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A list of Autolite/Motorcraft 2100/2150 carb flow rates.

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Bret

A list of Autolite/Motorcraft 2100/2150 carb flow rates.

Post #1 by Bret » Thu Feb 15, 2007 10:38 pm

I found the flow rates for MC2100/2150 2 barrels.

This information comes from CJOFFROAD.COM. That website has a ton of information on these carbs.

2V 2100/2150 at 3"Hg. Venturi size listed first.

0.98 = 190 CFM
1.01 = 240 CFM
1.02 = 245 CFM
1.08 = 287 CFM
1.14 = 300 CFM
1.21 = 351 CFM
1.23 = 356 CFM
1.33 = 424 CFM

In order to compare these carbs to 'metric' carbs, here is a conversion list. Remember that venturi size is not the same as bore size. In example, a Weber 32/36 has venturies of 26mm/27mm. The MC2100/2150 carbs have syncronous butterflies, just like the Weber 38/38 DGS carbs.

0.98 = 24.9mm/24.9mm = 190 CFM
1.01 = 25.6mm/25.6mm = 240 CFM
1.02 = 25.9mm/25.9mm = 245 CFM
1.08 = 27.4mm/27.4mm = 287 CFM
1.14 = 29.0mm/29.0mm = 300 CFM
1.21 = 30.7mm/30.7mm = 351 CFM
1.23 = 31.2mm/31.2mm = 356 CFM
1.33 = 33.8mm/33.8mm = 424 CFM
Last edited by Bret on Fri Feb 16, 2007 8:28 pm, edited 3 times in total.

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THE FRENCHTOWN FLYER
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Post #2 by THE FRENCHTOWN FLYER » Thu Feb 15, 2007 11:14 pm

Thanks for the info. This info is often sought after. It should be on the FAQ post above.

Remember that four barrels are flowed at 1.5 "hg. So these flow numbers do not equate to 4V flow. To convert divide by 1.41.

So, for example, a 190 2V would be equivalent to a 135 4V.
A tri-power using 3 of these 190s equals a 404 cfm four barrel.
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Post #3 by Stealth Bummer » Fri Feb 16, 2007 11:14 am

Good stuff-Thanx!
1959 F100, Short-wide box, big back window, IFS, 300/C4 trans (work in progress)
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Post #4 by mutt » Fri Feb 16, 2007 3:03 pm

went to the website but couldnt find the carb info- can you post the link??
Thx....

Bret

Post #5 by Bret » Fri Feb 16, 2007 5:51 pm

mutt wrote:went to the website but couldnt find the carb info- can you post the link??
Thx....


I'll try to post a link; I'm learning 'computer' very slowly. That site will allow guests/visitors to run searchs. Use 'Motorcraft 2100/2150' as the key word. I going to start referring to these carbs as MC2100/2150s. It seems to be more common nomenclature.

Bret

Post #6 by Bret » Fri Feb 16, 2007 6:07 pm

THE FRENCHTOWN FLYER wrote:Thanks for the info. This info is often sought after. It should be on the FAQ post above.

Remember that four barrels are flowed at 1.5 "hg. So these flow numbers do not equate to 4V flow. To convert divide by 1.41.

So, for example, a 190 2V would be equivalent to a 135 4V.
A tri-power using 3 of these 190s equals a 404 cfm four barrel.


I'm going to edit the list and add millimeter equivalents, just so we can sort of compare them to 'foreign' carbs, like the Weber.

I've also run across flow bench results for the MC4100/4300 4Vs. These carbs are interesting. The 1.08 venturi MC4100 puts out 441 cfm at 1.5"Hg. That would be excellent for alot of 300 applications. It's a very simple vacuum secondary design, with fuel bowls in the carb body like an AFB. Easy to tune with jets and power valves. I don't think they use metering rods. As a matter of fact, I don't think the MC2150's use metering rods, either. Let's do a little 'myth busting' about MC carbs while we're on this topic.

Keep in mind that flow rates can actually vary somewhat between carbs of the same model and same ventri size.

When we're done with this post, it would be cool to have it in the FAQ. Do the moderators do this, or can anyone just do it?

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Post #7 by shmoozo » Fri Feb 16, 2007 6:42 pm

I'd love to see a thread on various carb flow rates stickied. This one, perhaps retitled to something a bit more general, would be a terrific start for that. Alternatively a thread that collects info from this and other similar threads would do the job.

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Post #8 by SuperMag » Fri Feb 16, 2007 6:52 pm

Bret wrote: When we're done with this post, it would be cool to have it in the FAQ. Do the moderators do this, or can anyone just do it?


Done. :wink:

Bret

Post #9 by Bret » Fri Feb 16, 2007 7:37 pm

shmoozo wrote:I'd love to see a thread on various carb flow rates stickied. This one, perhaps retitled to something a bit more general, would be a terrific start for that. Alternatively a thread that collects info from this and other similar threads would do the job.


I'm behind this 100%. I want to focus on the MC2100/2150 for now, because there is much conflicting information on the internet regarding these carbs. I hope to exclude other carbs for now, because I have excellent books dedicated to Holleys, Carters, and Webers. I wish someone would write a manual for the Motorcraft carbs.

I'm also interested in compiling information regarding actual venturi sizes of all makes of carbs. Also flow rate break downs for 4 barrel carbs, in example, the 400 CFM AFB flows 200 primary/200 secondary, the 500 CFM AFB flows 220/280, etc. Stuff my carb manuals might not cover.

