WG actuator for spool valve?

[Remps]

Could a wastegate actuator, say off an hx35, be used to actuate a spool valve? What would be a good and/or cheap actuator to use? Thinking about building my own, got a big chunk of 1" steel here I could make a T3/T4 adapter with a flapper in it. No way am I paying 950 bucks for one. Was thinking about a fmw62/68/.83 T4 with a valve.

[fatty]

I think you probably could. Problem is that mild steel doesn't hold its shape very well when exposed to heat/cooling cycles. Then you will end up with exhaust leaks and potentially metal chunks through your turbo.

[Remps]

Do you mean the flange or the flapper and hinge? I was thinking stainless for the flapper. An EBay t3/t4 adapter might be an option, or install into the turbine housing volute itself, eliminating the flange. (With a t4 manifold)

[fatty]

The flange. Seems like SDX or someone was having issues until they switched to some special kind of steel.

[Remps]

I think the issue with the sdx flange was the bolts or screws holding the flapper to the hinge on the early models. The later ones were welded, or the bolts were welded iirc. That fmw62/68/.83 t4 is tempting at 800 bucks, but it will never spool like a .85 t3 without a spool flange. It would definitely spool faster with a flange, and flow a little more up top.

[fatty]

You're probably right about that. If you make one and it works good I'd pay you to make me one.

[Remps]

Well.. I think I just talked a friend into building me a t3/t4 spool valve for the cost of material. Should know in the next few days.

[Remps]

Any thoughts on using 321 stainless? Looks to have better high temp properties than 304.

[Remps]

Seeing as I have 4 12 valves with 4 ex manifolds, I plan on pulling one of them to experiment with. Going to see about installing an inconel diverter into the exhaust manifold outlet. No idea whether it will be possible or not, can't really say until I am eyeballing it. And if I end up botching it, well, I will have an undivided manifold to use with a regular spool valve. If it does work, I will probably go with a BW T3 turbo later down the road. Meanwhile, maybe an hx35 could make boost at 1k rpm?

[fatty]

If you do get one built and it works good, I want to be first in line to buy one. I like the top of my T4 turbo more than I like a quicker spooling turbo. If I could have both though, then I'd be real happy.

[Remps]

I am hoping I can build a diverter in place of a section of the divider of the exhaust manifold. Hinge pin would be on the end of the flapper. Ideally would have no leakage between front and rear cylinders in the full open position, and still have true twin scroll capability. Also the hinge pin and flapper aren't disrupting flow (as much) sitting in the middle of the volute. And also a better 40-50 degree flow angle for the rear to front exhaust flow diversion, instead of the back three firing against a closed valve and having to make a 90 degree turn and merge with the front 3's exhaust flow. If it works, a diverter in a T4 manifold would be something to try.