The reason double pumpers (mechanical secondary carburetors is their proper name) have these twin accelerator pumps is to prevent a momentary lean situation during quick throttle blade movement. All carburetors use an accelerator pump circuit, however many only have one on the primary barrels.
- Do I need a double pumper carburetor?
- Which is better vacuum secondaries or mechanical?
- Is the Holley Street Avenger a double pumper?
- How do I identify a Holley double pumper?
- What carburetor do I need?
- What is a high rise double pump carburetor?
- What is a 4 barrel carburetor?
- Where is the accelerator pump located?
Do I need a double pumper carburetor?
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.
Which is better vacuum secondaries or mechanical?
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.
Is the Holley Street Avenger a double pumper?
BOWLING GREEN, Ky. – Holley Performance Products has announced the introduction of its all-new Ultra Street Avenger and Ultra Double Pumper carburetors, which have been designed for improved performance, weight savings and show quality looks.
How do I identify a Holley double pumper?
It's like a "VIN" for your carburetor and should be hand-stamped on the front of the choke tower to the right of the vent tube on most typical Holley carbs. The list number typically is four to six digits long and may or may not have a suffix number behind it.
What carburetor do I need?
The formula for calculating how much CFM (cubic feet per minute) an engine requires is: CFM = Cubic Inches x RPM x Volumetric Efficiency ÷ 3456. Any ordinary stock engine will have a volumetric efficiency of about 80%.
What is a high rise double pump carburetor?
Double pump carb - carb with two accelerator pumps. Provides extra squirt of fuel to spin up the engine faster without leaning out the mixture which can cause detonation, pinging and knocking. All of which are bad news in a high performance engine.
What is a 4 barrel carburetor?
A four-barrel carburetor has two primary and two secondary barrels. At idle and low-rpm driving, only the primary barrels open. ... As the secondary barrels begin to open, more air travels through the carburetor, supplying the engine with the air and fuel it needs.
Where is the accelerator pump located?
By manipulating the cam, the quantity of fuel dispensed by the pump can be adjusted from a small spritz to a large squirt. The accelerator pump is located on the bottom of the fuel bowl of the carburetor. On a typical barrel system, there will be a single pump.