Nevermind. Again.
Annular boosters on a Tunnel Ram
- Thread starter MomsDuster
- Start date
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RB,
What they teach down under is physics & how to read, both instrumental in understanding how an air bleed works in a carb.
Not sure if I posted this earlier in this thread, but this is from the Carter Carb book by Dave Emanuel, p. 26. It couldn't be more clear....
'....a reduction in bleed size reduces vacuum signal requirements & fuel flow is more easily initiated'.
A smaller [ not larger] AB starts the system SOONER.
What they teach down under is physics & how to read, both instrumental in understanding how an air bleed works in a carb.
Not sure if I posted this earlier in this thread, but this is from the Carter Carb book by Dave Emanuel, p. 26. It couldn't be more clear....
'....a reduction in bleed size reduces vacuum signal requirements & fuel flow is more easily initiated'.
A smaller [ not larger] AB starts the system SOONER.
Rat Bastid
Dunamis Metron
Yep, and he’s WRONG again.
You know, you can test this on the dyno. You can test it in the car if you have a data logger. If you had access to that you’d see how wrong you are.
And I’ve already pointed out to Hysteric that you have different physics. And you BOTH failed reading comprehension.
Carry on and be wrong. There are guys on here who have tested the MAB and the results. And oddly, their results match Taylor. And my results.
Of course, down under it may be different.
You know, I hear toilets flush backwards down there. Maybe you should give him some slack. lol
Rat Bastid
Dunamis Metron
I heard that too. And then there is that Veggimite stuff. I hear it causes delusions and hallucinations. So there is that too.
RB,
What I am not deluded about is how ABs work, & neither are a lot of much smarter people than you are.....
And as for 'physics' our southern physics is the same as your northern physics, only yours is different, to suit the occasion.
Vegimite has one g...
What I am not deluded about is how ABs work, & neither are a lot of much smarter people than you are.....
And as for 'physics' our southern physics is the same as your northern physics, only yours is different, to suit the occasion.
Vegimite has one g...
Rat Bastid
Dunamis Metron
Yeah, I should have Googled the spelling. But you knew what I meant.
Obviously carb function is different down under.
Rat Bastid
Dunamis Metron
Let me ask you this. See if this gets into the hard nugget.
How does and emulsion ABOVE fuel level function?
Think on that and let me know.
I am quite happy to have a civilised discussion with you about emulsion.
I am not sure what you mean by function of emulsion above the fuel level?
The entry to the booster is 1/4 -1/2" above the fuel level in the fuel bowl, for all venturi style carbs & this is the theoretical level in the main well that feeds the booster. This is called the spill height. In a running engine at idle, the fuel level in the main well is actually slightly lower than this because nearly all American carbs take idle fuel from the main well. The only American carb I am aware of that does NOT supply idle fuel from the main well is the Comp Series TQ. It, like some Weber & Dellorto performance models, take idle fuel direct from the float bowl. I assume this is for more accurate metering of the main system.
To get fuel to the booster entry, the fuel has to be lifted 1/2". What does does that? Atmospheric pressure acting on the fuel in the bowl pushes out the fuel in conjunction with suction/depression at the booster nozzle. It should be obvious that any bleeding off [ MAB ] will delay the start up of the system [ the straw example ].
Air is drawn through the MAB which aerates/emulsifies the fuel in the main well. This makes it easier to lift the lighter emulsion as compared with solid fuel.
A smaller MAB starts the flow earlier because less signal is lost [ or bled off ] & a bigger MAB starts the system later because greater vacuum [ more air speed, higher engine rpm ] is reqd to overcome the signal lost to the bigger MAB.
I am not sure what you mean by function of emulsion above the fuel level?
The entry to the booster is 1/4 -1/2" above the fuel level in the fuel bowl, for all venturi style carbs & this is the theoretical level in the main well that feeds the booster. This is called the spill height. In a running engine at idle, the fuel level in the main well is actually slightly lower than this because nearly all American carbs take idle fuel from the main well. The only American carb I am aware of that does NOT supply idle fuel from the main well is the Comp Series TQ. It, like some Weber & Dellorto performance models, take idle fuel direct from the float bowl. I assume this is for more accurate metering of the main system.
To get fuel to the booster entry, the fuel has to be lifted 1/2". What does does that? Atmospheric pressure acting on the fuel in the bowl pushes out the fuel in conjunction with suction/depression at the booster nozzle. It should be obvious that any bleeding off [ MAB ] will delay the start up of the system [ the straw example ].
Air is drawn through the MAB which aerates/emulsifies the fuel in the main well. This makes it easier to lift the lighter emulsion as compared with solid fuel.
