5.3 Twin Turbo Jet Boat Project, What Size Turbos??
08-14-2014, 12:19 PM
#1
5.3 Twin Turbo Jet Boat Project, What Size Turbos?? Hey guys, I am picking up a '68 Tahiti 16' Berkeley Jet Boat. It's currently powered by a warmed over SBC, but like everything else I own, it's getting a a turbo'd LS. I have a 5.3 that would fill the role nicely, I am thinking twin turbos would ideal for both aesthetic reasons and because I want an extremely quick spool time. The 5.3 will be a stock short block, LS6 cam, head studs, LS9 head gaskets, and a 3 angle valve job along with a BTR double valve spring kit (pretty much a clone of my Monza long block). Will probably end up using stainless, flipped block hugger headers with T3 or T4 flanges welded on in place of the collectors.
So about the turbo selection, I am only looking to make 12, maybe 14 max lbs of boost. Going to run a dual inlet, single outlet, air to water intercooler since fresh lake water will never be higher than 75 degrees, which is ideal VS an air to air intercooler in this type of application. I want a quick holeshot, so I need to be into boost as quickly as possible. I want a quick spool, but not at the expense of the exhaust housings being a restriction in the 6,000+ RPM range. I was thinking somewhere along the lines of a 50 mm compressor wheel and a .48 exhaust AR turbine housing. Would two of those be too small for a 5.3?
The next step up would be a .68 exhaust turbine housing, then .84, etc.
Any suggestions on turbo sizing is welcome and thanked in advance.
So about the turbo selection, I am only looking to make 12, maybe 14 max lbs of boost. Going to run a dual inlet, single outlet, air to water intercooler since fresh lake water will never be higher than 75 degrees, which is ideal VS an air to air intercooler in this type of application. I want a quick holeshot, so I need to be into boost as quickly as possible. I want a quick spool, but not at the expense of the exhaust housings being a restriction in the 6,000+ RPM range. I was thinking somewhere along the lines of a 50 mm compressor wheel and a .48 exhaust AR turbine housing. Would two of those be too small for a 5.3?
The next step up would be a .68 exhaust turbine housing, then .84, etc.
Any suggestions on turbo sizing is welcome and thanked in advance.
Last edited by Ford_Assassin; 08-16-2014 at 08:46 AM.
08-14-2014, 02:10 PM
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Why are you after such quick spool? Remember this is a boat, so cruising rpm will be higher than that of a car. That said, you should have less lag at cruising speed when dropping the go pedal. Also you probably wouldn't want that small of an AR on the exhaust as it would always have you in boost while cruising.
08-14-2014, 02:18 PM
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A T4 p-trim turbine with the 0.68 AR might be a good starting point, you could always swap out the turbine to a slower spooling AR if needed. I don't think going as small as 50mm compressor is needed. Something in the 60mm range might be better.
08-14-2014, 02:19 PM
#4
Most boats are constant duty, similar to diesels. So you would spec your exh housing for the RPM you plan to stay sustained at. To me that means large wheels and housings. Why do you need it to spool up so quickly, are you drag racing it? Are you really going to be playing around in the rev ranges much or just wide open most of the time? Most boats I've been in are at 4-6k+ all the time. Unless your trying to build a big wave runner, P-trim wheels at minimum and 60mm compressors with .9x-1.0 AR would be my input. Id want some sort of good oil cooler and water cooled center sections on the turbos too if you plan on running it wide open for long.
08-14-2014, 08:49 PM
#5
Most boats are constant duty, similar to diesels. So you would spec your exh housing for the RPM you plan to stay sustained at. To me that means large wheels and housings. Why do you need it to spool up so quickly, are you drag racing it? Are you really going to be playing around in the rev ranges much or just wide open most of the time? Most boats I've been in are at 4-6k+ all the time. Unless your trying to build a big wave runner, P-trim wheels at minimum and 60mm compressors with .9x-1.0 AR would be my input. Id want some sort of good oil cooler and water cooled center sections on the turbos too if you plan on running it wide open for long.
Jet boats need/like low end grunt, which is why the Olds 455's were so popular, especially in ski applications. I plan on towing my fat assed friends about on tubes, skis, and wake boards. Cruising RPM will be in the 3,500-4000 range, even if the engine says in low boost, I can deal with that. I do want an incredible holeshot, as if I was going to be drag racing. I am planning on some type of an oil cooler than will also use the colder lake water to my advantage, and before the oil enters each turbo. I hadn't thought about using a water cooled turbo cartridge, but it definitely a great idea, especially considering the temperature they might be seeing when pushed hard.
