25lbs boost, E85..no intercooler...1000hp...

http://i227.photobucket.com/albums/d...psd97da131.jpg

Hahaha... gotta love 105 octain fuel. Not a huge fan of that gen camaro but I give respect to anything laying down those kinds of numbers.

New to boating, but know this one since years.
This I believe could be a "gold mine" for anyone wanting to convert a GM truck/car engine for marine use.

WARNING 60+ Megs
http://www.chevroletperformance.com/...CP_Catalog.pdf

Hell yes thats a good piece of information right there

so i figured I'd bring this thread back to life a little. if anyone has any additional information that would be greatly appreciated.

Checking in for info and will detail a project I'm working on soon. Sweet 16 Donzi, ls1 with a bravo.

I'm getting ready to Send my lq4 off to the machine shop sadly I have to wait to install til spring. But I think this engine platform is finally going to take off in the marine world.

I think the power these things make is unreal for what little needed to do...cost of parts still pricey but hopefully come down as more people start making parts...

Yeah its not cheap. Yes I could just stuff a junk yard motor in and go but what fun is that? :D. So just some more info on the what's needed. If you decide to run speed density, no maf, then you need an iat sensor installed some where. I'm putting mine in my egr plug in the intake manifold. The ideal iat to use is one from a 92-93 gmc typhoon as it has 3/8 npt so you can tap the egr plug for it. The fun part of the entire swap is the harness. I gutted mine and rebuilt it. Major advise tho... make sure to lable every pin as you re move them from the ecu. And major and here plug in all your sensors you are keeping before you start pulling wires. That way you know what is going where. Then you can lay out your harness any way you like. This will save you major time trying to read 20 pages of wiring diagrams. Then if you have doubts check your diagrams. The maf on most has the iat built in so you will have to cut those two wires from the maf plug and hook up a two pin connector to make it work. You will need. The connector for that sensor as well.

I think running a megasquirt II would be the way to go...tune from a laptop and run what inputs you need...run that in racecar(a III because do much more than needed in a boat) and a II in our boat with our own EFI BB w/procharger

Yeah it may be easier but my time is free...lol I've been trying to piece together the odds and ends, still looking for an adapter to hook my throttle cable up to the ls throttle body. If I had the extra cash I would love a plug and play system but I had to give my wallet a break...lol its taking a nasty beating as I start collecting parts...lol

you can buy a base megasquirt ECM and do all your own wiring...what we do...by the time you finish trying to tune the stock ecm you could have bought the megasquirt...

really... hmmm I looked at the megasquirt but i guess I'll take a deeper look at it. Justin at black bear charges 240 for a custom tune. but I can't argue with simplicity. thanks for the heads up.

and you will be able to do way more than with the stock ECM...

I've done a half dozen or so Megasquirts and I used factory ecms in my boat. I currently have a Megasquirt on my 69 Camaro SBC turbo'd
I think if you need to buy a tune for a factory computer you might want to skip a Megasquirt.
All the base configuration is done on a factory setup and you can get mail order tunes, you can get tunes for Megasquirt too but it is a lot more hands on IMO.

I have been thinking about swapping over to MS-II or MS-III on my boat though...

yeah I will need a tune for my ecu...lol with the marine kinetics cam I got and the 42 lbs injectors I don't think the stock ecu maps will work very well. I will say that prices for LS based performance parts arn't very cheap...lol Now having said that, I will say they are cheaper than my old 390 ford FE engine I built a few years back. the old saying on the 390 is that FE stood for freaking expensive... but anyone who has tried to move one of these pigs would say FE stands for the periodic table with FE standing for iron... those motors weigh a ton... stock intakes were 80 lbs. :eekdrop: but yes ls parts arn't as cheap as the old chevy motors. still I think this engine is the best bang for your buck in the long run. seeing how this thing is designed and built its like compairing a computer from 15 years ago to our modern hand held devices. efficiancy and raw strength of these motors is unhead of in a production block. I knew going in that an ls swap wont be super cheap. the exhaust is going to be the single biggest price hit. but any set of marine headers are not cheap. :D

also, your stock ECM will need a 02 in most cases to run, good luck with that...crap shoot getting those to live in a boat, the MS II is all thats needed in a boat...

