Rotary Car Performance General Rotary Car and Engine modification discussions.

Variable Geometry Turbos

Old Jul 9, 2005 | 10:09 AM
  #26  
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I know the basics of how the VATN works. The turbine blades can extend and retract to control the flow of the exhaust gas across the turbine side, eliminating the need for a wastegate and boost controller. But why are they not practical for gasoline engines yet?
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Old Jul 9, 2005 | 11:48 AM
  #27  
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Originally Posted by FCNutCase
Are you sure about this? Where do you get this information? I have found nothing about VNT turbos used on an VW products, let alone the 2005 Golf... I didn't even think the 2.0T engine was out in the Golfs yet. A search of VW's site found no info about VNT's either, and this seems like a tech worth making a stink over.

As for the technology of Variable Turbo, my undergrad schoo, UCSD, used a Variable turbo on 600 cc Yamaha sport bike engine for a SAE competition. It worked ok, but not great, had trouble getting the boost pressures they were looking for.

Collin Webster
89 TII

It's a VNT15, the motor I have is the Euro 100HP 1.9l using the individual pump injectors. From what I understand this motor isn't available in the US, only up here in Canada. The main problem with this motor is that if you adjust the boost you will make too much boost in the low end and end-up in compressor surge. So far it drives unlike any other turbo-diesel I've ever been in, about 1/4 second of turbo lag.
Grant
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Old Jul 9, 2005 | 12:00 PM
  #28  
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HKS has one in testing right now....i think the resons they aren't used in many applications is due to the cost and heat fatigue. With the death of production turbo rotarys i highly doubt we will ever see one thats tested to handle the temps on a consumer level.
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Old Jul 9, 2005 | 05:09 PM
  #29  
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The thing i dont understand is how the blades are flexed. I know its electronic, but what circuitry (besides an egt probe or 02 sensor) could withstand those kind of temps.?
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Old Jul 9, 2005 | 05:30 PM
  #30  
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dude, go read maximum boost or something, they are controlled by hydraulic pressure. It'd be very expensive to have electronics that can withstand that kind of spinning and keep some kind of connection (if that is even possible).

There is a huge *** thread on here about this stuff, Blue TII was doing it. Just search.
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Old Jul 9, 2005 | 07:29 PM
  #31  
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The variable geometry is on the outlet for the hotside.

The turbine itself and the blades and **** are fixed. The A/R changes - letting you have it smaller on the low end so it'll spin up faster and then open up so it wont restrict the exhaust and allow for top end flow.

Having the turbine inside itself change dynamically would be damn near impossible without the price going sky high!
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Old May 16, 2006 | 05:08 PM
  #32  
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Here's an update... https://www.rx7club.com/showthread.php?p=5657335 (read page 1 then skip to page 5 hehe)
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Old May 17, 2006 | 06:37 PM
  #33  
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http://www.everytime.cummins.com/every/misc/vgt.jsp
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Old May 17, 2006 | 06:48 PM
  #34  
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Def. interesting (and I dunno if the Borg Warner turbos have this simple sliding design or not), but too bad this is a diesel-only application...
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Old May 17, 2006 | 08:08 PM
  #35  
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Did I miss something or did no one mention the 997 turbo?

http://www.porsche.com/all/masterwerk/usa.aspx

Masterwerk, Act 1, VGT.

I see that you posted something on the other thread...

Well, now it's here.

Last edited by Railgun; May 17, 2006 at 08:12 PM.
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Old May 17, 2006 | 08:11 PM
  #36  
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You definitely did miss something. See the thread I posted a link to (post # 32...aka 3 posts before this one ) It's ABOUT the 2007 911 Turbo

~Ramy
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