Last year near the end of my final session at the track I noticed a sudden loss of power. I pitted in thinking it might be a simple blown-off hose, but I found out that the W/G actuator was very loose (the collar at the bottom of the actuator was missing/fell), I packed and went home.

Later on at home, I repaired/tightened the actuator and went for a drive. The car felt very laggy, almost no power below 4k rpm; after 4k, it snaps back to life. Since then I've been too busy to further look into it, I just parked it. Finally a nice warm day today after a long winter, which inspired me to take it apart and confirm my suspicious.

Fortunately, I still have my stock turbo.


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This is completely closed, it won't shut any further.


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HKS vs. stock

 

Have it fixed
The door warped as it had nowhere to sink hear since wastegate was loose

That can be fixed.

 

if you can have it fixed, i would. A great turbo. I feel sure you can attest to that while it ran. I know several folks that had issues with the actuator coming loose. That was primarily due to heat on the rod and the turn buckle style used. Yours is tempered and ready to go know---thinking FP sells the correct flapper size... thats what I have heard. Good Luck

 

Or weld it shut and get an external wastegate

 

its not a a warped anything. the bearing that the shaft rides in wears . there is no easy fix. hks does not sell replacement housings.

its not a DSM. you would need two wastegates welded to stock manifold. something i have yet to see anyone do.

 

The flapper itself is fine and the bearing is ok, but the shaft is warped/twisted near the corner.

 

How long have you had the turbo / miles?

It seems like the kind of thing a machine shop could service = fab new arm + TIG in place. It's going to have to be a nice alloy though to deal with the heat.

Worst case would be pull the flapper and run one of the MAP external gate downpipes.

 

You can try and run a Map external wastegated 02 housing like this.
http://www.maperformance.com/map-sta...-o2e-cg40.html
or this
http://www.maperformance.com/map-com...-cg40-o2h.html

I have the 1st of the 2 on my 7460r. I have the internal gate set to open at what ever wastegate is. And the external is set for 26psi. I have no issue with boost control and do odd dips in boost. But at the same time I don't track my car so my turbo does not see huge amounts of heat.

 

I've had it since 2010, with 10 -15k.miles.
The MAP setup is nice, but I heard you'll lose the divided twin scroll benefit, it woks great in conjunction with the stock waste gate.

 

Do you think you're on your way to this failure?
https://www.evolutionm.net/forums/10906857-post117.html

Is the assumption that the HKS actuator comes loose and causes the flapper to unseat and then overheat = warp or lead the actuator rod to twist? If that's correct, then would running a better actuator possibly prevent this for those of us who've not failed yet.

 

Yes.

I started the repair process today by grinding off the weld at the end of the lever (on the outside) hoping to slide the flapper/shaft out from the inside. As soon as most of the weld was gone, I put a pair of pliers on the lever and twisted to check if it was free yet. With very little force, the shaft snapped on the inside, near the flapper.

From looking at it, it seems that it was already hanging by a thread; indicated by the shiny part at the end of the shaft. As for the bearing, it looks fine with minimal wear, but a quick hone shouldn't hurt. I plan to replace the shaft with a new one and tig weld it back.


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let me know what you come up with for a new shaft. I have one broken just like this.

 

If its just the flapper arm that's failed, HKS won't sell the flapper arm individually? It looks like the housing itself is undamaged at least from the pictures.

 

http://www.mcmaster.com/#catalog/120/3758/=r1dzxj

 

The housing and flapper are in great condition, it's just the shaft... easy fix.