VNT - Variable Nozzle Turbine Turbo
23-Nov-2006, 03:57 PM
#1
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Location: Ontario
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VNT - Variable Nozzle Turbine Turbo
Also known as:
Variable Area Turbine Nozzle (VATN)
Variable Turbine Geometry (VTG)
Variable Geometry Turbo (VGT)
Variable Vane Turbine (VVT)
As I read on wikipedia:
1989 Shelby CSX-VNT was the first production car that used this turbo technology. Porsche 911 (997) Turbo also uses Borg Warner's VGTs.
Does anyone run this type of turbocharger? I was bathing myself in the world of turbocharger and did some research, came across this one. Sorry if this has been posted before, seems like search engine is down.
Variable Area Turbine Nozzle (VATN)
Variable Turbine Geometry (VTG)
Variable Geometry Turbo (VGT)
Variable Vane Turbine (VVT)
As I read on wikipedia:
...utilise a set of vanes in the exhaust housing to maintain a constant gas velocity across the turbine, the same kind of control as used on power plant turbines. These turbochargers have minimal amount of lag, have a low boost threshold, and are very efficient at higher engine speeds. In many setups these turbos don't even need a wastegate. The vanes are controlled by a membrane identical to the one on a wastegate but the level of control required is a bit different...
Does anyone run this type of turbocharger? I was bathing myself in the world of turbocharger and did some research, came across this one. Sorry if this has been posted before, seems like search engine is down.
23-Nov-2006, 05:47 PM
#3
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Join Date: Nov 2004
Location: Mississauga
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Honda first experimented with this idea quite a few years back, on a prototype named "Wing Turbo". To my understanding only a few were ever actually produced, which is a shame. I am glad to see they finally implemented the idea of a variable vane turbo in a mass production vehicle like the RDX.
I was also very intruiged about the idea of a VVT, and conducted a bit of research into the field. The main problem with these turbo's has been their reliability. Most of the mass produced VVT's were made for diesel engines, and the conditions, as I am sure you are aware, are different between a diesel, and gasoline engine. Thus people who have been trying to use these VVT's on their gasoline cars have eventually ran into some reliability issues because of premature wear. Another cause of the wear is simply because of moving parts, and the turbo's were not as advanced then, so the quality wasn't up to snuff either.
With the RDX coming factory equipped with a VVT, it is obviously now "easier" to come across, the technology and build quality are better, and it is designed for a gasoline engine. It would certainly make an interesting project if you decided to go ahead with it. I would almost encourage it, lol.
I was also very intruiged about the idea of a VVT, and conducted a bit of research into the field. The main problem with these turbo's has been their reliability. Most of the mass produced VVT's were made for diesel engines, and the conditions, as I am sure you are aware, are different between a diesel, and gasoline engine. Thus people who have been trying to use these VVT's on their gasoline cars have eventually ran into some reliability issues because of premature wear. Another cause of the wear is simply because of moving parts, and the turbo's were not as advanced then, so the quality wasn't up to snuff either.
With the RDX coming factory equipped with a VVT, it is obviously now "easier" to come across, the technology and build quality are better, and it is designed for a gasoline engine. It would certainly make an interesting project if you decided to go ahead with it. I would almost encourage it, lol.
23-Nov-2006, 08:36 PM
#4
I think they're gay
A properly designed well built turbo can cover an application very well
Key thing is to figure out what you wanna do .... drag cars need high CFM and high pressure, meaning big turbo... for like auto X or road racing... you want something less laggy, so when you fall out of your power band, you can boost your way back into it.
A properly designed well built turbo can cover an application very well
Key thing is to figure out what you wanna do .... drag cars need high CFM and high pressure, meaning big turbo... for like auto X or road racing... you want something less laggy, so when you fall out of your power band, you can boost your way back into it.
23-Nov-2006, 09:51 PM
#6
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Location: Streetsville/ Hamilton
Posts: 2,877
They're prominently used on diesels. Mark IV Jetta/Golf/Passats have these (Bruno should know). The reason why they are limted to diesels are because of the lower EGT's from the engine, for some reason most manufactuers havent gotten them to work on gas engines properly although the RDX does have one now. They also have problems with over and undershoot in relation to boost pressures.
Most ball bearing turbos have a wide enough powerband to accomodate most uses.
Most ball bearing turbos have a wide enough powerband to accomodate most uses.
Not sure if thats what your running.
24-Nov-2006, 02:25 AM
#9
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Originally posted by Nova_Dust
Yes, EGT was an issue with the VNT (so I read).
GT28, fast spooling enough?
Yes, EGT was an issue with the VNT (so I read).
GT28, fast spooling enough?
24-Nov-2006, 11:34 AM
#10
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Originally posted by weiRtech
the new rdx has one.
the new rdx has one.
More advanced VTG turbos have multiple individual vains that rotate to direct exhaust, mounted most of the way around the exhaust turbine.
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