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actuaters and boost

496 views 14 replies 8 participants last post by  rodgerq 
#1 ·
hey

i have a couple of questions

1, can you just confirm to me what an actuater does? i beleive it controls the amount of boost the turbo runs, though im not sure if this is correct!

2, wehn me and a friend where installing the let we had problems with it boosting, turnbed out to be spark plugs gaps to big, but my mate said he had turned the boost down on the actuater which i saw him do, he turnd the two bolts iwther side of the rod

3, my car only manages 0.4 boost or a bit over, by turning the bolts back will this increase the boost back to .05 where i beleive it should be

sorry fore the long winded questions but im stil learning and need to know these things!


cheers :beer:
 
#2 ·
/\STR/\ said:
hey

i have a couple of questions

1, can you just confirm to me what an actuater does? i beleive it controls the amount of boost the turbo runs, though im not sure if this is correct!

2, wehn me and a friend where installing the let we had problems with it boosting, turnbed out to be spark plugs gaps to big, but my mate said he had turned the boost down on the actuater which i saw him do, he turnd the two bolts iwther side of the rod

3, my car only manages 0.4 boost or a bit over, by turning the bolts back will this increase the boost back to .05 where i beleive it should be

sorry fore the long winded questions but im stil learning and need to know these things!


cheers :beer:
You're right, an actuator uses a diaphagm that provides resistance (determined by whatever boost controler you're using). You can adjust the boost by adjusting the bolts on the actuator as this is adjusting the mechanical travel or leverage the actuator has. Don't go too mad though - adjust by only half a turn or so at a time and see how it goes.
 
#7 ·
what do LETs have controllig how much boost gets through to the actuator then? Sorry for the hijkack :p
 
#9 ·
TurboCavGSI said:
The amal valve.
A solenoid that's electronically controlled?
 
#10 ·
The amal valve allows the ECU to control the actuator, which in turn controls boost by operating the wastegate which allows the exhaust gas to bypass the turbine. Simple, eh !
 
#11 ·
tathan said:
A solenoid that's electronically controlled?
aye pretty much mate. its got a pipe in from the compressor housing, and two pipes out. one to the actuator and one back into the breather system. depending on what levles the map sensor sees depends where the valve directs the boost - either to the actuator to limit boost or back into the inlet via the breather system to let boost rise.

rodgerq
 
#12 ·
rodgerq said:
aye pretty much mate. its got a pipe in from the compressor housing, and two pipes out. one to the actuator and one back into the breather system. depending on what levles the map sensor sees depends where the valve directs the boost - either to the actuator to limit boost or back into the inlet via the breather system to let boost rise.

rodgerq
Cheers guys - that's pretty much the same setup as my car. A vac comes off compressor housing for the sensor, and then another one comes off into a solenoid attached to it, then when it open another line lets it to the wastegate. Why's it called an amal valve though?
 
#14 ·
och ah dinnae ken. You can swap part of it for a later one to raise the boost the ecu can ask for, standard's 1.15 on my STI, 1.3 on later ones iirc. I've had to use a Pikey Device temporarily to get 1.3 :( and it's not to be recommended.

I guess that wastegate spring pressure should be set to about 1/2-2/3 of the target kind of area?
 
#15 ·
do you mean an external wstegate spring? if so its just a matter of adjusting it and testing it till the boost is what you want it to be. no wastegate creep either with an external gate, it stays closed till the very last minute till your boost has built right up then it cracks open.

rodgerq
 
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