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Intake runners and superchargers?

11K views 5 replies 5 participants last post by  68NovaSS 
#1 ·
Hey everyone,

I'm trying to understand this... What roll do intake runners play in a supercharged engine? Take a look at this picture, its a Chevy intake manifold for a Whipple supercharger using a Carburetor.

It looks like it has almost no intake runners? Also the blower outlet sits at the extreme front of the manifold, wouldn't there be fuel distribution problems before the boost built up?
 

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#3 ·
xxllmm4 said:
Hey everyone,

I'm trying to understand this... What roll do intake runners play in a supercharged engine? Take a look at this picture, its a Chevy intake manifold for a Whipple supercharger using a Carburetor.

It looks like it has almost no intake runners? Also the blower outlet sits at the extreme front of the manifold, wouldn't there be fuel distribution problems before the boost built up?
There are a lot of things that a supercharger overcomes. When running a supercharger the mixture is mixed real well in the rotors and is forced into the cylinders rather than relying strictly on atmospheric pressure to fill the cylinders.
I am not an expert by any means but it would seem that the size of the runners would be more important that the length.
 
#4 ·
Chet's right on, there's nothing wrong with that manifold, it's typical. Keep in mind you're force feeding a blower motor, port velocity as it relates to a NA motor doesn't come into play under boost. Other than that intake bolting to the heads from the inside, it works. Take a look as some top fuel setups, you'll see the blowers and injector hats appear offset by a bunch.
 
#5 ·
Most blower manifolds look like that on the inside. Length is not very important just no restriction to flow into the head.
Whipple is the best you can get for a positive displacement blower right now.
If you try to tune the length of the runner for a given RPM range, it would take a very long runner to help on a forced induction intake. The speed of sound is the deal, the pressure waves travel in the air at a certain speed and as pressure changes, so does the speed of the wave. A wave in the compressed air woucl require a runner that was very very long to work.
 
#6 ·
Hotrodrobert said:
Most blower manifolds look like that on the inside. Length is not very important just no restriction to flow into the head.
Whipple is the best you can get for a positive displacement blower right now.
If you try to tune the length of the runner for a given RPM range, it would take a very long runner to help on a forced induction intake. The speed of sound is the deal, the pressure waves travel in the air at a certain speed and as pressure changes, so does the speed of the wave. A wave in the compressed air woucl require a runner that was very very long to work.
Everybody has a right to their opinion, but to arbitrarily state one product or system is better than another, it needs to go a step further, posting some reliable data might help support your theory. IMO, your thoughts regarding runner length and velocity at "the speed of sound" and the wave thing aren't realistic or relevant for forced induction. I will agree, for NA motors, velocity is key; wave pulses? Maybe from rotor pulse or "push", certainly not something we count on for building power with forced induction.
 
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