Sorry another actuator question
Turbo Mini Forums

Without opening a can of worms here I have been researching this subject but can't find a clear answer, this may be because there simply isn't one !

I am waiting for my engine to come back from benross ( should give you an idea of spec ) , and I am planing on looking to run up to 16psi , mainly on 12 psi but am unsure if the standard actuator will be suitable for this, the turbo is a turbo technics unit ( unsure of model at this point ) however I have been advised its identical to a T3 ??? .

From what I can see there is an option to update the spring inside but this might not help much, what's people's experience with this ? Am I better to just buy a new updated one and start from there ? If so what's a good one to buy ?

Sorry if I am getting this wrong , I just don't want to make any more mistakes with my project as I already managed to bugger the rings by not setting up the timing correctly and have since invested in a MJ set up :$

Someone else may be able to confirm but i think a standard garrett -31 is 8psi and -34 is 12

i believe -31 is 15psi, i use one on mine at the moment with hardly any preload and it runs at 10psi. i roughly tested mine with the actuator fitted to the turbo, using an air line into the actuator housing with a boost gauge 'T''d off, increase the air pressure until you see the actuator start to open, then note the boost shown on the boost gauge. worked for me anyway. you can adjust this by using different preloads, cheers, dan

also you are not able to take the oe garret actuators apart to change springs, they are sealed units.

Thanks for all the help chaps

And in most cases, a simple bleed valve will work well for increasing boost pressure over base actuator pressure if needed.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

I might be missing a trick here ? Sorry . I have a bleed valve on the car but one thing that did seem apparent was that I could only boost up to 12psi , is this due to the actuator allowing the waste gate to open due to the spring pressure being less than the turbo outlet pressure ? Or have I got that completely wrong ?

It could be a variety of reasons. Without seeing or testing I cant say..
It could be as simple as the type of bleed valve or how it is plumbed.

But yes there will be a point when either the actuator is too soft for more boost, or the turbo itself is incapable of providing enough air.

But the best way to do it is using an actuator as close as possible to the lowest boost you will use. If that's 12psi, then it makes sense to use a 12psi actuator with no bleed off.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will