New actuator fitted dump valve open on idle
Turbo Mini Forums

Hello Chaps,
Finally got round to fitting a new actuator to my Garrett T3 owing to low boost issues. I purchased a bran new actuator which was fixed at 9 psi. After installing it, the car is a little rough on idle and I noticed that the dump valve is open slightly on idle and fully opens if you blip the throttle. I'm guessing that the increased boost is causing this? I took her for a spin and when you plant your foot the boost kicks in at around 4,000 RPM which is later then previous but it kicks in much harder and pulls very well. I want to know if there is anything I should do to prevent any damage like, twin buying a twin piston dump valve, rich up the mixture, spark plug gap etc?

Any advice greatly appreciated, cheers.

Fit an AFR gauge, an intercooler (9psi is a bit high without one) and take it to a rolling road to be set up properly.

You won't have any boost at tickover, and you'd be lucky to get any boost just blipping the throttle. The issue is with your dump valve.

Excellent AFR gauges are so cheap these days, it’s crazy to not run one.
I agree the issue is more likely the DV but you may also want to look at soldering up the butterfly poppet valve.

Thanks Guys, I've ordered an AEM wideband kit already as monitoring the mixture is near the top of my list. My question arose because I never had this issue before fitting the new actuator. I just wanted to make sure that I had done nothing wrong. Not sure how soldering up the poppet valve will affect this issue on tick over but I do have some plain butterflies which I will fit next time the carb is off. Cheers.

The spring on the poppet valve can become weak and cause issues. Which is what Dave was suggesting.

Phil.

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