Thru transom exhaust

[glenng]

I'd like to run the exhaust out the transom on a sport 40 boat. The pipes stinger Inside diameter is .422". What inside diameter would you reccomend from the stinger to the transom? Working in a tight area. Would .500"-.532" be O.K.?

Thanks,

Glenn

 

[Hydro Junkie]

I'm looking at doing the same thing with a Muck scale 7474 hull. I know the extension needs to be larger to prevent the pipe from causing excessive back pressure. I'm like you, however, wondering how much bigger to minimize the problem

 

[glenng]

I'm looking at doing the same thing with a Muck scale 7474 hull. I know the extension needs to be larger to prevent the pipe from causing excessive back pressure. I'm like you, however, wondering how much bigger to minimize the problem

H.J., I know for a FACT .750" works well on scale(.67 Green Head motors). Send me your E-mail in a P.M. and I'll send you a pic.

Glenn

 

[Hydro Junkie]

I'm looking at doing the same thing with a Muck scale 7474 hull. I know the extension needs to be larger to prevent the pipe from causing excessive back pressure. I'm like you, however, wondering how much bigger to minimize the problem

H.J., I know for a FACT .750" works well on scale(.67 Green Head motors). Send me your E-mail in a P.M. and I'll send you a pic.

Glenn

.750 inside or outside? I got my pipe from Allrc, just don't know which one it is or what the affect of extending the stinger will be. I'm looking at having to go 3 to 5" to get through the transom due to a forward engine placement. Guess that's what I get for buying a used glass hull

 

[glenng]

I'm looking at doing the same thing with a Muck scale 7474 hull. I know the extension needs to be larger to prevent the pipe from causing excessive back pressure. I'm like you, however, wondering how much bigger to minimize the problem

H.J., I know for a FACT .750" works well on scale(.67 Green Head motors). Send me your E-mail in a P.M. and I'll send you a pic.

Glenn

.750 inside or outside? I got my pipe from Allrc, just don't know which one it is or what the affect of extending the stinger will be. I'm looking at having to go 3 to 5" to get through the transom due to a forward engine placement. Guess that's what I get for buying a used glass hull

Inside Diameter Bud.

 

[P THOMAS]

Here is my extension tube for my 40 roundnose it is 1/2 inch thin wall K&S aluminum tube.

No problem with back pressure or getting hot.

 

[glenng]

Here is my extension tube for my 40 roundnose it is 1/2 inch thin wall K&S aluminum tube.

No problem with back pressure or getting hot.

Thanks very much Phil!!!

Glenn

 

[Hydro Junkie]

Phil, how tight of fit is there between the aluminum and the tuned pipe? I want to avoid the possiblity of radio interference

 

[Don Ferrette]

I'm looking at doing the same thing with a Muck scale 7474 hull. I know the extension needs to be larger to prevent the pipe from causing excessive back pressure. I'm like you, however, wondering how much bigger to minimize the problem

H.J., I know for a FACT .750" works well on scale(.67 Green Head motors). Send me your E-mail in a P.M. and I'll send you a pic.

Glenn

.750 inside or outside? I got my pipe from Allrc, just don't know which one it is or what the affect of extending the stinger will be. I'm looking at having to go 3 to 5" to get through the transom due to a forward engine placement. Guess that's what I get for buying a used glass hull

Inside Diameter Bud.

The personal rule I have always followed for thru transom outlet is add minimum 50% to the stinger i.d. For example a .450" i.d. stinger would get at least a .675" i.d. tubing leading to the transom.

 

[glenng]

I'm looking at doing the same thing with a Muck scale 7474 hull. I know the extension needs to be larger to prevent the pipe from causing excessive back pressure. I'm like you, however, wondering how much bigger to minimize the problem

H.J., I know for a FACT .750" works well on scale(.67 Green Head motors). Send me your E-mail in a P.M. and I'll send you a pic.

