turbo valve?

[Mimic4]

What did you do after it starting venting pressure to get 12PSI again?

[Growlerbearnz]

Standard practice is to put a hose clamp around the manifold and over the valve to hold it closed. Flexboi made a fancy adjuster here: http://dinoevo.de/pressure-valve-blocker/ and I've seen heat shrink used:

ValveHeatshrink.JPG (72.88 KiB) Viewed 4222 times

I cheated and replaced it with a brass plug. Not recommended unless you have a boost gauge and a boost controller.

reliefValve.JPG (55.25 KiB) Viewed 4222 times

[Mimic4]

Wow! Great pics, thank you.

So in both of these scenarios you don't have the line from the turbo attached anymore. So how do you control the wastegate??

Where exactly is the pressure releasing from out of curiousity, Is it the threads where the valve is screwed in?

[Growlerbearnz]

Ah. In my picture the engine is half disassembled- it's difficult to get a photo of the pressure relief valve with everything installed. The wastegate actuator is installed as usual, with the usual line going to one of the turbo's output spigots.

I suspect you might be getting the wastegate actuator confused with the pressure relief valve- my apologies if not. Here's a slightly clearer image (ignore the green arrows- I stole this off teh internets):

Actuator.JPG (45.97 KiB) Viewed 4215 times

The actuator is the large can that connects to the turbo. Its job is to manage how much exhaust gas goes through the turbine in order to control how much boost the turbo is making. If it's disconnected the turbo can make unlimited boost, which will damage the turbo and possibly the rest of the engine. Not good. It's set by the factory to control boost to around 8psi, but by messing with it (shortening the control rod, adding washers to lift the can up, or adding a boost controller) you can increase the amount of boost your engine makes.


The pressure relief valve is a backup emergency pressure relief. If your boost is set to the stock 8psi it never opens at all. There's a flat cap on the top- when boost pressure is too high (like if your wastegate actuator was disconnected), it lifts slightly and lets air out. The problem is that it opens at 12psi, which is easily attainable when tuning your engine.

[Mimic4]

Haha do you live on the forums? Thank you! I actually was confused, the close up pictures with a plastic sock on it confused me for the actuator.

I will investigate a bolt or shrink wrap. Thanks again.

Isn't the diaphragm in the actuator at risk of breaking in >12PSI?
Just IIRC from the manual.

[Growlerbearnz]

LOL I'm in New Zealand, so my hours are a little off. I'm not on here all the time, honest.

Yes, the diaphragm is designed to cope with 8psi, and running it at 12psi is technically outside its design spec. By shortening the rod or adding spacers you're putting more tension on the internal spring, and the diaphragm has to work against that. That said, many people on here have run their engines at 12psi without actuator failure being a recurring issue. Manufacturers sometimes use the same diaphragm and canister, but change out the spring for different applications- meaning the actuator is likely over-engineered and capable of handling 12psi .

The safest way to increase boost pressure is to add a boost controller in the line between the turbo and the actuator. A boost controller reduces the pressure the actuator sees- for example, if the turbo was making 12psi, the controller would allow only 8psi to pass through. That way the actuator is working normally at its rated pressure, while the turbo is actually making more boost. That's how those cheap boost control bleed valves work- they allow a small amount of pressure to escape from the control line, so the actuator sees less pressure. I'm currently running 18psi maximum (10psi at cruise) through a DIY boost controller as detailed here: http://www.autospeed.com/cms/article.html?&A=111350

I've tried using an electronic controller, but they're too noisy when the engine is in the cabin with you!