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Dual Port Waste Gate Actuator?


Guest jt240z

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Chris,

 

you are correct in asking what the spring pressure is but be aware that being dual-port has nothing to do with you reaching 20psi. If the standard spring pressure is high enough and the rod is adjustable, then you can make 20psi or you can add a bleeder or relief valve.

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Lockjaw or Speeder' date=' do you know what psi the WG opens at, and how high it will go? Looks like I need a dual port to get to my 20 psi goal.

Thanks.......chris[/quote']

 

It really depends on the rod tension. The shorter the rod the more tension you put on the spring in the actuator. Hence more boost.

 

Here is what I tried sunday and it works well. I probably make about 8 to 10 psi on the actuator alone, and will have to cut and re-thread the rod to raise it. However I ran the vacuum/boost signal to the bottom port thru an adjustable boost controller, and removed the vacuum/boost source from the top port.

 

Now I make a rock solid 15 to 16 psi, and it spools fast.

 

Anyway, you don't need a dual port as long as you have an adjustable rod, but if the rod is not adjustable, a dual port will help you control/manipulate the boost. That is what I really like about it.

 

Plus I believe the one we are duscussing has a stouter spring in it then the factory one.

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  • 2 months later...

Speeder or anyone, I'm about to install my new Turbonetics dual port wastegate actuator and was wondering what the default boost level is. For example, if I didn't run a boost controller what PSI would the wastegate open? My stock Nissan unit opened about 6PSI.

 

Thanks

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John,

Mine had an adjustable length arm, and I could lenghthen it enough to go as low as 8 PSI (although my wastegate puck was undersized and wouldn't hold boost that low) shortened all the way it would got to around 12-14 as I recall.

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Can one of you guys clarify what the dual port actuator does for me?

 

As far as I can tell, you run 2 vacuum lines, one to each side of the diaphragm. One line you put a restrictor in, the other you leave at straight manifold pressure. This I assume would help keep the WG closed until the pressure differential was higher than if you just used a 1 port actuator, aiding spool-up by keeping the WG closed to say, 10 psi before it starts creeping open. (?)

 

Would this be akin to raising the spring rate on the opposite side of the diaphragm?

 

I suspect this is how it works and why, just want to confirm it.

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Speeder and I have had many discussions on this topic. These actuators were used on many OEM setups but I have no idea how it was deployed and controlled. IMO, it would work best incorporated with some sort of electronics.

 

As you are aware, single-porters begining opening the puck before they actually reach the desired boost limit and lengthens the time it takes to reach that limit. With equal boost pressure applied to both sides of the diaphragm, the puck stays closed allowing the boost to reach a limit quicker. If the pressure at both ports remain equal then the puck will remain closed by the spring pressure until the pressure in the turbo pushing against the puck, forces it open. Not Good. However, if both pressure sources were controlled through a valve, then it is becomes magical.

 

Lets say you want to run 15psi, then as the turbo starts to build boost, if both ports have equal pressure, the puck stays closed and the turbo builds boost faster. When the boost hits 15psi, the pressure in the front port that would normally keep the pucked closed is suddenly reduced, causing the other port to move the rod and open the wastegate. The magical part for me is the ability to build boost on a t-brake or foot-brake (Sorry stick-shifters) and control how much boost you launch with. Lets say I want to launch with 12psi boost, with this I can put my foot to floor and never worry about the boost going above 12psi.

 

The Turbonetics unit has a default pressure of 7psi, adjustable to 12psi. But what if you want to run 20psi? Difficult w/o electronic control because when both ports have equal pressure, the puck is being held closed by 12psi of spring pressure. If you try to run 20psi, the pressure in the turbo will overcome the 12psi and open the wastegate. However, if the electronics controlling the back port (that normally opens the wastegate) is receiving less pressure, then the puck will be force to stay closed. When 20psi is reached, the electronics then makes the pressure in the front port less than the back port and that forces the puck open. While all of this is going on, the puck stays close to buid boost faster.

 

Sorry, but I think I rambled again and it makes perfect sense to me but I am not sure about anyone else. So, Speeder, when are we going to get going on the e-Boost controller? :D :D I here 9s calling me.

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As usual, thank you Scottie for your thorough reply. I am going to run a Blitz Dual SBC Type R controller with my dual port setup to go over 12psi. I'd rather do that than adjust the spring tension on the diaphram.

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The boost controller is slowly bubbling to the top of my rather lengthy to-do list.... I was just telling James 240ZTurbo the other day that I don't multi-task very well.

I have been doing a lot of thinking about how to do this, however (which explains the lingering odor of burning horse$hit around here) -

I'm working on an idea to hold control pressure completely off the back port while applying this pressure to the front port, holding the wastegate closed, until set boost level is reached - Then, applying enough pressure to the back port to control boost while removing pressure from the front port.

The "boost up" and "boost down" control pressures would be generated by solenoid valves under electronic control.

This way, you will always have boost Plus spring pressure acting to control boost level, which is a good thing if you have a somewhat undersized internal wastegate like Scottie and want a wide boost adjustment range or the ability to ramp the boost from a lower launch setting to some maximum value.

Of course, a gonzo giant external wastegate eliminates the control range problem. :D

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I run over 12 psi with a dual port. I use a MBC to introduce boost to the bottom port to control it, although I ran it for a while with boost just going to the bottom port.

 

One thing to consider, using the bottom port makes things work inversely, ie , to raise the boost, I adjust the boost controller to LOWER boost. Something for you guys to consider with this electronic route you are trying to take.

 

One way to adjust it is to thread the rod and adjust the spring pressure that way, and you can easily run in excess of 12 psi.

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  • 3 weeks later...

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