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I have an 07 Mastercraft X-45 Saltwater Series boat that is gong under the knife this winter. The current engine is a SBC (L31) that was somewhat underpowered (330hp) to begin with and after 500+ hours of pushing 8000+ lbs (4600 dry weight, 2250 ballast, 540 fuel, 400+ passengers, and 200+ gear - cooler, amps, speakers, wakeboards, anchors, cooler) through the water has taken its toll. The boat was also offered with an 8.1l engine (not sure on designation) and in later models with an LY6 as well. So I have sourced an LY6 from a junk yard (pic below) to get this thing at least into the 21st century (the L31 really didn't much use beyond 2000 in GM products). But what I knew from the hp and torque curves made me think this really wasn't likely to satisfy me either. So... I decided to pick up one of the Cadillac CTS-V take-off blowers and source the ZL1 lid and extras. I expect to remove the VVT setup and do a cam swap to include lifters, springs, and at minimum inconel exhaust valves.
Before anyone starts preaching about the internal differences between marine and automotive engines don't waste your breathe. As the Saltwater Series uses closed loop cooling (a heat exchanger acts as the radiator), the internal differences are negligible. I will be using the screened accessories to limit the chance of fire.
Anyway this is the engine as received.
As delivered.
This was the engine after about 2.5 hours. It is SOOOOOOOOOOOO much easier to work on this thing outside of the boat/car.
2.5 hours later...
Once I get a few more things off of the engine and get it onto the engine stand I will go ahead and begin assembling the supercharger as I wait for parts for the engine. Updates coming.
this going to be awesome! subscribed for this for sure.
ive always thought about swapping an ls into a 90's ski nautique or Malibu or something but don't have the extra cash laying around to go through with it lol
ive always thought about swapping an ls into a 90's ski nautique or Malibu or something but don't have the extra cash laying around to go through with it lol
A blown 6.0 in those would scream. Much lighter than this one.
Judging by your signature, this won't be your first six liter with a top mount supercharger, so I'm expecting good things from this.
That was one of the reasons I decided to tackle this. This one will be milder on the boost side and likely on the max rpms as well. Also, the fuel system on this one should be MUCH easier. The V1 fuel bucket was a PIA.
I did an iron 2005 5.3 with z06 cam, ported TB, truck intake, 91 octane tune in a '97 Ski Centurion making around 375hp I believe. It's much better than the carb'd 350 that came in it.
The most costly part of the conversion were the exhaust manifolds.
I used Marine Power units as they make them for the 6.2 setup and pretty much the only ones that I could find. If you need a set lmk. I have an account with them.
For my boat we machined a 2" thick spacer between the riser and the bottom part of the manifold for an 02 sensor bung to be drilled/tapped in there. A buddy of ours who is a tuner had to go out with us on the boat to tune as there is no way to simulate that load on land. You may think it's overkill... but you should maybe look into an aftermarket fuel management setup for it. I know that I paid nearly $1k in tunes over the years to clean this tune up after a few changes were made.
The CTSv blower is going to rock! I would'nt pulley it up too crazy since you have a cast crank and no piston oil squirters in your setup.
Also before you put the motor in the boat I would coat it with some hd paint as anything exposed will rust/corrode. Even bare aluminum cyl heads. Mine is also a sealed cooling system with heat exchanger. I have a fresh water pump where the p/s would be on truck accessories just below the alternator. Running an Fbody oil pan. Been running great for 3 years+ and countless trips.
My boat is for sale btw . After motor install all the interior was redone $4500! Asking price for boat now is $10K obo
I have owned many inboards personally and been a wakeboarder as well for 20 years now. I am also in the boat business and have sold many ls engine wakeboard boats at a previous job including several with basically the ctsv supercharged engine , it is a real torque monster with gobs of power under the curve where you need it to plane all that weight ( we have planed 18 people ,full ballast , and wedge down in 25foot wakesetter)
Sssnake any concerns of the outdrive holding the power from the 21'st century powerplant?
I have a buddy that has a blown vortec 350 in a 19 ish foot "regular" inboard/outboard just fresh water lake boat that we have to either find another vortec for or .?.?.
The most costly part of the conversion were the exhaust manifolds.
I used Marine Power units as they make them for the 6.2 setup and pretty much the only ones that I could find. If you need a set lmk. I have an account with them.
For my boat we machined a 2" thick spacer between the riser and the bottom part of the manifold for an 02 sensor bung to be drilled/tapped in there.
These are the manifolds I will be using and I will be building a DRY extension for O2 sensor bungs just like you suggested. I much prefer closed loop vice open loop SD only tunes.
The extension will go between the manifold and the elbows.
I have considered going with a PWM controller for the fule pump as I run one in my CTS-V currently. However, I am going to wait until I get it on the lake and tune it before assuming I need to go this route. Besides I will be doing all the tuning myself as I did on the V. The tunes should be similar as I will be running the same injectors and intake configuration in both.
