Exhaust Tube Question

Designs for inboard or outboard power

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Jimbob
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Exhaust Tube Question

Postby Jimbob » Thu Jul 27, 2017 8:47 am

I have been thinking about using a fiberglass tube (vernatube) as part of my wet exhaust system. Just found out that I can get 4" stainless steel tubing with wall thickness of .065 (1/16") for about $13 per foot in Sacramento. Anyone see any problems with going with the stainless steel tubing?
Jim
Jim Neeley
Building a Barrelback in Sacramento, CA

PeterG
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Re: Exhaust Tube Question

Postby PeterG » Thu Jul 27, 2017 9:40 am

Like all things stainless, the answer is it depends: it is probably fine, but the alloy is important as some stainless steels don't react well to the acidity of the exhaust and others don't like seawater. If it's intended for boats or vehicle exhaust service it's should work great.
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Bill Edmundson
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Re: Exhaust Tube Question

Postby Bill Edmundson » Thu Jul 27, 2017 6:27 pm

SS-316 is good with salt water. I don't know about acid. When I worked I had metallurgist to ask. Ain't worth going back!

Bill
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kens
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Re: Exhaust Tube Question

Postby kens » Fri Jul 28, 2017 2:12 pm

409 grade is common and it is SS, but it does not hold up well.
I got 409 SS and I wish I had upgraded to 304 or 316.
Oak is over rated, everything about it takes extra time; then it warps, splits or checks !!! :roll:

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steveh41
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Re: Exhaust Tube Question

Postby steveh41 » Fri Jul 28, 2017 4:17 pm

Agree with above comments; wouldn't do it with anything less than 316 stainless, and you might consider taking a look at the mill test report to confirm it's as advertised.

Steve
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slug
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Re: Exhaust Tube Question

Postby slug » Fri Jul 28, 2017 4:33 pm

4" seems plenty large to me. I used 3" stainless on my 351 Windsor Ford......same as in the donor boat.

Doug

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Re: Exhaust Tube Question

Postby Ozzieboat » Sat Jul 29, 2017 5:39 am

Jimbob
I used 316L for the exhaust pipes on my Monaco. They run from the engine compartment and out through the transom. Flanges were welded on to the pipes which are then screwed through the transom. The boat is only operated in salt water as downunder we are not blessed with the beautiful lakes like you have. The stainless steel is still, after 4 years of use as new. My headers are also stainless steel (see hitekmarine.com.au) pipes are coupled using silicon turbocharger hose.

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Roberta
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Re: Exhaust Tube Question

Postby Roberta » Sat Jul 29, 2017 7:15 am

Here is the source I used for the Stainless elbows in the Torpedo. They also sell tubing and other accessories.

http://www.verociousmotorsports.com/Sho ... less-Steel

I used the polished 45 deg. elbows and hose to connect them. I also used Centex Ski boat mufflers to keep things a little quieter. Nice rumble at idle but less annoying at speeds.

Roberta :D
Attachments
exhaust system 013.JPG
exhaust system 006.JPG
Roberta "Queen of the Boat Builders"
Built Zip "Oliver IV", Super Spartan "Jimmy 70", and Torpedo "The Glen L".

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Jimbob
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Re: Exhaust Tube Question

Postby Jimbob » Tue Aug 01, 2017 10:10 am

Now the metal supplier now tells me that I can get the tubing in either .065 (1/16") or 1/8" wall thickness.
Do you all think that the .065 is adequate? Or should I go with the 1/8" wall thickness?
Your responses will be appreciated.
Jim
Jim Neeley
Building a Barrelback in Sacramento, CA

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Roberta
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Re: Exhaust Tube Question

Postby Roberta » Tue Aug 01, 2017 2:37 pm

I think the 0.125 wall SS tube will be very heavy and as I PMd you, I would stick with fiberglass, silicone tube, and mufflers. I attached some shots of my entire system and the mounts I fabricated to hold the piping. My mufflers only weight about 4 lbs ea. I think the SS tube will be very much heavier.

Roberta
Attachments
exhaust system done 005.JPG
exhaust system done 004.JPG
exhaust system done 002.JPG
Roberta "Queen of the Boat Builders"
Built Zip "Oliver IV", Super Spartan "Jimmy 70", and Torpedo "The Glen L".

Ozzieboat
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Re: Exhaust Tube Question

Postby Ozzieboat » Wed Aug 02, 2017 3:39 am

16 gauge (.050") would be ample. For interest 14 gauge (.063") X 3" would weigh approx. 2.5 lbs/ft and 4" approx. 3 lbs/ft. If you are using the log style headers and S/S tube you will most likely need mufflers. The "HiTek" manifolds that I mentioned in my previous post are an extractor type system and do muffle the noise a little, but it still has a bark during acceleration.

rleete
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Re: Exhaust Tube Question

Postby rleete » Wed Aug 02, 2017 6:29 am

The 1/8" tube is for turbo boost setups that see high (20 psi and up) intake pressures. Pure overkill for an exhaust application.

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Jimbob
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Re: Exhaust Tube Question

Postby Jimbob » Wed Aug 02, 2017 8:28 am

Thank you all! I feel confident I will be making all of the right decisions based on your input.
I never considered noise levels, but now I am looking at mufflers. Will probably copy Roberta's setup using the elbows for easier alignment.
Anybody have any good sources for mufflers? I need 4" input and output as my exhaust comes out of the engine at 4" and the exhaust tips are 4". I don't want to use reducers if possible.
Thanks again!
Jim
Jim Neeley
Building a Barrelback in Sacramento, CA

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steveh41
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Re: Exhaust Tube Question

Postby steveh41 » Wed Aug 02, 2017 8:33 am

Take a look at Centek, they should have what you need.

Steve
The longest journey begins with a single step… then repeat as necessary!

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Jimbob
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Re: Exhaust Tube Question

Postby Jimbob » Wed Aug 02, 2017 8:46 am

Found it!
Thanks to Roberta. She directed me to Marine Parts Source. They have the muffler that I need, and have the best price around.
Now I can relax and proceed to my next problem(s) to solve. :lol:
Jim

p.s. Ain't this forum great!
Jim Neeley
Building a Barrelback in Sacramento, CA


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