Jump to content
SAU Community

Variable Turbine Geometry

geno8r

By geno8r,
in General Automotive Discussion

 Share

Recommended Posts

geno8r Grand Master

geno8r

Posted
Posted

http://www.autoblog.com/2005/11/27/next-91...rbine-geometry/

http://digg.com/tech_news/Porsche_s_new_tu...ogy_for_the_911

Next 911 Turbo to feature Variable Turbine Geometry

November 16 of this year marked the day a century ago that Dr. Alfred Buchi received the first patent for an exhaust gas turbocharger. Porsche will be celebrating the turbo's 100-year anniversary a little late when it introduces the next 911 Turbo sometime next year with Variable Turbine Geometry. This technology allows the angle of the compressor's turbine blades to continually adjust. While some diesel engines have enjoyed this technology since the Nineties, the higher exhaust gas temperatures created by gasoline engines necessitated the creation of new heat-resistant materials to handle the hotness. Porsche and Borg Warner Turbo Systems were able to overcome the heat issue and have developed a VTG turbo system that will be incorporated into the next 911 Turbo. The VTG turbo will allow Porsche's flat-six to mimic a twin-turbo setup with a much broader torque curve and more flexible powerband than a standard single turbo could provide on its own. Power ratings for the new VTG turbo engine haven't been released and probably won't be until the new 911 Turbo surfaces sometime next year.

2051115.002.mini1L.jpg

I'd love to see a working diagram of one of these turbos in more detail.

Link to comment
https://www.sau.com.au/forums/topic/127801-variable-turbine-geometry/
Share on other sites
scathing Grand Master

scathing

Posted
Posted
I'd love to see a working diagram of one of these turbos in more detail.

Your wish is my command.

http://www.porsche.com/all/masterwerk/flas...&height=513

Click Masterwerk once the Flash demo has finished loading.

Then under Act One click Variable Turbine Geometry.

scathing Grand Master

scathing

Posted
Posted

I thought the new 997 Turbo was running twin VTG's. Its only a single?

While I realise that using a VTG system can mimic a twin-turbo setup with a much broader torque curve and more flexible powerband than a standard single turbo could provide on its own....it begs the question, why not just run twin turbos? Occams Razor, etc......

On any V engine (and a boxer engine especially), you hit plumbing problems with a single turbo. What's the benefit of going back to a single turbine rather than running a pair of turbines?

Imagine this engine with a pair of VTG turbos?

TokyoTaxi Veteran

TokyoTaxi

Posted
Posted
It's not the turbine blades that move on VNT turbos, it's the blades around the edge of the turbine that direct the exhaust gas on to it. It'd be impossible to do it the other way around.

Correct. In commercial aircraft engines they are called Nozzle Guide Vanes ( NGV's ) in the turbine or Variable Inlet Guide Vanes ( VIGV's ) in the Compressor. They change the angle of attack of the air going into the blades ( vanes in the case of turbo's ). Keeping in mind that in aircraft engines, the geometry of the turbine is not variable because of reliability and cost.

I'll be very interested to see how this goes into the future !!

The engine is going to need to run VERY cleanly to stop the guide vanes from siezing up with carbon build-up and I would imagine that the turbo service life on the new 911 would probably be an overhaul at something like 60,000km intervals.

sh@un Grand Master

sh@un

Posted
Posted
The engine is going to need to run VERY cleanly to stop the guide vanes from siezing up with carbon build-up and I would imagine that the turbo service life on the new 911 would probably be an overhaul at something like 60,000km intervals.

Latest article I read, Porsche quotes 161,000km (100,00miles) for replacement or complete overhaul of the turbos :

TokyoTaxi Veteran

TokyoTaxi

Posted
Posted
Latest article I read, Porsche quotes 161,000km (100,00miles) for replacement or complete overhaul of the turbos :

I'd be extremely impressed if they can hold to that !!! ( and maintain full operating efficiency ).

Warpspeed Experienced

Warpspeed

Posted
Posted

These Garret VNT turbos have been around for about twenty years, nothing really new here.

