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Actual cfm used vs carb size

General engine tech -- Drag Racing to Circle Track

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randy331
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Re: Actual cfm used vs carb size

Post by randy331 » Tue Apr 09, 2019 12:51 pm

Why don't you post up your back to back testing data Fbird ??

I don't mean "I put one on and it did a big burn out" etc, but real back to back testing on a dyno where the theory can be validated.

Or maybe you haven't even actually tried one ?

Randy

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Re: Actual cfm used vs carb size

Post by Rick360 » Tue Apr 09, 2019 12:51 pm

Buy 3 of them 2 into 1 carb adapters. Put the first one on the carb opening on the intake. Then put the other 2 adapters on top of each carb opening of the first adapter and perpendicular to the first. Boom - 4 Carbs. It'd be awesome. :lol:

But seriously Fbird, where's the dyno (or drag strip) tests to show how good this worked for you? Or you just KNOW this would work?

Rick

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Re: Actual cfm used vs carb size

Post by randy331 » Tue Apr 09, 2019 12:57 pm

F-BIRD'88 wrote:
Tue Apr 09, 2019 11:49 am
If you show up with this at a single 4 bbl carb rules limited race class, they will ALL bock... Whine and squeel.
If your talkin about a 2 carb to single adapter,.... no they won't whine and squeel, they will laugh and send you packin cause you can't read the rules. LOL

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Re: Actual cfm used vs carb size

Post by F-BIRD'88 » Tue Apr 09, 2019 1:50 pm

You need not wait for me. You can do it yourself.
You may even come up with a BETTER 2x4 adapter than me. The only way You can debunk it, is to try it yourself.
Feel free. Mine is in the works. But you need not wait on me. It's not that hard either.
You're really going to bitch when your car picks up a bit....
:-)

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Re: Actual cfm used vs carb size

Post by F-BIRD'88 » Tue Apr 09, 2019 2:02 pm

randy331 wrote:
Tue Apr 09, 2019 12:57 pm
F-BIRD'88 wrote:
Tue Apr 09, 2019 11:49 am
If you show up with this at a single 4 bbl carb rules limited race class, they will ALL bock... Whine and squeel.
If your talkin about a 2 carb to single adapter,.... no they won't whine and squeel, they will laugh and send you packin cause you can't read the rules. LOL

Randy
If it was a disadvantage they would say ya sure run it.
But they know better 2x 4 bbl carbs have a advantage over 1 4 bbl carb especially on a V8. And you're right, you can only make the 4 venturi so big.
8 venturii are BETtER.

Even on a adapter, on a single 4 bbl intake.

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Re: Actual cfm used vs carb size

Post by F-BIRD'88 » Tue Apr 09, 2019 2:08 pm

6 venturii over a plenum of a single 4 bbl manifold's plenum also has an advantage over just 4 venturi of a single 4 bbl carb.
Another story.

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Re: Actual cfm used vs carb size

Post by CGT » Tue Apr 09, 2019 2:13 pm

Rick360 wrote:
Tue Apr 09, 2019 12:51 pm
Buy 3 of them 2 into 1 carb adapters. Put the first one on the carb opening on the intake. Then put the other 2 adapters on top of each carb opening of the first adapter and perpendicular to the first. Boom - 4 Carbs. It'd be awesome. :lol:

But seriously Fbird, where's the dyno (or drag strip) tests to show how good this worked for you? Or you just KNOW this would work?

Rick
Resized_20190409_130800.jpg
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You do not have the required permissions to view the files attached to this post.
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Re: Actual cfm used vs carb size

Post by randy331 » Tue Apr 09, 2019 2:19 pm

:cry:
F-BIRD'88 wrote:
Tue Apr 09, 2019 1:50 pm
You need not wait for me. You can do it yourself.
You may even come up with a BETTER 2x4 adapter than me. The only way You can debunk it, is to try it yourself.
Feel free. Mine is in the works. But you need not wait on me. It's not that hard either.
You're really going to bitch when your car picks up a bit....
So,..your just on here posting a bunch of BS as fact.

Randy

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Re: Actual cfm used vs carb size

Post by F-BIRD'88 » Tue Apr 09, 2019 3:06 pm

I might even come up with a cutzy name for it.

Just kiddin... And I knew you'd bitch the most.
Go build your own...

