Quick spool valve seems lilke a good thing if you have dual turbos

Cant see how it would work on a 7.3 blocking off a side of engine

 

The DPS vgt uses exhaust pressure instead of vacuum. When the throttle is let off during high boost the ebp drops and causes the vanes to close. This causes the turbo to surge at the compressor wheel. Ideally it would be better if the vanes remained static when the ebp suddenly dropped but that hasn’t been developed yet.

 

Yeah that's not the way I would have done it. Use intake pressure like every other engineer does.
I can hear my TDI turbo bark when I let off to shift sometimes but I never worry about blow back. You should hear some of the compressor stalls on sled pullers when they back out of it at the end of the pull!!

 

Compressor stalling on an airliner throttling back after takeoff run.

 

so does that mean you will be making a VGT that doesn’t rely on exhaust pressure like the dps?

 

..........

 

@Kwikkordead What vacuum source does your TDI use? You must remember that DPS is trying to make the Turbonator as universal as possible so exhaust pressure is the only thing readily available in most diesels.

This is what the electronic Turbonator does. The controller tries to maintain a programmed pressure ratio. I am pretty happy with my setup now after figuring out the issues with the REA.

 

There is an engine driven vacuum pump on the cylinder head on the opposite end of the camshaft from the timing sprocket.

 

Coming back to this after thinking about it for a day.
If there is still is some pressure remaining in the intake system, even after suddenly removing your foot from the skinny pedal, that turbo is still spinning at 100%. Giving enough boost pressure to hold those vanes open, if the control source is intake pressure, until the turbocharger rpm drops off. There's no throttle plate that's suddenly closed to restrict airflow and cut intake pressure on a diesel. So by the time all the exhaust pressure has exited the system and the vanes closing it's not really an issue. At least that's what I'm thinking when pondering the design theory of any turbo diesel. If there's intake pressure, then the vanes, or the wastegate if so equipped, will remain open until intake pressures drop off and then it's safe to default to closed anyway because the turbo has spooled down and then there's no worries of an overpressure situation on either side. And if for some reason the engine is still north of 3,000 rpm or something, there's still a lot of air exiting the engine, but that will just slow the eventual drop in pressure on both sides of the turbo.
I'm still scratching my head on why they decided to use exhaust pressure instead of intake pressure to drive their system.

 

Packaging convenience perhaps? We have already established that DPS may not be the sharpest tools in the shed.

 

LOL, there's a lot of lights that burn brighter than I do too.

 

I could try routing the actuator to the compressor side of the turbo to see if it makes a difference. I dont think it will help though, possibly hurt because the PSI the vanes fully open is pretty high, this may cause high EBP.

 

I would say the tiny TDi turbo and baby 1.9L engine is not a good comparison to the 7.3 PSD.

Also, the VGT is controlled by the ECU in factory-equipped engines (TDi/6.0/etc). The turbonator has NO IDEA what the throttle pedal is doing, so there is a delayed response to changing the vane position when snapping off the throttle.

If I recall correctly, FTN experienced a turbine shaft failure that was likely due to ‘turbo bark’ - basically the turbine wheel spinning and the compressor wheel trying to STOP. Yes, the lack of throttle plate means no restriction from that, but if there is no place for that air to go (low RPM/low air volume moving through the engine) - then conflict occurs. The BOV prevents the excess pressure on the compressor side.

 

So to get this back on topic, the quick spool valve is not a VGT, but at a fraction of the cost, it may be ok. I agree though, you would have to cut out the divider so the banks merge into 1 before it hits the quick spool valve right?