FrontEngineDragsters.Org Forum
Technical => Spud Miller's Cave => Topic started by: wideopen231 on February 18, 2016, 05:51:32 AM
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My hemi heads have been drilled and tapped for down nozzles,used fuel heads.While reading post on rotary injectors I noticed few comment about nozzle placement.Most sem to think dry runner and port aided in increase air.Having read few things about amount of fuel in intake charge occupying area instead of air it makes good sense.
Is there any gain by using down nozzle location.Since its NA motor seems I could just plumb regular nozzles in that location.Not something I want to do from start,figure get good baseline tuneup then try few things and this could be one thing to add to list.
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My take would have to be the time it would take to fill lines and the fuel rails (huge volume)inside the head with pressure running a small pump
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With spring check nozzle bodies it makes since to me the Sprint car guys have been doing it for years because it builds HP
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Volume no different than running nozlles in ports,as for rail it will require no more than what can get out.As for volume to fill on startup I have hard time seeing it being anything different.
Don't see why you would need spring check nozzles.They are doing same thing in head as ports except they are 3.5 inches closer and right above valve.Maybe somethingI am overlooking?With blower setup I can see need.
If there is reason explain,always ready to learn why something will not
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Built many a fuel rail for Nos top fuel cars running a 20gal pump,down load always showed a small pressure drop at the hit, went back to individual lines and it disapeared.
Sprint cars are a different animal since they rely on a rolling start before they mash the throttle
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Bruce
Are the Nozzel bodies even the same?
I thought the down Nozzel did not have the hole in them?
Oil vapor from beeing in the valve cover??
On a NA engine not sure much of advantage
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All nozzles bodies above the blower need airator bleed holes, below the blower you cant have holes in the body. Sprint cars running down nozzles have airator holes and are covered with a foam filter to keep dirt out, Primarly because the Hilborn type nozzles run fine mesh screen which can get clogged while the enderle style is a hole with a defector tip to fan/spreed the fuel
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Have 4 or5 sets of both w/hole and w/o.So 8 w/o is no problem.As for fuel rail still would not be problem.First I leave at 5000 stage maybe more. Second not planning on running a typical rail.Two number 4 lines per head feeding two nozzles each.Biggest thing I see as issue is possible condensation of line with alky running thru it and hot oil.
Back to gains.I had thought about this before and kind of dismissed it.Afer doing some reading and talking with a few others who have run the Rotary and think some of the gains where nozzle locations , given that good part was also air flow gains.Especially peaked my interest after post on rotary injector.