Swapping wastegate actuators...

[mullett]

After trial-fitting my R32 T3 to the GZE today, I've found that the standard wastegate actuator is going to foul on the gearbox quite badly. I've got a spare T25 actuator or 2 lying around, and it seems like with a bit of cutting and shutting it'll bolt up to the housing and the wastegate itself quite easily. Apart from actually making it fit, is there any basic reason not to do this? Oh...and does anyone know what the stock wastegate on a CA18 T25 is set to?

RM.

[Mr Ed]

Youll need to make sure the distance the pin moves is the same, possibly just check to see if the same pressure opens it. They arent electric so as long as you make sure it is actually going to open you wont have any dramas.

[mullett]

Yup, done and done I'm not sure what pressure the CA one opens at, I was kinda hoping someone here would know...but apart from that, it can all be made to fit I was pretty sure they were a fairly generic and interchangable part, so it should all be cool

RM.

[slide86]

im pretty sure that the factory actuator opens round 7psi.

as long as the actuator opens the gate properly with the distance that it travels you should have no worries.

external gate and screamer FTW! haha

[mullett]

hahah, yeah, for sure, but I've already had the cast manifold modified and welded, it'd be pricey to add a screamer pipe to it now, and right now all I want is the car back on the road 7psi I guess I'll have to live with, get some sort of boost controller later

RM.

[slide86]

im not 100% on that, but i fitted a stock rb turbo and stock actuator the other day and max boost was 7-8psi.

[mullett]

Out of sheer curiosity, what motor did you fit it to, and how did it perform?

RM.

[Mr Ed]

In terms of boost control its better to have a lower pressure spring than a higher pressure spring. You can bleed pressure much easier than you can build it.

Manual bleed valves can be had for under $20 these days.

[Draven]

[QUOTE=Sir_2jza70]In terms of boost control its better to have a lower pressure spring than a higher pressure spring. You can bleed pressure much easier than you can build it.[QUOTE]

I was under the impression you should be going for a spring as close to the boost level you plan to run as possible

[slide86]

fitted to a stock r32 with rb20. cooler and exhaust. went ok. but nothing to ring my mum up about.
boost cam in bout 2900-3200 and kept on strong till limiter. going to wind it up to 12 pound with electronic controller next week. should be a little better then.

previously had a massive turbs and the car was not streetable. very funny to drive.

[Mr Ed]

I was under the impression you should be going for a spring as close to the boost level you plan to run as possible

As close as possible without going over. An undersized spring is nowhere near as bad as an oversized one. You cant make the wastegate open any sooner than the spring will allow using any type of boost controller, you can however make it open later by bleeding off pressure in the actuator line.

If you have a spring set for 7psi you can esily make it run 12psi or wateva you want using a BC. If you have a15psi spring and want to run 12psi no boost controller is going to help you until ou change the sring.

If you correctly choose the spring there is no need for a boost controller but this also means if youre running boost on the limit of what your engine/injectors can take you risk it not opening quick enough. This means boost spikes which is bad when things are on a tight tollerance in AF ratios.

[hybridaddy]

I have a xr6 garrett gt35/40 turbo with standard internal gate and actuator.
I get 7 psi standard and with a bleedvalve all i can get is 16 psi.
Im actually running it with no signal to the actuator now because the signal is doing nothing,its the exhaust gas pressure that is over riding the spring tension and opening the wastegate flap.

Moral to story=get the actuator that is as close to the boost level you want to run cause there just isnt enough room to move with light actuator springs.

Anotrher option is to buy an actuator with a boost nipple on both sides of the diafragm and bleed boost out of the back side so it works against the front and holds more boost

[Mr Ed]

I have a xr6 garrett gt35/40 turbo with standard internal gate and actuator.
I get 7 psi standard and with a bleedvalve all i can get is 16 psi.
Im actually running it with no signal to the actuator now because the signal is doing nothing,its the exhaust gas pressure that is over riding the spring tension and opening the wastegate flap.

Moral to story=get the actuator that is as close to the boost level you want to run cause there just isnt enough room to move with light actuator springs.

Anotrher option is to buy an actuator with a boost nipple on both sides of the diafragm and bleed boost out of the back side so it works against the front and holds more boost

If you ran an electric boost controller you wouldnt have that problem, but yes manual bleed valves are fairly limited.

[JustCallMeOrlando]

Yes and no. I have a 7psi spring in my actuators, and I had to get an eBoost2 to control boost. The Gizzmo just couldn't cope with the way it ramps up very quickly. I think with a spring closer to the desired pressure, it would've been fine.

[hybridaddy]

If you ran an electric boost controller you wouldnt have that problem, but yes manual bleed valves are fairly limited.

wrong.
there isnt a boost controller in the world(short of one that has a vacuum pump) that could stop the exhaust gas pressure over riding the weak spring.

a solenoid controlled boost controller will generate a small amount of vacuum as the diaphragm tries to open when the solenoid is still shut but as frank stated it still wont be enough to control boost completely