Huffa

Hi all, new here and after some advice on a set up for my race jet boat. The plan is to run an LS engine, Twin turbo, air to water cooler, leave bottom end stock, do a cam, springs and injectors to suit. Now I normally play with a dirty old SB Chevy with carbs and a 671 so going down this way is all new but believe its the way forward, just need to research and learn. The engine will be running for extended periods of time in the 5000-6000 rpm range, so for starters what LS should I go for? It needs to be reasonably affordable and available down here in New Zealand so when it pops I can get another easily and transfer the kit over. Was thinking the 6.0 LQ4 engine cast block alloy heads 9.4:1 comp, but am open to any ideas. Have read good things about the 5.3 engines taking boost, but the smaller cubes seems a backward start considering I will be running in a class with 1000HP big blocks. So if I go the 6.0L what should I use for headers? The engine sits in a open engine bay so theres plenty of room. What turbos should I use? Internal waste gates or external? How big? Found these nice 417 Motorsports air-to-water intercoolers that go into a Holley HI Ram intake. Pricey but look tidy, are these any good for my application or would a external cooler be cheaper and just as good or better. Would be hoping to get as much HP as possibly reliable on 98 octane pump gas, 600-700?. Any help or advice will be appreciated, thanks

Blown06

iTrader: (32)

Pics or you will probably get banned.

Huffa

Trying to, don't boot me just yet

Huffa

Huffa

That's all I have at the mo. Decided to go with the little 5.3 LS LM7 engine due to price and availability but yet to secure one, just waiting to hear back from a couple of suppliers.

S2KIWI

I'd also go iron block but they're harder to find here in NZ..

Most of those 5.3s making big power, do it for seconds down a drag strip. That's nothing compared to the beating you'd give it on a river. Has anyone else had had success with this approach and application? Reckon you'd need to turn it down a bit.

Huffa

Yes planning on iron block. There has been a stock LS1 done in the same set up and has gone well.

codyvette

iTrader: (24)

Go with whatever LS motor you find cheap enough. If it's an LS1 or another higher compression Shortblock, there are different combustion chamber ratio heads to get it down in static compression. Then have your cam spec'ed to get the dinamic compression where it needs to be. Last but sure not least, get the right tuner to polish that to a nat's ***. It will live much longer than you may think @ 700HP.

Huffa

So if I plan to run up to say 800HP with twin turbos does that mean I only need two turbos capable of 450hp each? Looks like I will probably use the truck manifolds, do I run internal or external waste gates? Cant see boost going past 12-15 psi max, plan on running way less if I can get the hp I need. Would these be pieces of? I will only be running 4 or 5 races a year at this stage so not going to get thrashed every weekend, could they hold together?












http://www.trademe.co.nz/Browse/List...?id=1036098899

Tomhames

iTrader: (3)

Baddazzz boat man!

Trailer looks cool too....is the hull aluminum also?

Huffa

Thanks,yea hull is alloy,can't wait to get it wet!

chuntington101

There have been a few guy on here use LS engines in boats. Worth having a bit of a search and see what you can dig up. There has been some talk about how turbos on boats respond. I do to want to say something that's a load of b@llocks so will let you find it.

Red89GTA

Just make sure that whatever engine you end up getting, prep the lower end accordingly. Starting with a solid foundation will pay dividends down the road, even if it's a little more cash up front. Looks like a sweet boat, can't wait to see it flying down the water!

kainedogg

iTrader: (23)

In for a build thread if you do one brother.

smaz632

Currently in the process on my airboat

Huffa

Cool, what turbo are you running and what are your HP expectations?

Tomhames

iTrader: (3)

huffa asked about the turbo....& I will ask what hull and part of the country are you in?
I have a Hamant (hull) that I'm going twins on (ls6), stinger box....Microsquirt v3. (Denmah edition!).....south Florida.

I've searched and haven't found much to read on turbo (boats) in general....how they act in refence to the loads we have with props / or hull (resistance =constant work load)...
Have you guys??

smaz632

Turbonetics tc78. Hopefully make 700 at 10-12 psi.

Huffa

I haven't been able to find much info either, that's why I am here hijacking a car forum looking for info. Found this build tho and is what I would like to replicate(without the fancy heads!)
http://www.trucktrend.com/how-to/eng...5-3l-big-bang/

stevieturbo

Unless you're going to pulling a lot of rpm's, cant see the likes of a HiRam being of any benefit over say a plastic truck manifold. It may even be worse in the range you're working.
Unless you insist on using it because of the cooler kit.

A pair of smaller BW would easily meet the power needs and spool quick and lower rpm for lower boost options too.

http://www.agpturbo.com/borg-warner-...1-12709095019/

or you could go a little larger

http://www.agpturbo.com/borg-warner-...1-12769095003/

For only 800hp there probably isnt any point going bigger even with the extended duty they will see.

As for which base engine, just find whatever LS equipped vehicle is most common in breakers yards there and start from there.
It would make sense to fit decent rods and pistons at least, choose a CR to suit your fuel etc Again no sense pushing this too high to take risks given the application.

Pair of LSA heads or similar and ARP studs/LS9 gaskets and it should be good.