Actuators again
Turbo Mini Forums

I have the standard GT17 actuator from the Saab 2 litre that the turbo came from.

On its own, with minimal pre-load, it gives 5 psi.

With the bleed valve I can get 12 psi easily, which is fine.

However, I tried increasing the pre-load from 3-4 mm to around 15mm and its made no difference at all !

My other actuators are a bit bulky to fit, but they give 15 psi without bleed.

Which way do I go now ? ( and why is the first actuator not responding to greater pre-load ?)

http://www.neobrothers.co.uk/adjustable-wa...t17-p-1389.html

same, but on Ebay

http://cgi.ebay.co.uk/FORGE-ADJUSTABLE-WAS...5-/220635227258

Edited by Sprocket on 11th Jun, 2011.

How much boost do you want ?


And how much boost can it make when there is no signal line attached ?

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

15 psi is too much for road use IMHO, so 12 psi suits me well, but I,d rather not use a bleed valve if I can set it up on the actuator. Irrational, but I am.

I balk at paying £80/90 for an actuator so I may have to play with springs in the other ones that I have - its just a bit laborious as I have to take off the inlet manifold to get at the actuator.

Why does the existing one not respond to more pre-load though? I thought of weak spring, but it feels OK.

As to how much boost it can make, unregulated, I dont really want to find out as this happened with the T3 some while ago when the line split and it ran to over 20 psi.I was too busy trying to keep the car on the planet to notice - at first.

from my experience of driving it ,aspiring to keep all 4 wheels on the planet at any speed, is a voyage to a destination dissapointment ..
3 maybe , on a smooth road .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Go on Robert, admit it, you loved it !

absolutely !lol ,
id think about some very very sticky tyres for it though david if you cant get any lower than 12 psi on the launch .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

I'm having the same problem with my std Metro turbo actuator. I gave it a good "8 turns" in from the original "1/2 hole" set up. I have about 1.5 holes from the fully closed position but no increase in boost. I am stuck at 8psi :(

Hello Lenn.

Have you blocked up the standard "overboost relief" valve in the plenum? If you have not this could be your problem, this valve is lifting and letting out your boost.

lenn , the stock metro wastegate is a 3.4 to 4 psi one . so you have increased it by 4 psi odd . noice !

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Tom - Yes, I've blocked off the overboost valve and forge dump valve.

Robert - In addition to preloading the actuator, I'm also running the factory metro turbo bleed valve and solinoid with a 12v switch to keep it open.

I'm trying to hit 10psi and surprised that 8 turns is not making any difference. I was making 8psi WITHOUT the preload before.

I will try 10 turns, but I feel as though there is a "over pressure" valve being triggered or I have an exceptionally weak actuator spring.

ah fair enough lenn ,is the bleed valve definately clear ?

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Robert, I was thinking the same thing last night, so I shot 50psi of comressed air thought it. Couldn't find any blockages.

My next step is to inspect the turbo to actuator connection to see if there are any restrictions.

I have a solid 10psi now!

I wound the actuator arm all the way in (13 turns from the "half hole" position) and replaced the hoses to the actuator and to the factory bleed solenoid just to be safe. The actuator itself was bleeding off boost at approximately 4psi before. After the preload adjustment it cracks at about 6psi.