750 Brawler vs 650 AVS 2 at the track, right OOTB !

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iam more impressed with a 10 second car built with parts from the junk yard
hemi dart was in the 9s for almost nothing
if you spend 500k to run 8s your a dummy


Hmmmm not according to this.

Muscle Cars You Should Know: 1968 Dodge Hemi Dart

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A REAL 68 hemi dart or barracuda (your example) is a high dollar car. I agree with you, I like cheap fast cars. I had somewhere around $9000 in this 9 second car.....

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This is why I get my ducks in a row and get what I want out there in the first few post. Meaning, I do the update and results at the same time. Next update will be a new thread. I'll return to answer a question if I'm paged. Field is open, have at it ... :)
 
It's too bad a thread like this has to turn into an argumentative **** storm. 318WR was doing a fun comparison while having a great day at the track with his Mopar and wife. Take it for what it is.
 
What does all that do exactly?

The correct boosters atomize the fuel more with less of a vacuum signal so it vaporizes at the right time instead of staying in liquid form during the power stroke.
Vacuum is generated all the way through the intake tract even at the intake valve. Last time I looked vacuum is what the piston generates as it travels down the bore pulling the air and fuel in does it not?

Correct except in an engine built for any level of performance it's actually the scavenging effect of the exhaust pulse creating the vacuum before the intake valve opens far more than the piston moving down the cylinder during the intake stroke. The key point is that air is a compressible fluid and has inertia so the vacuum created at the intake valve can easily be lost trying to travel to the carburetor or throttle body especially during WOT if the intake port and runner design is bad.
The average Hot Rodder isn't Darin Morgan with a wet flow bench to actually see what the wet flow is doing is he?

How do you crutch an engine with a SSR that causes fuel separation?


Here's a thought, If the engine needs more exhaust residual to heat the incoming charge to help vaporize it helping it burn better what happens?

No but he/she can apply the lessons in any engine even if it's not a Pro Stocker. This isn't something you need a wet flow bench to discover anyway, OEMs figured it out before that was popular all you need is a way to draw air through a port while injecting some kind of liquid with a dye. If the port isn't keeping the fuel atomized the liquid will show up as a dribble or stain running down the chamber walls.

You "crutch" a port that causes fuel separation by increasing restriction which absorbs flow energy (thus power) or like you said, add heat which also reduces power by decreasing the charge density. Get the port right and you make max power because those "crutches" aren't needed anymore.

Your example of the big Ford running better with the smaller carb is precisely an example of that, the port design was bad enough to where there was a net gain in power by increasing manifold vacuum at WOT because the intake charge quality was trash. If the intake ports and runners were corrected it would have made more power with a bigger carb.

Sorry to the OP for getting sucked into the shitstorm but I think this is useful info for everyone. It applies to his situation as well because if the engine has decent intake flow characteristics it will indeed benefit from having a properly-dialed 750 cfm DP carb over the 650 cfm AVS with the annular boosters. Booster types can be easily swapped in Holley-style carbs anyway. If the carb is "too big" for the application and more booster signal and fuel atomization is needed at lower RPM then converting to annular boosters fixes that issue better than going to a smaller carb because it's not creating an airflow restriction, at least not nearly as much.
 
Maybe he can try a Dominator next and it will go faster will it not because you just gave it more air?


You keep imagining. There's so many places to do it and **** it up.......Valve size, port size, manifold size, exhaust size, Ignition strength fuel type and carb size to name a few. And yet if I say try a smaller carb you jump up and down when its the EASIEST thing to try/change to see what the engine wants...... You scream I'm restricting the engine.........Am I?

You cant get your head around the fact that big inch Ford NEEDED more vacuum at the top end to make power. You get hung up on "small" instead of thinking about what's actually happening in the engine to do it.

Just because you you give an engine more air doesn't mean it will use it. Why does it matter if the SSR is fucked?
Your doing back flips thinking this proves you right cause the 650 shows less than a 1% gain in mph, so far and unless 318willrun cares to do a full shootout all we know ootb on this combo on this day there pretty much on par with each other and if we were to make wild assumptions with the little we know, it goes against the case you make so far cause either A the 750 is vaporizing the fuel just as well as the 650 or B it's not but it makes little difference in performance anyways.
What it kind of proves though is why 650 and 750 are popular choices for a small block.
 
The correct boosters atomize the fuel more with less of a vacuum signal
No they don't. Both triple stage boosters and annular boosters increase signal because the are more restrictive. What is "correct" is to reference the booster signal required to the vacuum generated by the engine. Again stick a Dominator (1050) on a 318 and tell me all about atomization when you don't create enough vacuum to actually lift the fuel up through the main well and out to into the booster channel.

