All I got for Christmas was a VGT turbo

[SmithvilleD]

Well, it's the only thing I got for Christmas that this forum might be interested in anyhow.

Last week I won this turbo for $100 plus $50 shipping on ebay. They're from the latest 6.7 Cummins in the Dodge trucks & they've been routinely selling for $100-200 for a while now. My guess is the VGT mechanisms can gum up from carbon & drag causing parameters the PCM monitors to head out of spec'd range so the system throws codes. Dodge/Cummins warranty protocols say replace the turbo. Don't know this, but it's a reasonable guess.

The turbo I got was what you'd expect in a relatively low miles take-off turbo. No abnormal side or thrust play. VGT mech was carboned up a bit, but would move axially thru the range it's supposed to. The onboard processor/actuator & internal circuit board look unharmed - I've no way to test it yet.

Today I bead blasted the comp housing, turbine housing, & VGT shroud so I can work w/ clean parts. Then hit the turbine housing w/ hi-temp header paint to stop corrosion.

There are a few guys that have been working w/ this turbo on a 6.5 already. We've been exchanging info/ideas & there's definitely some progress being made.

This turbine has a unique flange that mates to the exh manifold. Sort of btwn T3 & T4, w/ the bolt patterns a bit on top of one another. My plan is to weld the current studs/bolt holes shut w/ hi nickel rod, machine the surface flat again, then drill & tap it in the T3 pattern. Then do any blending btwn 6.5 exh manifold & turbine flange that available material allows.

Will add more pics in the next post.

 

[JiFaire]

Sweet - this will be an interesting build, methinks. I'm quite interested in the electronic end of things; don't know enough about that, yet. Research appears to be in order...

Keep us posted with pics, please!

 

[NVW]

It will be interesting and different.

 

[SmithvilleD]

All I got for Christmas was a VGT turbo - II

In the stock configuration, the turbine housing outlet is v-band flanged to a beautifully smoothly tapered transition that takes outlet diameter out to fit a 4" exhaust. Not enough room for this to fit on the 6.5 trucks as it will interfere w/ the AC accumulator - but the whole diffuser transition from turbine wheel exit to the exhaust pipe is so nicely engineered, I had to show a pic.

Fleece Performance has a box they're selling for the 6.7 trucks that allows changing boost levels both to above stock levels & I believe it also has exh brake functions. There are some reports of 1-2 mpg highway mileage increases when playing w/ opening up the turbine to minimize drive pressures.

Searching for youtube videos will find a few videos of their work on controlling the VGT mechanism. The rumor is they're working on a standalone controller & might be close to bringing one to market. Supposed to have USB connectivity, read MAP, TPS input & have an internal boost map/table. Something allowing it to utilize drive pressure input might also be in the works. I'm finding all this 2nd hand, so I can't confirm what's what, but plan to call Fleece at some point in the future to learn more.

The electronic actuator includes some circuitry that does some processing onboard - it communicates w/ the Dodge truck's PCM via CAN & I don't know what's done in this onboard processor &/or what's done in the truck's PCM. The actuator has triple gear reduction on the motor drive which reinforces the idea they want significant force available to positively put the VGT shroud/mech were the PCM wants it. The turbo has a shaft speed sensor which I'd expect allows the PCM or onboard processor to consider if shaft speed is getting too high threatening a comp wheel failure. Gotta remember if that shroud sticks in the turbine "tight" position & the engine happens to be under load/getting plenty fuel - all that drive energy has to go somewhere & there's no wastegate - it's gotta go thru the turbine wheel. Essentially like a non-wastegated turbo that's sized too small.

The plan is to proceed rather slowly as I have no deadlines & want to give this my best shot at working well. I do expect the evolution of new/better solutions to possibly pick up speed as the # of us working the problems increases.

 

[Slim Shady]

How much force does it take to move the variable geometry ring? Does the ring need to move constantly or rapidly?

 

[SmithvilleD]

Sweet - this will be an interesting build, methinks. I'm quite interested in the electronic end of things; don't know enough about that, yet. Research appears to be in order...

Keep us posted with pics, please!

The onboard processor/actuator is made by Delphi. They're literature calls them "Delphi Smart Remote Actuators." Literature says its communication to the PCM can be CAN J1939 or PWM 5 - 99%.

I haven't been able to find much on the pulse width modulation angle. Did a little looking for an OEM application but haven't found anything. There's been some discussion on other forums that the circuitry might allow the same actuator to be capable of doing both types of communication.

Think about how cool it would be if the 6.5's PCM boost control code & tables could be tweaked to allow it to acceptably control the electronic actuator this turbo comes with. It's a huge stretch to expect this is possible, but it's an interesting concept. Any 6.5 PCM tweakers care to share your thoughts?

