Jets303ā¦
Very nice!
I noticed the 12 cyl. exhaust manifolds join three-into-one and join the other three-into-one at a two-into-one collector. Is there a reason for this?
Again, nice work.
RT
RT
This is from Burns Stainless:
"It should be noted that six-cylinder and 12-cylinder engines are inherently balanced and even firing. That is, for an inline-six (I-6) cylinder engine, the firing order is such that cylinders fire alternating between the front 3 and rear three cylinders with a separation of 120 degrees (720/6). The cylinders of a V-6, engine, typically arranged in a 60 degree āVā, fire in an alternating fashion between banks also with 120 degree separation. A V-12 is essentially two I-6s (or two V-6s) joined together at the hip, with cylinders firing in an alternating fashion from bank-to-bank separated by 60 crank degrees (720/12). The melodical sound of a Ferrari V-12 is testimony to the even firing nature of these engines. Typically, I-6 exhausts are setup as two 3-1 headers. The front 3 cylinders are combined into one collector and the rear 3 into another. A V-6 engine normally has a 3-1 collected system on each bank. A V-12 typically has two such setups (4 x 3-1 headers). In many cases, the 3-1ās are combined into a final 2-1 resulting in a single exhaust pipe from each bank of 6 cylinders.
With this exhaust setup, the exhaust pulses into each 3-1 collector for all these combinations are separated by 240 crank degrees. The exhaust pulses are far apart and do not compete for flow area in the collector allowing for a relatively small collector outlet and resultant increased power band. Also, unlike the 180 degree configuration necessary on the 90 degree V-8s, the header packaging is straight forward."
