zd 30 turbocharger adjust

[oglenelgo]

Hi I recently purchased a couple of turbochargers and fitted to my car without a problem but have a question in regards to this adjustment on the turbo do I leave it as how I got it or is that for tune up.
Cheers

[YNOT]

What boost are you getting with the new turbo and how are your exhaust gas temperatures?

Tony

[oglenelgo]

What boost are you getting with the new turbo and how are your exhaust gas temperatures?

Tony

Hi Tony.
I got this car from the auctions and it was over boosting when I purchased it and was boosting to 35psi.
I new this would of made it go bang so while overseas I got a new turbocharger for it. I had a mate who blocked the egr and fit the turbo and now it’s boosting to 18psi do you think this is too high? Oh and the egt gauge I haven’t fitted yet.

[YNOT]

18 Psi is abit high, 16 would be better. ZD30's are very sensitive to airflow changes so blocking the EGR may be part of the reason you're boosting to 18Psi at the moment.
You could try adjusting the turbo but I have no experience with that. I think the better solution would be to fit a manual boost control set up (dawes and needle valves) so you have proper control over maximum boost and how quickly the turbo spools (boosts) up.
You really need to fit an exhaust temperature gauge ASAP.
Have you fitted a PCV filter/catch can and cleaned the Mass Air Flow sensor?

Tony

[oglenelgo]

Hi tony.
My car has a catch can and a new Mass Air Flow sensor. Im going to fit the egt on the week end so ill let you know what temps im running. Thanks for your advice.

[big_fletch]

Hey mate, I have a zd30 with manual boost and blocked egr.. I run max 16psi.. At 100km's hour I sit on about 10 psi and temps around 260-320 degrees, I am also running 33" tyres..
Most I have ever had was about 550 degrees, fully loaded uphill with a full headwind towing a small trailer..
Hope this help mates

Fletcha

[oglenelgo]

Ok the update.
I got a boost controller and set it to 16psi,, I fitted the egt gauge and I had a temp of 420 and was a little concerned that was a little high considering it s not really a hot day so for one last treat for my car I purchased a set of change over injectors and oh boy what a difference the car is no longer a pig it purrs and I now have an egt of 240 so imp assuming the injectors were really gone. I have also done a full service and I used oil flush and anti wear treatment in my oil and I also use fuel treatment I swear by these products because your oil stays cleaner longer and cuts out engine noise by 20 percent and the smoke disappears. I purchased these products from costeffective.com.au . Thanks for all your input

[YNOT]

That's interesting how much of a difference reco injectors made to the performance. Post turbo EGT's of up to 500 degrees are OK (although you wouldn't want them staying up there too long).

Tony

[big_fletch]

I agree with you tony, 550 Is my limit.. when I get to there I back off, should help when I get the exhaust fitted though..
Normally the highest I would ever see is about 400 degrees

Fletcha

[oglenelgo]

HI ALL WAS GIVEN THIS TODAY IT MAKES SENSE BUT WOULD NOT RECOMMEND TO THE FAINT HARTED AS IT LOOKS LIKE A 2 PERSON JOB AND CAUTION WOULD BE NEEDED WHILE EXPERIMENTING WITH THE SET UP TO MAKE SURE THE EGT DOSNT GET TO HIGH BUT IN SAYING THAT IT’S A GOOD WAY TO HAVE THEM REDUCED ADJUSTING THIS ROD IS LIKE STANDING IN THE MIDDLE OF A SEE SAW BUT ANSERED MY ORIGINAL POST QUESTION

HOW a VNT turbo works

By using some adjustable vanes inside the turbine housing, it's possible to increase flow over the turbine wheel and speed it up at lower revs, this means it can spool up quicker than the traditional wastegate turbo. Then once the engine speed is fast enough the vanes open up as there is now enough air moving through the turbo to spin the turbine fast enough without the need for the vanes to be closed

This video shows the vanes in action:

http://www.youtube.com/watch?v=Gc2awh0O0Bc&playnext_from=TL&videos=t4j6OAsgZtU
The actuator controls the VNT rod, which controls the VNT mechanism (the vanes) which ultimately determine the boost the turbo produces. It’s moved one way by vacuum, and in the absence of any vacuum a spring will return it to it's resting position.



Common problems

Probably the most common is sticking vanes; also you could have incorrect VNT rod length, incorrectly set-up stop screw or a vacuum leak/blockage.

If the vanes are sticking then they are just going to jam in any position, normally fully closed, if actual boost is not near enough to requested boost for a given amount of time) then it will go into limp mode

If there is a vacuum leak then there might not be sufficient vacuum in the line to pull the actuator down against the spring, if this happens then after a certain amount of time (~2-3 sec) and still not enough actual boost then it will go into limp mode

If the VNT rod is too short then it will effectively make the turbo far too sensitive and as soon as the ECU requests boost, before you know it you have twice the amount of boost requested as it suddenly spikes. Once it does this, it's basically lost control of the boost and for some reason it won't go into limp mode, instead you will just feel a flat spot and if you have a boost gauge you will notice it going off the scale! The reason for the flat spot is the amount of exhaust manifold pressure suddenly generated is too much to get though the turbine, so the engine is choked and held back. Once the boost falls to a reasonable level you will feel the car start to pull again.

If the VNT rod is too long it will mean the turbo is not responsive enough and it may feel sluggish and laggy.

If you have a vacuum leak then it will be the same as above, sluggish and laggy and will not be able to apply enough vacuum to the actuator



How to adjust the VNT rod length

When these turbos are new straight from Garrett, the rod length and stop screws are setup professionally in accordance with their specifications. Since they do not publish these specifications alot of re built, re manufactured, re furbished turbos do not have them properly set up. This includes so called "Garrett approved turbo re-builders" most of the time they will just leave them as standard and expect them to work, and they will work most of the time but obviously there is going to be times when they don't. And because the hybrid turbos are different specifications, the rod length and stop screw specifications from Garrett will no longer apply. This means the turbo must be set up either on a flow bench or on the car.

Adjusting the rod length is necessary if you are getting erratic boost problems, if your boost is to high then the vnt rod needs to be made longer, and if your boost is low and needs to be higher then the vnt rod it needs made shorter.


Mmmmm interesting but not a job for me its just good to know if your ever stuck on the side of the road.