CT26 Actuator Spring - can I replace it?

[pauljones1976]

Hi everyone,

I finally got around to replacing my faulty actuator on my CT26 and now my Blitz DSBC works great! But, i'm not able to make any more than 15psi now.

I am certain the wastegate is opening as even with the compressor housing pressure nipple blocked off (ie, no pressure to actuator - actuator remains closed) I still only see 15psi. I do now have a problem with the said pressure nipple as I have shortened it to fit the different bracket and now it blows the tubing to the boost controller solenoid off.

Does anyone have a spare threaded pressure nipple to suit??? I'd be interested to buy a new one, otherwise I'll have to re-modify mine to make it stay on!

However, THIS IS NOT THE PROBLEM WITH THE BOOST BEING LIMITED! Please do not reply to this post and explain to me why my turbo won't make more than 15psi if the tube blows off the compressor side as I have blocked that off and re-tested!

The old actuator had a split/hole in the diaphragm and so it was continually closed but held the wastegate closed to 20+psi. I suspect it was probably opening after 20psi but my guage doesn't go over 20 & I don't want to run any more than about 18psi anyway since it's too risky if my guage runs off the scale.

Because I can't test the release pressure of the old actuator, I don't know what sort of spring it has in it although I suspect it's been upgraded (somehow?). Looking at both my actuators, they have different brackets (the old one has a long 20-25cm bracket, the new one has a short 1-1.5cm bracket) so maybe they are off different cars? ie: The old one of a supra, the new one off an MR2?

So my first question is - Is the factory boost on an MR2 different to that of a Supra? This may explain the spring difference (if there is one).

My second question is - Is it possible to replace the spring in the actuator? They look like they are sealed at a flange running around the centre when you look at it from the side. However, I think Jim (the previous owner) told me it had had the spring upgraded in the old actuator but it does not look like this flange has been opened and closed... The only other place I can see you could remove the spring is from the bottom (the part where the rod protrudes out of the actuator) but the hole is way too small to get it straight out - do you wind it out or something? If so, how?

Also, does anyone know how much boost you can reliably run through a heavily modified CT26 and 8.0:1 forgies in a 3TGTE? I'm thinking of running about 22psi...

Any help would be greatly appreciated!

Cheers,
-Paul.

[The Real Roadrunner]

you can buy different actuators from gcg and the rods also but you"ll need to make a bracket to suit.

cheers
linden

[pauljones1976]

Hi Linden,

Yeah I thought that would be the case. Do they have a website? Apparently there's a place called MTQ up here in Brisbane who does them too? I'm thinking I may need something like a 15psi spring so that I can run about 25psi maximum.

Cheers,
-Paul.