What about a .84 exhaust AR? I just worry two turbos, both with .94-1.00 AR will make the little 5.3 a tad lazy down low.
08-14-2014, 10:34 PM
#7
All good points.
Jet boats need/like low end grunt, which is why the Olds 455's were so popular, especially in ski applications. I plan on towing my fat assed friends about on tubes, skis, and wake boards. Cruising RPM will be in the 3,500-4000 range, even if the engine says in low boost, I can deal with that. I do want an incredible holeshot, as if I was going to be drag racing. I am planning on some type of an oil cooler than will also use the colder lake water to my advantage, and before the oil enters each turbo. I hadn't thought about using a water cooled turbo cartridge, but it definitely a great idea, especially considering the temperature they might be seeing when pushed hard.
What about a .84 exhaust AR? I just worry two turbos, both with .94-1.00 AR will make the little 5.3 a tad lazy down low.
Jet boats need/like low end grunt, which is why the Olds 455's were so popular, especially in ski applications. I plan on towing my fat assed friends about on tubes, skis, and wake boards. Cruising RPM will be in the 3,500-4000 range, even if the engine says in low boost, I can deal with that. I do want an incredible holeshot, as if I was going to be drag racing. I am planning on some type of an oil cooler than will also use the colder lake water to my advantage, and before the oil enters each turbo. I hadn't thought about using a water cooled turbo cartridge, but it definitely a great idea, especially considering the temperature they might be seeing when pushed hard.
What about a .84 exhaust AR? I just worry two turbos, both with .94-1.00 AR will make the little 5.3 a tad lazy down low.
Something like this would light off really fast. and look cool hanging off the side of the motor.
http://www.ebay.com/itm/GT35-T3-Turbo-Charger-Anti-Surge-Oil-Water-Cooled-Civic-Integra-Fitting-/160869622333?pt=Motors_Car_Truck_Parts_Accessories&hash=item257493a23d&vxp=mtr
Something like this for a "real" turbo.
http://www.ebay.com/itm/BorgWarner-Airwerks-S300SX3-60-S360-S300-88-A-R-Open-Scroll-Turbo-90-/300941698563?pt=Motors_Car_Truck_Parts_Accessories&hash=item461185e603&vxp=mtr
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08-14-2014, 10:46 PM
#8
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Im smoking blown alky bigblocks with a pair of on3 turbs jus sayin 
we 660ft/800ft/1000ft race and leaving the hole in frnt of a bigblock aint been a issue lol thats been my ace in the hole so far guys.17lbs is 7200rpms, im running 20lbs on avgas at the next big race laborday wknd
we 660ft/800ft/1000ft race and leaving the hole in frnt of a bigblock aint been a issue lol thats been my ace in the hole so far guys.17lbs is 7200rpms, im running 20lbs on avgas at the next big race laborday wknd
08-14-2014, 10:56 PM
#9
Turbos, cam, etc, etc
Are you wanting china stuff or real deal turbos?
Something like this would light off really fast. and look cool hanging off the side of the motor.
GT35 T3 Turbo Charger Anti Surge Oil Water Cooled Civic Integra Fitting | eBay
Something like this for a "real" turbo.
Borgwarner Airwerks S300SX3 60 S360 S300 88 A R Open Scroll Turbo 90 | eBay
Something like this would light off really fast. and look cool hanging off the side of the motor.
GT35 T3 Turbo Charger Anti Surge Oil Water Cooled Civic Integra Fitting | eBay
Something like this for a "real" turbo.
Borgwarner Airwerks S300SX3 60 S360 S300 88 A R Open Scroll Turbo 90 | eBay
Think the .63 AR will be okay? You seemed to think they were too small earlier in the thread.
08-14-2014, 10:57 PM
#10
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man I have wanted to do this for a while but first off I wouldn't want that cam for a jet boat, the higher they rev the more load.. the right impeller(think stall/gear) will do you right.. I would use a stainless a/b.. droop snoot and place diverter with a ride plate and a good loader..
now because this thing is not going to load until around 3k+ I would use something like bw t3 62/62/.91's on this.. plan on at least 6500 to 7200.. on that little boat depending on how bad the hook in the bottom is should get you around 90 to 105..
now because this thing is not going to load until around 3k+ I would use something like bw t3 62/62/.91's on this.. plan on at least 6500 to 7200.. on that little boat depending on how bad the hook in the bottom is should get you around 90 to 105..
