SoCal Jet Boats

Discussion => The No Wake Zone => Topic started by: JARVIS on October 30, 2014, 12:38:56 AM

Title: scoop question
Post by: JARVIS on October 30, 2014, 12:38:56 AM
so i had asked this in another thread.....didnt get a reply.  maybe wrong place for it....

for those of you who added a scoop, either for single or dual carb setups....did any of you notice a difference in performance??  higher rpm?....or?

thanks for any input. O0
Title: Re: scoop question
Post by: GT Jets on October 30, 2014, 07:27:07 AM
so i had asked this in another thread.....didnt get a reply.  maybe wrong place for it....

for those of you who added a scoop, either for single or dual carb setups....did any of you notice a difference in performance??  higher rpm?....or?

thanks for any input. O0

No.

Imho purely aesthetic.

The whole idea is to keep the rushing air from blowing "across" the carb top.

GT

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Title: Re: scoop question
Post by: Ralph Brunt on October 30, 2014, 08:09:11 AM
No.. I run mine facing the rear

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Title: Re: scoop question
Post by: lifted250 on October 30, 2014, 08:23:54 AM
Why do u think in drag racing  there forward  it rams more air down  fast



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Title: Re: scoop question
Post by: GT Jets on October 30, 2014, 08:39:10 AM
Why do u think in drag racing  there forward  it rams more air down  fast



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You are on a boat forum.  Our junk don't go 200 mph.. mine don't anyway.

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Title: Re: scoop question
Post by: tpltrbl303 on October 30, 2014, 10:04:08 AM
Mine faces backwards as well (mainly so Ralph doesn't spray me when he goes by)


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Title: Re: scoop question
Post by: Flusher on October 30, 2014, 10:07:21 AM
There is a lot to be said for a rear facing scoop on a boat.  Not because it takes advantage of the high-pressure area near a car's windshield, but in the event of crossing another's rooster tail or taking on a scoop of water.

Regarding a scoop functioning at low speeds, aerodynamic forces can be felt at meager speeds by simply sticking your hand out of the window of a moving car.  The forces increase four fold as the speed doubles.  The opening on a forward facing scoop can be made larger to take advantage of ram affect at slower speeds.

Some issues I have experienced:  once the ram affect gets to the point where "boost" is actually generated, as in the case of a Bird Catcher hat mounted on a tunnel ram, the rear cylinders tend to run leaner than the front.  Scoops mounted on carbs where there is turbulent air above the venturi or where air speed is high shooting across the top of a carburetor reduces booster signal.  If the carbs are not functioning properly, you will never realize your peak potential.

I like to compare anything connected to the induction to cylinder head porting.  It has always bothered me when somebody spends big dollars on ported heads, then bolts on some sub-standard induction and wonders why their dyno experience was less than hoped.  The induction system is really everything in between and including the combustion chamber/cylinder and the atmosphere, which also includes the scoop.  In my opinion, form follows function.

Just my $.02

Cheers,

Joe
Title: Re: scoop question
Post by: lifted250 on October 30, 2014, 10:24:38 AM
It really simple the more air u can get in the  better it mixes with fuel


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Title: Re: scoop question
Post by: Flusher on October 30, 2014, 10:32:23 AM
It's all about quality of flow, not just quantity of flow.

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Title: Re: scoop question
Post by: riptide84 on October 30, 2014, 11:25:02 AM
It's all about quality of flow, not just quantity of flow.

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Is there a certain scoop design that creates more of a quality air flow than others?
Title: Re: scoop question
Post by: Beaveretriever on October 30, 2014, 12:05:04 PM
Is there a certain scoop design that creates more of a quality air flow than others?

Mechanical fuel injection, especially crower 3" with red bells that match your boat, would benefit you the most. More power, more rpm. Imo

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Title: Re: scoop question
Post by: Flusher on October 30, 2014, 12:08:29 PM
Look at circa 1975 formula one cars for scoops that are compatible with what we are doing and are the pinnacle of technology.  In 1976, there was a rule change and scoop designs changed.

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Title: Re: scoop question
Post by: MorePower on October 30, 2014, 01:56:13 PM

Mechanical fuel injection, especially crower 3" with red bells that match your boat, would benefit you the most. More power, more rpm. Imo

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I agree! And you are selling the set up still, correct?


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Title: Re: scoop question
Post by: Beaveretriever on October 30, 2014, 02:02:45 PM
I agree! And you are selling the set up still, correct?


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That is correct Drew

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Title: Re: scoop question
Post by: JARVIS on October 30, 2014, 03:10:56 PM
Look at circa 1975 formula one cars for scoops that are compatible with what we are doing and are the pinnacle of technology.  In 1976, there was a rule change and scoop designs changed.