They are not really suitable for petrol engines which is why Garret are pushing their GT ball bearing turbos for performance petrol engines, and the VNT turbos only for diesel engines. If these things worked as well as people think they do, companies like HKS would be offering them.

I ran a Garret VNT turbo on my Ford Laser for around two years so I can speak from plenty of practical experience.

You can order one from any Nissan dealer, part number is 14411-VC100 (charger assy-turbo). Back in 2003 it cost me $1454.55.

These variable vane turbos are the standard turbo fitted to the 4.0 litre Nissan Patrol diesel engine in Australia, and that particular engine produces 150Kw, so they are a rather small turbo. Two of these would be required on a larger engine.

Porsche seem to have made it work, where nobody else has. No doubt it took a lot of fairly sophisticated engine management and a lot of development. Don't think you can just bolt one on to your Skyline and get the same sort of results without the control system to make it work properly. There is far more to it han just hooking up a standard wastegate actuator to the vane control arm.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • GTSBoy
      Mistakes were made, my R34 Story

      By GTSBoy · Posted

      Yup. You can get creative and make a sort of "bracket" with cable ties. Put 2 around the sender with a third passing underneath them strapped down against the sender. Then that third one is able to be passed through some hole at right angles to the orientation of the sender. Or some variation on the theme. Yes.... ummm, with caveats? I mean, the sender is BSP and you would likely have AN stuff on the hose, so yes, there would be the adapter you mention. But the block end will either be 1/8 NPT if that thread is still OK in there, or you can drill and tap it out to 1/4 BSP or NPT and use appropriate adapter there. As it stands, your mention of 1/8 BSPT male seems... wrong for the 1/8 NPT female it has to go into. The hose will be better, because even with the bush, the mass of the sender will be "hanging" off a hard threaded connection and will add some stress/strain to that. It might fail in the future. The hose eliminates almost all such risk - but adds in several more threaded connections to leak from! It really should be tapered, but it looks very long in that photo with no taper visible. If you have it in hand you should be able to see if it tapered or not. There technically is no possibility of a mechanical seal with a parallel male in a parallel female, so it is hard to believe that it is parallel male, but weirder things have happened. Maybe it's meant to seat on some surface when screwed in on the original installation? Anyway, at that thread size, parallel in parallel, with tape and goop, will seal just fine.
    • Kinkstaah
      Mistakes were made, my R34 Story

      By Kinkstaah · Posted

      How do you propose I cable tie this: To something securely? Is it really just a case of finding a couple of holes and ziptying it there so it never goes flying or starts dangling around, more or less? Then run a 1/8 BSP Female to [hose adapter of choice?/AN?] and then the opposing fitting at the bush-into-oil-block end? being the hose-into-realistically likely a 1/8 BSPT male) Is this going to provide any real benefit over using a stainless/steel 1/4 to 1/8 BSPT reducing bush? I am making the assumption the OEM sender is BSPT not BSPP/BSP
    • funkymonkey
      Jacks that fit under GTR lips that can reach the subframe?

      By funkymonkey · Posted

      I fashioned a ramp out of a couple of pieces of 140x35 lumber, to get the bumper up slightly, and then one of these is what I use
    • GTSBoy
      Mistakes were made, my R34 Story

      By GTSBoy · Posted

      I wouldn't worry about dissimilar metal corrosion, should you just buy/make a steel replacement. There will be thread tape and sealant compound between the metals. The few little spots where they touch each other will be deep inside the joint, unable to get wet. And the alloy block is much much larger than a small steel fitting, so there is plenty of "sacrificial" capacity there. Any bush you put in there will be dissimilar anyway. Either steel or brass. Maybe stainless. All of them are different to the other parts in the chain. But what I said above still applies.
    • Duncan
      Mistakes were made, my R34 Story

      By Duncan · Posted

      You are all good then, I didn't realise the port was in a part you can (have!) remove. Just pull the broken part out, clean it and the threads should be fine. Yes, the whole point about remote mounting is it takes almost all of the vibration out via the flexible hose. You just need a convenient chassis point and a cable tie or 3.
×
×
  • Create New...