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Need engine advise...

  1. #1
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    Default Need engine advise...

    I just purchased an 82 Cole runner bottom. I am ready to start building the motor, but I need some advise from the experts.

    I am looking to be in the 900 to 1000 HP range.
    Running 110 fuel is fine but if this can be accomplished on pump even better.

    Don't want to run alcohol.

    I definetely want to run a blower and enderly injection.

    So the question is how many cubic inches should I start with.
    What set of heads do I need to purchase.

    ECT... ECT....


    Thanks for the help...

    Dave

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  3. #2
    mo balls than $cents$ IMPATIENT 1's Avatar
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    e85 is calling yo name bro, look into it

    Dare to be different, if it turns out great you can claim you planned it that way.

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  4. #3
    steelcomp was here
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    Short deck for weight, displacement for power...540 is a good blown configuration and should be easy 1K on race gas. Heads can be something quality in the 320-325cc range.
    Last edited by scott foxwell; 08-02-2010 at 09:42 AM.

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    What size Blower should I be looking at 8-71 ??

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    IMHO 'horsepower is air flow' so you can make the required power with any sized motor. Smaller motors (400 cu in) just require more air flow which is done with 'more boost and more RPMs'. Larger engines (600 cu in) would require less boost and less RPMs to do the same work. Dyno-flo in Henderson Nev. can sell you a nice 540" long block kit that can make 1000 hp @ 7200 RPMs with around 8 lbs of boost. .630/.630 solid roller, 240/250 @ .050 on 110 (narrow powerband) will pull hard and save the springs and rod bearings. You don't need to have boost under 3K (rpms) when the prop isn't hooked up, it just 'pounds the rods out of the motor', for nothing. 10 3/4 " X 16 prop with 32/35/37 gears, and you will fly. Of course you could just put 20 lbs of boost to it and really fly ! PS ALWAYS run as big a blower as you can afford, size does matter !
    Last edited by GFINISHLINE; 08-02-2010 at 09:56 AM.

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    Quote Originally Posted by SANDSTORM FAB. View Post
    What size Blower should I be looking at 8-71 ??
    1071 minimum, IMO. Easier to build boost with that many cubes, less heat, easier on parts.

  9. #7
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    Quote Originally Posted by GFINISHLINE View Post
    IMHO 'horsepower is air flow' so you can make the required power with any sized motor. Smaller motors (400 cu in) just require more air flow which is done with 'more boost and more RPMs'. Larger engines (600 cu in) would require less boost and less RPMs to do the same work. Dyno-flo in Henderson Nev. can sell you a nice 540" long block kit that can make 1000 hp @ 7200 RPMs with around 8 lbs of boost. .630/.630 solid roller, 240/250 @ .050 on 110 (narrow powerband) will pull hard and save the springs and rod bearings. You don't need to have boost under 3K (rpms) when the prop isn't hooked up, it just 'pounds the rods out of the motor', for nothing. 10 3/4 " X 16 prop with 32/35/37 gears, and you will fly. Of course you could just put 20 lbs of boost to it and really fly ! PS ALWAYS run as big a blower as you can afford, size does matter !
    DynoFlo is great on parts deals, but too many bad stories about their assembled stuff.

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    gn7
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    Quote Originally Posted by GFINISHLINE View Post
    IMHO 'horsepower is air flow' so you can make the required power with any sized motor. Smaller motors (400 cu in) just require more air flow which is done with 'more boost and more RPMs'. Larger engines (600 cu in) would require less boost and less RPMs to do the same work. Dyno-flo in Henderson Nev. can sell you a nice 540" long block kit that can make 1000 hp @ 7200 RPMs with around 8 lbs of boost. .630/.630 solid roller, 240/250 @ .050 on 110 (narrow powerband) will pull hard and save the springs and rod bearings. You don't need to have boost under 3K (rpms) when the prop isn't hooked up, it just 'pounds the rods out of the motor', for nothing. 10 3/4 " X 16 prop with 32/35/37 gears, and you will fly. Of course you could just put 20 lbs of boost to it and really fly ! PS ALWAYS run as big a blower as you can afford, size does matter !
    When did boost from a roots blower become RPM sensitive. I always thought they were throttle position sensitive. And a slow running 14 is better than a faster running 10. Down to what point?



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  11. #9
    steelcomp was here
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    I think he's thinking that cam on the 110 L/C might narrow the power a bunch. I don't get it either. 1K hp @ 7200 with 8lbs...must have some serious static to start with.

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    Well these are general terms, is he using a Weiand blower or a custom built deal ? The 'close lobe centers' will bleed off boost until the motor gets some RPMs (and it holds cylinder pressure) and gets into it's powerband. IF he turns any blower TOO SLOW it won't make any/much boost even with a BIG OPENING in the top. Most mild blown gas drag motors that I know of run around 8.5 static compression, so they are able to 'spin up' the 10's/14's (at 15% over) without trouble. So he should have no problems on this deal. IMHO the rotating load between the two sized blowers (10/14) is minimal, and the boost loads (and heat) are the factor that guide me to ALWAYS go bigger. In the past I've run 14-71's on motors all the way down to 440" in prop drag boats. (carbs or a hat) They had 'no low end troubles', they ran the 'close lobe center cams', they lasted all season with only 'valve spring changes', and they won their High Points in class, for that year. CHEAP RELIABLE QUICK ! I actually like TURBOS but a runnerbottom must have a big blower on it . RIGHT ?

