Actuator

[Kingy69]

Recently ive had new injectors,Z32,turbo etc fitted.The car is running fine and now need to sort the boost out.
The turbo has come fitted with a dual port actuator,internal waste gate.The problem is anything over around 1.2 bar and it starts to play up.It will run around 1.4 but the gain and duty is far to high to achieve this.
When you put your foot flat it tends when trying to achieve high boost to shoot up then drop then up then drop and it goes on.I think the waste gate is opening to soon and needs greater control.
I dont know alot about these actuators but it is only connected on the top port and ive done some research and it looks like both ports should be used to hold the waste gate closed and to gain better control over boost.
I know one port you can connect to the turbo compressor housing and the other to the boost control but what i would like to know is what is the best way to do this and which way round does it connect.I have a greddy boost control so can control the air bleeding off but read that sometimes you have to invert the control.Eg when you want more boost you tell the control less due to the different air forces within the actuator.
If anyone has done one of these and understands what im going on about then could you please help me out.
P.s i dont have an air leak on the system...i found that out the hard way and have changed gaskets,pipes and pressure tested also turbo was re tested.Problem lies within control of the actuator.
cheers
chris

 

[Fazz]

Not familiar with dual port actuators myself, but sounds like this is where your problem lies...

2 suggestions - replace actuator with normal one

Or

pipe up the second outlet - does it run to the same part of the actuator? I assume there is only the vacuum so it has to. Maybe pipe the second port onto the first pipe via a t-piece, and so the boost controller should then have complete control as at the moment the second port is not.

 

[Kingy69]

Thanks for the reply, option one is a no go...well not an easy one.The actuator is a lot smaller and a really tight fit so no chance of fitting a single type in the space.
Second option with a t piece ill give it a go but ive tried running a seperate feed to it but it caused it to run at 0.7 regardless of what the boost controller was set at.Its suppossed to be the new option to run higher boost without using an external waste gate.....just proving to be a big pain in the **** at the moment!!!
i think you are suppose to use a constant pressure to hold it shut so to one is pushing it shut and then the other is like on a normal actuator pushing to open against the spring.These two forces then allow you to hold the gate shut tighter and for longer but then you bleed pressure from one to allow slow opening.Well thats how i think its supposed to operate.

 

[Kingy69]

Also the ports arent connected to each other.i dont know if they go into different chambers inside as you can run on one port only upto about 1.2 just like a normal actuator.They are supposed to be pretty good from what i have read else where as they claim standard type will star opening nearly straight away but with these new ones it keeps it totally sealed allowing greater boost build up and quicker.