27 H&H QSB 5.9 480 Exhaust Setup and Install

BillD

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25 Terry Jason with Cummins 370 power
I've started a new thread for the members here that want to follow along with the exhaust system mockup, fabrication and install.

This 27 H&H had a Cummins 6BT 210 with a 5" exhaust and a 5" Centek round muffler.

I could have kept the 5" exhaust with the QSB 5.9 480 by modifying the the existing 5" round muffler in the boat.
Drilling 3" holes in the front and back baffles of the muffler to accomodate the extra raw water flow of the of the 480 vs the 210.
The old muffler had to come out to do the modifications.
I decided to go with a new 6" exhaust to mitigate any modifications whatsoever and I don't want to cut install corners with the extra hp.

I will answer any questions as best I can on the how's and why's of my installation.

Regards, Bill D

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BillD

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25 Terry Jason with Cummins 370 power
the spillover height of the turbo on the new QSB 5.9 is 7" above the waterline. Not enough height to protect the engine from drinking salt water thru the turbo.
The engine will need an additional 8-10 inches in spillover height and a dry riser will be fabricated.

The last two pictures are the the dry riser install on the 6BTA 370 in the 25 T Jason.
The new riser mixer for the QSB 5.9 will look very similar

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MC35

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Looks Good! I have a 6" SS transom exhaust flange if your interested?
 

ARC

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The bottom of the riser is the important #. If you are in the water add a short piece of hose to any water intake lower the hose till water starts to spill over. That’s the true water .
 

xbskt

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the spillover height of the turbo on the new QSB 5.9 is 7" above the waterline. Not enough height to protect the engine from drinking salt water thru the turbo.
The engine will need an additional 8-10 inches in spillover height and a dry riser will be fabricated.

The last two pictures are the the dry riser install on the 6BTA 370 in the 25 T Jason.
The new riser mixer for the QSB 5.9 will look very similar

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You have 7 inches spillover now and you say you need an additional 8 to 10?
 

BillD

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25 Terry Jason with Cummins 370 power
You have 7 inches spillover now and you say you need an additional 8 to 10?
No doubt xbskt !
Cummins install spec is minimum 12"....the more height the better !!

I have 17 inches to the spillover point on the 6BTA 370 in the 25 T Jason with no surge tube (blue tint pics, shrink wrap)

Tomorrow I plan on mocking up the the rough measurements using the 6" Centek surge tube. The last two pictures

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