Ls or bbc

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71jeepster
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Ls or bbc

Post by 71jeepster » Wed Aug 27, 2014 1:49 am

I am going to build a boat for alaska this winter and still can't decide on bbc or ls the boat going to 16x8 or 18x8 the boat is going to be heavy and has to run dry all day I am also thinking 5-600 hp any help would be great thanks

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Re: Ls or bbc

Post by Sniper » Wed Aug 27, 2014 6:29 am

If thats what your going to be doing then there is only one choice the LS motor a BBC would never hold up to that kind of use, Waterthunder built a guy in Alaska a LS motor that ran cargo with his Airboat he would go threw as many a three Iron block motors a year he built him an LS motor and no more problems with replacing motors and with the kind of HP your needing that will be not even close to maxed out on a LS motor, If I were you I would build a 418 CI LS motor and you would be good to go pluss with the LS you are going to have a lot less weight and much better fuel economy
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air-roberts
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Re: Ls or bbc

Post by air-roberts » Wed Aug 27, 2014 8:25 am

the ls is 1/2 the weight and basicly close to same rod leigth stroke just a smaller bore being stock so thats a no brainer
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akblackdawg
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Re: Ls or bbc

Post by akblackdawg » Wed Aug 27, 2014 10:04 am

Jeep, you need to include Skip from North Pole in this decision. I have his number if you need it. He builds and runs 18' boats primarly, 500-700 hp, runs miles and miles of dry durning hunt season. His motors last for years, and yes his boats weigh in with the heaviest boats out there. The guys if Florida can be a big help with advice, but when talking about Alaska boats, Skip is the man. I have a BBC on my 15' boat, and yes, I'd rather go with a LS, but my boat is fairly light, I beleive the BBC hinders the performance due to its weight and balance, not so much with a bis 18-20 ft boat. If Waterthunder will guarentee his engines to last in a heavy boat, only then would I go in that direction. Up here longitivity is the key you are looking for. You don't want a major blow up 100 miles down river with a airboat. Bud
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crowhater
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Re: Ls or bbc

Post by crowhater » Wed Aug 27, 2014 4:25 pm

There is no doubt in my mind how I would do it. Call this company and buy a turn key LSA engine and never look back. The LSA weighs way less than a BBC and has a warranty. If you need more power just get it programed and put a smaller pulley on the blower.

https://sdparts.com/details/chevrolet-p ... e/19257456


This is the dyno sheet from an LSA engine I built for a friend a couple years ago and it was a monster. He beats it all the time and it has yet to miss a lick.

THESE ARE REAR WHEEL HORSE POWER NUMBERS NOT CRANK SHAFT NUMBERS!

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needcoffee
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Re: Ls or bbc

Post by needcoffee » Wed Aug 27, 2014 6:07 pm

One consideration is the octane of available fuel. Off the road system you are going to be lucky to get legitimate 87 octane and on the road system options are usually 87 and 90 . 100LL is pretty common though . This will limit your compression and amount of boost. Whether you are NA, turbo, or supercharged.

Just some considerations to have in mind before talking to a reputable engine manufacturer.

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Blown
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Re: Ls or bbc

Post by Blown » Wed Aug 27, 2014 8:08 pm

I vote LSA as well factory 560HP and with a pulley swap you can be about 630HP, it would require larger injectors after 630HP.
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Re: Ls or bbc

Post by Bangin6 » Wed Aug 27, 2014 10:32 pm

This thread made me pick My next motor. I have a steel crank 355 sbc, 496 bbc and 5.3 Ls waiting for me to figure which I wanted to use. Weight and power point to the ls.
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crowhater
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Re: Ls or bbc

Post by crowhater » Wed Aug 27, 2014 11:05 pm

This is nothing new, the corvette and LS guys have been doing this for years. I know several guys in my area driving 900-1000hp CTS-V Cadillacs. The LSA engine is proven platform. How we combat the detination issue is with Meth injection into the air intake, or by tuning the engine to run on E85 fuel.

