Any Reason I Shouldn't ...

Any I reason I shouldn't, upon beholding this turbo ...

knock down these ridges and make them smooth?

Then I could fabricate my own manifold.

I don't see the harm in smoothing out the transition in the inlet to the exhaust housing, but I wouldn't touch the areas around either wheel.

Exhaust side you can port ,smooth out whatever.Compressor Inlet side I would not touch with a ten foot pole.

I wouldn't bother. If it had a well matched and set up header/collector combination, then maybe.

scottdownsouth wrote: Exhaust side you can port ,smooth out whatever.Compressor Inlet side I would not touch with a ten foot pole.

I don't doubt you, but why?

Knurled wrote: I wouldn't bother. If it had a well matched and set up header/collector combination, then maybe.

It will be matched.

Is this sort of thing a tiny gain or easy to mess up?

By "matched" I mean that the runner inside diameters and lengths are optimized to maintain velocity and there are minimal bends and the collector has the optimal angle of collection.

Until it's set up to that point, a turbo manifold is just a pressurized box that goes into the turbo. And, really, if you were at that point, you'd probably be using a V-band turbine housing anyway.

I just left a job where we had a cold turbo tester. I played with it alot. Nine out of ten times messing with the inlet of the compressor side only made more noise. Think jet aircraft engine. It was made that way for a reason.

I suspect those spots in the exhaust side are to potentially strengthen the casting. So if you do remove those, go slowly and gently and blend them well. Then make sure the turbo is braced to the engine block to reduce the chances of things failing.

scottdownsouth wrote: I just left a job where we had a cold turbo tester. I played with it alot. Nine out of ten times messing with the inlet of the compressor side only made more noise. Think jet aircraft engine. It was made that way for a reason.

Alright, you convinced me. No effing with the intake side.

I just checked it and the ridges, which I'd assumed were just crappy castings, appear to be designed.

turboswede wrote: I suspect those spots in the exhaust side are to potentially strengthen the casting. So if you do remove those, go slowly and gently and blend them well. Then make sure the turbo is braced to the engine block to reduce the chances of things failing.

That I don't doubt at all. This tubo was designed to hang unbraced for half a million miles from the side of an ancient 2.9L deisel 4 banger. The Hyundai Mitsubishi J series was not what you'd call smooth. The turbo's very stout structurally.

Would I be right to assume my twincam 1.5L alpha wouldn't try so hard to shake it into tiny pieces of dust?

I thought turbo's from diesels were missing a seal that's needed when run on a gas engine. Something to do with the gas engine being throttled and the diesel not?

Tell that to all the Turbo Dodge/SRT/Honda/DSM guys running Holsets.