Controlling the VNT-15 Turbo from A4 TDi

[VWRacer]

I've been thinking about the talents demonstrated here with reference to controlling boost, and wonder if we might harness it to build a controller for the VNT-15. Dr Diesel, do you guys think that the same general approach to building your electronic boost controllers might work for building a nozzle controller for the VNT-15? After all, we have vacuum and 12vdc, which I understand are all that would be required. What do you think?

Thanks! Stan

[RedRotors]

I worked on that thing.. most of the programming is done, but i put this project aside.. I use the original N75 valve, a boost sensor ( motorola 3-29psi ) and a uControler ( PIC ).. The principle in theory is quite simple.. You sensor will send to your uC the amount of boost, and your uC will modulated the N75 to control the vanes actuator.. The program have to react fast or anticipated to boost comming up , because you don't want to get big spikes..

Marc/

[fspGTD]

I wonder if something simple and mechanical could be worked out.  I mean, sure it probably wouldn't be as optimal/sophisticated as an ECU controlled version but ya know, just something basic that uses the boost pressure as a feedback-loop.  Maybe convert the diaphgram that controls the variable vanes to work on pressure instead of vacuum, and then treat it like any other wastegate to get the boost pressure/spike set (as simple and an adjustable restriction & bleeder setup) where you want it.

Anyway... it's been a while since I've looked a the schematic/design of the mechanism, and I can't remember all the details at this point, but that was my general idea I got when I was looking at it last.  - something like, open the vacuum chamber so it sees atmospheric pressure, and put boost pressure at the spot where the diaphgram normally sees ECU-controlled vacuum.  I'll have to take another look - anyone got a link to a picture of one of these vane controllers online?

I'm sure an ECU controlled version would be way better.  But IMO a real racing Diesel engine doesn't have a vacuum pump!  

[RedRotors]

Is that what you are looking for Jake?




Marc/

[fspGTD]

I have a different schematic.  It shows a "Low-pressure box" with what looks like a diaphgram in the middle, with 2 sides: one connected to atmospheric pressure and another connected to vacuum.  What you posted above looks like it expands on how the vacuum signal gets controlled.  What I'm wondering is more about the design of the low pressure box - if it's "atmospheric" side could be isolated and hooked up to say boost pressure.  Then the side that usually gets vacuum could get atmospheric pressure.  And control could be applied to the boost pressure just like a wastegate.  It might just work!  I have not looked at one up close.