I agree with the prices and benefits of the LS platform... what I actually meant by having to buy the tune was if you were not going to tune the factory ECM yourself then the setup and tuning of a Megasquirt might be more than you want to do. IMO it would be easier for you to tune the factory stuff than setup and tune the Megasquirt. The factory setup you can basically plug it in and go if you buy a tune.

btw, ezstriper, been running my stock ECMs with now 02s open loop for a couple years now.
Really need a wideband O2 to tune a Megasquirt though.

So you aren't seeing any real negatives with running open loop? I can have my ecu programed to run with or without my o2's if I want. I just dont want to loose any benifits of these engines running open loop.

I've been reading up on running open loop, I think that may be a good option. so speed density, open loop operation on the ecu. From what I've read on the ls forums and what not, lots of people are running like that. Its all in the tune as to how well the engine will run with that set up. Justin at black bear has a very solid reputation behind him, so I have some faith that he can set up a good tune for me.

one other thing I have read a ton about is that the stock rocker arm is prone to throwing our needle bearings. Comp cams makes a trunion upgrade kit to fit the stock rocker arms. Most people are using this kit rather than running aftermarket arms. I figure for the cost its cheap insurance.

On a side note about any of the ls engines. so anyone who's ever had one of these motors knows they consume oil.... usually about a quart every oil change. So, I have been doing a lot of reading and some discovering on my engine build. I would highly recomend installing an oil catch can between the pcv and the intake. I have never seen so much oil built up inside of an intake in my life. it felt like 36 grit sand paper. i soaked my intake for 2 days in purple power and water then another day and a half in dawn ultra and water. i then used a scrub brush to clean out the runners. I had all kinds of stuff come out of that thing. Most everyone on the ls forums are running catch cans and they say it stops their oil consumption.

If you are going to spend the money, you might as well just buy real roller rockers. They really aren't that much money.

I was going to but the trunions are 130 and real roller rockers are 400-500. Most of the LS guys are simply running the trunions. The stockers are actually very light and very strong, other than the factory needle bearing design. If I was going to build a high rpm screamer i probably would swap the rockers. I'm not trying to cut corners just spending the money where it will do the most good. I could easily drop an extra 1500 on a fast intake and roller rockers and gain maybe 3 mph? The motor itself is mostly stock. other than the valve train, and bigger injectors. I'm going to take a guess at 450 Hp off this build and thats 200 hp over the stock 350 mag that I took out. The wife is being good to me not saying how much I can spend or not spend...lol She said just make sure its reliable. the boat made it back to the dock less than 50% of the time we took it out...lol I should have listened to my gut when I got the boat and gone through the motor... :(

Honestly, unless the cam is big, run the stockers with a trunion upgrade, way lighter easier to keep the valve train stable. I have a set of jessels on my ls7 and I would swap back but the valves I have are not stock height and the geometry would be way off. Unless its a solid roller with shaft rockers the the stockers with the trunion are the best bet imo. I don't really like any of the non shaft options.

sounds like you have a pretty mean ls7 in something. In all honesty I probably could have just dropped a stock lq4 motor in the boat and gotten the needed parts to make it mount and been done pretty cheap. Other than the exhaust... i dont want to scare anyone away talking massive money to make the swap happen. I just happen to want to get more performane out of it. :) I save a ton of money repinning my ecu myself. most places want 400-700 for a harness. I even went as far as to put nylon braided sleeves over the wires and heat shrink the ends of the sleeve. that took forever by the way but looks killer.
http://i776.photobucket.com/albums/y...ps20d77ed2.jpg
http://i776.photobucket.com/albums/y...ps8c23d49c.jpg
http://i776.photobucket.com/albums/y...psa0fde8a1.jpg

I laided it all out the way I wanted it then had to take it apart to fit the sleeve onto it... well worth it in my book. I'll be doing all my wiring in the engine room the same way. after pulling out the factory harness I can see several areas where it was rubbing on something and had worn the wire down to copper.

Do you guys think the 6.0 would have enough power and torque to replace a set of stock 340 HP big blocks in a 10,000 lb deep v offshore boat without going slower ?????? JOHN SR

I'll be putting down north of 450 HP with just a cam change, tune and headers. ( I may be conservative on this). These motors can lay down well over 700 HP without forced induction. I know of at least one person who wanted to do twin ls to replace the bbc. Also in the skater forum there is a 24' skater with twin 5.3's hitting I think 105 mph. In my opionon yes I can say twin mild build ls engines will smoke 340 bb any day. shave 300 lbs off each motor and pump them up to 500 HP each, yeah I believe you will love the results. Also the fuel consumption on the new ls engines is far superior to that of the old sbc and bbc.