 

[guybb3]

This is sweet!

 

[Slim Shady]

The onboard processor/actuator is made by Delphi. They're literature calls them "Delphi Smart Remote Actuators." Literature says its communication to the PCM can be CAN J1939 or PWM 5 - 99%.

I haven't been able to find much on the pulse width modulation angle. Did a little looking for an OEM application but haven't found anything. There's been some discussion on other forums that the circuitry might allow the same actuator to be capable of doing both types of communication.

Think about how cool it would be if the 6.5's PCM boost control code & tables could be tweaked to allow it to acceptably control the electronic actuator this turbo comes with. It's a huge stretch to expect this is possible, but it's an interesting concept. Any 6.5 PCM tweakers care to share your thoughts?

The current vacuum solenoid is PWM on the 6.5. Not sure how you would could modify it to be usable.

 

[SmithvilleD]

How much force does it take to move the variable geometry ring? Does the ring need to move constantly or rapidly?

My guess is the amount of force necessary will vary both for drive pressure conditions & due to varying levels of carbon gumming up the works. When it's clean, here on the bench, it moves easily enough. The VGT shroud's ID & OD seal to the turbine housing w/ what could be described as quite similar to piston compression rings. Clean on the bench, it looks like the majority of friction resisting movement is from those piston ring-like seals dragging across the shroud/nozzle ring's inner & outer surfaces.

The Delphi actuator literature says their actuator can do up to 2.0 Nm continuous torque output, up to 4.0 Nm peak torque. That's the spec, but don't know how much utility it provides the backyard turbo experimenter.

The turbo's center section includes water/coolant ports. I think the flow thru of engine coolant is just as much to limit heat in the electronics, as to limit oil coking in the ctr section.

I mention the carbon gumming up thing because I think it's an issue that's gonna have to be addressed long term. There's a drilled/tapped & plugged port in the center section angled/aimed towards the shroud. I've read that the first of these turbo's didn't have it. The thought is Holset incorporated the change so a dealer tech could try spraying something in there attempting to free up the works.

A neighbor that does a lot of VW modding work says the VW variable turbo guys even have a term for the cleaning - "vanectomy".

Believe the other make's swing vane type variables use hydraulics for vane actuation. This seems to me like another sign the OEM turbo engineers see the need to have some significant force available.

 

[SmithvilleD]

The current vacuum solenoid is PWM on the 6.5. Not sure how you would could modify it to be usable.

Understood & that's my point - that utilizing stock PCM control (if possible) could be a rather elegant solution. The trick would prolly be how tweakable the actual code is. Not just the target boost tables, but the rates the PCM varies PWM % to command/control boost level changes as all the engine parameters vary.

It's such a different system that I doubt the 6.5 PCM could do it?

There are a lot of posts on many different forums suggesting this VGT can vary on the order of 3-4 cm^2, all the way out to 25cm^2. If it really can close down that tight, it's not hard to imagine conditions that could cause shaftspeed to skyrocket in a hurry.

There were a number of reports that when Banks was sorting out the VGT on the HY55 used on his 5.9 Sidewinder Dakota (that set big mph records at Bonneville around '03), they grenaded a few turbos until they came up with their own electronic control method. The pics I've seen looked like this electronic controller was controlling the piston-type (as opposed to the common diaphragm type wastegate actuators) pneumatic actuator that Holset used as their first try at VGT actuation. Those actuators used OTR truck's onboard air system pressure.

 

[Slim Shady]

Understood & that's my point - that utilizing stock PCM control (if possible) could be a rather elegant solution. The trick would prolly be how tweakable the actual code is. Not just the target boost tables, but the rates the PCM varies PWM % to command/control boost levels as all the engine parameters vary.

It's such a different system that I doubt the 6.5 PCM could do it?

There are a lot of posts on many different forums suggesting this VGT can vary on the order of 3-4 cm^2, all the way out to 25cm^2. If it really can close down that tight, it's not hard to imagine conditions that could cause shaftspeed to skyrocket in a hurry.

There were a number of reports that when Banks was sorting out the VGT on the HY55 used on his 5.9 Sidewinder Dakota (that set big mph records at Bonneville around '03), they grenaded a few turbos until they came up with their own electronic control method. The pics I've seen looked like it might have been controlled the piston type pneumatic actuator that Holset used as their first try at actuators. Those actuators used OTR truck's onboard air system pressure.

That answered my question then, a fairly responsive control is needed to keep shaft speed from getting out of control. Simplifying the control to respond to boost pressure only, by a mechanical means that fails to the largest housing setting may be the safest way and simplest. Doesn't the variable vane just change the angle of the exhaust gas to the turbine wheel, it doesn't physically alter the turbine housing size? Just for clarification so we know that the actual housing size does not vary from 3-4 CM^2 to 25cm ^2.

