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I have a 454 magnum (rectangle port, forged pistons/rods, 4 bolt mains, 8.something:1 compression) in my donzi that was rebuilt 20 hours ago so it's fresh.
I'm toying with the idea of putting on a roots blower (6-71???) and a pair of carbs to up the 400hp I have to hopefully around 600hp.
How do these blowers work on a "normal" inboard/outboard boat? Are they hard to start? How will it do at part throttle? I spend most of my time at 3000-3500rpm. Lots of no wake zones too. Will my fuel economy go to crap at normal cruise, or will the blower "just be along for the ride" unless it's on boost?
I'd hate to drop $5k on a blower/carb setup and find out it's finicky and not worth using in a boat.
From what I've read, I want to upgrade to the ribbed blower drive in case it backfires. Anything else? Will my stock external merc fuel pump work?
What does the thermostat housing look like on a blower intake? I wonder if I can keep my closed loop cooling system intact- see the pic of my housing.
Looking for all the help/recommendations I can get.
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I might be able to help some, that thermostat housing will not work, contact with the blower belt most likely..You need low compression so you are good to go there you just cant overdrive the blower a whole lot, for a big block you might want to go with a 871 or 1071.. A blower moves up about 4 psi at the same rpm every inch they add to it. (671 compared to a 871 is 1 inch so you can make 4 more psi of boost rotating at the same speed) spinning the blower faster will create more heat especially with gasoline at idle and low RPM. The blower will work great at at mid rpm, power is there as soon as you start the motor, being its crank driven (always creating boost). Your fuel mileage will be worse because you will need dual carbs and probly alot of showing off . You should be able to get 600hp as a blower should give you around 50% power gain depending on your overdrive or under drive set up (pulley sizes)... You might have been watching to many top fuel races when a normal (non radical) engine has a blower it can take a back fire if it happens alot your rotor inside the blower will contact the upper part of the case ruining your tolerances, if you are really concerned with this get a pop-off machined into the manifold or buy one with it already, but if it backfires get ready to replace gaskets as it will most likely leak (valve spring style) or if you buy the plate system have several on hand it could get expensive.. If you keep the moter simple it should be reliable not hard to start.
For blower reliabilty make sure it has hard anodized rotors and inside the case, the rotors should have teflon..........Hope that helps a little
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DO NOT RUN A SUPERCHARGER WITH A POPOFF PLATE IN AN ENCLOSED ENGINE COMPARTMENT!!!!In the event of a backfire you could blow up your boat if there any fumes present.This is why Weiand does not recommend their superchargers for use in marine application with an enclosed engine compartment.There are superchargers that are designed for marine applications with an enclosed engine compartment.
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I have a 454 magnum (rectangle port, forged pistons/rods, 4 bolt mains, 8.something:1 compression) in my donzi that was rebuilt 20 hours ago so it's fresh.
I'm toying with the idea of putting on a roots blower (6-71???) and a pair of carbs to up the 400hp I have to hopefully around 600hp.
How do these blowers work on a "normal" inboard/outboard boat? Are they hard to start? How will it do at part throttle? I spend most of my time at 3000-3500rpm. Lots of no wake zones too. Will my fuel economy go to crap at normal cruise, or will the blower "just be along for the ride" unless it's on boost?
I'd hate to drop $5k on a blower/carb setup and find out it's finicky and not worth using in a boat.
From what I've read, I want to upgrade to the ribbed blower drive in case it backfires. Anything else? Will my stock external merc fuel pump work?
What does the thermostat housing look like on a blower intake? I wonder if I can keep my closed loop cooling system intact- see the pic of my housing.
Looking for all the help/recommendations I can get.
