the thing is those vanes also control your boost, and the speed of the turbo itself

 

... except that those vanes don't control anything on a 6.7L

 

Haven't the Dirtymax's been running VGT's for the past couple/few years?

 

I'm most curious if the VGT could be setup almost wastegate-like in having it be as tight as possible until a certain boost, then have it progressively open bigger and bigger to maintain boost at a certain level.

The Cummins approach is like having a continuously variable housing size that can go from a 9cm housing to a 16cm housing and anywhere in between.

Honestly, more than getting the VGT to work from a 6.7L, I'm more interested in getting the HE510 to work as a VGT primary in a set of twins.

Unfortunately, the biggest VGT Holset/Cummins turbo (the HE510) only flows ~96lb/min, so it's basically a GT4202 for size. It would spool tons faster and have a lot less drive pressure due to the VGT, but it's still only going to flow 96lb/min.

So it's not really a "big dog" kinda primary. But for the rest of us that will never see 600hp, this would be darn close to the ultimate primary for twins.

They are CHEAP on ebay too-- VGT for $600!

 

If you want a Big Dog primary, I like the HX83... at 110# dry, it's proportional to the Cummins heft.

 

Yeah, but I don't know of a single CTD that needs 200 lb/min. That's enough for well over 1300hp. Twins with that turbo would need something like a GT4202 ON TOP!

 

Well, I figured the divorced inlet would work great with the other CTD in the bed...

 

Thanks for the clarification, I'm assuming your taking the Holset VGT turbocharger. However both examples are VGT models, the picture I posted reflects the Variable Turbine Geometry more closely than the Holset unit which is more commonly described as a Variable Nozzle Turbine since the inducer/exducer is being altered not the AR ratio.

 

Holset no longer officially exists. It's now Cummins Turbo Technologies.

Just like Fleetguard is now Cummins Filtration. Onan is Cummins Power Generation, etc etc.

Hence, my reference to Cummins turbo vice Holset.

Oddly enough Holset still appears on their websites and such, so I'm guessing they are still transitioning.

If I'm not mistaken, the VNT type turbo goes all the way back to the Shelby CSX, right? I think that was one of the first attempts on the market-- and made by Garrett, if memory serves.

 

I think about setting up (or trying rather) a VGT/VVT all the time! And I can't remember who posted it, but yes the guy who can get these to market with whatever ecm interface required is going to make some change. Maybe package it for half the cost of twins.......I'd be sold! Saving up for twins is a lesson in learning extreme patience

Note though that the guys with them on the newer trucks are going back to the standard turbo's? Anybody heard of them putting on a larger variable turbo on the newer rigs? I think I ran across a post about someone doing it with the duramax?

 

Wouldn't RPM and fuel rate be the primary control and possibly boost as a secondary control for the VGT? A knowlegable person could get those values fairly easily from a VP44 truck I would think.

I am guessing on the 6.7 allot of mumbo jumbo code is in place for emmissions. Probably a big part is to ensure that the pressure ratio between drive and boost is setup correctly for the proper EGR flow. That control logic could be mostly ignored.

Is the VGT an open or closed loop control? I suppose you could tell if there was a position detection (feedback) device on the assembly. But I am thinking you could just bypass all of this also and just run in open loop with some tuning to get it to work well.

The E-Brake function would likely only need an "At Idle" signal from the APPS and an On/Off enable switch.

I wonder really how hard it would be? Interfacing would be the greatest challenge I am sure.

Jim

 

So with a sensor to measure turbine rpm and boost pressure it could be made to work?
a drive pressure sensor might be needed additionally/instead of turbine speed?

you could also base the VGT control off of pre- turbo EGT's?

if this could be made to work twins "MIGHT" not be necessary!

 

Turbo's still say Holset on them. However your right it's CTT now.

 

That's one reason I think that the current VGT setup is a little on the restrictive side. It's calibrated so that TIP is higher than boost in order to push the EGR flow along where it's supposed to go. If boost was higher than TIP, the EGR wouldn't flow, would it?

So while I think the VGT from the 6.7L is promising and could work well in a 5.9 performance application, the factory 6.7L programming is NOT suited to that purpose.

Progressive controllers for nitrous and water injection are out there and easily executed. There has to be a way to do similarly for VGT control/manipulation. Heck, maybe one could USE a progressive controller from a nitrous or water/meth injection setup and adapt it to perform as a VGT controller?

Just thinking out loud, here.

 

I'd expect them to say Holset on them for a long time still. They probably have a lot of cast covers and such they need to use up-- and why re-tool sooner than needed?