76 Sidewinder jetboat 5.3L turbo build
10-09-2011, 07:24 PM
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76 Sidewinder jetboat 5.3L turbo build Like the title says I picked up a 76 Thompson Sidewinder jetboat about a month ago and am in the process of swapping in an 01 5.3L. I picked the motor up from a local salvage yard for $750 complete with harness and ecu. Overall it was in pretty good shape. They told me that it had about 80K miles on it. I suspect a few more. Tore the motor down and it looked pretty good but I decided to freshin it up with new rings, ARP rod bolts, headgaskets, misc. gaskets, melling high pressure oil pump, and a slight deglazing of the cyl. walls. Threw a coat of ceramic Chevy orange paint to freshen things up.
This motor is going to see boost in the form of a Precision 76mm turbo to make up for the lack of cubic inches. This being said I opted for ARP heads studs and for kicks I even splurged and picked up a ARP crankbolt. I found a good deal on ebay for some cheapy stainless "shorty manifolds" and since the motor is out in the open for all to see I opted to get them. Any other application and would of just used the manifolds.
I havent decided on what intake manifold setup I will be running yet. Tough choice between a Super Victor efi setup or a LS6 intake. LS6 intake would be quite a bit cheaper though. I ordered a custom ground cam from Thunder Racing that specs out at 224/230 .615'' lift on int and ex on a 112 LSA. The cam features a "marine" style lobe that sets the valve down easier for sustained RPM. I originally had a Raptor cam on order when I was going to stay NA but I opted to go forced induction and the cam was just too radical. And that was before I realized that you cant really spin a jet pump with a big impellor over 7000 rpm where the little ci motor would be making power. Im a newb to the jetboat scene.
I also ordered a set of patriot daul gold extreme valvesprings with Ti retainers and new valve seals. Also ordered up a set of 2.020'' intake valves to replace the small intake valve on the 5.3 heads. They should bring the flow numbers up to around stock LS1 heads. I'll also be doing a light port job on the heads to gain a few more CFMs. They were also cleaned and decked .010. Which should bring the CR up to about 9.3:1.
I know im not the first to swap a LS motor into a jetboat but its a fairly new adventure. I seen several others on here that have done it also. I havent seen a turbo setup yet though. Anyways heres some pics of the build so far. I'll post up some more as time allows.
This motor is going to see boost in the form of a Precision 76mm turbo to make up for the lack of cubic inches. This being said I opted for ARP heads studs and for kicks I even splurged and picked up a ARP crankbolt. I found a good deal on ebay for some cheapy stainless "shorty manifolds" and since the motor is out in the open for all to see I opted to get them. Any other application and would of just used the manifolds.
I havent decided on what intake manifold setup I will be running yet. Tough choice between a Super Victor efi setup or a LS6 intake. LS6 intake would be quite a bit cheaper though. I ordered a custom ground cam from Thunder Racing that specs out at 224/230 .615'' lift on int and ex on a 112 LSA. The cam features a "marine" style lobe that sets the valve down easier for sustained RPM. I originally had a Raptor cam on order when I was going to stay NA but I opted to go forced induction and the cam was just too radical. And that was before I realized that you cant really spin a jet pump with a big impellor over 7000 rpm where the little ci motor would be making power. Im a newb to the jetboat scene.
I also ordered a set of patriot daul gold extreme valvesprings with Ti retainers and new valve seals. Also ordered up a set of 2.020'' intake valves to replace the small intake valve on the 5.3 heads. They should bring the flow numbers up to around stock LS1 heads. I'll also be doing a light port job on the heads to gain a few more CFMs. They were also cleaned and decked .010. Which should bring the CR up to about 9.3:1.
I know im not the first to swap a LS motor into a jetboat but its a fairly new adventure. I seen several others on here that have done it also. I havent seen a turbo setup yet though. Anyways heres some pics of the build so far. I'll post up some more as time allows.
10-09-2011, 09:26 PM
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Thanks. Just depends on what kinda shape the boat is in when you buy it. I do know that the driveline parts will cost you about $300 (pto flang and new driveshaft). A pump rebuild kit with stainless impeller and a new shaft is about $1000. And thats where it starts to snowball.
B.O.A.T= Bust out another thousand
I bought this boat with trailer for $1300. I plan to have about $6500 (or so haha) in it and around 600hp.
B.O.A.T= Bust out another thousand
I bought this boat with trailer for $1300. I plan to have about $6500 (or so haha) in it and around 600hp.
10-09-2011, 09:35 PM
#4
Thanks. Just depends on what kinda shape the boat is in when you buy it. I do know that the driveline parts will cost you about $300 (pto flang and new driveshaft). A pump rebuild kit with stainless impeller and a new shaft is about $1000. And thats where it starts to snowball.
B.O.A.T= Bust out another thousand
I bought this boat with trailer for $1300. I plan to have about $6500 (or so haha) in it and around 600hp.
B.O.A.T= Bust out another thousand
I bought this boat with trailer for $1300. I plan to have about $6500 (or so haha) in it and around 600hp.
10-09-2011, 10:28 PM
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Got the heads back today and set one on the motor just for fun. Cant wait to get the hotside put together.
As you can see im running a "cloosed loop" cooling system with a heat exchanger and an electric water pump. I have to give AEI CNC some credit as they cut my motor plates and did the BBC water pump adaptors. They do awesome work.
