What size marine carburetor do I need?

The formula for calculating how much CFM (cubic feet per minute) your engine requires is: CFM = Cubic Inches x RPM x Volumetric Efficiency ÷ 3456.

How do I choose the right size carburetor?

To arrive at the most appropriate carburetor choice, there's a basic formula: engine displacement multiplied by maximum rpm divided by 3,456. For example: a typical 355ci small-block—a 0.030-over rebuild—with a 6,000-rpm max engine speed would work well with a 616-cfm carb ((355 x 6,000) 3,456 = 616.32).

How much horsepower will a 750 cfm carb support?

As an example, a 750-cfm carb on one of my street/strip Chevy 383 small-blocks can make more than 600 streetable hp, whereas an engine less well spec'd may only make 540 to 550. For what it is worth, it is possible to get the BSAC figure below 5 lbs/hp/hr.

Is 600-cfm carb big enough?

A 600-cfm carburetor may perform quite well on a stock 350 Chevy. However, the minute you start weaving in power adders like a hotter cam, a dual-plane performance intake manifold, and aluminum heads you're going to need 700-750 cfm.

What happens if your carburetor is too big for your engine?

A carburetor that is too big will not be able to provide the fuel needed for the engine. This can cause a lack of power and poor performance.

HOW TO: pick the right carburetor. SIZE MATTERS!!! Don't overestimate, do the math.

What happens if carb is too small?

If the carburetor is too small, it restricts airflow into the engine. The cylinder can't fill up all the way. This starves the engine and results in slow acceleration and a lack of top-end power. A larger displacement engine running at higher rpm will require more air and fuel.

Is a bigger carb better?

Bigger Carb Vs Smaller Carb

But is a larger carburetor always better? Actually no. A bigger carburetor has enough room for more horsepower and is usually equipped with bigger engines. This means a bigger carburetor gives you power at the high RPM range.

How much horsepower will a 650 cfm carb support?

So, using your Google-Fu you type "How much power can a 650 cfm carb support?" Well, chances are that you'll get answers in the 450-470 hp range, but that's not really the right way to look at it. In fact, horsepower—or even torque, for that matter—doesn't matter at all.

Is a double pumper carb better?

Mechanical secondary carbs (double pumpers) are the better option for race cars, hot rods, and performance vehicles with manual transmission, automatic transmissions with looser torque converters, and lower (higher numerically) rear end gears.

Do I need a double pumper carb?

Certainly if the engine has high compression, a serious cam, a single-plane intake, 3.70:1-or-steeper gears, and a manual trans or an automatic with a high-stall converter, you should definitely run a double-pumper. Ditto if you have a very lightweight (under-3,100 pounds) car regardless of the overall combo.

What size carburetor do I need for 500 hp?

It will flow 850 CFM. When you order your carb make sure your getting the actual flow rate ! You need an 800cfm for 500hp.

What is a 600 CFM carburetor?

A 600 CFM carb can work well with engines making 250-450 horsepower depending on the combination of parts and the RPM where it makes peak power.

What does a 4 barrel carb do?

A four-barrel carburetor has two primary and two secondary barrels. At idle and low-rpm driving, only the primary barrels open. The throttle blades on the secondary barrels stay closed. As rpm increases, the engine requires more air and fuel to make power, and this is when the secondary barrels kick in.

Can I use a marine carburetor on a car?

If you don't have an air-cooled engine, then a marine carburetor is the perfect option for your car. It can provide increased performance and fuel economy while also being cheaper than other models on the market.

Can I use a different carburetor?

You'll have to ensure the draft is the same (side-draft carb replaced with a side-draft carb, etc). You could put a down draft carb in place of a side-draft, but it would necessitate some unwanted plumbing, pure ugliness at the carb location, as well as a probable loss of performance.

How do I calculate carburetor size?

The formula for calculating how much CFM (cubic feet per minute) your engine requires is: CFM = Cubic Inches x RPM x Volumetric Efficiency ÷ 3456. Any ordinary stock engine will have a volumetric efficiency of about 80%.

Which is a better carburetor Holley or Edelbrock?

As I mentioned before, right out of the box an Edelbrock will be better. However, if you're a DIY guy who likes modding things around – Holley will be your best pal. The tuning is more responsive and less touchy than not only Edelbrock, but most other manufacturer's carbs.

What's better vacuum or mechanical secondaries?

In summary, mechanical-secondary carbs are much more sensitive to engine size, drivetrain gearing, vehicle weight, and rpm range compared with the controlled secondary configuration, which is why the double-pumpers are offered in many more cfm ratings than the vacuum-secondary carbs.

Do carb spacers add horsepower?

Yes, they will give you more horsepower. But carb spacers have another important function. They also act as insulators which keep engine heat away from your carburetor to ensure cooler incoming air and fuel.

What is a 3 circuit carburetor?

Three-circuit metering systems bypass the metering blocks by pulling fuel directly out of the fuel bowl and into the venturi. They are easily identified by pullover tubes that protrude into the venturi near the throttle plate. “The third circuit is essentially a pullover system,” Benoit said.

How much horsepower does a Edelbrock Performer intake add?

After you fix what's limiting performance, an Edelbrock Performer intake can add as much as 10 HP.

Does changing carburetor increase power?

depends upon which carburetor you are going to use, if you use carburetor of small engine then milage will increase but power will become less than half. and if you use carburetor of big engine then power will increase and mileage will decrease.

Does changing carburetor increase speed?

A bigger carburetor alone will not make your bike go faster. In most cases, your bike won't even start or idle roughly with a carburetor that's too big. For more power, you should look into a full system performance exhaust and rejetting your carb (not replacing it entirely).

Does bigger carb need bigger jets?

A bigger carb uses a bigger main jet. More air, more fuel. If the carb is too big, it needs even a bigger main jet since you won't have as much vacuum to draw fuel in.