VNT control

[ahto42]

Hello
Sorry for my bad english!
I have a Nissan Primera IDI 2,0 TD(CD20T). It has a ECU controlled Zexel VE pump.
i was thinking to put some day a vnt 15 or vnt 17 on it.
it has no cabels in pedals, but has a vacum controlled EGR system with ecu controlled solenoid valve. i put my boost gauge to the vacum and i get over 1 bar vacum(gauges limit). It is controlled so: Idle=no vacum, accelerate hard=no vacum, accelerate medium= no vacum, acceletate light= no vacum, cruise=vacum, until coolant temp 70 degrees celsius=no vacum.

can i use the EGR vacum to control vnt? like so:  no vacum=vanes closed, vacum=vanes open. for boost control i have find a valve witchs is operated by boost, letting vacum to vnt controller when max boost.

i hope my idea isnt very bad

[jimfoo]

No, that wouldn't work at all. You need vacuum all the time, and the ability to regulate it. A better, though not ideal way to operate it would be get an actuator that works off boost, making sure it opens the vanes at the desired boost(open = less boost). Or make a cable to operate the vanes along with a boost operated actuator to limit boost.

[ahto42]

why vacum all the time, maybe a litlebit thru a vane and and egr adds more vacum, a spring pulls the vanes closed

[ahto42]

:?:

[ahto42]

:?:

[ahto42]

:?:

[zukgod1]

I think if you search a bit you will find some threads on VNT controls.

There have been a few done. I think Jimfoo has one as well if you search his name.

[ahto42]

they all are controlled by cabels, my car has electronical gaspedal

[jimfoo]

why vacum all the time, maybe a litlebit thru a vane and and egr adds more vacum, a spring pulls the vanes closed

Because you constantly need to control the vane position and it sounds like you almost never have vacuum, just cruising with a temp below 70*C, which won't work at all. If you can't control the vanes, you WILL destroy the turbo. You also have to be able to adjust how much vacuum you have going to it, you can't just have vacuum/no vacuum.

[ahto42]

so you think that a turbo wg accurator push the vanes open when boost comes is a better solution?

by the way, under 70 no vacum, over 70 is vacum

[gigaz2]

better than not having anything, but still bad.
try to get a ball bearing turbo sized for your application.
no control hassle, quick spool, lots of power (you can choose spool or power when sizing)

[OM617]

Right better than nothing but still a bad choice. That will make the turbo want to produce maximum boost at all times which will severely restrict the exhaust flow at low loads.

[ahto42]

or i switch the hoses: acclererate -vacum, cruising-no vacum, and a boost controlled solenoid or valve to reduce vacum, when boost comes?

[OM617]

No, get that EGR and its vacuum hose out of your head entirely.

You must have a method of control that varies boost based on engine load (throttle). That can be with a cable and wastegate actuator, variable vacuum signal, opposing vacuum and wastegate actuators or electronic control.

[ahto42]

Does anybody got it work with vacum?