I have a jet boat with a 5.3 in it currently. I am also currently running nitrous. While i love the bottle, i am considering doing a build this winter (just forging it) and started to think about building it for boost and turboing it.

I know nothing about turbo engines, i am slowly making my way through the FAQ on this site as well as the FAQ on other sites.

I do have a few questions about what I would need for my setup.

I would like to stick to the KISS method. SInce its in a boat, i dont need to worry much abotu clearance/engine temps/stuff like that.

I was thinking about buying a set of the "turbo" headers from ebay. The stainless ones. And doing twins since that would be the easiest/look the best

My questions are what all is needed for a carb blow thru deal. Heres what i think i need, again i know nothing

Headers
Turbos
Wastegates
Blow off valves (1 or 2?)
boost controller
Carb hat
Carb converted to blow thru
Boost referenced regulator
Plumbing for the charge pipe
Oil plumbing
Different cam

I think thats it? What am I missing? not looking to make stupid amounts of power here. Maybe 15 pounds of boost or so? Would like to make somewhere in the neighborhood of 750-800 flywheel hp

Just so we are on the page, the engine build plans are as follow
Iron 5.7
forged rods
forged pistons (C/R depends on if i do turbo or not)
Have Advanced Induction port my 243's
Possible cam change (current is 235/242 .621.595 111)
ARP Head studs and Main studs
Already have ARP 2000 rod bolts.

Thank you for any adivce or input. Ill continue to search around as well

 

You have a 5.3.

Step 1. Add boost to current engine.
Step 2. Enjoy.

 

lol yes... but what do i need?

Also, im at 10.0:1 with my 243 heads cut down. Isnt that a tad high?

 

I'm at 10:1 with my 243s and run enough boost to peg my 3 bar MAP sensor on pump gas. Since you have a carb and its a boat, what are the odds you could convert to E85? Pro Systems make a hell of a blow through E85 carb. A couple of local guys have used them with a ton of luck.

If you want bare-bones, use stock truck manifolds. They make great turbo manifolds, and they're basically free.

You'll need 1 wastegate for each turbo if you're running twins. One blow off valve. The $50 Tial knockoffs blow off valves work great. So do some of the cheap ebay boost controllers. There is one called Voodoo, probably the best one I've used so far.

You can use your stock cam too.

 

What fuel?
RPM target for jet drive?
1 50mm BOV is fine.


If your plan is truly KISS… You don’t need any of the engine parts or machine work. Even the little 4.8 has PLEANTY of bore/stroke.strength to make 1200 crank hp with a well setup twin turbo system.

Buy a used gen4 5.3/4.8. LS9 head gaskets and ARP studs. Leave the long block alone with untouched factory heads and bottom end. Alum block 5.3 would be my choice.

Your current cam will work but it sounds really aggressive. Don’t need an aggressive cam with turbos and your valve train reliability goes down the tubes. I’d run a mild lobe cam that will be stable/reliable at your target RPM range. Shouldn’t need more than .56x lift cam or over 220 duration. You don’t need to touch a factory head casting either. No porting or head work required for your goals.

Buy the best 60-70mm range turbos you can afford. BW S366’s would be my choice.

Personally I’d run fuel injection as well. If you aren’t able to build and tune your own blow-thru CARB, fuel injection will be cheaper and perform better in the long run. You’ll have much more control over fuel/ignition. As well as many extra features. A micro squirt ECU is around $300. You can make or have a harness made. Or buy the $800 plug and play kit form EFI source. Will be cheaper in the long run and tuning is 100x easier. The system literally tunes itself with the auto tune software.

The ebay turbo headers aren’t very strong and use tubing diameter that is way too large for what you’re doing. You’d be better off with a stout set of 1 5/8 shorty headers or even the factory manifolds. I realize they don’t look as cool, but hanging the turbos off the cheap china piping isn’t a good idea, and the huge piping diameter will slow your spool time. A set of truck manifolds are cheap/easy/strong with good heat shielding and easy plug access. Pretty hard to beat that combo IMO.

Good luck! Show us lots of pics, need to build me one those jet boat deals one day…

 

For sake of conversation. Heres the current stats and performance
Gen 3 5.3 (had 218k when i got it)
Replaced/gapped rings
Replaced Cam bearings
Added ARP 2000 Rod bolts
High volume pump
BTR Stage 4 NA cam (235/242 .621/.595 111lsa)
Stock 243 heads, milled .030"
Stock MLS head gaskets
Edelbrock Victor Jr intake
Holley 750
Daytona Smart Spark (basic locked out timing at 30*)
Magnafuel Fuel system with returns (-10an feeds)
NOS Cheater system jetted .63/55 (150 shot)

On motor i run in the low 70's at 5000-5200 rpm
On bottle im in the mid 80's at 6000-6200 rpm (weather dependent)

The premise behind building a motor is because this one is old lol

 

I looked into runnign e85 but i cant seem to create enough engine heat for it to work right (read 160-170* for e85 to work correctly). I am LUCKY to see 150* water temp

Good info on the wastegates/BC thank you

 

Ill answer your questions in the order i see them.

