Just got my build back together. During idle, I heard and felt exhaust leaking out the dump tube but it was not excessive(due to the gasket shape on this evo turbo it leaks a tiny bit, need to get a sealed divided gasket). Went for a drive, and really noticed it a lot more after a few minutes. All of a sudden, it sounds like I have open DP. When I get on it, the car is extremely laggy then I hear the wastegate close(gets really quiet), then the car starts building boost.

Does it sound like I may just need to tighten the actuator arm? I did not have this problem when I was running this turbo before and I did not touch the actuator so just seems weird.

Thanks

 

sounds more like an exhaust leak that's allowing the actuator to open early. The arm is fine. Time to check the entire turbo/exhaust system for gasket or exhaust leaks.

 

the weird thing is that as RPM's build, i can gear the wastegate close, then the car finally starts to build boost. This is around 5k rpms.

if i put my hand over the dump tube, all the noise goes away.

could it be an issue with the boost control solenoid?

why the hell would the gate close when there is more pressure trying to pry it open?!

just thought about this, maybe the arm is loose, and the increased exhaust flow causes a suction which then closes the flapper? otherwise, since the flapper is not sealing at idle, most of the air trys to escape through there instead?

 

there isn't any suction.

if you have a leak in a vacuum line it will bleed pressure off at first causing the flapper to close until pressure overcomes the leak.

also you could have a faulty boost controller or the diaphragm or spring in the actuator could be damaged or broken.

 

only reason why i think suction, is because when i cover the dump tube with my hand, i feel a slight suction.

ill check out the actuator

 

At idle maybe, under load there's positive pressure pre turbine in the exhaust manifold and turbine housing.

 

I'm thinking the diaphragm has melted or has a tear. internal wastegates absorb a lot of heat due to the linkage attached to the housing and given the actuators proximity to the manifold and turbo this isn't uncommon. most end up having to run a heatsheild on the actuator between it and the manifold/turbo.

 

That's what I'm thinking in this case. May have to use an upgraded actuator. Turbosmart has good actuators. Forced Performance sells a high psi actuator.

 

OK so, it was the most obvious. Loose actuator. Seems it was caused by the turbo slightly clocking itself. The bolt got loose. Re situated everything, and she runs great. No leaks. Just weird how I could hear the flapper close so I got very confused. Thanks guys for the help!

 

Good ol shodan trying to get people to buy things they don't need eh?

 

well no, it's no secret that most oem internal wastegate actuators really suck, regardless of brand.

that's why you see evo owners go with the turbosmart actuator and subaru owners go with the forge actuator.... and us honda guys go with whatever works lol.

I've had more than one oem actuator fail on me before

 

And I said may have to upgrade the actuator, not must For example, on the GReddy 18G turbochargers, the internal actuator cannot hold anything stable past 14psi, whether or not you've adjusted the main bolt, ajdusted the rod or changed the flapper door.

Many internal actuators can fail to a point where they need to be replaced. Since I'm not at his location, I think of problem elimination not just a bandaid.. But hey, that's just my approach..