Triple stage Boosters actually double the depression by multiplying the depression created by the initial booster.

Here's none other than John Kaase clearly showing the pulsations that take place in a manifold. What do you think is pushing his finger back towards the carbs? Look at all that "atomized" liquid fuel on the walls and runners making its way to the intake valve..........

Amazing Video: Jon Kaase Tests Airflow Dynamics With His Finger

What do you think those pulsations will do to carb signal? What do think all that black **** on the underside of the air cleaner is and how does it get there?
 
Your doing back flips thinking this proves you right cause the 650 shows less than a 1% gain in mph,
Only a 1% gain difference in performance from a lot less cfm.........Weren't they expecting a 2 tenths difference on the assumption the extra airflow would equate to more power? There's a clear difference in airflow yet not performance. Didn't the 650 have issues as well........Looks like it needs more time tuning than the 750?
 
Only a 1% gain difference in performance from a lot less cfm.........Weren't they expecting a 2 tenths difference on the assumption the extra airflow would equate to more power? There's a clear difference in airflow yet not performance. Didn't the 650 have issues as well........Looks like it needs more time tuning than the 750?

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Rat, i need to buy a carb soon.... was going to get a brawler, what do you recommend instead?

Save yourself the headache and call William Baldwin at Baldwin carbs and let him build you a custom carb. The cost is more but in the end you end saving time and money. A lot of time and money.

There is also Mark Whitener at Lightning carbs. He is building the best annular boosters for 4150’s (and Dominators) you can get. His carbs also work very very well.

And Dominic at Thumper Carbs. He is also a custom carb builder that builds them one at a time. He does great work. A buddy just bought a very nice 1150 Dominator from him. That engine should be going across the dyno here soon.

Any one of those three guys will hook you up. IMO its better to spend more money up front and get a quality product than it is to save some money up from and pay through the nose at the back end.
 
No they don't. Both triple stage boosters and annular boosters increase signal because the are more restrictive. What is "correct" is to reference the booster signal required to the vacuum generated by the engine. Again stick a Dominator (1050) on a 318 and tell me all about atomization when you don't create enough vacuum to actually lift the fuel up through the main well and out to into the booster channel.

Triple stage Boosters actually double the depression by multiplying the depression created by the initial booster.

Here's none other than John Kaase clearly showing the pulsations that take place in a manifold. What do you think is pushing his finger back towards the carbs? Look at all that "atomized" liquid fuel on the walls and runners making its way to the intake valve..........

Amazing Video: Jon Kaase Tests Airflow Dynamics With His Finger

What do you think those pulsations will do to carb signal? What do think all that black **** on the underside of the air cleaner is and how does it get there?

Once again, you are talking bullshit. There are annular boosters out there that do NOT restrict flow and make more power. Just because you don’t know it doesn’t mean it’s not there.

And EXACTLY how many CFM does an annular booster drop flow? Maybe 5 CFM? so thats 20 CFM per carb. Maybe. Yet there is 100 CFM difference between a 650 and a 750 so you still have (potentially) 80 CFM more.

Your “use a small carb” (or port, or header or whatever your slant is at the moment) to “vaporize” the fuel better is a CRUTCH. And it’s the WRONG answer for performance.
 
**** it... i'm just gonna find a old predator.... you guys make this too complicated :)
 
Here you go Hysteric proof a Dominator can be too big :)



This one not so much

 
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No they don't. Both triple stage boosters and annular boosters increase signal because the are more restrictive. What is "correct" is to reference the booster signal required to the vacuum generated by the engine. Again stick a Dominator (1050) on a 318 and tell me all about atomization when you don't create enough vacuum to actually lift the fuel up through the main well and out to into the booster channel.

Triple stage Boosters actually double the depression by multiplying the depression created by the initial booster.

Here's none other than John Kaase clearly showing the pulsations that take place in a manifold. What do you think is pushing his finger back towards the carbs? Look at all that "atomized" liquid fuel on the walls and runners making its way to the intake valve..........

Amazing Video: Jon Kaase Tests Airflow Dynamics With His Finger

What do you think those pulsations will do to carb signal? What do think all that black **** on the underside of the air cleaner is and how does it get there?

Annular and triple-stack boosters increase signal because they are more sensitive to the pressure differential and air velocity through the venturi.

