Turbo freak out

[Richard Hillsid]

I have a bad exhaust problem.
Problem is that the exhaust port of the turbo is 8 inches above WL at rest,
Blown 3 last summer.
Water in turbo during extensive reverse operations.
Have a diesel turbo 160 hp fitted very low on a 18 foot Rib.
Exhaust is wet and comes through transom, below waterline at rest.
I can move exhaust tip higher but cant move it to side of boat, any freaky design appreciated, and the extreme baking up events will continue.

I’m a sailboat man, you know blow boats, and excessive power is new to me.

[bilgeboy]

Can you put a riser on the exhaust immediately after the turbo?

The point of these things is to prevent turbo damage from water. Usually a wet exhuast injects raw water into the exhaust gas after the turbo, and a rise in the exhaust prevents the injected water from flowing into the engine (or into the turbo in equipped boats).

I've built one out of stainless, and its not hard to do, can be fun and rewarding. Turbos are not cheap! When my turbo went, I diagnosed a faulty stock cast iron riser. I built a dry rise that injects raw water immediately after the rise.

Whats your "overhead" clearance? I will find a pic to upload of what I have built.

Mike

[bilgeboy]

Here's a pic....I hope it works...





The circle with 4 holes mates to the turbo, then the rise, then into 3.5 " pipe that fits 4" muffler hose. The water injection occurs at the bottom, and a small nipple to the stuffing box.

Multiple areas where the design could be improved, but this was my first project. I have redesigned for the better. All 316 stainless.

Let me know if this might help you out.

Mike

[Richard Hillsid]

That’s a nice peace of work, not freaky at all. Thanks for the image.

There is 6” upward clearance; I think I will try to use your design, nice touch the stuffing box feed.
I will also lift the transom exhaust point by incorporating a swans neck, though I don’t think the pressure of water reversing should push any water past the elbow in your design, im not familiar how sudden pressure changes in exhaust gases work, I imagine if engine is gut back and stern wake hits hard there would be a bigger change of back wash than when reversing full speed as the engine is pushing exhaust out when reversing.

So: Inboard the ricer, outboard a drain hole where current through hull is then a swan’s neck. All 101,6 mm. (about 4") stainles tube.

How about a spring loaded flap at the tip, or would that put undo pressure on the turbo if the stern wake closes it with throttle pulled back?