Variable Nozzle turbine

R

rubes

Member
Joined
Sep 30, 2004
As I was learning about these motors this past summer and reading posts on here about big turbos beeing great, but with the need for huge stall, I was thinking..."wouldnt it be cool to develop a variable nozzle on the turbine inlet to speed up the air at low RPM and keep the turbo spooled, and then open up the nozzle at higher RPM to get rid of the restriction?"...Fast forward to this week. The company I work for was just aquired by Honeywell corporation, and as I'm surfing their site I see their automotive division (including Garrett Turbo) has just such an animal. see the link. I guess I'll have to ask for my employee discount :)

Honeywell
 
Vgt

Yep, they're called Variable Geometery Turbos. Diesels have been using them. I don't understand why they having filtered down to cars yet. (other than price) I guess it's a mater of time.

They do require a computer to control them with access to vehicle sensor data though. The aftermarket diesel kits have a seperate unit that controls it.
 
I saw the VG turbo's on tv and I was wondering why they hadnt filtered down to vehicles other than diesels. It seems like a great idea. Maybe we could get one of the Buick turbo manu. to start making them. I would buy one :D
 
I was thinking that chrysler had one maybe volvo.

I work for International and the new 4300 truck has a variable pitch turbo. It's our biggest warranty problem.
 
Aerodyne has offerend turbos with variable pitch inlet vanes for a while. they Aerodynes also have an interesting self-contained oiling system. as for as I know they don't make one large enough for a Buick.
 
interesting article, I had read about them a while back but did not realize that it eliminates the need for a wastegate. Do the diesel trucks with them not have wastegates either?
 
BarnesGN said:
I was thinking that chrysler had one maybe volvo.

I work for International and the new 4300 truck has a variable pitch turbo. It's our biggest warranty problem.
Click to expand...

No one feels the pain more than I....
I'm one of the guys at Melrose trying to fix all the VTG turbo problems. Biggest problem was corrosion of the turbine housing, but that's fixed now.

It'll be another 10 years or more before we see VTG's widely available in the performance aftermarket, considering the latest and greatest GT series by Garrett is now going on 17 years old in the diesel industry, but just hit the aftermarket in the last few years.

The VTG I work on would be appropriately sized to put a Buick into the tens, but the thing weighs in at about 55lbs! Plus if the vane rings get hotter than about 1400F they will warp and it will get stuck anyways.
 
The reason for the VNT turbochargers in diesels is that quick spooling reduces soot emissions, if what you say about warping is true it may be a bit before we see them in automobiles. I've heard of a couple people sticking the Dodge VNTs on other engines in V8 configuration, supposedly instant boost almost and very good top end. If I remember correctly the nozzles were changed by a diaphragm like a wastegate almost, but I'm not too sure on this.
 
Problems

I didn't know they made 'manual' controled one. That would bring the cost down a lot I bet.

Well, if heat is already a problem in the diesels, I would think it would be worse on gas engines. Aren't the EGTs higher on gas?

My co is going to international from freightliner, I wonder if they'll have the VGT. I might get to find out how they work first-hand. ;)
 
Yes lots of VTG or VNT turbos use wastegate type actuators to move the vanes. It's the simplest way to control boost / vane position. This would do the trick on a car like ours. Unfortunately there aren't a whole lot of units like this out there. Most are more complicated.

High tech diesels use a sophisticated control system with either electronic, hydraulic, or pneumatic actuators to precisely control vane position. The main reason we use the variable turbos now is to get exhaust manifold pressure under tight control. We do that to maintain a desired pressure differential across the EGR valve so we can drive the desired amount of EGR into the intake manifold.
 
I work for a transportation company, Hoosier Transit, that ships buses out of International in Conway and Tulsa...about 5K buses a year. We had heard about the problem as well as ahd a ton breakdown and get held at the plants for repairs from Garrett. Nice to someone on here has a common career!
 
Yep I was at Tulsa. We tore down and rebuilt more than 100 turbos there. But we found the problems we were looking for and fixed em. It was well worth the effort.
 
well if you ever end up at IC in Conway AR or Tulsa OK let me know...we'll do lunch depending on what office I'm at...LOL.
 
MJRWOOD said:
High tech diesels use a sophisticated control system with either electronic, hydraulic, or pneumatic actuators to precisely control vane position. The main reason we use the variable turbos now is to get exhaust manifold pressure under tight control. We do that to maintain a desired pressure differential across the EGR valve so we can drive the desired amount of EGR into the intake manifold.
Click to expand...

That's interesting- I did a ~ year long emissions research controls project that did that very thing about 8-9 years ago now :) However we found that it did not work as well as hoped, since when you try raising the exh backpressure it also spools up the VNT turbo and raises the boost pressure ;) lol <sigh>. That approach, or diesel EGR in general seems to need some sort of throttle restriction in the intake to get the desired pressure differential across the exh to int side. But when you introduce a throttle, there goes some of the diesel efficiency advantage vs a spark ignited engine...

Anyway, hate to sound like a broken record but a Garret VNT40 would be the sh*t for the typical fast street/strip GN IMO...

TurboTR
 
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