VTG turbos in the new 911....
Haven't we ALL heard this
Joined: Mar 2001
Posts: 3,948
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From: Indiana
How well does i deal with getting clogged up with soot from cars running a lil on the rich side.
So, like asked before could the vanes be alltered to build boost at the tree?
With the temp limits of the design it sounds like a two step is out of the question.
James
So, like asked before could the vanes be alltered to build boost at the tree?
With the temp limits of the design it sounds like a two step is out of the question.
James
NorCal 7's Co-founder
Joined: Aug 2002
Posts: 4,130
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From: Rocklin, CA
I am really interested to see what comes of this. If it could make a huge turbo streetable, imagine would it could do for a GT35 or GT40. 
You would have spool times identical to that of the stock twins on a heavy streetport!! 
Zach
You would have spool times identical to that of the stock twins on a heavy streetport!! Zach
Rotary Freak
Joined: Jan 2004
Posts: 1,890
Likes: 4
From: Belgium
Temperatures are the big issue for VGT turbo's. Diesels run can run about 400°C lower on load then high performance sportscars.
Weakest link here is the propellor shaft. But maybe soemone can build a VT turbo with an Inconel propellor shaft and make it work
I can imagine Inconel is too expensive for serial production, even for Porsche
Weakest link here is the propellor shaft. But maybe soemone can build a VT turbo with an Inconel propellor shaft and make it work
I can imagine Inconel is too expensive for serial production, even for Porsche
multipersonality disorder
Joined: Feb 2002
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From: so. cal
unlike garrett, holset actually answers customer questions.
NO WASTEGATE. cool, huh?
Dave,
The VGT does not need a wastegate due to the fact it will just open the turbine housing A/R up to the point where the drive pressure is less than the compressor pressure, thus slowing down the turbo. There are two kinds of VGT - Electric and Pneumatic. They use signals from certain sensors located on the engine assembly and feedback to the PCM where it will either: PWM the air compressor solenoid which will modulate air pressure, not vaccum to the "actuator" on the turbo which moves a lever arm. The other method drives the lever electrically through a gear box assembly. I will stress that the PCM is programmed with precise algorithms that tell the turbo how to operate. If these are not programmed properly or the control mechanism is not controlled properly, severe engine damage WILL HAPPEN.
NO WASTEGATE. cool, huh?
Dave,
The VGT does not need a wastegate due to the fact it will just open the turbine housing A/R up to the point where the drive pressure is less than the compressor pressure, thus slowing down the turbo. There are two kinds of VGT - Electric and Pneumatic. They use signals from certain sensors located on the engine assembly and feedback to the PCM where it will either: PWM the air compressor solenoid which will modulate air pressure, not vaccum to the "actuator" on the turbo which moves a lever arm. The other method drives the lever electrically through a gear box assembly. I will stress that the PCM is programmed with precise algorithms that tell the turbo how to operate. If these are not programmed properly or the control mechanism is not controlled properly, severe engine damage WILL HAPPEN.
NorCal 7's Co-founder
Joined: Aug 2002
Posts: 4,130
Likes: 5
From: Rocklin, CA
Dave,
Thanks for posting that. But you forgot to ask him if the VGT setup can withstand the high temps of a rotary exhaust. I think that might be one of the biggest concerns with this technology.
Zach
Thanks for posting that. But you forgot to ask him if the VGT setup can withstand the high temps of a rotary exhaust. I think that might be one of the biggest concerns with this technology.
Zach
multipersonality disorder
Joined: Feb 2002
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From: so. cal
na, the biggest concern is how to control it.
the actuator works off 100+ psi, or it'll need a lever cntrolled by a stepper motor or something like that. i dunno if the haltech will be able to pull this one off.
the actuator works off 100+ psi, or it'll need a lever cntrolled by a stepper motor or something like that. i dunno if the haltech will be able to pull this one off.
NorCal 7's Co-founder
Joined: Aug 2002
Posts: 4,130
Likes: 5
From: Rocklin, CA
I would think that the Haltech would have some sort of aux input/output it could use to control it. Or maybe the new Wolf v.4 could do it.
and I would think that our EGT's would be enough to cause some serious damage to this system. I thought someone had mentioned that they were only tested to like 900F or so. And that wouldn't be enough to tolerate our engines. I really want to see this tested and proven though because it is really interesting. I read the article on Borg Warner's site the other day about this system. Cool stuff!!
Zach
and I would think that our EGT's would be enough to cause some serious damage to this system. I thought someone had mentioned that they were only tested to like 900F or so. And that wouldn't be enough to tolerate our engines. I really want to see this tested and proven though because it is really interesting. I read the article on Borg Warner's site the other day about this system. Cool stuff!!