I reccomend you look at a Whipple Supercharger BEFORE you do anything. Call them and talk to Dustin. I have had a 3300 intercooled system on my 502 for three years w/o any problems. They are very efficient and the boost is right NOW. :) :)
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DO NOT RUN A SUPERCHARGER WITH A POPOFF PLATE IN AN ENCLOSED ENGINE COMPARTMENT!!!!In the event of a backfire you could blow up your boat if there any fumes present.This is why Weiand does not recommend their superchargers for use in marine application with an enclosed engine compartment.There are superchargers that are designed for marine applications with an enclosed engine compartment.
Thats an easy fix, leave out the springs for the back fire valve and bolt it straight to the manifold. Now it can't start a fire.
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He said a whipple supercharger lol, those are a joke, If your gonna run a supercharger run a real one.....and for wieand they dont want you to run theres because illegal immigrants build those, check the tolerances before you install... Buy quality I recommend Mooneyham Blowers the best in the business!!
There is no reason to run a popoff unless you or your engine builder can't tune an engine.
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He said a whipple supercharger lol, those are a joke, If your gonna run a supercharger run a real one.....and for wieand they dont want you to run theres because illegal immigrants build those, check the tolerances before you install... Buy quality I recommend Mooneyham Blowers the best in the business!!
There is no reason to run a popoff unless you or your engine builder can't tune an engine. What makes Mooneyham Blowers the best
just wondering why they are the best. i kinda think these are one
of the best blowers you can buy today. http://www.theblowershop.com/
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I might be able to help some, that thermostat housing will not work, contact with the blower belt most likely..You need low compression so you are good to go there you just cant overdrive the blower a whole lot, for a big block you might want to go with a 871 or 1071.. A blower moves up about 4 psi at the same rpm every inch they add to it. (671 compared to a 871 is 1 inch so you can make 4 more psi of boost rotating at the same speed) spinning the blower faster will create more heat especially with gasoline at idle and low RPM. The blower will work great at at mid rpm, power is there as soon as you start the motor, being its crank driven (always creating boost). Your fuel mileage will be worse because you will need dual carbs and probly alot of showing off . You should be able to get 600hp as a blower should give you around 50% power gain depending on your overdrive or under drive set up (pulley sizes)... You might have been watching to many top fuel races when a normal (non radical) engine has a blower it can take a back fire if it happens alot your rotor inside the blower will contact the upper part of the case ruining your tolerances, if you are really concerned with this get a pop-off machined into the manifold or buy one with it already, but if it backfires get ready to replace gaskets as it will most likely leak (valve spring style) or if you buy the plate system have several on hand it could get expensive.. If you keep the moter simple it should be reliable not hard to start.
For blower reliabilty make sure it has hard anodized rotors and inside the case, the rotors should have teflon..........Hope that helps a little
Well said and use common sense.
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What makes Mooneyham Blowers the best
just wondering why they are the best. i kinda think these are one
of the best blowers you can buy today. http://www.theblowershop.com/
Well quality would be the first answer, look on your website you posted they dont talk about anything on the blowers except that they are polished, now look closely you have to look into blower options to get teflon or nylatron (depends on your fuel)...if you dont run teflon in a gas blower you have metal to metal no cooling, teflon helps lubricate and keeps it cooler.Also the tolerances can be much closer .002 on the bottom. Without teflon your talkin .015 to .020 on the bottom, less effiecent , sorta like NOT putting rings on your pistons :idea: and hard anodizing this is an option? if it isnt hard anodized and it backfires hard the aluminum from the case and rotors will be trashed, smeared and grooved..
That is why I say Mooneyham Blowers are the best, there quality is second to none, you will have to ask not to have teflon or hard anodizing, they have been in business for over 30 years. Gene Mooneyham designed most of the stuff we run today, he was Thee supercharger pioneer. He passed away January this year at age 75 he was still building blowers for his customers.
Checkout mercury marine racing engine packages, if you want there little horsepower engines they use other supercharger manufactures but for there full race 900 hp offshore boats they run Mooneyham
Well everyone has an opinion this is mine!
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Here's a pic. of one in a 22.
The hatch scoop appears quite large(from what little ya can see of it).