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    Quote Originally Posted by steelcomp View Post
    I think he's thinking that cam on the 110 L/C might narrow the power a bunch. I don't get it either. 1K hp @ 7200 with 8lbs...must have some serious static to start with.
    That 20 open bow deal I sold a few years ago made 1013 HP @ 7100 with 8lbs. It was 540, Dart alum heads, mild 600 roller, 8-71, carbs, thru transom wet headers. (Dyno tested with car headers) The boat headers were big but they didn't help the power. YES, the close lobe centers IMHO really saves the 'wear and tear' on the motor overall. When you leave the 'rope', you want to 'burn your prop' to get the motor into it's powerband and to leave with some control and minimal down pedal, right ? If 500hp will burn the prop, why put 1200 to it ? As the boat 'sets' the prop hooks up and the motor is in full boost/power and pulling up thru it's powerband. Smooth transition to max power, VS hammering the rods/bearings, every pass for no good reason. It also cools the motor before and after the run. (blowing unburnt fuel thru the heads and out the zoomies) IMHO this helps keep the head gaskets seated too. I am a 'mild cam guy', but I want to pinpoint the powerband, and lobe centers does it for my use. If you have RPMs and are at WOT, you will have some kind of boost. HOW YOU APPLY that power to the motor, boat and finally the water is what makes it "zoom or boom".
    Last edited by GFINISHLINE; 08-02-2010 at 11:27 AM.

  14. #12
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    Quote Originally Posted by GFINISHLINE View Post
    Well these are general terms, is he using a Weiand blower or a custom built deal ? The 'close lobe centers' will bleed off boost until the motor gets some RPMs (and it holds cylinder pressure) and gets into it's powerband. IF he turns any blower TOO SLOW it won't make any/much boost even with a BIG OPENING in the top. Most mild blown gas drag motors that I know of run around 8.5 static compression, so they are able to 'spin up' the 10's/14's (at 15% over) without trouble. So he should have no problems on this deal. IMHO the rotating load between the two sized blowers (10/14) is minimal, and the boost loads (and heat) are the factor that guide me to ALWAYS go bigger. In the past I've run 14-71's on motors all the way down to 440" in prop drag boats. (carbs or a hat) They had 'no low end troubles', they ran the 'close lobe center cams', they lasted all season with only 'valve spring changes', and they won their High Points in class, for that year. CHEAP RELIABLE QUICK ! I actually like TURBOS but a runnerbottom must have a big blower on it . RIGHT ?
    I guess what I was saying is, a 14 is fine a motor as small as 440 like you stated. But seems a little over kill for a motor making 8 lbs of boost. Your are correct, rotor weight/rotational mass is zilch. Boost is the power consumer. Less boost + less HP to turn. But your spinning that 14 more than you need to, just to make up for the leakage. They actually make different sized blowers for different applications for a reason. Otherwise we would all just run 16s on 283 Chevies. Its not a "low end" thing. They will always make power, its an efficiency thing. a 16 leaks a higher percentage, specially at slow rotor speeds than a 177 B&M. Why use a blower that speeds a large amount of its time leaking like a sieve.
    Although the LSA does have an effect on the manifold boost pressure, it is prettt much fixed. A 110 will usaully have a lower manifold pressure than say a 114. But it doesn't change a noticable amount thru the RPM band. From off idle till the point where the blower looses efficiency. Did you mean to say bleeds off cylinder pressure?



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  15. #13
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    Quote Originally Posted by gn7 View Post
    I guess what I was saying is, a 14 is fine a motor as small as 440 like you stated. But seems a little over kill for a motor making 8 lbs of boost. Your are correct, rotor weight/rotational mass is zilch. Boost is the power consumer. Less boost + less HP to turn. But your spinning that 14 more than you need to, just to make up for the leakage. They actually make different sized blowers for different applications for a reason. Otherwise we would all just run 16s on 283 Chevies. Its not a "low end" thing. They will always make power, its an efficiency thing. a 16 leaks a higher percentage, specially at slow rotor speeds than a 177 B&M. Why use a blower that speeds a large amount of its time leaking like a sieve.
    Although the LSA does have an effect on the manifold boost pressure, it is prettt much fixed. A 110 will usaully have a lower manifold pressure than say a 114. But it doesn't change a noticable amount thru the RPM band. From off idle till the point where the blower looses efficiency. Did you mean to say bleeds off cylinder pressure?
    Not trying to jack the thread here, is there a rough rule of thumb for selecting a blower for your application? How do you choose an efficient setup for said Cubic Inch/Blower/Boost ?

  16. #14
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    Lets just say that when you look at boost charts for a combo, and it isn't listed, it probably isn't a very efficient setup. Like say a 14-71 on a 283 looking to make 5lbs of boost. But if you really need to get the most out of a blower, I would suggest talking to the people who build them for a living. I know when I asked two different blower shops about running a 14-71 17% under, verses a 8-71 3% over, they laughed. Yet the two theoretically move the same amount of air. So I would start by saying if you need to under drive the blower to get to the desired boost, you should consider a smaller blower. It comes down to the desired boost on a particular engine CID.



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