I have a Garret GT20 turbo which I had someone install for me. When I got this unit the wastegate was normally closed and we both looked at this thing and we could see some light through the wastegate and the turbo housing. We were told this was fine. Put the thing in, and had other issues which we resolved, then on it’s maiden voyage I had problem with the gasket and bolts holding it down. Took the unit off last night and the wastegate is wide open (see pics) and doesn’t close, looks like I’ll have to adjust the rod to get it in it’s proper location. I can move the rod to and it opens more but it looks like it’s at it’s limit for closing. Now I spoke to the guys installing it and they tell me that that adjustment was not touched. My question is, how could this have happened without an adjustment, nobody has touched the machine other than me and I didn’t mess with this? The mechanism doesn’t seem to be broken or anything, the wastgate opens and springs back to the location you see on the pics. Help!!!
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slymax
TY 4 Stroke Junkie
Shouldn't be easy to move by hand?? Check your actuator.
It's not that easy to open as it is spring loaded. How do you check the actuator???
Something is really wrong,Check the wastegatebell/spring.
Clearence from open to closed shouldn´t be more than 10 mm.
(Rodlenght)
Clearence from open to closed shouldn´t be more than 10 mm.
(Rodlenght)
Sorry:just noticed it is a Garret 
Don - you need to talk to Dave about this. That gate should be normally be closed with a slight amount of tension on it (pre-load on the diaphram spring).
General rule of thumb is that the 'crack' pressure of the gate will be 1/3 - 1/2 final boost pressure (closer to 1/3). So if your kit is designed to run at, say, 8lbs, the wastegate should start opening somewhere between 2-4lbs. Go to a pharmacy and buy a large (50cc) syringe. Connect the syringe to the signal line to the wastegate actuator and 'T' a boost gauge into the line. Use the syringe to put pressure on the actuator and note the pressure reading when the gate first cracks. Adjust the arm length as neccessary to get the required boost. Hopefully Dave can tell you what pressure you're looking for. If he's setting the pre-load a different way, just follow his instructions.
General rule of thumb is that the 'crack' pressure of the gate will be 1/3 - 1/2 final boost pressure (closer to 1/3). So if your kit is designed to run at, say, 8lbs, the wastegate should start opening somewhere between 2-4lbs. Go to a pharmacy and buy a large (50cc) syringe. Connect the syringe to the signal line to the wastegate actuator and 'T' a boost gauge into the line. Use the syringe to put pressure on the actuator and note the pressure reading when the gate first cracks. Adjust the arm length as neccessary to get the required boost. Hopefully Dave can tell you what pressure you're looking for. If he's setting the pre-load a different way, just follow his instructions.
slymax
TY 4 Stroke Junkie
For your wastegate to be stuck open like that, I'm thinking your actuator may be toast. I think there is possibly a broken spring or rod inside.
treewhacker
Expert
Deffinitley not right. The wastegate should be pretty hard to open by hand, never open with 0 pressure.
Buckeye
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You have alot of thread showing on the actuator. try shortening the rod length by loosening the locknut & turning in the end piece of the rod until the wastegate is closed. If it is still too long you will have to shorten the actuator rod by cutting some of the thread off. Although, with the Garrett you shouldn't have to.
Just appears that somebaody lengthened the rod too much. It is adjustable to fit different turbos.
Just appears that somebaody lengthened the rod too much. It is adjustable to fit different turbos.
Well, I ended up just loosening the lock nut and adjusting the rod until the wastegate was closed with a little pressure on it and it seems to be running great. I may have to tweak it by using Jim’s advise to get it set up just right. Don’t know how this could have happened other that someone adjusting it and it wasn’t I. Anyway there is no way this thing moved by itself. Thanks guys.
sledheadgeorge
TY 4 Stroke God
Similare thing happened to me. was running 8 lbs boost and when I installed the boost controller the boost was up to 15 lbs. turned the regulator down to nothing and was still running 11 lbs. boost, with the controller. Disconected the boost controller put it back to stock and was reading 11 lbs, the way it was set up before. Figure that one out. I think that that regulator spiked and damaged the diafram in the accuator. I then had lenghten the arm to bring to boost down so I could set up the boost controller.
There was nothing wrong with the actuator on mine, it's like someone had adjusted the adjustment rod so the waste gate was open, I could move the actuator and open the waste gate more. Anyways I just re-adjusted the rod and it seems to be fine, now if only I could solve the other problems.