What everyone is forgetting is that the LSA engine in a car is limited on innercooler size because of the make of the car. If you put an LSA on an airboat you could use an innercooler out of a diesel truck if you wanted. You can also construct a cool can and add ice. Another thing is a CO2 spray bar on the innercooler to drop intake temps when hitting peak boost. Unlike a carb style engine you have a very reliable computer system that can control all of this. You can also have multiple tunes in your ECM and switch from a power tune to a performance, to fast idle, etc.

Now all of this is based on the factory LSA engine which is nothing more than a LS3 engine with a small supercharger. If you want to make serious power call ERL and buy a forged 454 LS3 dry sleeve low compression short block for $5400, LSA heads assembled for $1100-1200, G3 camshaft, and a Kenny Bell, Magnuson, etc. get a ls3 wiring harness / computer from painless or a salvage yard and have someone tune the beast.

There is a company in Victoria called the Guerragroup.com. pat Guerra is a freaking Guru and probably the best tuner in the south. Call Pat G and tell him what you want to do, for $25 he will tell you the least expensive way to achieve it and have reliable power. My ERL 427 LS3 is a freaking beast, I shread 14" M/T drag radials at 70mph if I stomp the gas. All of these LS engines make great power and they weigh 460-480#, but the right combination of parts is the difference between making good power and making insane power.

If you go to YouTube and type ( polecat416 ) into the search you will go to some of my race videos. That LSA dyno sheet I posted above is in a ZL1 Camaro and you will see my car with its old 416 CI LS3 naturally Aspirated engine killing it in the 1/4 mile, as well as a GTR Nissan, and a ZR1 corvette. I built my combo to kill things in a short distance, if we went any farther they would pass me. If you tell Pat the rpm range you want your force induction engine to make sic power he will tell you the combo you need. The Camaro lost that race because of the driver not the car but a win is a win and I will take it.
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Re: Ls or bbc

Post by 71jeepster » Thu Aug 28, 2014 10:22 am

Thanks for all the input and that's a real good point finding fuel that is any high than 87 is not going to happen up here after u leave the road system

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Re: Ls or bbc

Post by Blackcoffee » Thu Aug 28, 2014 10:52 am

Maybe a BBC with fuel injection and running AV gas. You would have to tell the builder. I think you are going to need high octane to get at least 700 hp and ft lbs of torque to do what you are talking about.
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Re: Ls or bbc

Post by needcoffee » Thu Aug 28, 2014 11:30 am

It appears the lsa will derate to a upon sensing knock. Do they still run well at that point? It would be worth calling mast motor and asking them about exactly what you can expect performance wise with running 87 octane. If it still runs well but just loses 50 or so hp from retarding the timing and changing the fuel mapping it might still work for you.

That would be the cats meow.

Whatever you do I think fuel injection with anti knock protection is a good thing to protect your engine from not having enough c8 present to prevent pre ignition or detonation.

I have been thinking about an lsa. For all the reasons crowhater listed. They are bad azz. But if I have to fill up in Tanana or Circle. Will the engine still perform? I dont know yet. If you do call please post results of your discussion.

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skip olsen
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Re: Ls or bbc

Post by skip olsen » Thu Aug 28, 2014 1:59 pm

Well got to tell you I'm a bbc guy, But just finished a build for one of my customers It a 15.5 ft alumitech with 550 hp mast motor 2.67 belt and three whrilwind super wides. Got to tell you I was impressed it performed great, comes out the water fast and runs ground with no problem, Not sure about fly by wire gas pedal But time will tell.

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crowhater
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Re: Ls or bbc

Post by crowhater » Thu Aug 28, 2014 2:11 pm

needcoffee wrote:It appears the lsa will derate to a upon sensing knock. Do they still run well at that point? It would be worth calling mast motor and asking them about exactly what you can expect performance wise with running 87 octane. If it still runs well but just loses 50 or so hp from retarding the timing and changing the fuel mapping it might still work for you.

That would be the cats meow.

Whatever you do I think fuel injection with anti knock protection is a good thing to protect your engine from not having enough c8 present to prevent pre ignition or detonation.

I have been thinking about an lsa. For all the reasons crowhater listed. They are bad azz. But if I have to fill up in Tanana or Circle. Will the engine still perform? I dont know yet. If you do call please post results of your discussion.


