To sum it up in a nutshell, yes, shorter runners and a bigger plenum are tuned to high rpm, and vice versa.
Visualize the intake charge rushing into the intake port and into the cylinder. The valve slams shut, and the rush of air continues to move toward the valve. This charge cant go anywhere, so it compresses, then bounces back toward the plenum. The charge stretches out, hits the area of higher pressure, which is the plenum, and then bounces back again toward the valve. if the valve opens again right when the charge is rushing back towards the valve, this extra inertia pulls more air into the cylinder than it would have at another time. Its called passive supercharging. Practically every fuel injected modern motor has long runners to take advantage of this. Many late model cars use dual runners for each cylinder. One long one for resonant tuning condusive to low end torque, and another short one for high rpm resonant tuning. A computer controlled valve will switch from the longer runner, to the shorter one, at a given rpm, to maintain the strongest curve. Its possible to do away with this, and design a single runner that is a balance between the 2. This science is used to engineer motors of all kinds. Even Mazda tunes runner lengths for use in their turbocharged rotary motors. It doesnt matter what its used on. Its science. practically every modern engine uses an intake manifold that was designed with this phenomenon in mind. Theyve used supercomputers and advanced fluid software to come up with the most efficient intake manifolds possible. Why do you think the early Throttle Body injection systems were done away with? Because they all utilized short, carburation style intake manifolds, with shorter runners. Runners that were originally designed with space in mind, and keeping costs down by using old casts for their intakes. Dodge made these cross ram intake manifolds back in the day that used VERY long runners. These intakes were the hot ticket, because they were known to produce the strongest curve available. People try to say that its useless on forced induction motors, but thats only because the turbo appears to be overcoming the mismatch to a degree, and the motor is already making so much power that they really dont care about spending countless hours modifying intakes, when they could just add that much power by upping the boost a couple more pounds.
Do you need this technology to make big power on a Turbo buick? Hell no. But this phenomenon exists in all internal combustion engines, and if you can take advantage of it, why not? More power, a stronger curve, better fuel economy.
Visualize the intake charge rushing into the intake port and into the cylinder. The valve slams shut, and the rush of air continues to move toward the valve. This charge cant go anywhere, so it compresses, then bounces back toward the plenum. The charge stretches out, hits the area of higher pressure, which is the plenum, and then bounces back again toward the valve. if the valve opens again right when the charge is rushing back towards the valve, this extra inertia pulls more air into the cylinder than it would have at another time. Its called passive supercharging. Practically every fuel injected modern motor has long runners to take advantage of this. Many late model cars use dual runners for each cylinder. One long one for resonant tuning condusive to low end torque, and another short one for high rpm resonant tuning. A computer controlled valve will switch from the longer runner, to the shorter one, at a given rpm, to maintain the strongest curve. Its possible to do away with this, and design a single runner that is a balance between the 2. This science is used to engineer motors of all kinds. Even Mazda tunes runner lengths for use in their turbocharged rotary motors. It doesnt matter what its used on. Its science. practically every modern engine uses an intake manifold that was designed with this phenomenon in mind. Theyve used supercomputers and advanced fluid software to come up with the most efficient intake manifolds possible. Why do you think the early Throttle Body injection systems were done away with? Because they all utilized short, carburation style intake manifolds, with shorter runners. Runners that were originally designed with space in mind, and keeping costs down by using old casts for their intakes. Dodge made these cross ram intake manifolds back in the day that used VERY long runners. These intakes were the hot ticket, because they were known to produce the strongest curve available. People try to say that its useless on forced induction motors, but thats only because the turbo appears to be overcoming the mismatch to a degree, and the motor is already making so much power that they really dont care about spending countless hours modifying intakes, when they could just add that much power by upping the boost a couple more pounds.
Do you need this technology to make big power on a Turbo buick? Hell no. But this phenomenon exists in all internal combustion engines, and if you can take advantage of it, why not? More power, a stronger curve, better fuel economy.
