FrontEngineDragsters.Org Forum
Technical => Spud Miller's Cave => Topic started by: wideopen231 on January 30, 2016, 05:53:53 AM
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Spud,
Wondering if you knew cfm ratings(lots of factors for actual) of enderle hats.Bug,bird and buzzard. More less just like to know for educational reasons.
Also if don't mind.Whats if any thoughts on injector size for NA engines.Asking because I have 3 options for motor and pretty sure I will be trying all and more at some time. Have D ported bird,personally think way overkill.I have a 3 blade low profile home built piece.Also have a two blade(bird catcher butterfly's) piece thats lot like Ron's toilets and bolts to sheetmetal intake.Lowest and easiest to see over. Would scoop help here or no real effect? Sure would kill sight advantage of it.
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Bug: 2287 CFM
Bird: 4605 CFM
Buzzard: 5994 CFM
If you have a huge amount of butterfly area, getting a low, smooth idle will be difficult. In some cases, I've seen the butterflies CLOSED and the engine still idles too high. A guy has to start covering nozzle body vent holes to get the idle down in that case.
If it's naturally aspirated, a bug flows more air than you're likely to ever need.
I read a couple of things a long time ago that concluded there was no real benefit to scooping air from forward vs. down into a vertical opening on the drag strip. Land speed might be another story.
Spud
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Thanks Spud.Very helpful info. Kind of confirms what I have argued for while about size requirments when using hat.I have also debated with few on smaller ones seem to be more consistent and seem easier to tune.My thought being velocity differance.
If you look at most Jr. Fuel cars with stack style injector and the performance's with almost zero hight above butterfly it would support the lack of need for scoop.With my deal being bracket setup keeping trash out of engine while driving thru pits,crappy return roads and sitting behing car doing burnout or leaving line can be trick. Add in that the two butterfly setup I have(same area as bug) are 4.375 inch and thats lot of area for piece of gravel to land and cost cpl thousand in damage.
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How about a screen gasket ?
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I also have pee rock and sand a flyin at the burn out hit. Outer ware has a product to cover stacks. It can be pulled off before staging. Gotta be a little careful though as it is not backfire proof.
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When talking about CFM on a dry injection deal isn't always way more CFM than you would compare to a carb--I mean it takes way more dry air in an injection unit vs a carb Like a 11-1200 throttle body would be like a regular 750 carb when comparing--right? Just thinking out loud here
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A Ron's 4" is rated for 1434 cfm area wise that is 12.56 sq. in.What is open area for carb flowing that much?Asking because about only thing I know about carb is what Alan Starr said" A good trash can deserves better".Yea those old fuel guys not much on anything except injection.Old alky guys are about the same way.LMAO
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Air Flow = Fuel Flow with a carb.
That why too big won't run.
With MFI, not think it an issue if (like Spid said) you can keep it driveable and will idle.
And on the scoop deal, read once that a forward facing scoop was worth like 1.2 psi at speed, does that hurt anything??
Take care, K