Trust me at first these new engines with their computer can be scary for an old school mechanic but it's not that bad. If you purchase EFIlive or HPtuner software you can do anything you want with that engine or any other GM product. You can also data log the engine while you are running it and post the log on EFI forum for other to look at. An airboat is a big air Dyno, so by looking at the data log you can tweak your tune.

For instance if you show octane knock it could be from the reduction, exhaust noise, etc. the first thing you do is check your sparkplugs to see if it is true knock. If its false knock you can dummy down the knock sensor settings. Now when you get true knock you can set how much timing you want pulled and for how long. You also have an intake air temp sensor that pulls timing when it hits the range that is set in the system, this is all adjustable. Unlike a carb engine, the LSA will stop you from hurting it if you have your parameters set correct. It will also auto learn every time you drive the boat. You have two short term and two long term parameters that are constantly fine tuning your fuel curve. They now have programming that will allow you to run regular gas or E85 and it will adjust all on its own. As for running low octane fuel I would set the engine up to run perfect on the cheap fuel and add a Methanol spray system. These systems are very common on force induction cars like Vetts, Camaro, Cadillac CTS-V. You can set it to spray at what ever boost level you want. So say your engine does not show knock until you get into peak boost and you only do this at wide open throttle, set it to spray at WOT. If you drive like a normal person a 1 gallon can of Meth sound last four or five tanks of fuel. You can also cut the Meth 50/50 or use blue windshield water fluid in a pinch.

These engines use water to cool the supercharger! you can splice into this system and add a cool can. If you need to get on it because you are stuck or towing another boat, just open the lid to the cool can and fill it with ice. When the ice is all melted open the petcock and drain the can then fill with ice again.

Other tricks are coating your headers with ceramic heat coating, exhaust ports, combustion chambers, you can even have the inside of the supercharger coated to stop heat sync.

If you port the mouth of an LSA supercharger you will pick up as much as 35 rear wheel HP on a car.

On a boat the LSA engine only needs to drive the water pump and the Alternator so that is a HP gain over the factory numbers.

A 25% under drive crank pully is good for some free HP also.

GM needle bearing upgrade to the stock rockers is good for some free power and cost like $60-80.

A real no BS oil catch can is a mandatory on any LS engine, breathing oil will cause detination.



Now just add the redneck factor and the sky is the limit. Say it's a hot day and the engine is pulling timing because of the high intake temps. Make a spray bar on your innercooler, put a small pump in the boat and hook the hose to the drain on your beer cooler. Mist melted beer cooler water through the inner cooler fins as the engine is running and watch those temps drop.

You can take an LSA engine and hold it wide open at 7k for 5mims no problem, try that with a Built BBC and see what happens.
18x8 Alum, 496 BBC, 2.6 CH4, 4B 82" S-blades

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Blown
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Re: Ls or bbc

Post by Blown » Thu Aug 28, 2014 11:00 pm

If you run the LSA on 87 you will need atune to retard the timing but I would do it on a blown engine, you really need to upgrade the heat exchanger and have a 2 gallon reservoir for the blower and run 93. If that is not available then nothing wrong with a properly built BB to run on 87octane.
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71jeepster
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Re: Ls or bbc

Post by 71jeepster » Sun Aug 31, 2014 1:38 pm

Thanks for all the information it has got me thinking that the ls is the right direction to go dose any one have know what the fuel burn might be on a heavy 18x8 boat with ethier motor built for those numbers thanks again

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Re: Ls or bbc

Post by :) » Mon Sep 01, 2014 12:59 am

BBC and sbc are good for what they are but they are old technology, kinda like an aircraft! :stirpot: :fishing The LS is really come along way in a short time and will continue to improve.
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Re: Ls or bbc

Post by needcoffee » Mon Sep 01, 2014 1:48 am

As Bud said. Give Skip Olsen a holler. He is located in Fairbanks and runs big 18x8 with cab style boats. I would believe your are going to be in the 12-15 gph on a boat that size. Depending on what you are running and how hard you hit the skinny pedal. Either way you will be flushing a toilet full of 100's every run. Break Out Another Thousand lol.

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