Tunnel Ram Tune

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Bewy said:
Mattax.
'None of these carbs are sucking directly from the bowl.'
Yes they are, through the m/jets. And you can remove the m/jets & you will get a horribly rich mixture. If the fuel doesn't come from the bowl, then how would fuel get to the booster/t.bores? The word sucking gets used a lot because it is easier to understand; fuel flows because of a pressure difference. Atmospheric pressure on one side of the jet & venturi vacuum [ depression] on the other side. VV is NOT the same as manifold vacuum.

RB.
Your statements confirm that you know little about how a carb works. The straw example I gave is a perfect simulation of how the AB works & how it's size affects the starting point of the main cct. For those interested in this, find a book [ or internet ] diagram of the main system of a carb & you will see the straw comparison is a perfect fit.
'You ignore air speed'. Uhhhh no actually. You missed it. Suction & airspeed in a carb are mutually dependent. I wanted to keep the straw example simple so it was easy to follow. Air speed through the venturi where the fuel outlet is located is increased when the throttle is opened to increase engine rpm; at the same time, pressure in the venturi decreases. Atmospheric pressure in the bowl will at some point be higher & push fuel out of the nozzle. Adding an air bleed bleeds of some pressure, so more vacuum [ depression ] needs to be created in the venturi to get the fuel to flow. If the AB size is increased, the pressure signal is weakened & more vent vac is reqd to start the flow. This additional vent vac is created by opening the t/blades further to increase engine rpm [ & therefore air speed ]; flow starts. Larger MAB starts the system later [ higher rpm ] & smaller MAB starts at a lower rpm. The straw example is a perfect example of the system works. It is just physics.
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You are in over you're head on this one.
 
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lead69 said:
That's because one is leading the other and they are out of sync, you need to build a carb sync and adjust accordingly.
Edelbrock 4025 Edelbrock Uni-Syn Carburetor Balancing Instruments | Summit Racing
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Certainly a handy gadget to have!

27AFD60B-AB90-4E2C-8FE2-A2D55C86E8C8.jpeg
 
j par said:
Well I think everything on my carbs for doing fine... It runs good, my AF gauge is happy and so are my spark plugs...
I ain't planning to fix something that's not broken...
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I guess there is Right and there is not broken :poke: :D
 
lead69 said:
I guess there is Right and there is not broken :poke: :D
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I guess there's guys who think there's only one way to do things and guys that after 7 years of drag racing and street driving their stuff they have a good idea of when their motors running good...:thumbsup:..
If I ran out and bought every gadget and did every thing every guru on this forum said to do I'd be broke...:thumbsup:..
 
j par said:
I guess there's guys who think there's only one way to do things and guys that after 7 years of drag racing and street driving their stuff they have a good idea of when their motors running good...:thumbsup:..
If I ran out and bought every gadget and did every thing every guru on this forum said to do I'd be broke...:thumbsup:..
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Or at least fast :lol:
 
j par said:
LOL you would lead people to believe that you have something for me LOL...
Oh I forgot you were talking top speed..
You have the slant six overdrive transmission...:poke:...
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Actually as you have gone more street mine is getting allot more race, looking forward to seeing what it will do next season. You only get one shot so I figure better make it good while I can, I will still have wipers and a heater lol.
 
lead69 said:
Actually as you have gone more street mine is getting allot more race, looking forward to seeing what it will do next season. You only get one shot so I figure better make it good while I can, I will still have wipers and a heater lol.
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Have you got a time slip with that car yet?
I have no wipers and ac!... Good luck with that heater at Woodburn.. lol...
 
j par said:
And crickets....lol...
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What do you want me to do?, keep posting random crap in a tunnel ram tuning thread?, start a thread of your own titled "lead69 call out thread" or some sort and we can have all the mindless banter you want. :thumbsup:
 
lead 69,
Not in over my head [ post #27 ]. If you do not understand the simple principles involved, then all you are showing is your ignorance.....
Are you aware that Rat Bastid who is trying to tell us how air bleeds work is on the Racing Fuel Systems website asking questions about air bleeds.....
 
Bewy said:
lead 69,
Not in over my head [ post #27 ]. If you do not understand the simple principles involved, then all you are showing is your ignorance.....
Are you aware that Rat Bastid who is trying to tell us how air bleeds work is on the Racing Fuel Systems website asking questions about air bleeds.....
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:BangHead:
 
RB,
Can you explain the two straws? Happy to be proved wrong but I don't think two straws is going to do it..
 
lead69 said:
What do you want me to do?, keep posting random crap in a tunnel ram tuning thread?, start a thread of your own titled "lead69 call out thread" or some sort and we can have all the mindless banter you want. :thumbsup:
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LOL more turning around on me LOL...
I gave my thoughts on the subject and you're the one who started banter with me lol... Telling me I don't know how to tune my carburetors leaving it out in the air like you do... If I don't run out and buy the tool that you say I should I don't know what I'm doing... In the very big one calling my car slow with 7 years of Time slips and you don't have one in the last 7 years that anybody knows about...
Does he go by rat bastid now...:poke:..
I wouldn't know I have all toxic people on ignore....
 
