Pachanga 22 exhaust question
07-01-2016, 08:54 PM
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Pachanga 22 exhaust question
I have a 90 pachanga 22 with a 7.4 bravo 1. I have removed the water boxes and am trying to route the exhaust so that it will drain properly.
I am trying to use the factory 90 out of riser to pipe to another 90 and out of the transom. I am finding that where it comes thru the transom from factory is very high and am having trouble getting the downward slope I would like.
I am wondering what you would consider a minimum slope. From the last 90 and out the transom is a very good slope but from the riser to that last 90 is my worry. I realize i have to be cautious coming off plane, reversing and etc. (I may add inline shutters for piece of mind) If the boat is not perfectly level im worried what may hang up in the 1.5 foot horizontal section may not drain. Is this something to worry about or should I be good to go.
Its not water coming back through the exhaust thats my concern its water not 100% drained in the nearly horizontal section when boat is not level that im second guessing.
Any insight would be greatly appreciated.
I am trying to use the factory 90 out of riser to pipe to another 90 and out of the transom. I am finding that where it comes thru the transom from factory is very high and am having trouble getting the downward slope I would like.
I am wondering what you would consider a minimum slope. From the last 90 and out the transom is a very good slope but from the riser to that last 90 is my worry. I realize i have to be cautious coming off plane, reversing and etc. (I may add inline shutters for piece of mind) If the boat is not perfectly level im worried what may hang up in the 1.5 foot horizontal section may not drain. Is this something to worry about or should I be good to go.
Its not water coming back through the exhaust thats my concern its water not 100% drained in the nearly horizontal section when boat is not level that im second guessing.
Any insight would be greatly appreciated.
07-01-2016, 09:03 PM
#2
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[quote]Originally Posted by SB
If you don't have an angle finder, here is a good chart that shows how much drop in inches per foot equals certain degrees.
Slope Conversion
3° = 5/8 in./ft.
6° = 1¼ in./ft.
7° = 1‑7/16 in./ft. .
10° = 2‑1/8 in./ft. .
12° = 2½ in./ft.
14° = 2‑15/16 in./ft. .
19° = 4‑1/8 in./ft.
Min rate of fall is 6* for all Mercruiser 'black' sterndrives other than the 8.1L (496) which min is 9*.
The first 18 in. (457 mm) of exhaust hose should drop the specified minimum relative to
horizontal. Thereafter, 3° of drop or 1/2 in. (13 mm) of drop per 12 in. (305 mm) relative to
horizontal is a MINIMUM requirement for the rest of the exhaust system.
• Exhaust hoses should not restrict the flow of discharge water from the elbow. The exhaust
hose cannot be bent more than 5° relative to the exhaust elbow outlet as a hot spot
in the hose will occur and burn through.[/qote]
[quote]Originally Posted by SB
If you don't have an angle finder, here is a good chart that shows how much drop in inches per foot equals certain degrees.
Slope Conversion
3° = 5/8 in./ft.
6° = 1¼ in./ft.
7° = 1‑7/16 in./ft. .
10° = 2‑1/8 in./ft. .
12° = 2½ in./ft.
14° = 2‑15/16 in./ft. .
19° = 4‑1/8 in./ft.
Min rate of fall is 6* for all Mercruiser 'black' sterndrives other than the 8.1L (496) which min is 9*.
The first 18 in. (457 mm) of exhaust hose should drop the specified minimum relative to
horizontal. Thereafter, 3° of drop or 1/2 in. (13 mm) of drop per 12 in. (305 mm) relative to
horizontal is a MINIMUM requirement for the rest of the exhaust system.
• Exhaust hoses should not restrict the flow of discharge water from the elbow. The exhaust
hose cannot be bent more than 5° relative to the exhaust elbow outlet as a hot spot
in the hose will occur and burn through.[/qote]
07-02-2016, 09:10 AM
#3
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Add 2 90 degree turns and add inline shutters you will be fine. There are several pics posted in the Sea Ray forums.
07-02-2016, 10:05 AM
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i have no shutters or flaps. i turn a 90 out of the riser. used staineless exhaust pipe over to the another 90 rubber boot connected directly to the factory tail pipe in the corner. ive never had a problem. i got my 90s that attach to the tail pipes at a big truck shop. they are meant for the the turbo inlet on them.