Zach
multipersonality disorder
Joined: Feb 2002
Posts: 5,656
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From: so. cal
if you can find a solonoid that can handle the frequency, and 100+ psi, you can use an air compressor from airbag suspension. then, i wonder if you can use the haltechs boost control function to do it.
NorCal 7's Co-founder
Joined: Aug 2002
Posts: 4,130
Likes: 5
From: Rocklin, CA
You're the Haltech guy, you tell me. But seriously, there has got to be a way for a Haltech or the new Wolf to control this setup. I'll talk with Chris Green at Wolf USA this weekend to see if he has any info that would be useful for us.
Zach
But seriously, there has got to be a way for a Haltech or the new Wolf to control this setup. I'll talk with Chris Green at Wolf USA this weekend to see if he has any info that would be useful for us.Zach
Rotary Freak
Joined: Jan 2004
Posts: 1,890
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From: Belgium
Las t month there was an article in Motor und Trend, a leading German car magazine explaining the function of the system and explaining that it has been used in diesel engiens so far but not in gasoline cars.
Main issue was that in high performance carsthe manifold/exhaust temperatures could reach upto more than 400°C higher than diesel engines. Resulting in exhaust wheel and axle melting and desintegrating.
The Porsche now has a special material for these parts. Let's assume they used Inconel axles and wheels to cope with that problem.
A similar problem was found in the new diesel cars being equiped with diesel particle filters. It has come forward that these filters are blocking up exhaust gasses too much when the car has been chipped that the additional heat will destroy the turbo's hotside manifold, wheel and axles.
Main issue was that in high performance carsthe manifold/exhaust temperatures could reach upto more than 400°C higher than diesel engines. Resulting in exhaust wheel and axle melting and desintegrating.
The Porsche now has a special material for these parts. Let's assume they used Inconel axles and wheels to cope with that problem.
A similar problem was found in the new diesel cars being equiped with diesel particle filters. It has come forward that these filters are blocking up exhaust gasses too much when the car has been chipped that the additional heat will destroy the turbo's hotside manifold, wheel and axles.
Junior Member
Joined: Oct 2005
Posts: 11
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From: va
The turbo in the photos is material rated to 1050*C, so it should be quite happy in a wankel. The hardware appears to be inconel, and I will verify this. There should also be no problems with soot loading via a rich idle or tune, since this methodology is well proven in diesels.
However, it should be noted that even though some tuned diesels will reveal high exhaust opacity under full load, the soot does not accumulate very much inside the volute, or turbine wheel surprisingly. A light coating is normally all you find.
As far as control, there are many ways to control the vanes, and the logic can be switched very easily; pressure is not always needed if you are using a pneumatic actuator. The more sophisticated the control logic, the more you will get out of the turbo. The same analog can be made whilst controlling a wankel power unit!
Yes, you can build boost while staging at the line, likely without resorting to using a 2 step rev limiter. On another engine, I was able to build 5 psi at 2K rpm with no load, and the vanes aggressively working. Any more boost was counter productive to the 60' time!
Thanks for the information about the A-spec T-6 manifold, as I will contact them shortly.
However, it should be noted that even though some tuned diesels will reveal high exhaust opacity under full load, the soot does not accumulate very much inside the volute, or turbine wheel surprisingly. A light coating is normally all you find.
As far as control, there are many ways to control the vanes, and the logic can be switched very easily; pressure is not always needed if you are using a pneumatic actuator. The more sophisticated the control logic, the more you will get out of the turbo. The same analog can be made whilst controlling a wankel power unit!
Yes, you can build boost while staging at the line, likely without resorting to using a 2 step rev limiter. On another engine, I was able to build 5 psi at 2K rpm with no load, and the vanes aggressively working. Any more boost was counter productive to the 60' time!
Thanks for the information about the A-spec T-6 manifold, as I will contact them shortly.
Originally Posted by Speedworks
Las t month there was an article in Motor und Trend, a leading German car magazine explaining the function of the system and explaining that it has been used in diesel engiens so far but not in gasoline cars.
Main issue was that in high performance carsthe manifold/exhaust temperatures could reach upto more than 400°C higher than diesel engines. Resulting in exhaust wheel and axle melting and desintegrating.
The Porsche now has a special material for these parts. Let's assume they used Inconel axles and wheels to cope with that problem.
A similar problem was found in the new diesel cars being equiped with diesel particle filters. It has come forward that these filters are blocking up exhaust gasses too much when the car has been chipped that the additional heat will destroy the turbo's hotside manifold, wheel and axles.
Main issue was that in high performance carsthe manifold/exhaust temperatures could reach upto more than 400°C higher than diesel engines. Resulting in exhaust wheel and axle melting and desintegrating.
