Why not just boil it down to a Mad Max-style control scheme?

You know:

Switch OFF = Economy

Switch ON = BOOM!

 

Doubt they would dish out the $$$ to change the casting, got a feeling it will say holset for awhile.

 

I doubt a variable geometry turbocharger will produce the results people are thinking is possible. All versions alter the AR ratio to aid spool-up, but to provide sufficient airflow the turbine wheel needed can only create positive pressure so quickly.

 

I agree with Don, a big ole 70mm inducer is not going to perform down low, regardless of the VGT. It still take a lot of shaft hp to spin that heavier wheel, not to mention it takes shaft hp to compress air, more air, more hp required.

Has anyone measured the inducer on the 6.7 turbos? I wonder what they can flow?

 

Inducer is the same diameter as the 04.5-07 5.9 charger.

 

No one is saying it will, that I can see. If anyone is suggesting such, it was not the original poster.

The purpose of VGT isn't to allow a person to spool a ridiculously oversized turbo. The purpose is to enhance response of a properly sized turbo, while still allowing maximum turbine efficiency associated with a larger A/R housing.

When applied to a primary in a twins setup, VGT would allow much sooner spoolup and a much more efficient management of boost. A wastegate is wasteful. A VGT recovers this wasted energy by eliminating the need for a wastegate to a large degree onthe larger turbo (probably still necessary on the top charger in twins, though-- even wide open the top VGT (if used) most likely will be overwhelmed by the primary's flow).

Most turbos will hit a PR limitation long before they run out of available mass flow. This is because we are trying to make big power with both low RPM and relatively low displacement.


A 360" gas engine could rev to 5000 or even 7000 rpm-- drastically reducing the amount of boost needed to flow x amount of air. But since most of us are under 3500rpm (or even lower) then
the amount of pressure needed to make the same mass flow goes up by a huge degree.

JH

 

My 2 cents..... The HE351 turbos are just HX 35 Compressors with a Varable exhaust housing. Think of it this way, spool like a 9 and flow like a 14 on the exhaust side, compressor side is the same as a HX or HY 35. Basically it boosts up to the claimed 27.5psi and then opens it like a waste gate to keep it there...giving much better high RPM flow that the HY 35's so desperatly lacked. Controlling it could be done easily with a mechanical waste gate type actuator, just may need to be bigger or doubled up for the added power needed to move the slide and wouldn't be as accurate as far as the EPA nonsense (who cares anyway!). The brake could be done with a solenoid and microswitch on the throttle. The real thing I would be interested in is making it a hybrid with an HX 40 compressor housing and wheel and a fat shaft ala 62/12 or 64/12.....that would be the ultimate streetable turbo probably good for 550 hp with no surge, good towing egts, and ridiculous spool!

 

Enlarging the compressor on the VGT would be a step backwards, imo.

 

VGT turbos are use to increase throttle responses, low end power, and to create back pressure for the exhaust brake and to push exhaust through the EGR system. I've worked on alot of these on Detroit 60 and Cummins engine like the ISX and the ISM. Like previously stated they basiclly act as a varible displacement turbine housing, allowing for high exhaust velocity to aid spooling. The best way i can describe it is to take a garden hose and a pin wheel, turn on the hose and pour it on the pin wheel, and it petals around but stick your thumb over the end of the hose(increases water velocity) and spray it on the pin wheel and watch it really spin. Your thumb is operating as the variable part of the turbo. With this breed of turbo you dont need a wastegate. manf. control boost pressure and turbo speed with the variable portion of the turbo. They have speed sensors built in. the ISX we had would set a code if it spun fast that 145K rpm. and would Defuel/stop engine light at 155k rpm. These turbos will allow for alot of boost. Our 600hp ISX was good for 68PSI and will get there very fast. One could make it work it you monitored boost pressure, turbo speed, EGTs, and throttle postion or calc. load percentage. All of which Insite(cummins engine control software) monitors. you would have to make a standlone box that would watch this data and feel it to the VGT. but someone would have to make a map for it(the VGT) to follow for proper operation streetablity.

 

I have read about that. How come this is the first I've seen it mentioned? I know I don't read every post out there, but I am constantly researching stuff and this is the first time I've run across it. I figured it couldn't do much for us
seeing as how it's not talked about much here. Any of you have this device/reader/thing? What have you used it for? I can start a new thread if needed.

 

i have access to the software though work. the software in the onroad stuff is called insite thus ISb, ISc, ISm and ISx. the software in the equipment is call Quantum so their engine are called QSb, QSc, QSm and QSx

 

That would seem to be true, but the part about the "I" series is not.

The ISB stands for Interact System, not Insite.

I think your comment on the Q system is correct.

 

https://insite.cummins.com/insite/faqs/index.html
here is a link to info on the software stuff. with this software you can actually change the engines horsepower rating most of the engines

 

I am guessing it has a simple electro servo actuator or possibly a pilot valve so that boost provides the motive force for the main actuator?

You have access to electrical prints for it? What signals that are required to make it work?

In our appplication we would want very fast spool up, and likely boost and/or cold pipe pressure used to control the VGT position once the bottom turbo lights.

Jim

 

i'll see what i can find for wireing diagrams. detroit uses airpressure to control there VGT part cummins uses electical actuator, which in my opinion is better because you could watch amps and make sure its moving. if your are high on amps you know you have an issue, the same if you are low on amps