got my road and track in today and was reading on the new porsche 911 turbo. it has VTG variable turbo geometry. which is adjusting blades surrouding the turbine wheel that optimize the exhaust flow on the wheel. it changes the responce and torque quite a bit. the 05 911 has 415 lb-ft at 2700 rpms. the new 911 with this turbo setup has 457 lb-ft at 1950 rpms. now it also says that diesels have been using this technology since the 90's. why arnt any turbo makers moving onto this setup? it makes turbo lag almost non existant. anyone else hear of these types of turbos?

 

steve, i have been trying to get a hold of you, i stopped trying like 2 weeks ago... i wanted to know if you still had that FB for sale for a friend of mine... PM me and lets talk.

(sorry for thread jacking)

 

VGT's have been junk on the diesels

 

I think they are quite expensive.

 

go to porsche's site if you want to see an animation of it

 

WOW that animation is pretty cool. That's exactly what a 13b needs. Also just imagin that technology on a GT42r . I wonder how long before other manufacturers adapt to this same technology or something similar. You know that turbo has got 50 thousand patents. LOL

 

That stuff has been around since the mid 80's i think some of the audies or something use to use them, they never went any where, i think the design is a little complex.

CJG

 

I lookied into this when I was in college before, and I spoke with some engineers from Garrett about it. The biggest reason they aren't on rotaries is due to the very high EGT's. The vanes that adjust the angle of attack to the turbine can seize up if the EGT gets too high. This could then create the problem of overboosting very easily.

 

There are a few different types too... air controlled, oil pressure controlled, etc.

 

 

Dave (aka GuitarJunkie) showed me this link:

http://www.holset.co.uk/files/2_5_1_...20geometry.php

 

To me this is like that old debate to use sythetic in rotary's. With the tech available today, why not use Inconel for certain parts in the turbine section to overcome the heat related issues? Sure it would be a little more expensive, but I think these can be made to handle rotary's.

 

Exactly, the stock t wheel on fc turbos are inconnel i believe.

James

 

I agree. Inconel is nice, but it expands and contracts as well. If it is going to happen I think the advencements in ceramics will play a major role.

I think that you have to look at the tolerances. In the area where the vanes are, you want all of the exhaust energy to go where the vanes direct it to go. If there is too much of a gap, some of the exhaust will "slip" past and do it's own thing. At which point it will not impact the turbine the way that the vanes are directing the majority of the flow. So now we are creating vortices and swirls in an area where we are looking for as laminar a flow as possible.

Everything expands as it contracts. The hotter it gets, the more expansion. So if they can bring the tolerances in a little bit tighter by limiting the EGT's that this turbo can handle, they can produce a turbo that will appeal to the masses. Unfortunately, rotaries are not as massive as we would all hope and we are a very small demographic to consider.

This is kinda off topic, but a friend of mine sent me a thread from a big-block type forum, and someone posed a very interesting question: "Where would the rotary be today, if it had one tenth of the development and resources that are normally allocated for say, the Chevy 350?" Very good question indeed. I think that I remeber reading that the engine development for the Renesis was done by a handful of Engineers in their spare time. They loved the engine so much that they didn't want to see it tucked away in the archives of what once was. It may not be the most powerful, desireable, or serviceable, but I think that we owe a debt of gratitude to those that helped keep the trochoid alive. This way we can look toward the future as well as the past. If you read this far, thank you.

 

i emailed a boatload of places about getting ahold of a vtg....no response from anyone

 

I took apart one of these about 2 weeks ago. It was/is a prototype for a diesel company. Very cool stuff. Pain in the *** to take apart (didn't have a large selection of tools)
I work for a Ceramic Coatings company, and in the very near future we have a coating coming out that may be useful with this technology. Bell Helicopters, and some folks at a government agency tested it 3rd party for us. We've already published stuff on it, so i can finally mention it. I am not allowed the specifics of it yet, but i think in the next week or so i will be allowed more info. Obviously the proprietary stuff i can't talk about, but i'll share what i can with you guys.

 

Here is one for you guys:

Garrett VGT GT45R 102 (mm major compressor). Turbine materials rated to 1050C.



The VGT mechanism:

 

Hrmm the possibility of making a GT45 streetable...

That's scary

 

does it come with the sprite can?

 

so if the normal GT45R is costly...wtf would that thing run....

 

No, I had to buy that separately. I placed it back into the fridge when I finished taking the photos.

I need to have a manifold constructed (it is a T6 turbine inlet, with a ~5" V-band outlet) in order to test out just how streetable it is. My past experience with VGT's has yielded that they are exceptionally streetable.

The vanes can close down nearly all the way, which not only provides more constant energy for the turbine wheel, but also very effective sound pressure level control

 

now is that garrett a variable nozzle, or variable turbine?

 

It is a variable geometry turbine machine. This photo might help. You can see the vanes, which are at 100% maximum in the pic.

 

Just curious also, by what means will you be controlling the vanes?

 

how soon will they be available for sale, and what sizes?