Down nozzle question

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by rb0804, Dec 15, 2017.

  1. rb0804

    rb0804 Member

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    How does the down nozzles rail seal to the fittings in the side of the head? I was looking at the ones RBS has for sale and it looks like they just slide into the fittings? Is there an o-ring inside the fitting? Is it possible to just buy the fittings and make my own rail? Who sells just the fittings? Here is a link to the ones I was looking at. Thanks.



    http://www.rbssuperchargers.com/Pro...Fuel_Rails_Noonan_Black_Hawk_Alch_--7003-0076
     
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  2. HootersFunnyCar

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    Yes There is an O-ring inside the fitting.

    RBS sells the fittings.
     
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  3. jay70cuda

    jay70cuda Member

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    What is the purpose of down nozzles ? A hp gain or smoke and mirrors?
     
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  4. Mike Canter

    Mike Canter Top Dragster

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    I will be interested in hearing the answer to that question. It would be helpful if somebody who has used them and has real data.
     
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  5. TADHemiracer

    TADHemiracer Member

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    I always that fuel cars used the down nozzles because of the volume of fuel being injected. I doubt the down nozzles would make gains for alcohol.
     
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  6. TOL

    TOL Active Member

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    I too would be interested to hear results.

    Are these down nozzles simple fans or shotgun/whirled designs against the backsides of the valves?

    Theoretically they should have an advantage in terms of combustion?
     
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  7. TADHemiracer

    TADHemiracer Member

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    I thought that the standard down nozzle that fuel cars use is the standard angled deflector. Just "shove the nitro in and let the magic happen" thinking.I don't know about the swirl or that but the residence time for alcohol in that use of down nozzles is as close to zero as there is.
     
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  8. Mike Canter

    Mike Canter Top Dragster

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    There is only one correct Air Fuel Ratio regardless of where you put in the Methanol. I agree with pushing in the nitro because that has a crazy 1:1 AFR
     
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  9. MaineAlkyFan

    MaineAlkyFan Active Member

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    I wouldn't think there would be enough time for proper vaporization & not much cooling density benefit that close to the valve. It seems like if there is any potential gain, keeping the repeatable effective AFR window tuneable would be a huge challenge.

    Chris Saulnier - Team Tigges
    Mechanic Falls, Maine
     
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  10. Mike Canter

    Mike Canter Top Dragster

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    Chris, I agree with you. It is far better to use a spray bar just behind the butterflies. So you live in Mechanic Falls, I live in Brunswick
     
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  11. blowntuner

    blowntuner New Member

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    The only change between the nozzle lacation is the gain in air flow thru the intake runner
     
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  12. rb0804

    rb0804 Member

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    Which is probably negated by the increase in temp of the fuel by using the down nozzle location.
     
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  13. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    A couple of legal pro mod teams told me it was worth 30 hp on the dyno. This was several years ago.

    I haven't back to backed it, but Lindberg had down nozzles when he went the .36. I ran them on McVey's car, but we went to 8 ports/8 down nozzles. I was trying something in the fuel system, it didn't really work, but at the same time we got some other things right and started running good speed, so I just decided to leave it alone. Whenever I get my car out, I will run the 8 down nozzles.

    For what it's worth, it looks a lot cleaner with no port nozzles.
     
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  14. Mike Canter

    Mike Canter Top Dragster

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    It would seem to me that if somebody gained 30hp from them the tuneup/AFR was not correct on the port nozzles to start with.
     
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  15. rb0804

    rb0804 Member

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    Hmmm. Seems we have opened a can of worms, now the question is which way do we point the nozzle? Up towards the intake so the fuel has time to atomize? Down towards the valve? Or towards the port wall so it’s a finer mist?
     
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  16. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    most use a sprayer nozzle, not a directional.
     
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  17. TOL

    TOL Active Member

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    Straight shot right toward the backside of the intake valve, toward where the stem/head intersect, from say 2-2.5 inches away. A tight conical spray plume so as to largely miss the bowl and walls (or a very high velocity impaction type pencil stream).

    Thinks about down nozzles this way......

    The intake valve is relatively hot and will help overall vaporization. The air shear velocities at the valve/seat interface will vigorously bust up much of the fuel that does not vaporize. Liquid fuel that does get into the chamber will readily vaporize during the compression stroke and early stages of ignition. Why would any of this be inferior to a normal fan port nozzle, say 5-6 inches away from the valve, which is largely just wetting the port walls?
     
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  18. ITS IN MY BLOOD

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    To try and answer the second question from an outsider..lol..,."why down nozzles in the head"..Its a Nitro fuel thing,..these nozzles are Run nozzles and open up after the return/ or by pass slot in the barrel valve closes these nozzles open up usually about 28psi naturally aspirated and 40-45.?? on blown app, and depending on the position of the transfer slot for wide open throttle, they aid and provide for a few things , one at the hit it ensures there is plenty of fuel in the cylinder to prevent that momentary lean spot from idle to wide open throttle that causes that dreaded back siding of the piston, including when doing the burn out, ...two, ..the down nozzles help with the amount of volume/consumption of fuel percentage it takes to burn a said given load power/ and torque,.3rd..the nozzles being as close as possible to the chamber insures it is getting all it can as quickly as it can,.4th..it also provides a momentary cooling of valve train,.and last there is not much need for the fuel to travel threw a runner for atomization because of the fuel pressure they run, which creates its own spray pattern right out of the nozzle.,..With a alcohol motor I think the rules dictate what you cant do and leaves you only with hat and port nozzles only.......Just my opinion of how I see it,.I am no rocket scientist but I did sleep at a Holiday Inn express last night......
     
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  19. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    I wouldn't say down nozzles are just a nitro thing. I don't know if they still are the hot ticket, but I know several years ago down nozzles on a blown sbc was worth some power, and if I'm not mistaken, some sprint car teams use them.
     
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  20. nitrowannabe

    nitrowannabe Member

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    I just saw them recently on a hot ticket pro mod. Noonan heads ? Can't remember.
     
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