A smaller MAB starts the flow earlier because less signal is lost [ or bled off ] & a bigger MAB starts the system later because greater vacuum [ more air speed, higher engine rpm ] is reqd to overcome the signal lost to the bigger MAB.
Rat Bastid
Dunamis Metron
So close, yet so far away. Read what you wrote, and then go read the whole chapter in Taylor where I pulled the quote. See if that helps you get it.
What happens when you change the size of the emulsion bleed above or right at fuel level? pick either way, making it larger or smaller. Either one.
I actually have some questions, but I gave the **** slam up several posts ago. Piss on both of yall.
Rat Bastid
Dunamis Metron
Ask them. You’ll get two different answers. Then go use them both and see who is full of ****.
Remember all the **** I got right here in this forum for telling people to stop using half intake idle vacuum to set power valve opening. A regular crap factory.
A couple of guys went out and tested it and found out that for decades Holley and their mouth pieces have been giving wrong tech. And they still do it.
Ask away. Then go test and post your results. That would settle it. Well it won’t because some will never learn. But YOU will know.
Looks good Mark!
I find it interesting every forum I go to, there are differing understanding of AB and how they work. Two groups arguing over the same info. Multiple experts quoted which seem to be saying the same info, but understanding it differently.
My understanding: With more air coming in the bleed, fuel is being aerated which in turn allows it to flow easier, which seems like it would come in sooner, but also the volume of fuel is less due to the aeration. Even erratic through the booster if the added air is too much. Does anyone agree with this statement?
I find it interesting every forum I go to, there are differing understanding of AB and how they work. Two groups arguing over the same info. Multiple experts quoted which seem to be saying the same info, but understanding it differently.
My understanding: With more air coming in the bleed, fuel is being aerated which in turn allows it to flow easier, which seems like it would come in sooner, but also the volume of fuel is less due to the aeration. Even erratic through the booster if the added air is too much. Does anyone agree with this statement?
MomsDuster
Well-Known Member
Thanks Eric, I would tend to agree with you on all points. Now let me throw another factor in there. As i understand it, the air bleed is by design meant to be more of an activation tool that can also affect the mixture of the fuel going to the booster. The emulsion stack is where the mixture is actually created. Therefore if the emulsion is out of whack to begin with then it can throw off what the bleed is actually doing. Does that make sense? Hopefully we can get some good input to these questions without a bunch of useless fodder being thrown out with it. The whole thing is confusing enough for me without having to read between the insults.
Demon,
Your understanding is correct about creating emulsion. But emulsion is getting mixed up with when the system starts & the relationship THAT has to the MAB.
The smaller AB starts the system earlier & vice versa.
Your understanding is correct about creating emulsion. But emulsion is getting mixed up with when the system starts & the relationship THAT has to the MAB.
The smaller AB starts the system earlier & vice versa.
I already know who I will believe. I'm not gettin in the argument and bullshit. I just wanted an answer.
Rat Bastid
Dunamis Metron
BOOOOOOOOOOOOOOOOOOOOOOOM!!!!
You GET it.
For those who don’t get what the argument is, read and read and read and read this over and over and over and over until it makes sense.
Your post is EXACTLY why a larger air bleed starts the mains SOONER. EXACTLY.
With a bigger MAB, there's more air flow so it pulls more fuel. Not difficult to grasp.
Rat Bastid
Dunamis Metron
How much MORE air flow is there at idle and low engine speeds and what does that do to the pressure drop across the booster?
Thats what Taylor is saying. At low air flows the pressure differential makes the MAB act like an emulsion. The signal is now weaker and the MAB start is DELAYED.
You have to think in terms of air flow and pressure differential across the booster and the bowl vent.
When you think about that, it becomes clear what Taylor is saying.
Plus, if you can do algebra you can mathematically calculate it out.
Thats in the Taylor books and Oberts “Internal Combustion Engines” and I think “The Design and Tuning of Competition Engines” by Phillip Smith.
You can’t just read one quick quote like I posted above. But I can tell you 100% that Tuner says this is true and Shrinker says it’s true and my testing says its true.
Air flow changes the pressure differential across the booster and that changes the way the MAB acts.
You can also find this is NACA (I think it’s now NASA) Report 49 and also in Effects of Air-Bleed Systems on Carburettor (sic) Performance by Yasuke Asano, Toshitska Chuma, Heiichiro Haga and Tadahiro Mochida.
I can‘t remember where the latter came from so if you can’t find it, PM me your email and I’ll have the wife scan it and email you a copy.
RB,
I sent you a PM, not sure if you saw it, a while back. I was essentially asking your thoughts on my combo and what I am seeing. Would you be willing to take a look now that I am starting to get it?
Rat Bastid
Dunamis Metron
Send me the PM again. I don’t see it in there.
I sent a reply to the same pm. Does it show a notification?
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