08-14-2014, 11:28 PM
#11
man I have wanted to do this for a while but first off I wouldn't want that cam for a jet boat, the higher they rev the more load.. the right impeller(think stall/gear) will do you right.. I would use a stainless a/b.. droop snoot and place diverter with a ride plate and a good loader..
now because this thing is not going to load until around 3k+ I would use something like bw t3 62/62/.91's on this.. plan on at least 6500 to 7200.. on that little boat depending on how bad the hook in the bottom is should get you around 90 to 105..
now because this thing is not going to load until around 3k+ I would use something like bw t3 62/62/.91's on this.. plan on at least 6500 to 7200.. on that little boat depending on how bad the hook in the bottom is should get you around 90 to 105..
The Berkeley pump currently on it is a 12JA-B-H
I am new to the jet boat world, used to prop boats.
08-15-2014, 07:33 AM
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Lol 100 aint happening with the hull he has.my tunnel hull weighs 1350 with me sitting in it ive been runnin a turbo ls jet for yrs and know what can be done.have been nto jetboats for 30yrs and im generally in the top 5 boats at a race lol
ive been runnin a turbo ls jet for yrs and know what can be done.have been nto jetboats for 30yrs and im generally in the top 5 boats at a race lol
08-15-2014, 04:50 PM
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Very dangerous to do and if motor died you d hang a left turn so fast chances are you wont stay in the boat.been there done that, no more vhulls over 85 for me lol had a 11 to 1 460bbf with 200hp shot thatd do 87 & im lucky to still be here after msd box quit at full tilt. the plan u have in mind will work awesome tho bud im excited for ya!! Turbo 5.3 against a jetpump is sick and pulls like crazy....
08-15-2014, 05:23 PM
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ok so your pump has an a/b impeller but your going to want to get a stainless one, a drop snoot pushes from lower and free's up the boat a little, a ride plate is just a flat plate that goes below the jet.. place diverter makes the nozzle adjustable up and down 20*.. plus the "rooster tail"
the cam, ls6 is a good starter cam, but not made for high rpm and there is plenty to be gained from having a cam made by martin at tick cams, its worth the 400 for one for sure, I did and gained 6mph in the 1/4 before I tuned it and noticieabley quicker spoolup..
my old boat went 114 on gps, but it was an eliminator and tunnel boats are the chit..
but my buddy had a Tahiti with a blown 527 that would go 98, but had a AA impeller in and American turbine pump..
the cam, ls6 is a good starter cam, but not made for high rpm and there is plenty to be gained from having a cam made by martin at tick cams, its worth the 400 for one for sure, I did and gained 6mph in the 1/4 before I tuned it and noticieabley quicker spoolup..
my old boat went 114 on gps, but it was an eliminator and tunnel boats are the chit..
but my buddy had a Tahiti with a blown 527 that would go 98, but had a AA impeller in and American turbine pump..
08-15-2014, 05:25 PM
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On3 70mm .81 twins with 228r texas speed cam cut by comp cams. hit me up on fb and u can go thru my build pix on my profile there. tom ethridge be glad to help anyway i can bud!!
08-15-2014, 05:28 PM
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ok so your pump has an a/b impeller but your going to want to get a stainless one, a drop snoot pushes from lower and free's up the boat a little, a ride plate is just a flat plate that goes below the jet.. place diverter makes the nozzle adjustable up and down 20*.. plus the "rooster tail"
the cam, ls6 is a good starter cam, but not made for high rpm and there is plenty to be gained from having a cam made by martin at tick cams, its worth the 400 for one for sure, I did and gained 6mph in the 1/4 before I tuned it and noticieabley quicker spoolup..
my old boat went 114 on gps, but it was an eliminator and tunnel boats are the chit..
but my buddy had a Tahiti with a blown 527 that would go 98, but had a AA impeller in and American turbine pump..
the cam, ls6 is a good starter cam, but not made for high rpm and there is plenty to be gained from having a cam made by martin at tick cams, its worth the 400 for one for sure, I did and gained 6mph in the 1/4 before I tuned it and noticieabley quicker spoolup..
my old boat went 114 on gps, but it was an eliminator and tunnel boats are the chit..
but my buddy had a Tahiti with a blown 527 that would go 98, but had a AA impeller in and American turbine pump..
Im running alil over 117 now but bout to lay better fuel to it and 3lbs more
08-15-2014, 08:01 PM
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Id wait and find a better cam, ls6 cam wont get much done.i built a singl s475 turbo system for my uncle with that cam and i wasnt impressed at all with its power.i found a nice used 228r for 240 shipped off here.nothing against martin but cars aint boats what works in one doesnt mean itll work as well in a boat.i turn a detailed b cut well over 7000. best dragboat cam guy i know is chris straub and its worth the $$ to have him do your specs.we figured out my specs and the 228r was too close to them to order a custom cut cam. chris does business as straub technologies.