hoodoo

I've talked to him a few times, probably a good source. But if I remember right they will need a set to copy.
Not sure if they meant they could work off a stock manifold or if they actually need a water cooled set to copy. I think the first set would be expensive, then less and less as more get built. At the time I thought he did cast but he told me the other day that they only weld.
They are pretty easy to cut and fit but hard to weld without warping.
Need to use an old block and heads for a jig.

Biggus

Just popped into this thread, have not read much but I am very familiar with MDS in Sweden having been involved in countless MDS/Duramax/Konrad packages. If you are looking for a pair of exhust manifolds, you might want to shoot an email direct to MDS http://www.marinedieseleurope.com/en...es/vgt-series/ I'm sure replacement parts can be purchased.

kidturbo

Thanks Biggus. I ask both Sweden and TX contacts a couple years ago, they said only available as replacement to existing customers. This may have changed, so would like to hear what they tell someone else now.

One reason I've been focused on building SS headers with a universal Vband attachment, there is really no need to stick with the stock GM turbo location in a marine build. GM placed it there out of convenience to clear the hood and fit multiple vehicles. If keeping the with stock VNT turbo and power levels, then up pipes will need to be as shown above. However if you change to a T4 turbo design, then why not move everything out of the intake valley?

[ATTACH=CONFIG]555828[/ATTACH] [ATTACH=CONFIG]555829[/ATTACH] [ATTACH=CONFIG]555830[/ATTACH] [ATTACH=CONFIG]555831[/ATTACH] [ATTACH=CONFIG]555832[/ATTACH] [ATTACH=CONFIG]555833[/ATTACH]

The acceptation here may be when replacing the engine in a Bravo1 setup. Room between turbo and transom becomes an issue. As you can see below, routing the exhaust to factory thru-haul locations can be tight. This exhaust setup has a short 3" dia by 8" long inside tube dumping exhaust into the 4" dia outside tube which Y pipes off to each thru-haul with flappers. All engine cooling water exiting the boat sprays into the 4" pipe right back of the turbo, off a manifold of 3x3/4" tubes. The inside 3" tube keeps everything flowing in the right direction, and stops water from making it's way back into the turbo.

[ATTACH=CONFIG]555824[/ATTACH] [ATTACH=CONFIG]555826[/ATTACH] [ATTACH=CONFIG]555827[/ATTACH]

kidturbo

I've been slacking on updates, but for good reasons. Actually started on a nice twin engine conversion with another forum member. So have been trying to put everything together to get things moving. Once it gets rolling I will start a new thread, but for now lets just say it's 40' and will be spinning WMD's and was previously twin 900's with 6's...

[ATTACH=CONFIG]556532[/ATTACH][ATTACH=CONFIG]556535[/ATTACH]

kidturbo

Now that we have our engine together and ready to drop in the boat, we need to design the cooling system layout. The choices here will ultimately depend on how and where you plan to use the boat.. The easiest and most economical design is an open loop cooling setup, and what the first Duramax boat relied on. The only down side to this setup is lack of heat exchanger, meaning no long term salt water usage. I ran mine in the gulf a couple times, flushed it thoroughly with salt-away after each use. But keep in mind you have aluminum heads, end covers, water pump, and a water cooled turbo system that were never designed for that harsh environment. So let look at our cooling system parts one by one.

Starting out with the seawater pump options. The Merc 46-807151A9 with serpentine belt pulley below will work for most installations. This is the same impeller based pump found on a majority of small block and big block GM based engine packages. In an open loop setup, it will supply enough water to cool all the Duramax components up to about 650 hp. I designed a simple mounting bracket that attaches this pump to the front of the block in the mounting location show below. Bang for the buck this set does the trick fine.

[ATTACH=CONFIG]556631[/ATTACH] [ATTACH=CONFIG]556629[/ATTACH] [ATTACH=CONFIG]556630[/ATTACH]

For added volume performance upgraded, the Hardin 1075 replacement pump also fits in this same location, This one allows you to easily split the charge cooler from engine cooling supplies.

[ATTACH=CONFIG]556628[/ATTACH] [ATTACH=CONFIG]556632[/ATTACH]

Which ever setup you go with, be certain it has sufficient inlet supply line and good quality sea strainer. A flush out port and shut off valve are also worth plumbing in there before the pump.

DeanMiller412

I came across your thread my Father Bought a new cheetah deck boat 26' fast cat and put a duramax in it. He has built his own headers and all a very clean build. running 2200 rpm it runs 82 mph with imco scx drive with 32" prop If i remember correctly here is a link to it via youtube it was in performance boat mag as well.

https://youtu.be/SQdzUaWqPoI

if you want to know more or anything hit me up and I will get you in contact with my dad.
Good luck.

kidturbo

That's a cool build also. I believe we've spoken before, several years back when I was working on the Warlock.

I've wondered how the Cheetah and your dad is doing. Haven't seen anything new in a while. Fell free to post some updates like hours logged so far, issues and such.

DeanMiller412

as of now he has just started working on it again he had prostate cancer and went through treatment but now he is up and going again. since he has built his own headers, when I spoke to him last night he was going through a later version wire harness to run. He is trying to get it back up and running for 4th of July to run it in Havasu. He picked up a 35 foot advantage on memorial weekend with twin 502's and black hawk drives it was a steal of a deal. ill try to get some pics and info of hours run next time i go to Havasu to work on my boat project.

kidturbo

Once again apologies for falling behind on these postings. Been busy sourcing parts for an actual marinization project I'm working on. One of these parts fits with our next topic here, air charge coolers also known as an after cooler.