1. What fuel? - Currently i run mix of 91/100LL av fuel on motor. I run pure 110 on the bottle. Im not worried about fuel, i can easily get 100LL and 110. Would like to stick with one of these two

2. RPM target for jet drive? - The higher the better... I can control the RPM by the impeller selection. currently im at 5k on motor and 6k on the bottle. Would like to keep it down around 7k or less


Thats a good idea on the gen 4 deal. I would assume studs and rod bolts?

Thats good news, if i can cam it to hang around the rpm i want. Ill just throw my stock 243's on. Only thing im worried about is that they are cut .030", or would you stick with the stock 5.3 heads?

60-70mm turbos, great info. I knew nothing about sizing.

Ill consider EFI. But with EFI wont i need an intercooler? I hear with a CArb it drops a lot of temp. Another reason im hesitant on EFI is that with a Carb deal i can always find parts to get it going. Say im out of town on vacation and an injector dies or something...

Thanks for the info on the headers. One question, I expect the "boost" rpm to be 4k plus... does it really take much more RPM than that to spool a turbo hard?

Ill get some pics of what i have now and a video or two shortly.

Thanks!

 

If you switch to fuel injection and E85, you won't need an intercooler, especially with lower water temps. You could even run pump gas with an air/water intercooler that draws from the water and you wouldn't have to worry about placement or air flow.

Injectors failing is pretty rare, especially with all of the large OEM injectors available. A failure from one of them is very rare.

With the right setup, you could see boost below 3000 RPM and still hit your goals.

 

How do we feel abotu the FITech systems?

Its 1200 ready to go supposed to be good to 1200hp

http://fitechefi.com/30012.html

Or would you go back with a stock syle intake and the microsquirt?

the fitech would not require changing the intake or many changes to the fuel system

 

I would without a doubt go to a stock style setup and microsquirt before using an FITech system.

The FITech would still require changing the entire fuel system, and it doesn't control timing or have knock support. Its also more expensive than a stock style system with upgraded fuel system and microsquirt.

 

The hard part with EFI. Is i really cant run an intank pump. SO that limits my external fuel pump choices

I am already dialed in with return lines. My current pump (magnafuel 275) is good to 18psi.

kind of wanna stick with the fuel system i have now, but its not set in stone

 

The AEM 380 is an external with lots of potential. The Magnafuel 275 doesn't have enough fuel pressure for EFI. Its also less than half the price of a 275 so you could probably sell that and end up money ahead.

 

this?
http://www.aemelectronics.com/?q=pro...flow-fuel-pump

 

Yes, that's it.

 

How does changing the boost level work?

I mean i get it, you use a controller

but the tune?

Say i bump the boost from 15psi to 20psi. Will the microsquirt know this somehow? Or does it take another tune?

 

1.) Nothing wrong with a carb if that’s what you are familiar with. If you don’t run an intercooler, you’re charge temps will be plenty high for E85. I’d go that route if you stick with a carb. It will work better than 110.

2.) Shouldn’t need a lot of RPM with a turbo. Keeping the RPM down keeps cost down. If you need more power add boost and keep RPM lowish. Quick blasts to 6800-7k are pretty common in drag racing and probably fine. I’m not a boat guy though I’m not sure how the jet drive loads the engine. We don’t stay at higher RPM for extended periods of time.

If you can find an ALUM 5.3 they usually come with the good heads. 799’s or 243’s. They are also about 80lbs lighter. I’d rather have a thicker head deck and less SCR personally. Esp. with no IC. Even a 7:1 motor can make retarded power by 4k with a turbo setup. I’d sell off the .030 heads. 243’s should be easy to sell!

As far as the 60-70mm turbo thing goes, make sure to check in with a good vendor or run your choice by some people that know turbos. There’s a lot more to the turbo that just the compressor size. The exh. housing size, exh wheel sizes, and designs are just as important and can vary a ton.

Properly sized twin setups aren’t usually lag monsters. If setup correctly you should be at full boost by 4k (in a car that is) So spool time might not be a concern in your application. You can also brace the headers/turbos. Lots of guys run those ebay headers and like them.


There is a sensor that measures your boost pressure. It will tell the ECU what boost you are at. The ECU reads off a MAP that says run X amount of fuel at Y boost and Z RPM.

There are also many cheap capable intank pumps the WALBRO 450 for example. You can even run multiple in tank pumps.

http://www.ebay.com/itm/like/181571770363?lpid=82&chn=ps&ul_noapp=true

 

I am still considering the ebay headers, and just fabricating some mounts for support.

A jet boat works very similar to a very loose converter..


Heres a video of a idle launch with my pump. My pump is a tad bit loose but works okay. Kind of gives you an idea how they load the engine down

FWIW its not a linear load on the engine. At 4k rpm im cruising at about 38mph. At 5k im at 70... so that last 1k rpm really builds a lot more power

 

Ls3 Camaro manifolds would be cool for a TT setup. I dont know how crazy you will be able to get with stock internals in a boat. Cars have stalls converters and the pulls done in the Big Bang theory articles didn't start until 4.5 5k rpm. You will be stressing the rods way more.

Just read the post above. Looks perfect lol.

 

Which one? Lol My post or the one by Forcefed86?