actuator

[Ricky]

I need to change the actuator on my gt20 from a vacuum one to a normal one, anyone know if a gt25 one will fit? I don't mind a bit of modification to get it to fit, but don't want it to be completely different.

[cwspellowe]

Flip the spring to the other side of the diaphragm, i've just done it with my GT2056. Saying that i'll be controlling boost with an MBC so poundage doesn't matter so much.

You can use pretty much any actuator as long as you can mount it properly and the spring is the right strength for the boost range you want. Oh and the actuator arm needs to be shorter than the vacuum one.

Measure the distance between mounting bolts and look for something the same size. IIRC the GT range are all pretty similar anyway, but even the actuator from my T2 would have fit ok.

[Ricky]

I think its a sealed unit so doubt I could swap the spring, will have a closer look later though, cheers.

[cwspellowe]

You can. I made a small nick with a hacksaw blade then used a flat headed screwdriver to prise it open. Use a set of pliers/mole grips to bend the metal back into shape when you're done and hey presto, as long as the diaphragm is crimped in place it'll seal. You need to change it anyway so give it a go

[Ruan]

You might end up needing to place a shitload of preload on the spring dependant on how high your exhaust backpressure gets, or it'll just blow the gate open under pressure... Just watch out for that when you realise it won't make any more than 16psi, coaling like a train, and smelling very hot lol....

[cwspellowe]

Yeah tbh Ruan the actuator on my GT now feels stiffer than the one on the T2 that's holding at 28psi, so should be ok.

[Ben]

The springs must get weaker as time goes on? Because my t2 used to peak at over 30 psi and now only just gets over 20 psi before the gate creeps open. Completely ruins the boosting experience!

[Dave]

I replaced mine with a valve spring

[Ricky]

I replaced mine with a valve spring

That must just stay closed surely?

[Dave]

ground it down to weaken it abit, but can pretty much dictate what pressure you want it to open at then.