Bewy said:
lead 69,
Not in over my head [ post #27 ]. If you do not understand the simple principles involved, then all you are showing is your ignorance.....
Are you aware that Rat Bastid who is trying to tell us how air bleeds work is on the Racing Fuel Systems website asking questions about air bleeds.....
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Yes, I ask a lot of questions. Most of which are over your head. I’ll say this a different way so maybe it will connect with you. The MAB an low air speeds acts as an emulsion bleed. That’s why it only changes the fuel curve at higher air speeds (through the booster). If it was you think, a bigger air bleed would lean the fuel curve at ALL air flows. It doesn’t. A smaller MAB will make the fuel curve richer at higher air speeds, not across the fuel curve. Once again, you ignore the change in viscosity of the fluid in the main well. You can see a similar result adding more emulsion bleeds or area or both. You can get enough air in the fuel that it goes dead rich everywhere because you are pulling more fuel sooner. Keep adding emulsion after that and you will get into “slugging”. You will pull a “slug” of emulsified fuel and it goes rich and then you will a lean spot. You can continue to ignore fluid viscosity. And you will still be wrong. I’ve made this as simple as possible so maybe you understand. And yes, I ask questions when I don’t know the answer. Notice I didn’t ask you. There is a reason for that.
 
Ahhhh RB,
Your ignorance just grows & grows.....
I never said a bigger MAB would lean the curve at all speeds...or anything remotely like that.
The fuel curve in the mid range gets trimmed by the emulsion holes: their size, position & in some carbs like Webers, the number of holes. The MAB supplies the air & it does double duty by controlling when the system starts. Agree that smaller MAB richens the mixture at the higher rpms.

We are all still waiting to here about two straws, post #25.....
 
Bewy said:
Ahhhh RB,
Your ignorance just grows & grows.....
I never said a bigger MAB would lean the curve at all speeds...or anything remotely like that.
The fuel curve in the mid range gets trimmed by the emulsion holes: their size, position & in some carbs like Webers, the number of holes. The MAB supplies the air & it does double duty by controlling when the system starts. Agree that smaller MAB richens the mixture at the higher rpms.

We are all still waiting to here about two straws, post #25.....
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One more time. If what you think is true, a bigger MAB delays the start of the mains, that would mean it’s bleeding signal at low air speeds through the booster. That’s the ONLY away that can be. I’m not explaining anything to you. When you get the operation of the MAB correct then maybe I will.
 
mbaird said:
Now I will be afraid to ask for advice on tuning my TR ...lol
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Don’t be. Doing a TR is different but not hard. The first thing is to unlearn all the nonsense being spread around. Mattax somewhere on here posted a link to NACA 49. Find that and read that paper. Larew wrote a great book. Taylor wrote a bunch on carb function in his books. The first thing to get your head around is fluid viscosity. Change the viscosity of any fluid and you change it’s behavior. Simple as that. One easy example is two stroke tuning. If you take 5 different premix oils, mix them at the same ratio and they will all have a different viscosity. That affects tuning a bunch. Now get an oil that mixes at say 80:1 and compare that to an older oil like one of the Pennzoil premix oils that mixes at 32:1 and compare the two. The pennzoil mix will require a bigger pilot, more main jet and a rich needle. Not only because at 32:1 there is significantly more oil in the jet relative to fuel then an oil mixed at 80:1, the pennzoil mix will be a higher viscosity because the oil is thick. So that translates right into any carb tuning. Changing an air bleed (among other things) will change the viscosity of the fluid. Change the viscosity of the fluid and you change how it behaves. Air speed is the other thing. One example is using annular boosters over a down leg. The AB will have a much higher signal so by that one characteristic will change how much and when you need emulsion. It’s relatively simple when you think it through.
 
Rat Bastid said:
Don’t be. Doing a TR is different but not hard. The first thing is to unlearn all the nonsense being spread around. Mattax somewhere on here posted a link to NACA 49. Find that and read that paper. Larew wrote a great book. Taylor wrote a bunch on carb function in his books. The first thing to get your head around is fluid viscosity. Change the viscosity of any fluid and you change it’s behavior. Simple as that. One easy example is two stroke tuning. If you take 5 different premix oils, mix them at the same ratio and they will all have a different viscosity. That affects tuning a bunch. Now get an oil that mixes at say 80:1 and compare that to an older oil like one of the Pennzoil premix oils that mixes at 32:1 and compare the two. The pennzoil mix will require a bigger pilot, more main jet and a rich needle. Not only because at 32:1 there is significantly more oil in the jet relative to fuel then an oil mixed at 80:1, the pennzoil mix will be a higher viscosity because the oil is thick. So that translates right into any carb tuning. Changing an air bleed (among other things) will change the viscosity of the fluid. Change the viscosity of the fluid and you change how it behaves. Air speed is the other thing. One example is using annular boosters over a down leg. The AB will have a much higher signal so by that one characteristic will change how much and when you need emulsion. It’s relatively simple when you think it through.
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Did we just switch to 2 strokes ? Lol
 
Holy carb tuning guru! This RB reminds me of somebody....
I had to unlock this page to find out why it was jumping around so much...
 
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