Looking for a little more power

[QC]

Re: Looking for a little more power

Glenn,<br /><br />The fire extinguisher comment had to do with the nitrous . . . Sorry, had to mess with you a little. I'll bet those Supercharger numbers you're looking at are for fuel injected engines. Unless you are a gear-head, you are in for a lot of work. My guess is that it will never be right. Not being pessimistic, but you're asking . . .<br /><br />Most data I have seen shows that the best top speed is with a prop towards the bottom of the RPM range with an I/O, which is where yours is. Others here may say differently.<br /><br />Be aware, all of the comments above are very valid. The only right way to do this is re-boat or repower . . .

 

[jastacey]

Re: Looking for a little more power

If one is going to go the nitro route, one has to have forged pistons, also the same with a super charged engine, but you'll have to drop the compression a point or two, one question, where are you going to get consistant high quality gas, to run that kind of set-up?, why not just drop in a small block v-8, you'll be able to run it all day at 3500 -4500 rpm and have no problems, remember the need for speed = huge cubic dollars

 

[fireship1]

Re: Looking for a little more power

"More horses need more oats" I would get the V8 if you are in it for the long run.

 

[ramster]

Re: Looking for a little more power

I would skip the blower, and have the heads ported, and shaved to bump up compression a bit, get a hotter cam, and 1.6 ratio rocker arms. This should be good for close to 50 hp, and much cheaper than a blower.

 

[RubberFrog]

Re: Looking for a little more power

50 horse out of a head job?

 

[Silvertip]

Re: Looking for a little more power

There's only a couple of problems with hot cams, shaved heads, and 1.6 ratio rocker arms. Remember that a boat has no transmission. It always starts in high gear. Do all of these things and you kill low end torque. Unless the RPM range goes up you still have the same speed, although theoretically you would be able to achieve those speeds with a heavier load. NO2 is for short blasts (as in drag racing). If adding NO2 to a boat I'd have a steel plate or some other protective blanket under the engine as the pieces of metal escaping from the engine may find their way through the bottom of the boat to Davey Jone's Locker. I would think the manufacturers have all experimented with this stuff and would be doing it if it was practical. But then if one has a thick wallet -- go for it. My nephew is running a "huffer" on his Chevy Avalanche and it works great. But it shattered the tranny internals so those needed to be replace with all high perf pieces. Beef up one end of a marine drive system and you need to look at the other pieces as well.

 

[fendersfender]

Re: Looking for a little more power

even the "go fast" boats dont use nos or blowers....if they want more speed, they drop in larger engines....I think its safe to say that a blower or nos is neither practical or safe for a marine application....my 2 cents

 

[Glenn and his VIP]

Re: Looking for a little more power

Ok peoples..... It was a boaters dream this weekend. Water was like glass ! I hit 39 mph (GPS) I watched everything very close, Im running 4100 rpm's trimmed like I should be. I have a 14 1/2 X 19 stainless steel prop. Any ides if Im getting max out of my boat ?<br />I get confused with prop. settings, bigger,more pitch and ect.Also not sure of what rpm's I should be at for peak performance. Thanks !

 

[Don S]

Re: Looking for a little more power

Way overpropped. You should be seeing between 4600 and 4800 rpm. Book says 4400 min. But you are still way under that.

 

[Glenn and his VIP]

Re: Looking for a little more power

Help me out here, "way under" means too much pitch not enough prop.? What book are you referring to ? I need to find a book on mine. Thanks !

 

[murphini]

Re: Looking for a little more power

Glenn:<br /><br />After reading all of the posts, it's simple: Get a new set of friends with Pontoon boats and you'll be the man.<br /><br />Deckboats are great at what they are as pontoon killers, not speedboats. I bet you could trade your VIPliner with someone that has a deepV runabout with a v8. Heck, I'd trade you my 1989 20' VIP Victory (50.2mph with GPS) with Cobra 5.0/OMC outdrive straight up...

 

[vipzach]

Re: Looking for a little more power

Glenn, he said over propped, not under. Like I said before, you motor is not turning enough RPM's. 4200 is too low, your motor should be turning between 4600 and 4800. You need a smaller pitched prop. The book that Don is referring to would be an owners manuel or shop manuel.

 

[ramster]

Re: Looking for a little more power

A friend of mine just rebuilt a 4.3 for his Bayliner 1850 LS, he cleaned up the heads and bumped up the compression to 9.7, and used an Edelbrock Performer cam, which is "hotter" than stock but not radical, the motor runs great with tons of bottom end.

 

[Glenn and his VIP]

Re: Looking for a little more power

Hey Boaters ! Im still here. I found another motor that I really like but Im woundering how much trouble it would be to swap it out from my V-6? I have a Alpha1 outdrive. Shouldnt it just bolt right in ? Same housing ? There both carb.Heres the motor that I have found, Please give me some input. Thanks ! blueprintengines.com/popular_configurations/index.html?topic=specs&pc_id=47

 

[Don S]

Re: Looking for a little more power

Your best bet would be to start a new thread. Lots of people will only read and answer your original question. Besides, this one is over 30 posts in length.
and over a year old.