Biggest difference between an automotive setup and a marine setup is how we cool charged air, or boosted air. In a truck the charge air goes from the turbo to a big air to air exchanger mounted in front of the radiator then to the main intake. Reason they are so big, thermal efficiency on these air to air exchanger is very poor. However a water to air charge cooler can easily obtain 80-95% thermal efficiency when sized and supplied properly.

First thing you need to know, the charge cooler should be first in line off the sea water pump. When using a single stage pump, I run all the water to the cooler before even adding a pressure bypass. The outlet air temp of the turbo can exceed 450F under heavy load. We need to get this air into the sub or low 100's before feeding it into the engine. While there is plenty of cheap aluminum charge coolers on the market, pay close attention to the CFM and water flow ratings. Better to buy a good unit the first time than find out it can't do the job after you've plumbed it all in.

Popular on Volvo and Yanmar engines, these double pass breadbox style coolers are proven trouble free units that typically mount on the engine. With proper water flow [40gpm] they should work fine on a stock 6.6L Duramax. I wouldn't push them much above stock power levels though.

[ATTACH=CONFIG]557174[/ATTACH]
Specification: Double Pass Air, Single Pass Water, In Production Since 1991 O.E.M. Peninsular 6.5 GMC 300 HP @ 3400 RPM Air Flow 500-600 C.F.M. Air Temperature 'In' 187' F Water Temperature 'In' 80' F Water Flow 40 G.P.M. Air Pressure +15 (Hg) The 3800 would achieve: Air Temperature 'Out' 90' F Water Temperature 'Out' 82' F Air Pressure Loss 2 ("Hg) The Thermal Efficiency is 90.6 %

[ATTACH=CONFIG]557175[/ATTACH][ATTACH=CONFIG]557176[/ATTACH]

Another unit I've tested with are the Frozen Boost coolers. Their largest units are actually very affordable, and capable of handling 1000hp diesel needs. Size does make them a bit awkward to mount on an engine, but each application is different. They are also an aluminum core, so using in salt water for extended periods without flushing will likely limit the life expectancy.

[ATTACH=CONFIG]557172[/ATTACH][ATTACH=CONFIG]557173[/ATTACH]

Next thing to consider is mounting locations. If you move the OEM turbo, or are going for that clean OEM look, you'll likely be tempted to place the charge cooler above the engine. I have some experience with this setup that tells me not to do it. When I first purchased the PPE boat the cooler was on top of the engine and turbo as shown above. While it looked nice and clean, several cylinder walls showed signs of etching from water setting on top the pistons when I tore it down. I felt this was most likely due to condensation out of the charge cooler running down into cylinders after shutdown. While not an issue when the engine is running, heat soak after shut down could cause water droplets to form and drain directly into the main intake runners. I moved my cooler to front of the engine to insure it couldn't happen after the rebuild.

I'd much rather have a condensation puddle in the charge cooler mounted low, cause it gets blown into the engine where it's evaporated on start up. I know it's common on gas engines to place the coolers under the blower, but I can speak from experiences. My friend who recently removed his Frozen Boost charge cooler mounted above the transmission for servicing another issue, thought he had a core leak. He reported several cups of water drained out of the charge tube when he removed the clamps. After pressure testing the cooler, it was all from condensation...

[ATTACH=CONFIG]557177[/ATTACH][ATTACH=CONFIG]557178[/ATTACH]

One design that took this issue into consideration was the Banks Marine intake which I recently purchased a pair of. While they mount directly on top of the head, Banks used an up flow design that puts the inlet below the cooler core and the intake runners above. According to his engineers, this condensation issue was his reason for this design. While it has a great design and a cupronickel core that can withstand harsh salt water environment, it does require 80gpm of water flow to function properly. That's more than a single stage Merc pump is rated for.. So it will take some heavy duty plumbing to feed this thing with the 900hp engines it will be cooling.

While doing some research on water flow and pipe size, I found a cool calculator that takes orifice sizes and pressures then gives a maximum GPM flow rate possible. Figured I should post these values here so everyone can use it when designing the rest of our cooling system layout.

.50" Dia @ 20psi = 23.31GPM
.50" Dia @ 30psi = 28.55GPM
.50" Dia @ 40psi = 32.97GPM

.75" Dia @ 20psi = 52.45GPM
.75" Dia @ 30psi = 64.24GPM
.75" Dia @ 40psi = 74.18GPM

1" Dia @ 20psi = 93.25GPM
1" Dia @ 30psi = 114.21GPM
1" Dia @ 40psi = 131.88GPM

1.25" Dia @ 20psi = 145.71GPM
1.25" Dia @ 30psi = 178.46GPM
1.25" Dia @ 40psi = 206.07GPM

1.50" Dia @ 20psi = 209.83GPM
1.50" Dia @ 30psi = 256.99GPM
1.50" Dia @ 40psi = 296.75GPM


Also here are some links on water to air charge cooling for your reading pleasure.

Banks design testing of the intake above.

Dragzine tech article on charge coolers.

UK provider of marine coolers.

pstorti

That core in the last picture looks just like the core from my Yanmar 6LP after cooler. But the airflow in mine passes through the core twice, from the turbo through the core, around the back of the core, and then through the core again into the intake. The second pass of air through the core is actually on the side that water enters the core. There are fuel and power steering coolers in front of my after coolers though. I had wondered about modifying the engines to add larger after coolers but I don't think they make enough HP to warrant the effort.