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Re: Actual cfm used vs carb size

Post by F-BIRD'88 » Tue Apr 09, 2019 3:18 pm

CGT wrote:
Tue Apr 09, 2019 2:13 pm
Rick360 wrote:
Tue Apr 09, 2019 12:51 pm
Buy 3 of them 2 into 1 carb adapters. Put the first one on the carb opening on the intake. Then put the other 2 adapters on top of each carb opening of the first adapter and perpendicular to the first. Boom - 4 Carbs. It'd be awesome. :lol:

But seriously Fbird, where's the dyno (or drag strip) tests to show how good this worked for you? Or you just KNOW this would work?

Rick
Resized_20190409_130800.jpg
Like this?
Ha ha. ! I have to keep that. Hang it on my fridge.
:-)

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Re: Actual cfm used vs carb size

Post by novadude » Tue Apr 09, 2019 3:25 pm

Doesn't the "add as many carbs as you can" theory ignore the fact that you need some air speed through a venturi to make a carb meter fuel properly? Doesn't splitting that airflow among more venturis decrease the signal in any one venturi? After all, the engine can only pull so much air volume based on other limiting factors.

I'm surprised that we are still having the old "more flow is always better" discussion on this forum. Might as well grab some heads with the largest CSA you can find if it's really all about minimizing pressure drop along the length of the intake tract.

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Re: Actual cfm used vs carb size

Post by F-BIRD'88 » Tue Apr 09, 2019 3:35 pm

8 venturii perform better than 4 venturii.
And over a wider rpm range too. Allowing more net airflow as a side benefit. 4 venturi do not do this as good as 8 do. Especially on a V8. Get away from single 4 bbl holley carb thinking. You are limited by the performance of 4 venturi. 8 is better. The height of the carbs also adds another advantage. The higher the Y shape inside the better. (Compared to the single 4 bbl)

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Re: Actual cfm used vs carb size

Post by ClassAct » Tue Apr 09, 2019 4:19 pm

CGT wrote:
Tue Apr 09, 2019 11:55 am
F-BIRD'88 wrote:
Tue Apr 09, 2019 11:49 am
There is nothing there to say this will work badly.
It has been done before and does work.
Expect to meet or Exceed the power of a big dominator carb on a capable motor. 500+ + hp.
Yup it does lend itself very will to supercharged single carb blower applications where 2 carbs are desired.
It will also work in N/A high power engines.
The more capable the engine (power output), the better it will work.
If you show up with this at a single 4 bbl carb rules limited race class, they will ALL bock... Whine and squeel.
Because they Know you have a advantage.
You'll go a bit quicker/faster. Great for bracket racing.
Easy jet changes to weather tune it if needed.
(It will tend to not be so sensitive to different or changing weather conditions)
Yup every guy that sells single 4 bbl carbed engines will whine, squeel, bitch and swear. "That cannot work"
It will.
920x920.jpg



Where is that dang LIKE button!!! This post deserves it for sure.

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Re: Actual cfm used vs carb size

Post by CGT » Tue Apr 09, 2019 4:57 pm

ClassAct wrote:
Tue Apr 09, 2019 4:19 pm
CGT wrote:
Tue Apr 09, 2019 11:55 am
F-BIRD'88 wrote:
Tue Apr 09, 2019 11:49 am
There is nothing there to say this will work badly.
It has been done before and does work.
Expect to meet or Exceed the power of a big dominator carb on a capable motor. 500+ + hp.
Yup it does lend itself very will to supercharged single carb blower applications where 2 carbs are desired.
It will also work in N/A high power engines.
The more capable the engine (power output), the better it will work.
If you show up with this at a single 4 bbl carb rules limited race class, they will ALL bock... Whine and squeel.
Because they Know you have a advantage.
You'll go a bit quicker/faster. Great for bracket racing.
Easy jet changes to weather tune it if needed.
(It will tend to not be so sensitive to different or changing weather conditions)
Yup every guy that sells single 4 bbl carbed engines will whine, squeel, bitch and swear. "That cannot work"
It will.
920x920.jpg



Where is that dang LIKE button!!! This post deserves it for sure.


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Re: Actual cfm used vs carb size

Post by prairiehotrodder » Tue Apr 09, 2019 5:12 pm

go easy on F-bird. I think he knows what he is talking about. I considered putting a pair of Q-jets back to back on a single to dual carb adapter. Then the four big barrels would be right in the middle and it could use a pair of factory throttle cables run to a single cable adapter. I just haven't found 2 Q-jets yet that work right !! Might not set the world on fire but it would be relatively cheap and fun to try. Look cool on a rat rod.
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