Emulsion bleed depth

[Right hand drive]

What are the thoughts on the void or space left behind screw in emulsion bleeds as pointed out in yellow in pic below?

Is an unwanted turbulence created?

[Right hand drive]

Reason I ask the question in post 1 is the emulsion in factory Demon block in pic below would not have that thread void. Bubbles directly into main well fuel flow



But doing the below would create that void as threaded hole is around 7mm deep and screw in bleeds are 3 - 4mm long



Would Holley and Quickfuel have the same thread void?

[jmarkaudio]

If you are taking under the threaded bleed as long as it's double the diameter or more of the bleed size itself there isn't an issue. I usually drill them .070 if they need to be drilled. Now there will be turbulence if any splinters from drilling protrude into the mainwell...

[Right hand drive]

What I am getting at is when metering blocks are manufactured like in the first image I posted post #1 air is entering the main well through the bleed flush with the main well wall. See in green pen on crude drawings below. When we open up the factory drilled emulsion hole (you’re opening up to .070”), tap and fit screw in bleeds and there is a gap between the new .070” hole and the exit end of the screw in bleed (Blue pen below) would there be back flow of some fuel through the .070” hole to the new bleed and would this cause some flow disturbing eddy’s and currents? Could it disrupt the bleeds effect?

I could see that if you were to drill .070” hole and were able to bottom out a non flanged set screw on that hole there would not be such a situation but most I see and the ones I use are a flanged head to positively stop on a stepped hole.



It was the recessed bleeds in the first below pic that got me thinking about this compared to black block in first post and red blocks below

[BradH]

I had a similar thought re different length of e-jets of the same drill size... at the time I was wondering if / how the different "nozzle" length would impact the air stream flowing into the main well. And, IIRC, somebody on the old board gave me a good explanation on the possible changes... but I'd have to go look that up again to even remember.

Re the "void" after the e-jets on some blocks, yep, they're there on some of them. The BLP, Holley Ultra and Demon blocks I've had were all drilled "big" through to the main well. The 5-e Quick Fuel blocks are, too, I believe. However, their gas 4-e blocks (and the comparable blocks from Proform) are threaded, but pre-drilled for .028 and only have blank e-jets where plugs are used. Their instructions say if you want to be able to change the sizes that you should drill out the .028 to .050 and then use typical drilled e-jets.

When they're used as they come from Quick Fuel or Proform, it's basically the same config as an "old school" Holley cast block where there is a larger drilled opening leading to a smaller drilled bleed. Here's a pic from the side showing both an old Braswell-modified Holley cast HP block next to a Quick Fuel with the original drillings that are used w/o replaceable jets. I have to ASSume, since I'm not going to cut apart any metering blocks to know for sure, that when they're done this way there is no effective "void" and the opening of the drilled e-bleed is right into the main well.
.

.
Then consider that the cartridge used in a RapidJet metering block has all of it's tuning orifices (emulsion, IFR, PVCR) drilled straight into the "tube", and the emulsion bleeds are drilled into the thinnest section area. No void there, but not much of a "lead in", either... just a hole.
.

.
At some point you'll realize that all this stuff can drive you crazy looking for "answers". And for myself, I have to wonder even if I find "the answer" to one of my bazillion questions on this subject, is it going to make any detectable difference to the end result of how effectively my carb(s) work?

Hypothesis and theory take a back seat to reality once it's bolted down and fuel & air are flowing through it. I need to remember this as much as anyone.

[Right hand drive]