Varible Vane - Borg Warner VTG Turbocharger...

[moahten]

Hey All:

Borg Warner is currently manufacturing a VTG turbo that is the OEM solution for for the Porsche 997TT. I've included some links below.

http://www.turbos.bwauto.com/products/vtg.aspx

Since this turbo (duals on the Porsche 997TT) is configured for a 3.6L (Flat-6) engine, I can't imagine a single unit would be a great system and significantly improve low-RPM response of an 1.8L inline-4 engine (1/2 of 3.6L - perfect for Honda & Miatas). The aftermarket companies modifying these systems claim to be able to produce ~750 hp in a twin turbo setup, so a single Turbo 1.8 producing ~375-400HP seems achievable.

Unbalanced Exhaust Pulses
With the inline4 (I4) the exhaust pulses would be balanced, and probably gain even better response.
No unbalanced exhaust thrust at the turbine section. See my crappy detail below:

   (4Cyl/Inline = EVEN exhaust pulses 2x2)   VS.   (6cyl/Flat-6 -3x2banks = 2x1 UNEVEN exhaust pulses per turbo)

Since the boost is more constant over the RPM range with the VTG Turbo system, it should perform better then from convential non-VTG units available from Garrett.
This turbocharger also looks like is has a built-in BOV.

So, my questions are:
I was curious if anyone knows how the vanes are controlled? In doing research an aftermarket companys named AWE, EVOMS, & Sharkwerks mentions the vanes are controlled via the ECU.
Is anyone aware if it's getting inputs more then just boost pressure to manipulate the vanes?
Other then Engine RPM, Shaft RPM, and total boost pressure, what would need to be accomodated? How would this work on the VEMS ECU? How could we control this unit? Could it just as easily be controlled using an internal Boost controller on the VEMs ECU?

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Aftermarket 997TT turbo images & information -
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AWE
Website - http://awe-tuning.com
Turbo Pic - http://awe-tuning.com/media/products/awe/997TT/750R/gallery/AWE_750R_turbos.cfm

AWE Propganda-At the heart of this powerful kit is a pair of A.W.E. Tuning VTG Turbos, developed in a joint venture between A.W.E. Tuning and BorgWarner, who is the manufacturer of the OEM 997TT turbos. These turbos maintain Porsche's VTG technology and are a direct plug and play application. Whereas the stock compressor wheels are cast aluminum, our turbos utilize high flow compressor wheels CNC machined from high strength forged aluminum. Forged aluminum construction allows for safe operation at higher rotational speeds which these turbos see at full power. Knowledge gained from doing software tuning as a technical partner of G.I.A.C.

Costs - prolly' made of unobtanium... But there got to be a way to source just one (that's all I want) reasonably.

EVOMS
Website - www.evoms.com
Turbo Pic - http://www.evoms.com/marketplace/LargerGallery.asp?imageid={749C8C27-E88F-404E-9150-000895C37D2A}

EVOMS Propganda-
An integral part for the power generated in our tuning system is the redesigned factory Variable Turbine Geometry (VTG) turbocharger. The Evolution Variable Turbo *ECT) is an engineering masterpiece it’s own right. Our CAS designed 5 axis CNC machined billet compressor wheels are larger and more efficient then the OEM VTG turbochargers found on the stock 997TT. The EVOMS EVCT incorporated technology form our pedigree of earlier turbochargers that we designed  and have used in previous Porsche turbo applications. Our more aggressively designed ECT compressor wheels improve boost efficiency allowing a broader and more linear delivery of airflow thus maintaining a flat torque curve. Additionally, our compressor housing incorporates our patent pending, CAD designed and CNC machined piston type boost bypass valve which improves boost bypass recirculation and recovery for unparalleled performance.

Costs - Probably still unbearable $$$$ for one of these custom units.


I welcome any thought inputs and insights on utilizing one of these turbos!

Many thanks,
Mo-

[GintsK]

I have not experience with Porsche. But Mercedes use some kind of serial connection between ECU and VNT actuator.

I think about using diesel variable nozzle turbo on spark ignition engine. Much of them have pneumatic actuators.

Gints

[gunni]

I´ll be using a Holset VGT on a ignition engine, more on that later.
servo motor will operate the VGT setup, and pwm will operate the servo.

[Sprockets]

Careful with diesel turbos on petrol engines boys.  They don't like the heat!  Also, diesel turbo VNT controllers are vacumn operated from the vac pump on the diesel.

I'm currently working on a standalone VNT turbo controller for aftermarket diesel apps.  A lot of the mechanical diesel guys are wanting to run the VNT turbos and have come up with varying solutions with springs and cables off of the throttle arm lol.

I've also come across that merc setup.  It's basically a linear potentiometer.  the VAG stuff doesn't have this, which causes problems as the turbo vanes stick and cause havoc but all the ECU knows is it can't get the boost it wants and shuts down!

-Gavin

[gunni]

The VGT setups are not the weak vane setups.
http://www.holset.co.uk/mainsite/files/2_5_1_5-VGT.php

This thing about heat has been seen and hasn´t been a problem, the holset´s have shown to work amazingly on petrol engines,
HX40 has shown over 600whp at HIGH boost, I think it´s only the VNT ones that have issues with petrol heat and not the VGT stuf.

Edit.
Don´t forget the truck boys run 40psi boost and haul massive trailers and whatnot, meaning 40psi could be sustained for long periods of time, they also see high EGT´s

[rob@vems.co.uk]

I heard from a Holset engineer that the problem with using the diesel turbos on petrol engines was more to do with the material of the turbine housing being a different alloy, which corroded badly as a result of chemical reaction with the gasses from the petrol engine.
Bullseye do a steel turbine housing for the Holsets.

[gunni]

I think the turbo swedes, lot´s and lot´s of the BMW, DSM ,Honda and related crowds have shown that it´s not an issue.
Some of those are running 40psi on the "diesel" turbo´s