Im trying to avoid having any belts running up front or having to do a high mount alternator so im considering running the alternator off the yoke of the driveshaft. Luckily im a machinist and have access to CNC/machine tools and CAD software. I made pretty some pretty rough models of the what I was thinking about doing. Nothings to scale or correct dimensions. Just proof of concept. I talked to another guy over on performance boats forum who ran his alt. like this. I'd love to hear some feed back about what others think of this. Basically I would turn a portion of the yoke about a 1/2in. wide and make a flange that I would weld to the yoke then turn true after welding. Then make a custom pulley to bolt to the the flange. Would look similar to the pic below.
Always smooth!!! Idk who came up with these but they really have a sense of humor!!
As you can see im running a "cloosed loop" cooling system with a heat exchanger and an electric water pump. I have to give AEI CNC some credit as they cut my motor plates and did the BBC water pump adaptors. They do awesome work.
Im trying to avoid having any belts running up front or having to do a high mount alternator so im considering running the alternator off the yoke of the driveshaft. Luckily im a machinist and have access to CNC/machine tools and CAD software. I made pretty some pretty rough models of the what I was thinking about doing. Nothings to scale or correct dimensions. Just proof of concept. I talked to another guy over on performance boats forum who ran his alt. like this. I'd love to hear some feed back about what others think of this. Basically I would turn a portion of the yoke about a 1/2in. wide and make a flange that I would weld to the yoke then turn true after welding. Then make a custom pulley to bolt to the the flange. Would look similar to the pic below.
Always smooth!!! Idk who came up with these but they really have a sense of humor!!
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10-11-2011, 02:59 PM
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How would shaving .010" off the heads bring the comp up to 9.3to1 when the stock comp is 9.48to1? Lol boat looks bad *** love the heavy flake gelcoat. It will make alot more than 600HP im guessing it will make 600 at 8psi with that setup. What size injectors you planing on running? And what fuel do you plan to run? As far as intake manifold I would think the proflow xt would work and look bad *** on that thing. And in the end it will cost less that the super Vic and tb elbow.
10-12-2011, 11:29 PM
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How would shaving .010" off the heads bring the comp up to 9.3to1 when the stock comp is 9.48to1? Lol boat looks bad *** love the heavy flake gelcoat. It will make alot more than 600HP im guessing it will make 600 at 8psi with that setup. What size injectors you planing on running? And what fuel do you plan to run? As far as intake manifold I would think the proflow xt would work and look bad *** on that thing. And in the end it will cost less that the super Vic and tb elbow.
Guess im wrong. I havent got far enough to think about injector size yet, but I would guess somewhere around 120lbs. Might run E85 so bump that size up by 30%. Some helpful suggestions on injector size would be appreciated. I'll probably end up running E85 actually because my dad is a farmer and hauls corn to a local ethanol refinery. It would make his day. The proflow is a good option but i really dont like the looks of it. I really want the super vic setup but more than likely I'll end up with a LS6 intake because of the budget. We'll see. I sure hope my cam and **** shows up friday so i can finally put it all back together. Ive been waiting over a month now for the valvetrain. Im going to work on the alternator setup and port the heads this weekend either way. Ill probably order the AN fittings and hose tomorrow to do the cooling system. DAMN its going to be expensive.
ZMG give me that damn LS1 intake off of your car. Fo free
Getting ready to order some crap, K member,rod bolts,dzus rails for my hood,abs delete,and the gaskets for the cam swap. Going to do work after Oktoberfest
10-13-2011, 01:21 AM
#14
Sounds like a fun project.... especially going turbo with it.
I did a 5.3 in a '97 Ski Centurion ski boat and it was a new take on LS conversions for me.... learned a bit more about boats..... but lots of little sh*t to figure out. I stayed n/a and did a Z06 cam/springs and ported TB, with some water cooled manifolds (Marine Power). The most expensive part of the swap was the manifolds. But they work as described.... It runs..... but I still need a tune. Very thirsty on fuel as it sits and making about 60% as much power as it should I'm guessing. Goal is to have the bikini babes and do some wakeboarding/skiing next spring. Hell... this winter with some Kahlua and coffee to fuel us up
.
Make sure you can tune your setup. ie provisions for a wideband O2 for sure in the system and/or OBDII port
I did a 5.3 in a '97 Ski Centurion ski boat and it was a new take on LS conversions for me.... learned a bit more about boats..... but lots of little sh*t to figure out. I stayed n/a and did a Z06 cam/springs and ported TB, with some water cooled manifolds (Marine Power). The most expensive part of the swap was the manifolds. But they work as described.... It runs..... but I still need a tune. Very thirsty on fuel as it sits and making about 60% as much power as it should I'm guessing. Goal is to have the bikini babes and do some wakeboarding/skiing next spring. Hell... this winter with some Kahlua and coffee to fuel us up
.Make sure you can tune your setup. ie provisions for a wideband O2 for sure in the system and/or OBDII port
Last edited by gnx7; 10-13-2011 at 09:47 AM.
10-13-2011, 08:46 AM
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I saw that boat over on jet boat performance I believe. Looks good and it will for sure have a OBDII port.
10-21-2011, 08:33 AM
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Well not too much to update here as of lately. Im STILL waiting for my cam, springs, and pushrods. Ive been working a sh*t ton of hours lately. Not much time to play with toys. Im almost done porting the heads and I did get one box of goodies in the mail to finish the cooling system. Crap ton of bills to pay this month too. I'll need to sell a kidney.. first $15,000 takes it home 
11-01-2011, 07:44 PM
#18
That is one slick boat! Great workmanship and forethought! Any guesses at top speed? I am sure you are limited to the rpm's and pitch but it will get there in a hurry. Anyone that likes to go fast on the water has bigger nuts than me. I have been 86mph two times on my dads boat with me driving and I will not do it again. It felt like I was running double that on land. Great thread and plenty of pics, keep 'em coming.
