Is my wastegate too small? Cant stop free boosting

gt1r

New Member
Hi all just got a new set up put on my car. Brand new genuine mitsubishi TD05 big 18g custom made with 3" v band dump no internal wastegate running a 38mm external and I cant stop the thing free boosting. Ecu is a link g4 boost set at 6psi in ecu. Running a 3 port EBC.

I have tried everything to solve this problem, tried manual boost controller, tried 7psi wastegate spring, every way you can set up the vacuum lines, changed to a different gate and everytime boost shoots up over 30psi (that's all my guage goes to) nothing has made any difference.

All I can think of now is that my external wastegate is too small but it shouldn't be. My question is can I take the spring out of my gate and run it with no spring? If I still over boost then its telling me it is too small and I need to get a bigger one.

Will this damage my turbo at all? Any help or ideas will be a good help Thanks
 

gt1r

New Member
That's
Sounds like your wastegate is not opening at all rather than it is too small.
That's what I'm trying to figure out? I have tried everything to see if its opening but all has same result. That's why I'm thinking of taking spring out and seeing what happens. If its still over boost then gate is too small but if I don't get boost then its just not opening. I'm wondering if I will do any damage to my turbo if I run the gate without a spring tho?
 

The Doc

Moderators
Staff member
If it was too small you would get boost creep which is a differant issue altogether, your wastgate is stuck closed.
 

Fast Guy

Moderators
Staff member
I have put a 7psi spring in the gate can open by pushing on it quite easy
The spring and preload are different things. Normally when you align the hole in the actuator arm with the wastegate rod, you have about half a hole offset (preload) on the too short side. A cheap way to increase boost before all these fancy electric gizmos was to make that distance bigger, say a complete hole offset, so you had to force the rod onto the wastegate, this meant the turbo made more boost to overcome the increased loading and open the wastegate.

I take it your wastegate isn't stuck closed when you say "can open by pushing on it quite easily"?

Try disconnecting the boost line to the actuator at the other end and put a foot pump with a gauge or something on it and see if the wastegate opens when you pump it up.

Is there any leaks in your boost line to the actuator? Where's it run from?
 

gt1r

New Member
The spring and preload are different things. Normally when you align the hole in the actuator arm with the wastegate rod, you have about half a hole offset (preload) on the too short side. A cheap way to increase boost before all these fancy electric gizmos was to make that distance bigger, say a complete hole offset, so you had to force the rod onto the wastegate, this meant the turbo made more boost to overcome the increased loading and open the wastegate.

I take it your wastegate isn't stuck closed when you say "can open by pushing on it quite easily"?

Try disconnecting the boost line to the actuator at the other end and put a foot pump with a gauge or something on it and see if the wastegate opens when you pump it up.

Is there any leaks in your boost line to the actuator? Where's it run from?
I'm running a external wastegate not internal so no rods or anything. Turbo is custom built with a 3" rear housing so all I can run is a external gate. No leaks all brand new boost lines when I got it tuned. The guy that was tuning my car told me any 38mm gate was too small but I didn't believe that but I'm starting to now
 

gt1r

New Member
Update I have fixed the problem. The boost source was not working from the factory wastegate vacuum or any over vacuum on the intake manifold. I had to weld a vacuum nipple into the intercooler piping just after the intercooler right below turbo. Was hard to figure out but a easy fix
 

johnny gtir

Well-Known Member
Glad it's sorted and thanks for putting the out come as so many probably guilty myself. Forget once it's fixed to put the result which helps others
 
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