Bracket Talk
50cc pumps on Holley 4150 carburetors

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https://drr.infopop.cc/eve/forums/a/tpc/f/80760912/m/1937035696

July 10, 2021, 08:15 PM
50fordsst
50cc pumps on Holley 4150 carburetors
Any experience? using 50cc pump on primary side? 850 and up carbs. Before I try it.
July 10, 2021, 09:34 PM
Lenny5160
On alcohol, yes I do.


Tony Leonard
July 11, 2021, 09:01 AM
vetman
yes on alcohol added them to my 750s on tunnel ram been on there 5 years it took away the stumble on when you mat it on the line


The difference between ignorance and stupidity. Ignorance is lack of knowledge. Stupidity is the inability to learn. Don't be stupid
July 11, 2021, 12:22 PM
Eman
Why? My understanding is the bigger pump gives you a longer pump shot and the squirter gives you a bigger pump shot along with the cam. My alcohol carb has 30cc pumps but the squirters have been drilled out, can't remember the size but it's big from Rupert.

This message has been edited. Last edited by: Eman,
July 11, 2021, 08:26 PM
Tom396
50cc pumps have always worked great for me. Especially when the carb is actually too large for the application and you have a big hole to cover up on the initial hit. Take care. Tom Worthington


If it seems that bracket racing has gotten too expensive for you, maybe you are just doing it wrong.
July 11, 2021, 09:37 PM
Canted Valve
I think the question to be answered is, do you need it? More isn't always better if all is working well. But if what you have isn't working, and I suspect it is not, it's a tool you can try. I've used 50cc's on different occasions with success.


Illegitimi non carborundum
July 12, 2021, 06:47 AM
Curly1
quote:
Originally posted by Canted Valve:
I think the question to be answered is, do you need it? More isn't always better if all is working well. But if what you have isn't working, and I suspect it is not, it's a tool you can try. I've used 50cc's on different occasions with success.



That is it many on gas do not need it when tuned right or use it as a crutch to cover up tuning issues.


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July 12, 2021, 08:52 AM
undacuva67
i used 50cc on front and back on 4150,s footbraking and sg racing and had excellent results on gas .
July 12, 2021, 08:55 AM
Mike Rietow
50cc, if ya got low signal.

Put a roller camshaft, that'll fix it.

Or just put a Reher Morrison shear plate on it.



July 12, 2021, 10:38 AM
TOP38
quote:
Originally posted by 50fordsst:
Any experience? using 50cc pump on primary side? 850 and up carbs. Before I try it.


Why are you asking!!!!!!!! Probably no reason to do this.
July 12, 2021, 12:21 PM
Brktracer
One thing you can be sure of - the combination will tell you what it needs/wants. Listen to what it tells you!


Matt Ward



July 12, 2021, 01:18 PM
50fordsst
This is not my personal problem. I run a 4500 Doninator on my 468 similar engine, but have a good friend that is determined to run a 4150/950 80496 and seeing my performance would like to achieve the same by making them similar. His car leaves like a snail. Granted he is now trying different converters and maybe there could be a another problem that he needs to be address, but the 50cc pump could? help. Was hoping there would be more racers that use the big pump, but it seems that's not the case. He will try and see if it makes a difference. Thanks for your input. Bob Richmond
July 12, 2021, 02:20 PM
TOP38
quote:
Originally posted by 50fordsst:
This is not my personal problem. I run a 4500 Doninator on my 468 similar engine, but have a good friend that is determined to run a 4150/950 80496 and seeing my performance would like to achieve the same by making them similar. His car leaves like a snail. Granted he is now trying different converters and maybe there could be a another problem that he needs to be address, but the 50cc pump could? help. Was hoping there would be more racers that use the big pump, but it seems that's not the case. He will try and see if it makes a difference. Thanks for your input. Bob Richmond


It's not the accel pump causing his issue unless it bogs when he goes WOT. The it could be that or the size of the squirters causing a bog. Otherwise it's in the combo!
July 12, 2021, 03:35 PM
Eman
What size squirters and what pump ams are on the carb now? Squirters are simple bigger number more fuel. Cams have different profiles if you do the google there's a graph of the different cams by color by how quickly they deliver the fuel.
July 13, 2021, 05:10 AM
1320racer
quote:
Originally posted by 68TSCAMARO:
i used 50cc on front and back on 4150,s footbraking and sg racing and had excellent results on gas .

this for over 25 years


https://youtu.be/rbKYio6OvKM

and still now top bulb and throttle stop racing.
July 13, 2021, 11:23 AM
TOP38
If you are using a transbrake the squirters/accel pump size etc. just allow the motor to get to the launch rpm cleanly, after that they do nothing with regards to on track performance... Foot braking is another story...
July 14, 2021, 10:32 AM
FootbrakeJim
quote:
Originally posted by 1320racer:
quote:
Originally posted by 68TSCAMARO:
i used 50cc on front and back on 4150,s footbraking and sg racing and had excellent results on gas .

this for over 25 years

Same. Much better throttle response off the foot, and quicker 60', especially with a slightly tight converter and/or heavy car.


Dan "Jim" Moore
Much too young to feel this damn old!!
July 15, 2021, 07:56 AM
jmarkaudio
All of the bigger 4150's I build have the 50cc pump and diaphragm, but use the correct pump cam for the fuel and engine requirements. A green or blue cam on gas is more than enough, if it isn't usually something else is amiss. Bad ignition components, timing incorrect, plug heat range wrong... Also correct primary t-slot exposure can help with stumble issues. And when holes are drilled in the throttle blades it will usually not allow for enough-t-slot exposure.




Mark Whitener
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