We don't want the thread to become too convoluted though.
Last edited by Bret on Fri Feb 16, 2007 9:43 pm, edited 2 times in total.

Bret

Post #10 by Bret » Fri Feb 16, 2007 7:52 pm

THE FRENCHTOWN FLYER wrote:
Remember that four barrels are flowed at 1.5 "hg. So these flow numbers do not equate to 4V flow. To convert divide by 1.41.

So, for example, a 190 2V would be equivalent to a 135 4V.
A tri-power using 3 of these 190s equals a 404 cfm four barrel.


This means the largest MC2100/2150, the 1.33 (at 424 CFM) is equal to a 598 CFM four barrel. I can't quite get my mind around this. Maybe someday I'll understand.

Also, I still don't understand how a Weber 32/36 is too small for the big six. I'm not saying it's not. Only one person I've talked to says they've used a 32/36 on a 300. He said it worked great, but he could not remember how it was configured.

I saw a MC2150 on Ebay that was listed as a 1.38. I've also seen one that was described as a .89. My list may not cover all sizes of these carbs.
Last edited by Bret on Fri Feb 16, 2007 8:36 pm, edited 1 time in total.

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Post #11 by THE FRENCHTOWN FLYER » Fri Feb 16, 2007 8:33 pm

Bret wrote:Keep in mind that flow rates can actually vary somewhat between carbs of the same model and same venturi size.


That is because the size and style and placement of the venturi booster which fits in the middle of the venturi can vary greatly from model to model. Bigger ones give less airflow and stronger signal and smaller ones promote greater airflow at the expense of signal strength, in general.


Bret wrote:When we're done with this post, it would be cool to have it in the FAQ. Do the moderators do this, or can anyone just do it?


I posted it in the FAQ Bret. Thanks again.
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Post #12 by THE FRENCHTOWN FLYER » Fri Feb 16, 2007 8:49 pm

One more comment:

Bret wrote: As a matter of fact, I don't think the MC2150's use metering rods, either. Let's do a little 'myth busting' about MC carbs while we're on this topic.


2100s don't use metering rods. 2150s use metering rods (aka "baseball bats") in the air bleeds. These are similar to metering rods except they work in reverse to control part throttle air/fuel mixtures more closely, operating inside the air bleed wells to regulate the fuel emulsion at part throttle conditions.
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Post #13 by Bret » Fri Feb 16, 2007 9:07 pm

THE FRENCHTOWN FLYER wrote:That is because the size and style and placement of the venturi booster which fits in the middle of the venturi can vary greatly from model to model. Bigger ones give less airflow and stronger signal and smaller ones promote greater airflow at the expense of signal strength, in general.[/i


I know the difference between the 500 CFM AFB and the 600 CFM AFB is just the primary booster. The 500 has a pair of larger primary boosters. The bores and butterflies are the same. I'm also aware that certain models of the Weber are tuned, in part, by selecting the proper booster.

(The AFB and the AVS were designed by Carter. All Edelbrocks are Carter designs.)

My comment regarding variance within the same make/model/venturi size was in reference to Motorcraft carbs. I looked at the bench test results from four different MC4100s, all with 1.14 venturies. Max flow varied about 60 CFM between these carbs. They all presumably had the same size boosters, because as far as I know, there aren't any different ones available. I just meant that, apparently, identical carbs can max out a little different.

Booster effect was a good addition to this thread. Excellent point!

Bret

Post #14 by Bret » Fri Feb 16, 2007 9:41 pm

Myth number one was that MC2150s don't have metering rods. Looks like they do.

Here goes myth number two: Some people claim that certain models of the MC2150 have "altitude compensators". It looks to me like these things are actually bi-metallic idle boosters, designed to increase idle speed when the carb reachs a designated temperature.

Maybe I should post a new topic for each MC2100/2150 question. I like the idea of a thread that compares and contrasts carbs across the board.

I appreciate everyone's help. I'll assist in editing my posts on this thread to make it more coherent.

Should I just keep plugging away? What's our focus here?

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Post #15 by mutt » Sun Feb 18, 2007 2:49 pm

Should I just keep plugging away? What's our focus here?

Bret, you are exemplary. Theres fellas like me who pick others brains, and try to shine some light and not muddy the waters too much.
Then theres guys like FTF (as a SINGLE example- there are many others, the "Peenemunde 6 banger Brain Trust"- the rocket scientists- who lay out comprenhensive chunks of info that all can draw from.
When I found this site I had a woefully inadequate 80 van. I pieced together all I could, and got great answewrs to my questions, & now have a great runnin truck. Having a wealth of data on the 2100/2150 in one place is a greataddition to an exemplary layman gearhead website.

The guys who havespent SO much time learning the ins & outs of our favored 6's are as generous with thier knowledge as one could be.
So- the focus is codifying & making available the sum total of 240/300 knowledge. Wack away, Sir.......

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Post #16 by mutt » Sun Feb 18, 2007 7:39 pm

BIIIIG improvement running the vac advance off the timed port in the carb, rather than the manifold.
In Brets collection of 2100 Facks, he might include: "Junior Rocketeer Mutt reports much better off idle & low speed performance if vacuum advance is run off idle port. He thinks also this will boost mpg in around town driving.
This is based on 15 plus k miles w/ vac from manifold, & 10 miles with it put right".

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