The Porsche now has a special material for these parts. Let's assume they used Inconel axles and wheels to cope with that problem.
A similar problem was found in the new diesel cars being equiped with diesel particle filters. It has come forward that these filters are blocking up exhaust gasses too much when the car has been chipped that the additional heat will destroy the turbo's hotside manifold, wheel and axles.
Like VGT said, they're good for 1050*C. I'm surprised no one has done the research (instead of just asking) cuz I found all the info I could ever want (and then some) in about 3 seconds on google 
1) http://www.theautochannel.com/news/2...28/212040.html
"Porsche's variable turbine geometry (VTG) setup on the 2007 911 Turbo was developed in close cooperation with Borg Warner Turbo Systems, and is based on technology which has been widely and successfully applied to diesel engines since the early 1990s. It is nearly identical in concept to other turbo manufacturers' variable nozzle/geometry compressors, including a system that was briefly used on a series gasoline production engine in the late 1980s. This application encountered difficulties due to high operating temperatures -- a problem not easily solved with contemporary materials -- and production was stopped after a limited run.
After nearly two decades, aerospace-grade materials have allowed the progression of variable-geometry turbo technology to the point that it can now reliably operate in the higher-temperature environment of turbocharged gasoline engines. Porsche's version of variable turbine geometry in the 2007 911 Turbo incorporates these latest material applications, plus a sophisticated control algorithm. The combination produces the advantages of both small and large turbochargers, generating a much wider plateau of torque and providing quicker response compared to the previous generation 911 Turbo, while providing the reliability of fixed-vane turbochargers.
2) http://www.turbos.bwauto.com/en/products/vtg.asp - Borg Warner Turbo Systems
- A bunch of info about the turbos (which they developed) can be found there
- They list the gasoline-engine turbos under their "Passenger Car Gasoline" section, showing turbos as small as 160hp to as large as 335 hp, 4 out of the 5 of which employ the twin-flow turbines and 1050°C technology.
If these are seriously doable on a rotary (they're obviously available; the question is can they be adequately controlled and tuned for by an ECU), I'm gonna do it. Seriously.
~Ramy
PS. VGT, where in VA are you?
1) http://www.theautochannel.com/news/2...28/212040.html
"Porsche's variable turbine geometry (VTG) setup on the 2007 911 Turbo was developed in close cooperation with Borg Warner Turbo Systems, and is based on technology which has been widely and successfully applied to diesel engines since the early 1990s. It is nearly identical in concept to other turbo manufacturers' variable nozzle/geometry compressors, including a system that was briefly used on a series gasoline production engine in the late 1980s. This application encountered difficulties due to high operating temperatures -- a problem not easily solved with contemporary materials -- and production was stopped after a limited run.
After nearly two decades, aerospace-grade materials have allowed the progression of variable-geometry turbo technology to the point that it can now reliably operate in the higher-temperature environment of turbocharged gasoline engines. Porsche's version of variable turbine geometry in the 2007 911 Turbo incorporates these latest material applications, plus a sophisticated control algorithm. The combination produces the advantages of both small and large turbochargers, generating a much wider plateau of torque and providing quicker response compared to the previous generation 911 Turbo, while providing the reliability of fixed-vane turbochargers.
2) http://www.turbos.bwauto.com/en/products/vtg.asp - Borg Warner Turbo Systems
- A bunch of info about the turbos (which they developed) can be found there
- They list the gasoline-engine turbos under their "Passenger Car Gasoline" section, showing turbos as small as 160hp to as large as 335 hp, 4 out of the 5 of which employ the twin-flow turbines and 1050°C technology.
If these are seriously doable on a rotary (they're obviously available; the question is can they be adequately controlled and tuned for by an ECU), I'm gonna do it. Seriously.
~Ramy
PS. VGT, where in VA are you?
Last edited by FDNewbie; May 16, 2006 at 05:09 PM.
Nifty stuff. The vanes are functionally identical to the 'wicket gates' used in hydroelectric turbines. Which btw have been in use for over a century - this idea is hardly old or untested - it simply lacked adequate controller power and sufficient materials.
All I have to say is good$ luck$. Even if this material holds up at 1000C, there remains the question of how long. Adopting this technology at the moment will put you on the very bleeding edge, so I would expect this to be expensive and have a moderate-high failure rate. The second and third generations to be used by the masses are mostly likely to be much better. But it's perfect for those ever-changing wildly modified street/track machines.
Dave
All I have to say is good$ luck$. Even if this material holds up at 1000C, there remains the question of how long. Adopting this technology at the moment will put you on the very bleeding edge, so I would expect this to be expensive and have a moderate-high failure rate. The second and third generations to be used by the masses are mostly likely to be much better. But it's perfect for those ever-changing wildly modified street/track machines.
Dave