Glenn

.750 inside or outside? I got my pipe from Allrc, just don't know which one it is or what the affect of extending the stinger will be. I'm looking at having to go 3 to 5" to get through the transom due to a forward engine placement. Guess that's what I get for buying a used glass hull

Inside Diameter Bud.

The personal rule I have always followed for thru transom outlet is add minimum 50% to the stinger i.d. For example a .450" i.d. stinger would get at least a .675" i.d. tubing leading to the transom.

Between Don and Phils reply I got a bit confused so I dug out the old high school algebra book and started checking volume and found a 9/16 bore (.562") has 1.77 times the volume of my .422" stinger-I think I'll try this first as space is limited going over the strut. Can't argue with Don's theory-the U-25 he sold me is the fastest boat I have.

Thanks Guys,

Glenn

 

[glenng]

I'm looking at doing the same thing with a Muck scale 7474 hull. I know the extension needs to be larger to prevent the pipe from causing excessive back pressure. I'm like you, however, wondering how much bigger to minimize the problem

H.J., I know for a FACT .750" works well on scale(.67 Green Head motors). Send me your E-mail in a P.M. and I'll send you a pic.

Glenn

.750 inside or outside? I got my pipe from Allrc, just don't know which one it is or what the affect of extending the stinger will be. I'm looking at having to go 3 to 5" to get through the transom due to a forward engine placement. Guess that's what I get for buying a used glass hull

Inside Diameter Bud.

The personal rule I have always followed for thru transom outlet is add minimum 50% to the stinger i.d. For example a .450" i.d. stinger would get at least a .675" i.d. tubing leading to the transom.

Between Don and Phils reply I got a bit confused so I dug out the old high school algebra book and started checking volume and found a 9/16 bore (.562") has 1.77 times the volume of my .422" stinger-I think I'll try this first as space is limited going over the strut. Can't argue with Don's theory-the U-25 he sold me is the fastest boat I have.

Thanks Guys,

Glenn

Formula for Volume of a cylinder is- Volume= 3.1416 X radius X radius X height.

 

[TimothyJones]

We use pie at work alot, it sucks though when its in your face

Tim

I'm looking at doing the same thing with a Muck scale 7474 hull. I know the extension needs to be larger to prevent the pipe from causing excessive back pressure. I'm like you, however, wondering how much bigger to minimize the problem

H.J., I know for a FACT .750" works well on scale(.67 Green Head motors). Send me your E-mail in a P.M. and I'll send you a pic.

Glenn

.750 inside or outside? I got my pipe from Allrc, just don't know which one it is or what the affect of extending the stinger will be. I'm looking at having to go 3 to 5" to get through the transom due to a forward engine placement. Guess that's what I get for buying a used glass hull

Inside Diameter Bud.

The personal rule I have always followed for thru transom outlet is add minimum 50% to the stinger i.d. For example a .450" i.d. stinger would get at least a .675" i.d. tubing leading to the transom.

Between Don and Phils reply I got a bit confused so I dug out the old high school algebra book and started checking volume and found a 9/16 bore (.562") has 1.77 times the volume of my .422" stinger-I think I'll try this first as space is limited going over the strut. Can't argue with Don's theory-the U-25 he sold me is the fastest boat I have.

Thanks Guys,

Glenn

Formula for Volume of a cylinder is- Volume= 3.1416 X radius X radius X height.

 

[glenng]

Thanks Tim, I've got 11 months to go before I retire-kinda expecting a pie in the face instead of a gold watch.

Glenn

 

[Bill Gibson]

Glenn...and to think i thought we all just played with lil toy boats!!! too deep for my SIMPLE mind! :lol:

 

[glenng]

Glenn...and to think i thought we all just played with lil toy boats!!!

too deep for my SIMPLE mind!

That's all we are doing here Bill. Sent a couple pics to your E-mail. .562" I.D. from stinger to transom. Now get back to work on the Pay&Pak

.

Glenn