Custom Exhaust Fabrication Questions

[Stephen Oliver]

As probably (not probably – definitely) the most knowledgeable bunch regarding exhaust design, I have some questions. 

I am looking at moving from the crappy std cummins elbows which I know are no inherently safe, however mine were replaced 4 years ago (and due to costs kept std) I know they have limited life left in them, so am designing a new set of ‘risers’ to get fabricated locally (shipping and exchange rate make this kind of thing out of my reach from SBmar.. but your parts are still good value 🙂 )

I have very limited headroom in the engine room so am limited with what I can do. With this in mind I wanted to mock up a design using 3d printed parts (printed to same size as off the shelf steel tubes and bends) so a few questions:-

Stainless Tube / Bends – I can get 1.6mm thickness or schedule 10 at 3.02mm thickness – which would be prefered? 

I am thinking 304 (in the dry section) as its a bit more vibration resistant  and 4″ – does this sound reasonable.

Wet section (shower head) I’m thinking 316 for corrosion resistance.

Regarding the dry section When insulated – what sort of heat ends up externally – as this riser will be fairly close to timber floor beams – i’m concerned about charring.. as I know this dry section will be getting hot. I can get it ceramic coated to help.. just cant get a feel for how effective the blankets are over a period of time.

I think thats it for now. 

Thanks in advance

Steve 

Topic

[Luke Nelson]

Look up AHM fabrication. They did a set for me for a couple of Volvos. Def not worth the stuffing around for the cost.

[Tony Athens]

3.5″ PIPE measures 4″ OD (same as 4″ tube– smallest I’d use)

[Stephen Oliver]

Thanks Tony I did and now I know it was what I was looking at anyway (Weld els)

Agree on the hand picture.. 

Final question – Any thoughts on using 3 or 3.5″ pipe for the dry section? Could save me some space and get a bit more height.. 

Steve

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1969Roamer46

[Tony Athens]

Schedule 10 Weld Els 

Industry term describing 90’s and 45’s 

Play with it on GOOLGLE

[Tony Athens]

Dry Riser temps using a good heat wrap

Rob’s heat gun pics say it all–But the “HAND” is the key and eliminates any doubt.—-Thanks

[Stephen Oliver]

Tony

Thanks – I will do with measurements – once I can get to the boat as the walkway to our section collapsed 2 months ago and getting to the boat is hassle now.. I’m just getting prepped for doing the work over our winter.

I’m currently 3d printing the pipe sections (doing 45 deg segments so 2 make a full 90 deg) based on 4″ SH10 pipe so I can mock something up and know it fits… I’m hoping to get away with simple, maybe 3 90’s welded and then to the shower… Headroom is measured in Inches.. not feet! Possibly 9-10″ from turbo outlet centre on the stbd side and possibly 10-12″ on the Port side.. Its not going to be safe in your favourite terms.. but its going to be a hell of a lot better than it was with Std Elbows. Are there any options to use 3 or 3.5″ pipe for the dry section or is this too restrictive (6bta 330)

Never heard of WeldEls.. but now i have and now I know 🙂 Thanks… that is what I was looking at anyway. Thanks for the info on the insulation.

Rob – A picture paints a thousand words eh? Thanks – gives me some reassurance i’m not going to have to fireproof the timber 🙂

Steve

[Rob Schepis]

Some screenshots when I sea-trialed new dry risers with Seaboard ATP wraps.  This was at 2,400 rpms.

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Tony Athens, Stephen Oliver

[Tony Athens]

Post some really good pics of your current set up-No close-ups

Need to see what space you have to work with..

304 is fine for the dry side..   

Good insulation work fine-You do not need any coatings–Surface temps with the insulation we use is under 160F (cooler than many engines surfaces)

 

Working with “schedule 10 pipes sizes and weld-els” is usually way easier and less expensive than “tubing”. 

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Stephen Oliver

[Author]

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