 

[SmithvilleD]

Yes, I agree. Whatever the control mech, it needs to be "normally open" so to speak.

There are some folks out there that have made mechanical systems work. Tough to know how well. One of the guys I've been chatting w/ on these problems posted a link to one such system running on a 5.9. He posted it on the "other" site.

Again, my apprehension w/ a mechanical system is - will it absolutely be able to force the turbine open (if necessary) 30k miles down the road when the works will prolly be stickier than when one is first installing whatever system you come up with.

Part of my plan is to include an IC in the plumbing. Certainly for the normal charge air cooling benefits. But also because I intend to be as protective of my new engine as I can think to be. If there were to be a turbo mishap w/ comp wheel carnage, IC's can act to some degree as a "screen" keeping turbo shrapnel out of the engine.

I'd like to figure out a cost reasonable way of being able to read shaft speed from this turbo's sensor. Seems like something could be figured out cheaper than Garrett's speed sensor/gauge setup (if it's even compatible w/ the Holset sensor).

 

[iamdave0887]

I'll be watching this closely.

VGT on a 6.5. Amazing what owners/enthusiasts can do isn't it?

Boost pressure is what my buddy's HE351VE VGT section will be controlled by when it's all said and done. He has a later model Powerstroke boost referenced actuator that's set at 18 psi. Right now it's wired full open and he still hits 15 psi boost and will overboost the truck with ease. He still has the factory ECM in his truck and doesn't have a boost fooler wired in yet either. The truck certainly moves well. I believe his only other performance mod is the 4" exhaust.

This is one hell of an innovation.

Smithville i'll be watching this with great interest. If all goes well i may be looking into a VGT turbo myself.

Smithville since this is your thread. do you mind if i add in Don's video of his HE351VE on his 6.5 burban?

- Dave

 

[SmithvilleD]

That answered my question then, a fairly responsive control is needed to keep shaft speed from getting out of control. Simplifying the control to respond to boost pressure only, by a mechanical means that fails to the largest housing setting may be the safest way and simplest. Doesn't the variable vane just change the angle of the exhaust gas to the turbine wheel, it doesn't physically alter the turbine housing size? Just for clarification so we know that the actual housing size does not vary from 3-4 CM^2 to 25cm ^2.

The shroud moves axially, changing the turbine volute exit area. It's not so much changing angle of attack. It's changing the exit/flow path area available for the exhaust to pass thru. Think when the exhaust enters the turbine throat. While it goes around the turbine snail shape, the escape path (to get to & cross the turbine wheel) is thru the inner slot leading to the turbine wheel. The shround/nozzle wheel is essentially changing the passage area heading into the turbine.

Could loosely compare this to the variable nozzle on the end of a garden hose, spraying at a water wheel. Tightening up the nozzle (reducing the flow path area the water must squirt thru) results in increasing the velocity of the water squirting out the nozzle tip. The higher the water velocity, the faster the water wheel spins.

Loosen up the water hose nozzle/loosen up the turbine, & the fluid moves more slowly = wheels turn more slowly.

 

[SmithvilleD]

Not at all Dave. I've been working with these guys. Just don't want to take any liberties posting their work, as I figure I only have rights to my own work.

Don's setup is a pioneering effort & he's approaching it very logically. He's collecting good data. Some of my ideas have certainly evolved from what's he's doing & has shared.

 

[iamdave0887]

Not at all Dave. I've been working with these guys. Just don't want to take any liberties posting their work, as I figure I only have rights to my own work.

Don's setup is a pioneering effort & he's approaching it very logically. He's collecting good data. Some of my ideas have certainly evolved from what's he's doing & has shared.

Ask and you shall receive.

http://www.youtube.com/watch?v=3okOHAh8IuU

 

[SmithvilleD]

Here's a link to the youtube video (regarding Fleece Performance's controller efforts). that really caught my eye.

http://www.youtube.com/watch?v=7EDCKvkQoaE&feature=channel

There are a number of other related youtube videos on the subject for those who are interested.

 

[SmithvilleD]

Here's one where you can hear the turbo speed changing primarily from cycling the VGT mech.

http://www.youtube.com/watch?v=ntGDWAtN9jM&feature=related

 

[iamdave0887]

Here's one where you can hear the turbo speed changing primarily from cycling the VGT mech.

http://www.youtube.com/watch?v=ntGDWAtN9jM&feature=related

Damn that thing whistles! Sound like a jet taking off. ):h Love the sound of it.

 

[Woody35]

so how much boost do these turbos make. and i guess since it is vgt it has simlar spooling up time compared to the gm x series