actuator?

It opens the wastegate to let exhaust gas bypass the turbo which means the turbo makes less boost. HTH

Fraser

A vacuum operated switch with a rod (bit like a servo). Depending on boost or vacuum, it either holds in place or pulls on the rod.

If it pulls, it opens the wastegate. Looks a bit like

but I don't think CT20 and CT26 ones have the thread adjustment.fits like something similar. the wastegate is just a metal flap with a small lever that the actuator hooks into and is held by either a circlip, E-clip or R-clip, or a combination of them.

it's the big thing that sticks out the top/bottom.side of the turbo a round thing with a pipe or 2 coming off of it and a metal bar coming out the bottom set to a predetermined level, the turbo produces boost to this level once this level of boost is reached the pressure inside the turbo housing overcomes the settings of the actuator and this, in turn, forces the rod to move (out in all cases that I've seen) and open the wastegate flap in the exhaust side of the turbo this vents the exhaust gas out through this hole rather than using the exhaust gas to spool up the turbo to produce more boost

technically everyone knows them as wastegate actuators because that's what they actuate :)

lengthen the length of the actuator rod can increase the amount of boost you get OR you can also get in car boost adjusters these tap into the pipe coming from the turbo to the wastegate actuator so that you can adjust the boost it opens at you have one pipe coming from the turbo the bleed valve you have one going back to the actuator in-between these there is another pipe which is opened by a screw (the knob) as you screw the screw in or out you are opening the valve up so that the air coming from the turbo to pressurise the actuator is being leaked off to atmosphere so you need more pressure from the turbo to overcome the strength of the spring inside the actuator

this can lead to minimal power hikes or lots of engine rebuilding

adjusting the boost electronically is also done via this way but on a totally more technical scenario rather than "twiddle this know for more power" :)

HTH

cheers people explains it well :) i also looked at fensport.co.uk and they had info on them next to the uprated actuator. so basically if i ever stop being a wimp and grab an apexi AVCR it would plumb into the actuator somehow? as well as other cables i presume. not that i'd attempt to fit such a thing, adjusting boost is something i dare not try myself as engines are exspensive :)

I've fiddled with the boost on nearly all the turbo cars I've own. The key is having a really decent boost gauge and a fuel/air meter so you can watch for detonation and boost spikes. And only use 98 Ron fuel. The WRX has it all controlled by the unichip so I haven't bothered. but it does have a VDO boost gauge because Subaru are too tight to put them in the car as standard.

Fraser

...but you fit a boost guage before you start, so you know exactly what's going on.

If you decide to ignore what it's telling you, then it serves you right if your engine pops :)

(obviously this assumes that you aren't trying to run higher boost than the engine is mapped for, etc.)