Hey guys. Scratching my head on this one.

Bit of background: I have a stock evo 8 turbo on my built honda

I have the gate dumping to atmosphere, and i noticed that the dump started sounding like an open downpipe with tons of exhaust leaking. When I drive the car, it lags like a *****, although I can hear the gate close and the car eventually builds boost and sustains my 15psi setting. What can cause this? I recently got my car running again after several months of down time, and this issue was not apparent back then. I tightend the actuator arm before i rebuilt my motor, so i know its tight, it couldnt have gotten loose could it?

Thanks

 

Try a new one.

 

Tighten it more. More tight is better.

 

the oem wastegate can be adjusted, maybe someone adjusted it before and that is causing your problem. try adjusting it, but review the thread on it first

 

It is a stock O.E.M. MHI VIII actuator right? As slowsrt4, states above you should adjust it tighter so that higher spring pressure will pull the flapper valve down onto its seat in the turbine housing's bypass port exit.

If it is cracking/lifting at idle then you need to adjust the actuator rod shorter overall.

 

Keep in mind that the factory VIII actuator has an internal spring rated at a wimpy 10# when new. Overtime due to thousands of repeated work cycles that spring and diaphragm have deteriorated.

The WGA's internal spring takes a set overtime and loses its original temper. It does the equivalent of an old 300,000 mile suspension spring on an old jalopy. It sags. Or in the case of the actuator spring the first coil compresses more easily which allows the flapper to ride up off the seat even at idle.

Remember that even at idle when your boost gauge is indicating vacuum your engine is producing exhaust gases which flow into the turbine inlet area of your turbine housing and some of it gets directed through the bypass port which terminates at the flapper valve.

At idle, spring pressure is the only force supposedly pulling the flapper valve down onto its seat. So, exhaust gases flowing through the turbine housing's bypass port are exceeding the actuator's 8# of spring pressure. That is why the valve cracks up off its seat and lifts.

So if new from the factory the spring was rated at 10# after a long service life it has deteriorated into being a 6-8# spring. Truly wimpy.

 

How much peak boost are you gonna be running anyways? You can get a high mileage OEM actuator to work for boost levels up to about 24-26 max by modding it.

 

thanks guys for the responses. I figured it out. the turbo had clocked it self a small amount. turns out the bolt for the band loosened itself up :-/

i tightened everything down, and the adjusteter was still loose(weird because i tightened it before i finished the build the last time). anyway, i couldnt get enough play out of it so i had to modify the bracket to give me a an extra 1/4 inch of play. tightened that puppy down tight, and zero leaks.

i have it set to 15 psi right now, and she worked beautifully. although will be tuning for around 24 psi.

she was holding 24 psi fine on my last build. unfortunatly, i hired a ****ty tuner who added waaay too much timing and i was detonating all over the place wihtout knowing it until i installed my det can and heard it, but it was too late. 3 cracked ringlands later, i decided to street tune myself. got her up to 15psi. feels great but need better tires!