Blown vs NA HP figures
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Blown vs NA HP figures

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    Member Gopher711x's Avatar
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    Default Blown vs NA HP figures

    If for example , 555 Blown @ 4psi I'm spinning a Dominator SS A with inducer and stuffer plate to 6800/6900
    on the impeller chart this supposedly puts me at 1150-1200hp

    Now if I was to just run a single Carb (1250cfm ) ....what would the expected HP be ?
    It's me Gopher711 that's been on here for many years till the site got hacked , just added the "X" behind my old name

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    Village Idiot fc-Pilot's Avatar
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    I don't understand the question? if it is spinning "X" RPM as either a blown engine or NA engine, there is X amount of power being put to the pump. Whether it is through a single 1250, a pair of 1250's or an injection hat that can flow 3000CFM. A jet pump is a water brake Dyno.

    Paul

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    Quote Originally Posted by fc-Pilot View Post
    I don't understand the question? if it is spinning "X" RPM as either a blown engine or NA engine, there is X amount of power being put to the pump. Whether it is through a single 1250, a pair of 1250's or an injection hat that can flow 3000CFM. A jet pump is a water brake Dyno.

    Paul
    Paul , I guess I should have stated ....with going from blown @ 4# boost to NA ,how much power would l lose ? It's on e85 also
    It's me Gopher711 that's been on here for many years till the site got hacked , just added the "X" behind my old name

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    I'm assuming the question is, what would be the result of, if the blower and carbs were replaced with a single 1250 with no other changes.
    Since you're running e85, you'd be screwed unless you raised the compression.

    If you're trying to figure the end result of the boat performance, don't forget that removing the blower and one of the carbs will also reduce your boat weight by about 125 pounds or so, too.
    Last edited by jimsplace; 10-10-2017 at 01:03 PM.

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    Quote Originally Posted by jimsplace View Post
    I'm assuming the question is, what would be the result of, if the blower and carbs were replaced with a single 1250 with no other changes.
    Since you're running e85, you'd be screwed unless you raised the compression.

    If you're trying to figure the end result of the boat performance, don't forget that removing the blower and one of the carbs will also reduce your boat weight by about 125 pounds or so, too.
    Yes just drop blower and use one carb .Static Compression is 9:75/1
    It's me Gopher711 that's been on here for many years till the site got hacked , just added the "X" behind my old name

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    Quote Originally Posted by Gopher711x View Post
    Yes just drop blower and use one carb .Static Compression is 9:75/1
    That could make a good pump gas motor, but that would appear to be a large drop in potential horsepower and torque from using e85 with a blower. I would think a cam change might be necessary also going to pump gas, but I don't know.
    Is this possibly a change in direction from where you were going with the boat?

    I have a good friend that is running a slightly larger motor on pump gas making in the mid 900 horsepower range if that helps. His motor is pretty well set up and runs good.

    The biggest issue is the 9.75 compression on e85, maybe. I don't know how well that would work. Most naturally aspirated on e85 run rather high compression.
    Personally, I'm rather biased toward using e85 with a blower. Your blower combination with 9.75 compression is excellent. I run 9.4 and it works well.

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    A 555 with that much compression and a single carb, blower cam, probably BIG heads, would maybe make 700hp.
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    Quote Originally Posted by jimsplace View Post
    That could make a good pump gas motor, but that would appear to be a large drop in potential horsepower and torque from using e85 with a blower. I would think a cam change might be necessary also going to pump gas, but I don't know.
    Is this possibly a change in direction from where you were going with the boat?

    I have a good friend that is running a slightly larger motor on pump gas making in the mid 900 horsepower range if that helps. His motor is pretty well set up and runs good.

    The biggest issue is the 9.75 compression on e85, maybe. I don't know how well that would work. Most naturally aspirated on e85 run rather high compression.
    Personally, I'm rather biased toward using e85 with a blower. Your blower combination with 9.75 compression is excellent. I run 9.4 and it works well.
    Trying to tame it down and use it more often ......BUT I still want it to run fairly decent , I don't want a jet ski to hand me my ass
    was gonna pull Blower and just run one of the carbs and NA to try and get better fuel economy and possibly cruise it more...this thing is a beast on fuel ....I can go thru 11 gallons in about 15-20 minutes if I stand in it a couple times or cruise at speed
    with the old 454 and on gas I could go 1/2 a day on our lake putting around ....not anymore
    It's me Gopher711 that's been on here for many years till the site got hacked , just added the "X" behind my old name

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    Quote Originally Posted by scott foxwell View Post
    A 555 with that much compression and a single carb, blower cam, probably BIG heads, would maybe make 700hp.
    320cc runners ,119 chambers , undercut valves ..flowed right at 400cfm with the Stock valves but didn't flow them again after swapping out
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    Last edited by Gopher711x; 10-11-2017 at 08:41 AM.
    It's me Gopher711 that's been on here for many years till the site got hacked , just added the "X" behind my old name

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    11 gallons in 15-20 minutes? Holy shit! Kinda takes the fun out if constantly getting fuel.

