The Story Behind The Bundle Of Snakes Exhaust System -

The Story Behind The Bundle Of Snakes Exhaust System

When the phrase "bundle of snakes" is uttered about an exhaust system, two cars come to mind: the Ford GT40 and Lotus 38. These were not the first vehicles to use this type of exhaust configuration, but they were the first to be called a "bundle of snakes" and make exhaust systems look more like art than science.

In the all-new Ford 5.2-liter V8, the connecting rods attach to the flat-plane crankshaft at aligned 180-degree intervals – creating what looks like a flat line of counterweights when viewed down the axis of the crankshaft. This crankshaft configuration improves cylinder exhaust-pulse separation, improving airflow and increasing power.
In the all-new Ford 5.2-liter V8, the connecting rods attach to the flat-plane crankshaft at aligned 180-degree intervals – creating what looks like a flat line of counterweights when viewed down the axis of the crankshaft. This crankshaft configuration improves cylinder exhaust-pulse separation, improving airflow and increasing power.

When the phrase “bundle of snakes” is uttered about an exhaust system, two cars come to mind: the Ford GT40 and Lotus 38. These were not the first vehicles to use this type of exhaust configuration, but they were the first to be called a “bundle of snakes” and make exhaust systems look more like art than science. These complex exhaust systems were created as a solution to the problem caused by the use of a flat-plane crankshaft.

Most engines use a cross-plane crankshaft. On this type of V8, the crankshaft fires every 90 degrees, and two pistons in a bank are always at the top and firing. This is good for scavenging exhaust gases because the exhaust pulses and the cylinder to be scavenged are on the same bank if using a four-into-one exhaust collector. But, a cross-plane crank does not rev as quickly due to the weight of the rotating mass caused by the counter weights.

A flat-plane crankshaft is lighter due to the lack of counter weights. But, the exhaust pulse needed to help scavenge a cylinder is 180 degrees apart and now on the opposite bank of the engine due to the crankshaft configuration and firing order. This is what the “bundle of snakes” solves.

The bundle of snakes uses two four-into-one collectors. The equal-length exhaust runners crisscross so the appropriate runners are positioned next to each other in the collector to create the scavenging effect.

For the 2015 Shelby Mustang GT350, Ford is using a flat-plane crankshaft for the 5.2L V8. Putting a bundle of snakes under the hood was not an option. Instead, Ford engineers had to go with a four-into-three-into-two design that does not look as efficient.

Courtesy Underhood Service.

The all-new Ford 5.2-liter flat-plane crankshaft V8 found in the Shelby GT350 and GT350R Mustang will produce 526 horsepower and 429 lb.-ft. of torque. At 102 horsepower per liter, the engine is both the most power-dense and the most powerful naturally aspirated road-going engine in Ford history
The all-new Ford 5.2-liter flat-plane crankshaft V8 found in the Shelby GT350 and GT350R Mustang will produce 526 horsepower and 429 lb.-ft. of torque. At 102 horsepower per liter, the engine is both the most power-dense and the most powerful naturally aspirated road-going engine in Ford history.

 

1964 Ford GT 289 engine
1964 Ford GT 289 engine


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