variable geometry turbo

[slow&low]

So I was just watching Trucks! on Spike and the 2011 Ford super duty comes with a variable geometry turbo. I don't know much about diesels, but I wonder how the size on a 6.7l compares with a big turbo for our cars. I assume it would be bigger as compared to a GT35 series, but being a variable vane type, maybe it wouldn't be so bad. Just spit ballin here but it got my curiosity raised. Anybody else thought the same thing?

[ZimbutheMonkey]

One guy has done a holset variable geometry build. I've seen some vids of it accelerating and it's quick. However (and correct me if I'm wrong) it seems as though he never quite got it running the way he wanted. Long story short, it's been done, but it requires a lot of fabrication and know-how.

[Outerfroggy1]

VGT's are pretty mainstream in the diesel world these days. They started really catching on about 6 or 7 years ago.

However the units I am familiar with are all ECU controlled. Either using a high pressure oil solenoid (like fords) or a small electric motor/pushrod assembly (like hinos).

I haven't done much research into VGT's on gasoline setups, but I'm guessing it would be quite alot of work to graft one on to a car that did not come with a VGT from the factory. These units are the future of turbochargers and you will see them more and more on factory applications.

[Doug@FrankenTurbo]

Industry-standard VGT componentry for diesel motors doesn't do well in higher-temperature gas engine exhaust streams. BorgWarner has their BV50-series units on Porsche's turbos but it is difficult and costly.

[JoshDub]

Don't Audi's new turbo engines have VGT's? Atleast thats what the guys over in the mk6 section of vortex think.

[ZimbutheMonkey]

What people don't know on Vortex could fill a warehouse. Where are they saying this?

[Dan[FN]6262]

VGT is cool. apparently a bitch to tune because of how fast they spool. but thats just what I've heard.

[JoshDub]

What people don't know on Vortex could fill a warehouse. Where are they saying this?

Don't Audi's new turbo engines have VGT's? Atleast thats what the guys over in the mk6 section of vortex think.

I thought I read on the front page of AZ one time that audi was using a VGT on some new model.

[slow&low]

VGT is cool. apparently a bitch to tune because of how fast they spool. but thats just what I've heard.

That is wicked awesome. Know I understand how they work on the inside. Thanks for the little vid!

[walky_talky20]

I think they guy who was using the variable holset turbo on his Audi had a problem with steady state cruise. He had the "gate" spring loaded towards the smallest setting, so it would get bigger as the boost increased using a normal wastegate actuator. The problem was at steady state cruise there was no boost, so the gate (variable nozzle part of the thing) would be at the smallest size and the thing would overheat. To fix it, it would need to be computer controlled so when there is no boost request, the thing would open up wide to help with exhaust flow and not overheat the turbine parts.

[themadscientist]

Google DSM VGT Holset. You'll find some threads about a guy who did one up on his talon. Ithink he even has some vids on YouTube. The actuator really needs to be electronically controlled to get the most out of it. Iirc, he was hitting 24psi around 4k rpms on a 2.3 but had very good spool at cruise.

It's definately the way of the future for turbo systems. We just need a few motivated people to work the kinks out.

[ZimbutheMonkey]

That is wicked awesome. Know I understand how they work on the inside. Thanks for the little vid!

The Holsets are a little different. Instead of vanes they have what could best be described as a notched cylindrical sleeve that slides back and forth over the turbine area (lengthwise of the turbo). Also, I find it really funny when Porsche makes themselves out to be the first to implement VGT turbos on a production car. The vid that Dan posted is of a turbo on an 80's Chrysler Shelby Daytona.

[sean1.8t]

Industry-standard VGT componentry for diesel motors doesn't do well in higher-temperature gas engine exhaust streams. BorgWarner has their BV50-series units on Porsche's turbos but it is difficult and costly.

nice copy-paste.

[westie180]

the main issue with vgt's right now is that most of them are designed for cooler diesel exhaust gases rather than gasoline exhaust gases. until more are produced with materials that can take more heat (and perhaps with the implementation of titanium-aluminide in rotating components as well), it'll be difficult to make them work reliably on our gasoline engines. i do have a nice big borg warner vgt sitting at work though. however, the vanes are seized, and i snapped a bolt off the turbine housing.

[NyteEscape]

+1 for the moving image. definitely gives me a clear idea of how they work.