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Need help with wastegate actuator


mikeatrpi

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I mounted the wastegate actuator onto my turbo today and attempted to determine what PSI caused movement of the lever. Well, it was very difficult to get it to bolt up, and the rod was under tension. With the WG actuator attached as shown in these pictures, I am unable to move the flapper with my hand. 20 psi blows through without actuating anything... I can feel / hear the air leaking out.

 

Any suggestions?

 

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I initially thought it was clocked a little bit off as well. The wastegate shaft has a bump and rubber washer, presumably where it mates with the diaphragm part. That bump and washer are fully extended... clearly seen in my first photo. I can't imagine it having any additional extension beyond that point.

 

I also had to grind a little bit off the drain fitting when I was bolting that up for a test fit. The side of it hit a bolt nearby. At the time I chalked that up to an order of operations error. Now it seems like more evidence that its clocked a little bit goofy?

 

Time to figure out how to fix that...

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If it's all stock, the wastegate lever should open the gate around 7psi. Disconnect it from the gate arm and make sure the servo operates at 7psi or more. Don't be afraid to bend stuff (bracket or rod) to get it to move without binding up.

 

The flapper should move very freely with the servo link disconnected

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20 psi blows through without actuating anything... I can feel / hear the air leaking out.

 

 

Air shouldn't blow through the wastegate actuator. Sounds like a ruptured diaphragm.

 

You can see what it should open at with it removed from the flapper. The more tension on the WG diaphragm spring (preload), the more pressure it will take to open it.

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The turbo did indeed need to be clocked. I loosened the bolts around the perimeter was was able to easily rotate the outside. I did not adjust the hot side at all. I basically did it using the notch in the drain as reference for the bolt nearby.

 

The wastegate flapper moves easily without the actuator. Due to the improper clocking, the actuator was fully extended. After fixing the alignment, the wastegate actuates at 12 psi. That says the diaphragm is good. Unfortunately its too high for me. The seller told me it was modified when I bought it. My fault for thinking that could be easily un-done.

 

Anyone got a spare 7psi actuator? Anyone need a 12psi one?? ;)

 

Thanks for all the advice fellas.

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The turbo did indeed need to be clocked. I loosened the bolts around the perimeter was was able to easily rotate the outside. I did not adjust the hot side at all. I basically did it using the notch in the drain as reference for the bolt nearby.

 

The wastegate flapper moves easily without the actuator. Due to the improper clocking, the actuator was fully extended. After fixing the alignment, the wastegate actuates at 12 psi. That says the diaphragm is good. Unfortunately its too high for me. The seller told me it was modified when I bought it. My fault for thinking that could be easily un-done.

 

Anyone got a spare 7psi actuator? Anyone need a 12psi one?? ;)

 

Thanks for all the advice fellas.

 

I haven't had much to do with turbo s yet, but couldn't you add an external spring to pull away (toward ?) from the actuator, thus reducing the actuator internal spring pressure ?

 

Nigel

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The seller told me it was modified when I bought it. My fault for thinking that could be easily un-done.

 

I'm pretty sure it can be undone, just lower the preload by lengthening the actuator rod like so:

 

1200_sheath2.jpg

 

Notice the threaded rod and added sleeve.

 

Hope this helped...

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I have seen the spring on the outside trick, but I need to do some more reading on that. As for lengthening the rod... won't this open the flapper a little bit?

 

It may do that if you lengthen it too much.

 

Now that I look closer at the photos, I can see how the P.O. modded it to be a higher boost level. I think they opened up the canister and added another spring, or replaced the OEM spring with a stiffer one. Then they welded on some tabs to seal it back together.

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I disassembled the actuator. There were five tabs epoxied on the sides holding it together. It sure is a big spring in there! He installed a washer and used screws to pre-load the spring from underneath. I removed the washer and screws. Now, it seems to open slightly sooner than 12 psi, though I need a more precise measurement method to be more accurate.

 

The wastegate flapper should be fully closed when < 7psi, correct? When it starts to open, how much should be open? This one goes fully-open around 15 psi.

 

Photos of the insides:

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The wastegate flapper should be fully closed when < 7psi, correct? When it starts to open, how much should be open? This one goes fully-open around 15 psi.

 

What it starts to open at is about the boost you'll have. It doesn't take alot of movement to bled off enough pressure to control the boost. If it starts to open at 7 and is fully open at 15 psi, I would say you will be well under 9 psi, maybe even 7 psi if you don't preload the rod too much. You only need to pull the rod out a small amount to get it on the flapper. Like an 1/8" max.

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  • 2 weeks later...

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I ended up cutting about 1/2" out of the arm, and threading it with a 1/4-20 (coarse) die. It was really hard to start the die by the way! Then I put a spring from the hardware store between some washers and reconnected the arm with a connecting nut. I adjusted it to open at only a couple of psi... I can easily adjust this in the future. I have more photos at the link in my sig.

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Nice job. You will definitely be tweaking that setup to get it right after your first test drive. It looks like you have left plenty of room for modification and further adjustments later on. Trust me, you will be yearning for more PSI within minutes of the first few boosted drives.

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Thanks guys. It was really hard to start the die - I put the small end in my drill press to get leverage, and rotated the chuck by hand. The rod that was connected to the wastegate however was more difficult... I used vice grips and a c-clamp to attach it to my bench, then basically put all my weight and force into the die while rotating.

 

Raff the PO is a well known guy on this forum *cough* bruce lee z *cough*. He basically gave me this actuator along with the bulk of the turbo parts I bought from him. He couldn't remember the details of all of the modifications - if the spring was stock or not - but with the help from this forum I found a solution that will let me dial the boost back to a usable level for my application!!

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