by swank » Mon Feb 18, 2008 12:48 am
i've started a couple threads on this subject. (i've got four different vgt turbos sitting in my garage). i've come to the conclusion that the system used on a cummins motor needs to be replicated. good luck getting any info. i found a pdf on holsets site that went through the basic stuff. got some old pm's on tdr (that i can't access anymore, and are probably deleted by now) that i squeezed the max shaft speed out of a guy who supposedly worked for holset.
the actuator (on the pneumatic ones) is set up to be wide open at rest. that means that you need air pressure to get it off the line. it is also like that so when something malfunctions when you're cruising down the road at 75, it doesn't slam shut and grenade.
so, what you need to make is a controller that can regulate air(or a heat shielded servo motor, if you've got one that already has that on there) based on these variables:
shaft rpm
engine rpm
ambient air temp
charge air temp
manifold pressure
barometric pressure
exhaust temp
exhaust pressure
i think there is another thing or two as well. can't remember right now though.
so once you get the thing built, you can hire a couple monkeys like banks did(really smart ones though) and have them go through and plot charts based on the that stuff. then have them write the program for the controller.
i'm not trying to get you down on this stuff, but i've spent a LOT of time thinking about these things while staring at the turbos i spent a pretty penny on. not wanting to blow them up, i decided that it was worth doing right. i'm in an engineering program now, and have every intention of get some of the kids at school to help me with the stuff. compruter types and what not. anyway, if you come up with anything, i'd love to hear about it. there was a guy on tdr a long time ago who i was never able to get ahold of who supposedly got one going (hx40 equivalent). took him two or three tries, but i guess he ran one for a while. never got any details on his set up though. if you want, do a search on dtr under my name and, i think, "look what brown did for me". two or three years ago by now.
dave
truck