Okay, every thread I've read says that internal wastegates are shitty because they can't hold lots of boost and they creep and all that. But what about something like a SCM-3427E or SCM-5027E or other turbo designed for internal gating and at the same time high horsepower? Has anyone on here had experience with an internal wastegate set to hold 20+ psi? The things about the SCM's that make me want to go that route are that they are high quality turbos, my hood will be safe from an external gate, and I'll be soon running a 14b with HF manifold setup; the SCM's have the same turbine inlet as any other DSM turbo, and from the pics I've seen and my own assumptions I think the downpipe side looks to be the same as my 14b's, which will have a full 3" downpipe off the turbine housing. All I really want to know is, is it a worthwhile venture to purchase an SCM and use my HF/DSM manifold?

 

I have sold plenty of the SCM turbo with internally gated. None of them have had any trouble with keeping the boost low. Comon cause for boost creep is the surface area of the WG hole is too small. Back in the days (1995) when I ran 14B, I ported the WG hole larger to keep the boost down. The Precision SCM have larger opening since the turbo is designed to push more hp than stock DSM turbo.

Common rule of thumb is to boost about 1 bar past the WG spring. So if your spring is 14 psi, I wouldn't boost pass 21 psi. All Precision Internal WG are heavy duty unlike the stock DSM, so they're a lot more stable in holding boost.

stan

 

Bump, any more?

 

Hey this ****'s old, but it's mine, so bump. Anyone use an SCM lately?

 

Okay I've looked on some DSM forums and those guys have said their SCM's have blown after 500 miles in a few cases, many others after a few thousand. Like the seals blow out on them or something. Then some guy said that was just for older versiona and the design has been fixed. Anyway... bump.