As big a fan as I am of the LS platform... a boat that heavy really needs the torque of more cubic inches. Just my 2 cents.

The LS engine will respond to almost anything and make HP/TQ by accident. And as far as oil consuption, I know the 5.3's had an issue at first, but my LQ4 in my '03 HD hasn't used a drop, and has towed alot. Everyones experiences may vary.

The LS engine may well respond differently in a boat than in a car but our 2002 Corvette (5.7 350 h.p.) has 114,000 miles, uses no oil between changes, still gets the same economy and has the same power as when it was first broken in. With cam, heads, and headers it is easy to get 425 h.p. The LS3 makes that h.p. in stock form. The LS7 in our Z06 is a brute! I could only imagine a 29-32' stepped Fountain with twin LS7s. 85-90+ m.p.h?

One of these days I'm going junk yard scrounging and snagging a LQ9 out of an Escalade and putting it in a single 22-23' Bravo Drive boat to see how it works.

I drive a 2005 Escalade ESV with the LQ9 Police Edition and it snatches that 3 ton beast around like a rag doll. In comparison I have had Suburbans with 454's in the past that wouldn't stay close to my Escalade.

I think the 5.3 and 6.0 LS motors are the sleepers of this era. My brother has a '94 Silvarado Step Side 1/2 ton with the fiberglass bed and rear fenders that is a serious candidate for a 6.0 LS....talk about your classic sleeper!!

I'm itching to put a pair in a boat.

the corvette used a different type of pcv system if I'm not mistaken it uses a port in the valley cover and not in the valve cover. the valve cover location sucked up tons of oil. thats why most people are running catch cans to reduce the amount of oil in the intake.

the lq9 has 10:1 compression ratio just watch that in the marine environmen. but yes they are stout engines with out a doubt. lol the 2005? i believe and up lq4 got the same internals as the lq9 with the exception of the piston, dished vs flat top. but the rods are the stronger ones used in the lq9.

I ran a lq3 extensively for GM in a super light 24 Cigarette Firefox with a Volvo drive. I like the engine. It
was a 72 MPH boat would have been faster with a single prop. (boat went 83MPH in f1 trim hp 500 carb)
Steve

just run the the stock rockers with the CC kits, adding the heavier roller rockers upsets the lightweight valve train according to the LS people...thats all we used in out 1000hp 6.0

But what all would it take to get one of the lq4's to make 500hp? I know you said 450 with just a cam swap, headers and tune.

I'm probably being conservative on my figures. 500 hp is easy with some head work. I just want to keep my torque curve in the lower rpm range so I'm not porting the heads. Yes porting can make big numbers but can kill low end power. A stroker kit in my build I'd be pushing mid to upper 500... but that much more grunt to the engine would destroy my alpha drive. So I'm keeping the stock cubic inch. They cranked out 1200 hp out of a 4.8 with a turbo kit. A guy with an s2000 with a bone stock 5.3 junk yard engine put a turbo on it and broke 9's in the 1/4.

So a cam swap and turbo are they way to go on these motors? I am the same way on i don't don't want to be turning 7000rpms.
Id like to be making good power and never go over 5500rpm. Plus im still up in the air about doing this swap into my velocity 280.

You can alway build a stroker ls. The bigger cubes will help shift the power band. Match that to a good custom cam and headers with the truck intake and power will be brutal under 5500. Like I said they are 300 lbs lighter than a bbc. Talk to bob madara about a good cam. Yes there are issues you need to address. But ill be covering most of them on my scarab build and on this link as well. You could alwaya strap a magnuson supercharger on these bad boys and really pick up some major grunt. They usually pick up well over 100hp at the wheels on a stock motor. Have a cam made for that in mind and a custom tune and that will make all the powe you could want.

After some reading and research, your right they did make big power with the 4.8 on a dyno. But if you read into things more and think about it, a dyno isn't putting anywhere near the load on a motor that car/truck will. plus if your putting it in a boat you can multiply a car/truck load by 10, So you would never get that same motor to last very long in a car/truck let alone a boat. I'm looking for a good 500-600hp and not wanting to kill and engine by twisting it to the moon and back so i'll prob do a cam swap and maybe a little turbo setup. that should be enough to get the boat back into the 85-90mph range and it still hold together.