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    Quote Originally Posted by Gopher711x View Post
    4# boost
    Hey Gopher, how have ya been man?

    I gotta wonder how much power it takes to spin the blower, to only make 4psi. Is there even a gain? Or, therefor, a loss to be had if you remove the blower? Just a thought. It's a good question. Seems it shouldn't be all that much different. I don't think the difference would be hundreds... off the cuff without thinking about it too hard. Who knows?

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    Quote Originally Posted by Budweiser View Post
    Hey Gopher, how have ya been man?

    I gotta wonder how much power it takes to spin the blower, to only make 4psi. Is there even a gain? Or, therefor, a loss to be had if you remove the blower? Just a thought. It's a good question. Seems it shouldn't be all that much different. I don't think the difference would be hundreds... off the cuff without thinking about it too hard. Who knows?
    Doing great 👍🏼 How you been ?
    There is a lot of potential left in motor , it's cammed to make peak HP at 7800+~
    Im just not thrilled about spinning a Weiand street blower with cast rotors at overdrive under high boost so I'm not leaning on it ...planned on buying a billet 10/71HH till work slowed down 😡 And
    i planned on racing it but that didn't happen , so during this off season I'm either gonna throw on a pair of Gas Dominators and sell the e85 carbs or just run one e85 carb so l can at least cruise and hang out with the crew on the lake . The boat just sits and for all the money I put into it pisses me off its not being used when I have a chance ..Our lake does mandatory water releases to the city of Corpus Christi so it gets pretty low most of the time . I've got a 24'DCB also but as water levels drop there are lots of shallow areas and Low Water pickup on out drive has picked up too much crap and plugs off the coolant system ......and here I have a jetboat that would now be Perfect to use .....but impractical as far as fuel goes....the carbs have had full conversions done on them and eat fuel , I might as well be on straight alky
    Last edited by Gopher711x; 10-12-2017 at 04:20 AM.
    It's me Gopher711 that's been on here for many years till the site got hacked , just added the "X" behind my old name

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    Quote Originally Posted by Gopher711x View Post
    Doing great 👍🏼 How you been ?
    There is a lot of potential left in motor , it's cammed to make peak HP at 7800+~
    Im just not thrilled about spinning a Weiand street blower with cast rotors at overdrive under high boost so I'm not leaning on it ...planned on buying a billet 10/71HH till work slowed down 😡 And
    i planned on racing it but that didn't happen , so during this off season I'm either gonna throw on a pair of Gas Dominators and sell the e85 carbs or just run one e85 carb so l can at least cruise and hang out with the crew on the lake . The boat just sits and for all the money I put into it pisses me off its not being used when I have a chance ..Our lake does mandatory water releases to the city of Corpus Christi so it gets pretty low most of the time . I've got a 24'DCB also but as water levels drop there are lots of shallow areas and Low Water pickup on out drive has picked up too much crap and plugs off the coolant system ......and here I have a jetboat that would now be Perfect to use .....but impractical as far as fuel goes....the carbs have had full conversions done on them and eat fuel , I might as well be on straight alky
    I hear ya. 9.8:1 CR... I'd put any easily obtainable GAS carb and manifold on and give'er a go. If all I had was a 750 and a dual plane, I'd run it. Just getting off the E will give you some economy back. However, my experience with jets is, if an I/O is getting clogged up, I'm going to have to go swimming to pull weeds out f the jet intake grate too. Maybe ya need a hovercraft or airboat? LOL

    Keep me posted. I wanna hear what you end up doing, and how well it works out.

    -Seth-

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    Quote Originally Posted by Gopher711x View Post
    Paul , I guess I should have stated ....with going from blown @ 4# boost to NA ,how much power would l lose ? It's on e85 also
    run gasoline when you go NA

    you should change the cam if you can

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