where would be the easiest place to get a 700cc carb?
05-08-08, 07:28 PM
#1
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where would be the easiest place to get a 700cc carb?
i need a used 700cc carb with a square flange where might i find one? did they comne on any production cars i might find at the wreakers?
05-08-08, 09:31 PM
#2
I unfortunately don't know the answer to your question, but I have a question of my own...
Two in fact:
1. Do you mean 700cfm? 700cc isn't a term I usually hear attached to carbs
2. If you do mean 700cfm, then why do you want a carb that obscenely huge? Are you running a supercharged 13b?
When it comes to carbs, bigger does not equal better. There is easily such a thing as too big of a carb. You need a good balance of two things with a carb : flow and velocity. The cfm rating is the maximum amount of air the carb can flow in cubic feet of air per minute. While this is an important measure, what you can't easily measure or put a number on is what the *velocity* of the air is going to be going through the carb.
Think of it this way. You have your tap outside your house where you connect your garden hose. If you just take the hose as-is, you get okay flow and okay velocity. Now without changing the tap (no change to flow) put your thumb over the end and cover half. Now you have closer to twice the velocity with the same flow because you made the opening smaller. Now hook a firetruck hose to it. You'll barely get any force out of it at all - still the same flow, no velocity.
Why is velocity important? because the air going through the barrels of the carb has to be going fast enough to pull the gas from the main circuit into the venturis and atomize it so that you can get a good air/fuel mix.
The biggest carb a stock port 12a or 13b needs is about 450cfm. So the Holley 450 or a Sterling Nikki. Your engine can't require more flow than that N/A because as a pump it just can't do it. Even at 10,000rpm it won't flow that much. So anything bigger than that will just have bigger barrels (firetruck hose) and the air going through at the low end won't be going fast enough to pull the fuel out and atomize it.
So bigger than 450cfm on a stock port (or even street port) 12a or 13b is not going to net you anything but a bog at the low end and a lack of power.
Better explanations here:
https://www.rx7club.com/showthread.p...ric+efficiency
If you are still looking for a 700cfm carb, check ebay or places that cater to larger V8 motors
Jon
Two in fact:
1. Do you mean 700cfm? 700cc isn't a term I usually hear attached to carbs
2. If you do mean 700cfm, then why do you want a carb that obscenely huge? Are you running a supercharged 13b?
When it comes to carbs, bigger does not equal better. There is easily such a thing as too big of a carb. You need a good balance of two things with a carb : flow and velocity. The cfm rating is the maximum amount of air the carb can flow in cubic feet of air per minute. While this is an important measure, what you can't easily measure or put a number on is what the *velocity* of the air is going to be going through the carb.
Think of it this way. You have your tap outside your house where you connect your garden hose. If you just take the hose as-is, you get okay flow and okay velocity. Now without changing the tap (no change to flow) put your thumb over the end and cover half. Now you have closer to twice the velocity with the same flow because you made the opening smaller. Now hook a firetruck hose to it. You'll barely get any force out of it at all - still the same flow, no velocity.
Why is velocity important? because the air going through the barrels of the carb has to be going fast enough to pull the gas from the main circuit into the venturis and atomize it so that you can get a good air/fuel mix.
The biggest carb a stock port 12a or 13b needs is about 450cfm. So the Holley 450 or a Sterling Nikki. Your engine can't require more flow than that N/A because as a pump it just can't do it. Even at 10,000rpm it won't flow that much. So anything bigger than that will just have bigger barrels (firetruck hose) and the air going through at the low end won't be going fast enough to pull the fuel out and atomize it.
So bigger than 450cfm on a stock port (or even street port) 12a or 13b is not going to net you anything but a bog at the low end and a lack of power.
Better explanations here:
https://www.rx7club.com/showthread.p...ric+efficiency
If you are still looking for a 700cfm carb, check ebay or places that cater to larger V8 motors
Jon
05-09-08, 03:02 AM
#4
To answer your question you have a few places to check for that 750cfm carb you have jegs, summitt racing, ebay, autozone, kragen blah blah blah...
I don't konw, i don't see any problems with my setup running a holley 600cfm on my setup...
So to whereiscarmensandiego venture out and don't be affraid but i will say this a 700cfm carb on a stock block may be a little too much go with a 600 or even at most 650
I don't konw, i don't see any problems with my setup running a holley 600cfm on my setup...
So to whereiscarmensandiego venture out and don't be affraid but i will say this a 700cfm carb on a stock block may be a little too much go with a 600 or even at most 650
Last edited by teddyrx2; 05-09-08 at 03:08 AM.
05-09-08, 01:40 PM
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well al i know is what i was told that i needed a 750 cfi doble pumper with mechanical secondaries for a half bridge ported t2 motor with s5 high comprotors and in the near future somtihg along the lines of a to4 set to about 8 to 10 psi
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05-09-08, 10:03 PM
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05-11-08, 03:15 PM
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you can run a 700 cfm on a rotory its just gonna bog at low rpms a ton
for a single turbo id recommend a 500 cfm 4 barrel of if you can get an old demon with adjustable venturies would be nice setup use small primaries and huge secondaries this has cured the problem of low rpm bog but lets the engine breath at higher rpm's but for stock engine i wouldnt run anything bigger than a 500cfm
im using a 600 cfm on a turbo 12-a with 18-20 lbs of boost before the turbo started dying and yes it still bogged at low rpm's good luck hope this might help a little
for a single turbo id recommend a 500 cfm 4 barrel of if you can get an old demon with adjustable venturies would be nice setup use small primaries and huge secondaries this has cured the problem of low rpm bog but lets the engine breath at higher rpm's but for stock engine i wouldnt run anything bigger than a 500cfm
im using a 600 cfm on a turbo 12-a with 18-20 lbs of boost before the turbo started dying and yes it still bogged at low rpm's good luck hope this might help a little
05-11-08, 04:29 PM
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The question is: blow-through or draw-through? If blow-through, I recommend a 500 or possibly 600 CFM mechanical secondary Holley (or Weber 48 IDA if you're not opposed to 2bbl). If draw-through, I'd go with a 650 CFM Edelbrock Thunder Series.
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