single plain intake
CO River Rat
Joined: Feb 2004
Posts: 3,209
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From: Lake Havasu City AZ
Single-plane manifolds are pretty much for competition and don't function well on the street; for that you'll want a dual-plane manifold. Some of them are advertised to increase torque, good for off road and rock-climbing.
Steve
Steve
Posting Legend
Joined: Sep 2001
Posts: 30,255
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The above is correct. 
A dual plane manifold places half of the engine cylinders on half of the carburetor and the other half on the other side of the carb. This reduces the effective volume in the manifold and increases the vacuum signal to the carb which improves metering and throttle response. A dual plane more direct flow path for the air fuel mix to the cylinder without being pulled or diverted to other cylinders. The dual plane name comes from the configuration used on a V8 engine and is somewhat of a misnomer if used on inline engine configurations. It would be more appropriate to call it a divided manifold but that term is not used.
A single plane manifold allows each cylinder to draw air fuel mix from the entire carb which decreases flow resistance and improves high RPM power.
You may also find another type of manifold called the dual PORT manifold mentioned which have two distinct runners to each head port. Tunnel ram manifold configurations are similar to a single plane but are configured for a very direct individual runner to each intake port from a central plenum. These manifolds are used for specialized applications.
A dual plane manifold places half of the engine cylinders on half of the carburetor and the other half on the other side of the carb. This reduces the effective volume in the manifold and increases the vacuum signal to the carb which improves metering and throttle response. A dual plane more direct flow path for the air fuel mix to the cylinder without being pulled or diverted to other cylinders. The dual plane name comes from the configuration used on a V8 engine and is somewhat of a misnomer if used on inline engine configurations. It would be more appropriate to call it a divided manifold but that term is not used.
A single plane manifold allows each cylinder to draw air fuel mix from the entire carb which decreases flow resistance and improves high RPM power.
You may also find another type of manifold called the dual PORT manifold mentioned which have two distinct runners to each head port. Tunnel ram manifold configurations are similar to a single plane but are configured for a very direct individual runner to each intake port from a central plenum. These manifolds are used for specialized applications.
Last edited by Torque1st; Mar 25, 2007 at 08:10 PM.
Moderator
Joined: Dec 2001
Posts: 22,436
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From: Louisville,Ky.
Yep a dual plane will have good throttle response and make usable power from idle to around 5500rpm. A single plane has a higher rpm range from anout 2500 to 7500 rpm. Not good for a heavy truck or nearly stock engine.