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without getting into heated debates....
my understanding of changes in f-1 were for many reasons.  including some that restrict top speed by reducing aerodynamics.....so they cant scream thru a corner as fast....making them safer ....??  same with the tire change....using grooved tires instead of slicks....slowed them down a little....at least in corners.
circa 1975....if you made some changes to aerodynamics....the previous scoop design may hinder max efficiency....so it needed a change to compliment the rest of car.  i can see some of the scoops were high...maybe looking for 'cleaner' air....undisturbed by front wing, body, etc.  could also provide some quality control, distribution of air. 
speaking of....while im no expert, i found it hard to believe the scoop actually generates boosts.  engine is under vacuum....which has to be over come to create boost....right?  i wouldve expected intake vacuum perhaps to reach '0' and not have enough force to create pressure in the intake down to intake valves.  perhaps a scoop makes the engine breathe easier, not having to 'suck' hard to get air volume.....and again to improve quality of air getting to engine, distribute it evenly among all cylinders.  again no expert here....actually expecting to face the firing squad on this one.....i dont smoke, but i should lite one up.....


Title: Re: scoop question
Post by: JARVIS on October 30, 2014, 03:19:09 PM
this is all good info. 

main reason i ask:  in another thread we talked about making a scoop of a different design....something out of the norm.  there seemed to be a few interests there.  however....me making a scoop of a different animal....while i would try to follow any rules i can find...i thought might hinder performance.  if the survey says more for looks than performance-particularly in our applications-then i may have some art work to do....run it by you guys for approvals.

otherwise.....its just art work on paper.  thanks gents! :beer:
Title: Re: scoop question
Post by: icecreaman on October 30, 2014, 09:23:48 PM
I think this falls into the category that most our boats aren't near efficient enough, and our set ups aren't good enough to worry about how much effect scoop design is going to have.  How many boats run the Dooley style scoops in everything from drag boats to GN boats.  There's not a whole lot of engineering in those scoops.  If you're set up is so efficient that your looking for .010 or .001  of a second then maybe spending a bunch of time working on air flow induction may be a concern.  For me it's more about cosmetics or the look.  I run spark arrester's in my scoop.  I ran them on the dyno and found they only cost me like 1% in HP.  That's not enough to worry about in a play boat IMO.
Title: Re: scoop question
Post by: JARVIS on October 30, 2014, 09:52:36 PM
I think this falls into the category that most our boats aren't near efficient enough, and our set ups aren't good enough to worry about how much effect scoop design is going to have.  How many boats run the Dooley style scoops in everything from drag boats to GN boats.  There's not a whole lot of engineering in those scoops.  If you're set up is so efficient that your looking for .010 or .001  of a second then maybe spending a bunch of time working on air flow induction may be a concern.  For me it's more about cosmetics or the look.  I run spark arrester's in my scoop.  I ran them on the dyno and found they only cost me like 1% in HP.  That's not enough to worry about in a play boat IMO.

I hear ya.  sounds like ill be sketching up some ideas.
Title: Re: scoop question
Post by: East County Kona on October 30, 2014, 10:17:19 PM
If it looks like it adds horse power people will buy it.


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Title: Re: scoop question
Post by: icecreaman on October 31, 2014, 08:41:02 AM
I made mine because I wanted something a little different from what every one else was running.  Plus I had this idea of an old school nitro scoop, or at  least that's what I call them.  I had no experience doing this kind of stuff (plug making) so I  just winged it with some high density foam.  I'm happy with it and that's what counts.  I wasn't trying to do something everybody would want. Here's a few shots of what I did,

Title: Re: scoop question
Post by: icecreaman on October 31, 2014, 08:48:55 AM
It's since been painted (Twice!).  If I only had Sam's talent with a spray gun.
Title: Re: scoop question
Post by: Jet Boat Maloney on October 31, 2014, 11:11:04 PM

I made mine because I wanted something a little different from what every one else was running.  Plus I had this idea of an old school nitro scoop, or at  least that's what I call them.  I had no experience doing this kind of stuff (plug making) so I  just winged it with some high density foam.  I'm happy with it and that's what counts.  I wasn't trying to do something everybody would want. Here's a few shots of what I did,
I have to say that came out pretty bitchin. Great job!!!!


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Title: Re: scoop question
Post by: Roadrunner on November 01, 2014, 02:00:07 PM
I really like the way it looks. Very nice job.


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Title: Re: scoop question
Post by: JARVIS on November 02, 2014, 05:34:58 PM
let me ask you guys this....would anyone care if scoop was plastic, such as lexan, ABS, acrylic....or would you feel it to be to fragile?...
Title: Re: scoop question
Post by: Ralph Brunt on November 02, 2014, 06:06:50 PM
Finney s makes them out of lexan or acrylic. So they do work

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Title: Re: scoop question
Post by: JARVIS on November 02, 2014, 06:26:55 PM
perfect!
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