HI- Helix vs std helix
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HI- Helix vs std helix

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    Default HI- Helix vs std helix

    A buddy of mine is putting together some roots setups for his 42 Fountain. Pump gas builds. He is looking at either a pair of std helix littlefield 10-71's, or a pair of 8-71 hi helix. He was told hi helix 8-71's are the way to go. He wants to run 10-12lbs of boost. Blower shop intercoolers. 8:1 522CI engines. I think he might be pushing the envelope a bit on pump gas with the idea of 12lbs?

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    Quote Originally Posted by Mild Thunder View Post
    A buddy of mine is putting together some roots setups for his 42 Fountain. Pump gas builds. He is looking at either a pair of std helix littlefield 10-71's, or a pair of 8-71 hi helix. He was told hi helix 8-71's are the way to go. He wants to run 10-12lbs of boost. Blower shop intercoolers. 8:1 522CI engines. I think he might be pushing the envelope a bit on pump gas with the idea of 12lbs?
    You can run pump gas with 10-12lbs of boost in a boat with 8:1 no problem

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    Quote Originally Posted by jimclauss View Post
    You can run pump gas with 10-12lbs of boost in a boat with 8:1 no problem
    Which blower would be the best choice? He found a deal on a pair of 10-71 s but his guy told him new 871 hi helix would be better

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    gn7
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    He is right in the range where you weigh the pros and cons.
    I understand the builder suggesting the 8s, but if the price is right on the 10s.......

    The 8 is lighter and cheaper, and the 10 isn't going to make a single HP more at that blower speed.



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    Quote Originally Posted by gn7 View Post
    He is right in the range where you weigh the pros and cons.
    I understand the builder suggesting the 8s, but if the price is right on the 10s.......

    The 8 is lighter and cheaper, and the 10 isn't going to make a single HP more at that blower speed.
    If he goes with the 10's he found he'd save quite a bit of money. His concern is he doesn't think they will make the power as the hi helix 8-71's his buddy recommended. I am unfamiliar with the hi helix stuff. His buddy said "hands down the hi helix is the way to go" for his application.

    I can't see there being a big difference in air temp or power output between the two, but thought I'd ask here. I know you guys are well versed with these blowers.

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    Sorry to get off topic but how is 12lbs ok on pump gas in a heavy boat ??
    I have never heard that before even at 8-1 comp .....even innercooled.

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    12 pounds heavy boat fuel and timning easy
    Wags

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    When I say heavy boat, it's 12,000 lbs and wot can be for several minutes/miles at a time.

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    So it's ok to run that much boost on pump gas in an offshore style boat?

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    Quote Originally Posted by 1bdhondo View Post
    So it's ok to run that much boost on pump gas in an offshore style boat?
    My advice to my buddy was keep the boost around 9-10 psi and let it live a long time. He's low compression, but I feel his cam is a bit too conservative to be running that boost level with the $hit gas we have around here. With offshore boats you can't pull a bunch of timing bc on long runs the exhaust temps get to hot.

    He is trying every different Avenue to find a way to safely run 12 lbs of boost. I don't think the answer is exchanging the std 10-71 s for high helix 8's but that's why I posted this. I'd be putting my money towards better heads and cam combo vs trying to make power with boost.

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    gn7
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    at 8 to 1, I wouldn't want to take it passed 8 psi without an innercooler, with an innercooler, maybe 10.
    12 you are walking a tight rope I wouldn't want to try in a offshore deal.



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    Quote Originally Posted by gn7 View Post
    at 8 to 1, I wouldn't want to take it passed 8 psi without an innercooler, with an innercooler, maybe 10.
    12 you are walking a tight rope I wouldn't want to try in a offshore deal.
    I agree GN. I been trying to tell him that. He talks with a lot of race car guys, and sometimes those guys don't understand how hard an offshore engine is worked. Its not on the gas for 10 seconds then let off. More like on the gas for 10 minutes, then let off. Out of all my buddies with SUCCESSFUL blown offshore engines, the norm is between 6-10psi depending on the setup. Others have tried more boost, but it usually doesn't end up good. With that being said, his engine setup is 522CI. Lunati double cut blower cranks, Oliver rods, JE pistons with upgraded pins, Dart blocks. Edelbrock Marine performer RPM Rect ports and a 242/248 112LSA hyd roller. He also has another pair of 252/262 115LSA cams on the shelf. He wants to make 1000HP at minimum at 6000RPM on pump.

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    Quote Originally Posted by Mild Thunder View Post
    My advice to my buddy was keep the boost around 9-10 psi and let it live a long time. He's low compression, but I feel his cam is a bit too conservative to be running that boost level with the $hit gas we have around here. With offshore boats you can't pull a bunch of timing bc on long runs the exhaust temps get to hot.

    He is trying every different Avenue to find a way to safely run 12 lbs of boost. I don't think the answer is exchanging the std 10-71 s for high helix 8's but that's why I posted this. I'd be putting my money towards better heads and cam combo vs trying to make power with boost.
    OK, maybe I'm missing something not having a lot of experience with blown gas, but IMHO, 10 lbs boost is the same HP regardless of if it comes from a B&M 144 or a high helix, double throwdown 16-71. There may be a bit of HP difference due to heating the inlet charge by paddling the hell out of the air with a tiny blower, but boost is boost or am I missing something?
    Personally, I agree with the idea make the motor a better air pump with heads/cam whatever if you need to keep the boost down. And at 12,000 lbs, we're talking about a ship, not a boat

    Edited to add that if I wanted that HP level at that RPM, i'd be looking at going to a 632 with a decent head package. Normally, I don't like a 4.75" stroke but at that RPM level, it wouldn't bother me... Put 8 lbs on top of that motor and 1k HP should be a cake walk at 6k RPM...
    Last edited by David 519; 02-07-2014 at 12:15 PM.
    Quote Originally Posted by gn7 View Post
    ....... David 519 is 100% correct........

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    .....I think people forget that racing is supposed to fun. Losing shouldn't be discouraging it should motivate you work on your pile to make it faster.....

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    Yea, I just can't see there being a big difference in power output or air temp change between a standard 10-71 or 8-71 high helix. I always thought the high helix worked better at high rpm. I never played with a delta opening blower. How is the fuel distribution on them?

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