The blower won't get pullied up because I need to be able to run 87 octane gasoline. This will be tough and I may have to go to meth injection to combat knock. That is also a variable I will figure out once the boat is in the water and at least the initial tune completed.
The engine is definitely getting a good paint job but I wasn't going to paint the heads as I didn't think they were likely to corrode. I guess I can go ahead and paint them with then engine (I need to look into what is involved).
BTW - great looking engine and boat. I LOVE THE HEAT EXCHANGER. Do you have a part number/source for that one?
I have owned many inboards personally and been a wakeboarder as well for 20 years now. I am also in the boat business and have sold many ls engine wakeboard boats at a previous job including several with basically the ctsv supercharged engine , it is a real torque monster with gobs of power under the curve where you need it to plane all that weight ( we have planed 18 people ,full ballast , and wedge down in 25foot wakesetter)
Just began wakeoarding this year but have been surfing for a couple. The new LSA derivative boat engines are what got me on this kick. Hopefully I won't botch the job.
Sssnake any concerns of the outdrive holding the power from the 21'st century powerplant
There is no outdrive as this is a V drive boat. I do have concerns about the transmission but have identified possible replacements already.
Well technically the LY6 is a vortec engine but if you wanted Gen I vintage equipment I should have a SBC available soon My biggest concern on this one is getting the controller to interface with the CAN bus gauge cluster. Otherwise this shouldn't be too terribly difficult (famous last words). If you are using a open loop cooling system you may want to go into the bottom end and open up the ring gap some as the block won't reach the temperatures that are seen in automotive engines. I will experience some of this as well but with the closed loop cooling it will be much more comparable to automotive engine temps.
Finally got some more time to work this. I have been spending more time cleaning up the engine than I have turning wrenches. You can tell from the pics below of the oil pan and the heads that this thing was filthy. I went with the LS9 cam and VVT delete. Added the Melling high volume pump. Then put the new timing cover and CTS V harmonic dampener in place. Once I get the valve seals that I initially forgot to order I should be able to get the engine buttoned up enough for block cleanup.
You can see the areas that have been cleaned and the grimy stuff. About 1/4" of stuff removed prior to priming.
Comparison between a clean and dirty head.
Oil pan and valley cover primed and awaiting paint.
I went with the dog bone style chain dampener as the original tensioner was broken.
Melling high volume pump in place. This is a LOT easier to do with the engine out.
Have you considered adding the a/c pump back in to your accessories, and running the supercharger coolant through a closed loop a/c coolant heat exchanger?
No meth, no mess, no refilling your safety net... Whole system, including hoses, takes up the same space as a five gallon bucket.
Have you considered adding the a/c pump back in to your accessories, and running the supercharger coolant through a closed loop a/c coolant heat exchanger?
No meth, no mess, no refilling your safety net... Whole system, including hoses, takes up the same space as a five gallon bucket.
David,
I did think about a killer chiller style setup BUT that only cools the intake charge it doesn't provide the additional octane. So which is more important? I'm not really sure as I haven't seen any conclusive evidence on the trade-off between the two. However, keep in mind that I have a unlimited supply of water that is typically 10 degrees or more cooler than the ambient temperature (raw water pump on the boat). So I can use a heat exchanger to cool the charge fairly efficiently and the meth/water mix will increase the efficiency of the blower (better rotor seal) and add octane. Would an AC powered intercooler that drops the charge temp lower be more effective? I don't know... If you have some evidence either way I would be very interested.
Now that is a pretty wide range but given I will only have access to 87 octane I would assume I would be on the upper end of the scale but lets just pick the lowest value, 8 points, for comparison.
So each octane point is worth 8-10 degrees in temperature. We have 8 octane points multiplied by 8 degrees. So it would take a 64 degree difference in intake charge temp to offset the octane boost. Water temp in August was between 86 and 89 degrees. So for the AC system to make sense the charge temp would need to be reduced to 25 degrees or less. This ignores the cooling effect of the meth (in a roots blower with intercooler I am not sure there is much) and the drag the AC places on the motor. I don't know I just don't see it. Particularly when I believe that the octane bump will be closer to 14 points (we used 8 for comparison).
BUT I am new to meth and charge cooling beyond standard IC/HE so let me know if I am missing something.
You aren't wrong. Meth will have the advantage of raising the knock threshold of your fuel, an active intercooler will not. Personally, I plan on using both.
The a/c integrated intercooler will deactivate during wide open throttle, because the a/c pump is disengaged at WOT. So, I plan to have my meth injection system set to activate at anything over 70% throttle position, to maintain continuous iat control.
Finally made a little more progress. Both heads are pretty clean (a few external nits need taking care of) and one has been lapped and loaded with new valve springs, seals, and locks.
10-07-2015, 10:39 AM
6.0l blown ski boat 
. After motor install all the interior was redone $4500! Asking price for boat now is $10K obo 
