise.
Both compressors and turbines are designed to work efficiently in a certain rpm range. Pairing a K16 compressor to a K03 turbine makes for a pretty big disparity in compressor/turbine wheel specs.
I don't have any specs for turbine rpms, but you can get the picture by seeing the max rpms at which the compressor wheels operate efficiently.
K03, 207K rpm
K04, 183K rpm
K16, 160K rpm
On a completely different note, there has been some recent speculation by Mike2ks4 that the way the compressor fits into a ground-out hybrid housing has an effect on efficiency. The K16 does not come anywhere near matching the physical dimensions of a K03, K04, or even an RS6 compressor wheel.
I don't have any specs for turbine rpms, but you can get the picture by seeing the max rpms at which the compressor wheels operate efficiently.
K03, 207K rpm
K04, 183K rpm
K16, 160K rpm
On a completely different note, there has been some recent speculation by Mike2ks4 that the way the compressor fits into a ground-out hybrid housing has an effect on efficiency. The K16 does not come anywhere near matching the physical dimensions of a K03, K04, or even an RS6 compressor wheel.
09-15-2005, 07:55 PM
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I'll have to argue on that one ;)
The physical dimension of the compressor wheel going into a compressor housings doesn't really have any bearing to efficiency as long as there is ample material in the housing. There can be an issue if the compression area inside the housing becomes too small but there is plenty of room with the K16 wheel.
btw, those c-whl rpm's are way out of max efficiency.
btw, those c-whl rpm's are way out of max efficiency.
09-16-2005, 08:09 PM
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My thoughts on hybrid turbochargers:
<center><img src="http://www.s4biturbo.com/k04/k04-0025.jpg"></center><p>
When thinking of Hybrids one should try to keep in mind the systemic loop of turbocharger operation: What gets pumped on the compressor gets expelled on the turbine end further spinning the compressor...etc.
What I've been seeing in the K16 and K24 hybrids is an increase of effective PR at a certain flow rate. IMO this is due to the decreased compression area in the housing. I don't see much wrong with this on K16's/K24 at 23-25# or so. K16/K24 have killer midrange because of this.
BUT where does that leave us as a total system?
Compressor side: We have a bigger wheel in a smaller housing that requires a higher PR to make the same amount of flow at a lower turbine RPM.
Turbine side: We have the same turbine spinning at a lower rpm unable to evacuate all the turbine inlet gases like it would normally. And it's flowing through a housing smaller than is needed to most efficiently move the type of flow the larger compressor provides. SO we need to evacuate these gases more effectively.
Thankfully Jacob and other manufacturers offers clipping, clearancing porting and Extrude Honing of turbine and WG housings and upgraded actuators to deal with these issues. A thoughtful combination of these options should take care of the exhaust side problems and prevent Turbine Inlet Pressure from getting so high it affects performance.
Given the above thoughts: The RPM range and just the map (flow and PR) of the K04 wheel in a K03 seem more compatible, just as the RS6 in a K04 are.
On to the K16/K03 combination: It makes some damned impressive power, but it could be better, IMO. I look at the Jacob's dyno chart and see a pronounced pyramidic shape. To me, this represents a couple potential issues. Either the wastegates are opening due to TIP or there is a significant flow restriction in the exhaust housing at higher RPMS. Considering the flow potential of the K16 wheel as well as the flow potential of the K03 hotside either is entirely plausible.
My choice of K04/RS6 hybrids are what I consider a very-well matched hot/cold system. The map of the RS6 wheel matches the K04 very closely. I've never measured it, but by looking the RS6K04 and RS4K04 housings seem closely matched in volume. The smaller compressor housing should only work to stretch the PR up a bit, which seems to be the case. The Extrude Honed and Clearanced housing should have no problem dealing with the excess flow and providing maximum force to the turbine without excessive Turbine Inlet pressure.
This is why I made my choice and it's really paid off in airflow, driveability and performance.
I wrote so damned much here I might as well repost it up top
When thinking of Hybrids one should try to keep in mind the systemic loop of turbocharger operation: What gets pumped on the compressor gets expelled on the turbine end further spinning the compressor...etc.
What I've been seeing in the K16 and K24 hybrids is an increase of effective PR at a certain flow rate. IMO this is due to the decreased compression area in the housing. I don't see much wrong with this on K16's/K24 at 23-25# or so. K16/K24 have killer midrange because of this.
BUT where does that leave us as a total system?
Compressor side: We have a bigger wheel in a smaller housing that requires a higher PR to make the same amount of flow at a lower turbine RPM.
Turbine side: We have the same turbine spinning at a lower rpm unable to evacuate all the turbine inlet gases like it would normally. And it's flowing through a housing smaller than is needed to most efficiently move the type of flow the larger compressor provides. SO we need to evacuate these gases more effectively.
Thankfully Jacob and other manufacturers offers clipping, clearancing porting and Extrude Honing of turbine and WG housings and upgraded actuators to deal with these issues. A thoughtful combination of these options should take care of the exhaust side problems and prevent Turbine Inlet Pressure from getting so high it affects performance.
Given the above thoughts: The RPM range and just the map (flow and PR) of the K04 wheel in a K03 seem more compatible, just as the RS6 in a K04 are.
On to the K16/K03 combination: It makes some damned impressive power, but it could be better, IMO. I look at the Jacob's dyno chart and see a pronounced pyramidic shape. To me, this represents a couple potential issues. Either the wastegates are opening due to TIP or there is a significant flow restriction in the exhaust housing at higher RPMS. Considering the flow potential of the K16 wheel as well as the flow potential of the K03 hotside either is entirely plausible.
My choice of K04/RS6 hybrids are what I consider a very-well matched hot/cold system. The map of the RS6 wheel matches the K04 very closely. I've never measured it, but by looking the RS6K04 and RS4K04 housings seem closely matched in volume. The smaller compressor housing should only work to stretch the PR up a bit, which seems to be the case. The Extrude Honed and Clearanced housing should have no problem dealing with the excess flow and providing maximum force to the turbine without excessive Turbine Inlet pressure.
This is why I made my choice and it's really paid off in airflow, driveability and performance.
I wrote so damned much here I might as well repost it up top
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