The "vacuum" used to draw fuel through the boosters is created by the venturis themselves. The simple fact that there is air flowing through them does it; it has no relation whatsoever with the amount of vacuum in the intake manifold below the throttle butterflies. If it was dependent on manifold vacuum then there would be no purpose in having a venturi in a carburetor in the first place; even if you put a lawnmower carburetor on a big block so it has 10 in-Hg vacuum at WOT it won't function without a venturi.

@318willrun stuck dual 600 cfm carbs on a mild 318. There's probably hardly any manifold vacuum to speak of at WOT yet it has excellent response and power if you go watch his videos. I'm over arguing about this, believe what you want.
 
Here you go Hysteric proof a Dominator can be too big :)




Why can it be too big?

Once again, you are talking bullshit. There are annular boosters out there that do NOT restrict flow and make more power.
Deep Roots explains it well:

Annular booster carburetor flow test

By being more of a restriction the Same volume of air has to move faster around and through it. The engine pulls more fuel.
Main air bleed, jetting, and pvcr’s need to be changed to accommodate that.

Evaluate the well designed Autolite carburetors that came with annular boosters. Pump shot is small, idle circuit pretty much just addresses idle, transition is almost non-existent as the booster starts early and does almost all of the metering. The rest is addressed with bleed air.
 
Bigger is not always better........
One carb might have more airflow, but does not atomise the fuel as well.
most people over carb their cars engine can only use so much , after that it is all show
 
Why can it be too big?


Deep Roots explains it well:

Annular booster carburetor flow test

By being more of a restriction the Same volume of air has to move faster around and through it. The engine pulls more fuel.
Main air bleed, jetting, and pvcr’s need to be changed to accommodate that.

Evaluate the well designed Autolite carburetors that came with annular boosters. Pump shot is small, idle circuit pretty much just addresses idle, transition is almost non-existent as the booster starts early and does almost all of the metering. The rest is addressed with bleed air.
Why did it take a carb about 4 times the calculated optimal size too not function properly?
And carb twice the size of calculated optimal size made best power through out the rpm range on a turd of an engine? How does this go along with your arguments? Don't worry I don't expect you to come up with a valid explanation just more strawman argument.
 
Why did it take a carb about 4 times the calculated optimal size too not function properly?
And carb twice the size of calculated optimal size made best power through out the rpm range on a turd of an engine? How does this go along with your arguments? Don't worry I don't expect you to come up with a valid explanation just more strawman argument.
So the engine didn't make the most power everywhere with the Dominator? Why not........But you gave it more air didn't you?

Um......its 292 cubes is it not? You think a 650 is too big for a nearly 300 cube engine?

Didn't Mopar put Thermoquad's on 318's?

Ford put thermoquads on 302's locally........How much do the smaller thermoquads flow? 750 to 800 cfm?

Like I said earlier in post 88

A milder engine can tolerate a bigger carb.........Why is that?
 
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So the engine didn't make the most power everywhere with the Dominator? Why not........But you gave it more air didn't you?
Like I said strawman, who's arguing that there's not a limit to workable carb size and that there's an optimal carb size or more correctly carb.
Um......its 292 cubes is it not? You think a 650 is too big for a nearly 300 cube engine?
For an small ish engine that hp peaks at 3800 rpm the carb formula would say 300 cfm at best.
I'm not saying it's too big, on the dyno it's obviously not. Your pushing that a 750 is too much for a mild 360 and a 650 is way better, so in your mind how is a 650 not to big for a big 6 that makes 40% the power. A 450 ish hp @ 5500 rpm 451 calculates to about 650 cfm carb.
Didn't Mopar put Thermoquad's on 318's?

Ford put thermoquads on 302's locally........How much do the smaller thermoquads flow? 750 to 800 cfm?
So make up your mind what side of the fence your on lol
How can a 750 be too big for a mild 360 but 750-800 fine for a stock 302-318?
or how a 650 is good for a 150 hp 292 and a 350 hp 360 at the same time?

rpm x cid /3450 = max cfm, A cheater way 345 ish displacement is to drop a zero off rpm, 360 is close enough 360 x 5500/3456 = 573 cfm or 5500 drop a zero = 550 cfm and that's 100% VE which were not at.
 
Your pushing that a 750 is too much for a mild 360 and a 650 is way better
Am I? Here's my original post:

Wait what.......The smaller carb didn't kill the top end............Who'd a thunk it.
Reductionism at its finest.
So make up your mind what side of the fence your on lol
How about you use yours? Maybe just maybe that 360 doesn't use more air than that 650 already provides.

Can you grasp the difference between a spread bore design and a square bore design? Both can be rated at 800 cfm but have totally different metering characteristics.
 
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