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31' copeland race cat

Old 09-16-2019, 04:29 PM
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Default 31' copeland race cat

I am restoring/building an old popeyes race cat. Ive got kaama surface drives and twin 454 mercs. I wanna do something one off just have some technical questions that are above my mechanic abilities. Im looking at twin turbocharging both motors. The engine bay is wide open so space is not an issue. I have plenty of ventilation so im not that concerned with heat. The issue ive been googling and cant seem to get a good answer is how to get passed the water/exhaust coming out of the block and into the manifolds and risers than out of the exhaust. Water in a turbo is all bad. Ive been reading about dry exhaust but still doesnt get me passed the water coming out of the block. Any help? I plan on doing this all myself. Not looking for 50k set up. Im not rich. Lol thanks in advance!
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Old 09-16-2019, 07:04 PM
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I saw this listed

https://dallas.craigslist.org/sdf/bp...962219014.html
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Old 10-11-2019, 11:37 AM
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That looks like a good deal! Gale Banks setup; either "like" or actually a version of the Mercruiser 475 package. You can see how the water goes through the turbo cooling housing, and then back into the tailpipes. The water-cooled turbo covers worked very well at keeping heat to a reasonable level. The Banks setup also has a unique draw-through plenum with poppet valves under the carb. that allowed for easy starting and idling. Pretty ingenious and worked really well.

We had a 38 KV Scarab with similar package and made an easy 675 HP with a few simple mods. Wish I had it today, knowing what I do about turbocharging. Boat was 11,000 # and would cruise all day at 55 MPH. Topped out at about 75.

Let's see some pix of the cat!!!

JB
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Old 10-15-2019, 12:15 PM
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I see he has dropped the price both motors 4k

https://dallas.craigslist.org/sdf/bp...998174499.html
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Old 11-16-2019, 07:19 PM
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If you don't have a decent amount of experience in tuning or playing with a turbo motor, a boat is a poor place to learn. If you plan to enjoy turbocharged marine motors, you need a buddy who is good at this and you need to plan on spending money for all of the gauges and stuff you'll need to keep from melting one. Gauges with warning lights are available, OR you can have a slew of warning lights external to your gauges.

As far as exhaust stuff, all you need is to determine where you want to mount your turbos. towards the front of the motors - towards the rear of the motors - in the center.

Most manifolds are center riser manifolds, which will put the turbo exhaust snail about midway back (the remainder of the turbo will be towards the front, and you can end up with the intake horns slightly behind the front of the motors.
You'll want to decide whether to run cast manifolds or stainless headers. The headers will already come with water outlet bungs at the riser flange, so you won't have to modify them there. Manifolds that are designed to pass cooling water from the jackets to the risers will need adapter plates to dump the water thru a port before the turbo. Water cooled turbos are almost a necessity in an engine compartment, although I don't guess anybody is going to MAKE you run them. They are advised though.

Water routing will go from a pump or pickup source, thru a debris strainer, into the exhaust jackets, out of the exhaust jackets and either overboard or into the tailpipes and out the boat. The exhaust heat in a turbo setup is WAY more than you'd expect, so the exhaust needs its own water source. Using the water that normally comes thru the block, trans cooler, oil cooler is not sufficient for a turbo exhaust. You'll need more.

If it were mine, I would make sure my thru hull pickup was large enough, I would make sure my strainer was rated for enough flow, and I would use a sea water pump to feed the engine and coolers, and then dump that water into the turbocharger cooling jacket and then discharge it out of the boat (in a pisser that you can see from the driver's seat). I would pull from a separate circuit thru another sea pump into (if you have one) the intercooler, and then into the exhaust manifolds, then into the tailpipes. you can also use water jacketed tailpipes and introduce water into the exhaust stream way down from the turbos.

Exhaust heat is hard on stainless headers. You'll probably end up cracking them a bunch of times. Good old cast iron exhaust manifolds may be your best bet if you plan on keeping hp under 800. GLM or stockers may be the most durable. You'll need that adapter plate I was talking about to dump the water out at the turbo flange.

M
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Old 11-19-2019, 11:38 AM
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Mcollinstn thanks for all the help. I have a buddy whos great with turbos. And a lot of the stuff i already have from previous builds. The boat has 454s now. Im contemplating on running ls motors. Selling the big blocks and running either s475s or twin 68mms. Ive been reading up. Heat seams to be the biggest issues. My engine compartment is well ventilated. They say water can suck back up into the motor so why not just run a heat exchanger and intercooler? Thoughts? Or just do a blow thru system on my 454s with a tuned carb? My velvets and kaamas will handle the power of either im sure
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