turbo's

[shlacks]

can variable vein turbos be used on older cars? is there some sort of controller you can buy that can make it possible?
i would like to put one on a 1hz in an 80 series.

[shlacks]

anybody????

[scuba steve 22]

been told you need an external wastgate to stop it over boosting???
not a mechanic my self just what ive been told

[Tapage]

Mmm pretty sure could be ..

How much it gonna cost .. mm

Option .. fix the variable vane function. With proper resources you can found the best boosting spot and fix this position ( on the variable vanes ) to allow the turbo boost at your desires rpm .. and exhaust flow ( how ? I good question .. )

Other option it's ( maybe ) get all stuf .. from variabkle vane controler motor ( most case electric or vacc activated ) ECU ( if it's electronic controled ) or vaccum stuff ..

It all depends .. thought the electronic stuff coul be a little more complicated even you havn't all ECU signals and info ..

[tweak'e]

the early ones used a diaphram like a waste gate does to operate the vnt. however it fairly limited, you can't get he boost up as quick as you can with electronic control. i id see somewhere an electronic controller for them but you can be sure it won't be cheap.

also some of the early ones also used a wastegate as well as vnt control.
it may vary depending on application.

imho the big advantage in useing ecu control of the vnt is for emmisions. the ECU can increase the backpressure to force more EGR into the motor.

[PGS 4WD]

Could be done, the GU 3.0 uses a vacuum pump to activate the variable vane(dosent have a wastegate) they do seem to have some problems with reliability due to the variable vane sticking, over and underboosting, I'd go a roller for reliablity and similar performance if turbo selection is careful.

Joel

[KiwiBacon]

The ones I have (not fitted yet) use a vacuum actuator controlled by an electrical valve. The reason for that instead of pressure is that signal loss opens the vanes and that the vacuum is always available.

the vacuum actuators also use the same two bolts to mount the can as many wastegate actuators do. I intend originally to just use a wastegate actuator to control boost. Still several months away from running though.

There are mercedes enthusiasts using custom electronic controllers to drive their VNT turbos on engines which were previously fully mechanical control. I haven't yet heard a good description of their controller, but a 12v PLC will cost you about $400.

[PGS 4WD]

It would be possible to control with a PWM output from an aftermarket piggyback chip like a Haltech or Chip torque by connecting to a map sensor for load reference, could do it but would think cost to be $1500 or so using that method.

Joel

[shlacks]

ok i actually have a few variable nozzle turbos as i am a mechanic and i know boosting specs of them just not sure how they would match onto the 4.2 and wondering how to operate the vacuum diaphram as on the gu it's a electrical controlled vacuum solinoid and the only problem with the gu turbos are if you have an earlier oil and water cooled turbo they get a slight coolant leak internally and rust the vains and they stick open causing over boost and put the car into limp home mode till foot comes off accellerator... i have a navara d22 turbo which is a wastegate type turbo but im thinking it would be to small for this application so i might look into that 12v plc or just resign to buying a gt28bb kit for it

[Tapage]

and the water internal leack can be solved . ?

[KiwiBacon]

It would be possible to control with a PWM output from an aftermarket piggyback chip like a Haltech or Chip torque by connecting to a map sensor for load reference, could do it but would think cost to be $1500 or so using that method.

Joel

PWM is simply a digital way of acheiving an analogue signal. Varying the voltage between 0-12v gives the same result as varying the pulse width from 0-100% on a 12v lead.

For hacks like me analogue is easier to understand, but digital gives you way more control options.

Shlacks, what are your turbos off?
I had a couple of GT2052V's (from VW/Audi 2.7l diesels, one a runner, one for parts) but I sold them before fitting. They measure up as slightly bigger than a T25.
I now have a GT2256V from a mercedes 2.7L diesel which is about halfway between a T25 and T28 compressor size. Compressor maps for the variable vane turbos are very difficult to find, they use smaller trim and A/R than fixed geometry turbos of the same wheel diameter, a result of needing to run higher boost at lower airflows.

There's a real gulf between the small variable vane turbos and the large ones. Plenty available for 3L and smaller diesels, plenty available for 6L and upwards but not much in the middle. I was hoping the 4.5L V8 70 series cruiser engine will provide some relief, but I haven't found any specs on that turbo yet.

[shlacks]

tapage: yes it is solved as all new turbos fitted at nissan for the patrol zd30 are oil only turbos and a kit is fitted to block coolant lines from the head.

kiwibacon: my turbos are off patrol zd30 and d22navara zd30 and a d40navara yd25

[KiwiBacon]

kiwibacon: my turbos are off patrol zd30 and d22navara zd30 and a d40navara yd25

I've driven a ZD30 powered terrano which had a GT2052V similar to the audi/VW ones I had. Same vacuum actuator setup too.