 

[wire2]

Re: Looking for a little more power

Although that engine is labeled "Marine", I have to question it. It looks like an automotive distributor, and I don't see a clear hose return between the carb & fuel pump. That cast iron intake will weigh ~68 lbs, (alum is 16 lbs).
370 hp is nice but an alpha is rated for 300 hp max. And that's with the proper 1.47:1 gears.

Sorry to burst your bubble but you'd better keep looking.

 

[Tail_Gunner]

Re: Looking for a little more power

The 4.3 is one great motor, but after a year or so i have found a solution

The 4.3 and 5.7 (or any small block Chevy) are the same engine. The accessories will even bolt up the same. Only difference is what you said, 4 in longer and 2 more cylinders.

Bell houseing, fly wheel, starter, all the same.

As long as you go with the same year style.

GM sells a direct bolt in 5.7 for 4.3 replacement. Was featured on Truck TV

This would be my choice. http://www.crateenginedepot.com/ZZ4-...2609-P4C2.aspx

ZZ4 Crate Engine 350CI 355HP HO with Aluminum Heads 24502609

Click here for: Warranty info, Start Up Instructions​

SKU: 24502609
RETAIL: $5,357.14
YOUR PRICE: </B>$3,779.00



ZZ4 Crate Engine 350CI 355HP HO with Aluminum Heads 24502609 Description Imagine an aluminum head small block that makes 355 horsepower.
What if it had a steel roller camshaft, four bolt main block, undercut rolled fillet crankshaft, high silicon pistons and strong PM connecting rods? We imagined it, and then engineered, developed, tested and built it. The ZZ4 is the evolution of our popular ZZ series of small blocks that power thousands of street rods, hot street cars, circle track racers and drag racers. With over 400 ft.lbs. of torque, the ZZ4 is the best way to put an aluminum head, roller cam, high performance small block between your favorite fenders.

The aluminum angle plug cylinder heads have screw in rocker studs, 1.94" intake and 1.50" exhaust valves and 58cc combustion chambers that yield a crisp and responsive 10 to 1 compression ratio. Also included are our lightweight valve spring retainers that weigh half as much as our previous design. The valve seats are radiused and we've included valve stem seals to help keep the oil where it belongs.

To compliment the cylinder head design, we've incorporated a steel roller tappet camshaft with .474" intake and .510" exhaust valve lift. The combination makes 355 horsepower at 5250 rpm and has that great sounding muscle car idle, with just enough lope to let people know that this is no station wagon engine.

Also included with the ZZ4 is an HEI distributor with an ignition timing advance curve developed for performance, a dual plane aluminum intake manifold that accepts your spread bore or square bore carburetor, an 8" high-RPM torsional damper, 12.75" auto trans flex plate and cast iron water pump.

The ZZ4 is currently our most popular crate engine, and you can see why. With a long history of successes in circle track and drag racing as well as street rods and other performance applications, the ZZ4 may just be the bullet for your next project.

The ZZ4 is not intended for marine use, and should only be used in 1976 and earlier pre-emissions street vehicles or any year off road vehicles.

( They do not like this engine used in Marine without a 7-8 quart oil pan.) So change the oil pan and you have it.


__________________
Just pull your old motor and e-bay it to help offset the cost's.........Not cheap but it will be effective. You will need to marinize that motor ( not to sure about the cam yet), but the old 4.3 should cover those cost's. That's really the only way to make enough HP to see a marked difference.



Or as Don has stated new prop
4100@19P
4300@18p
4500@17p
4700@16p *
4900@15p *

Assuming your tach's on (and i would check it first) id go here http://www.iboats.com/mall/propfind...id=448&**********=675860897&*******=557166705

 

[180shabah]

Re: Looking for a little more power

50 horse out of a head job?

40-45 of that came from the cam upgrade

even the "go fast" boats dont use nos or blowers....if they want more speed, they drop in larger engines....I think its safe to say that a blower or nos is neither practical or safe for a marine application....my 2 cents

Merc makes a line of racing engines that are supercharged, 600+hp

Glenn:<br /><br />After reading all of the posts, it's simple: Get a new set of friends with Pontoon boats and you'll be the man.<br /><br />Deckboats are great at what they are as pontoon killers, not speedboats....

Don't forget, now you can get a Big Block. Bravo III powered "triple tooner" that'll run close to 70MPH

 

[Silvertip]

Re: Looking for a little more power

Hotter cams result in the increased possibility of water intrustion during quick throttle pull back which results in hydrolock. Although I didn't check, I think you are looking at the turbo charged 4.3 engine GM used in the GMC Syclone some years back. It was a beast and fuel injected, but certainly not suitable for boat use. Nitrous is used in short blasts (sort of like an afterburner on a jet) to get you up to speed. Prolonged use will destroy the engine. Remember, when an engine lets go in a boat, the pieces that escape from the engine go through the pan. When that happens, they will also go through the bottom of the boat and a 1000 g/hr bilge pump will not keep up with the amount of water coming in. Find a wrecked 454/502 complete with outdrive and have a real, reliable sleeper.

 

[Tail_Gunner]

Re: Looking for a little more power

super charing or nitrous or turbo charger's are not the answer, we are not talking car's, it's boat's. See that engine up there i posted........ it's as light as a 4.3, now let's ask Don or Bondo if that cam will work.....