Nissan V8 180 Degree Headers

[elwesso]

In the world of exotic motors, an exotic exhaust system would be more than appropriate.

Ever wonder what gives ferrari V8's that distinct sound compared to a regular V8? The main reason is because they use flat plane crankshafts, which in the end means that the 2 banks fire alternately.

In a nearly every V8, they use cross plane cranks. The main reason for this is refinement. However, in exotic sports cars this is not important, and in the end flat plane engines end up being rev-happy. This is why exotic sports cars sound similar to 2 4 bangers side by side vs the "blub blub blub" sound most other V8's we all know and love.

The point of 180 Degree Headers is to pulse the exhaust properly so that, in essence, the engine acts like a flat plane motor from an exhaust point of view.

Why are we talking about crankshafts? Well it is important to know how the cylinders fire in relation to the exhaust. In a flat plane crank motor, the left and right banks fire alternately. So in one complete engine cycle, it would go L-R-L-R-L-R-L-R. In cross plane motors, they fire in pairs, like R-L-R-R-L-R-L-L..

As we all know, in the firing order each cylinder fires 90* in relation to the ignition cycle (or on the distributor/CAS), so it would be 180* on the crankshaft. The advantage a flat plane crank has to this, is that you can pair the cylinders down each bank and you have the effect that we are speaking of automatically. Basically, flat plane cranks just have to make a standard header design and it works great.

Since cross plane motors dont fire directly alternately, we have to cross over some of the pipes to get this effect.

The essence of what we are doing is using the exhaust gas from one cylinder to pull the exhaust gas out of another. If you go to your tail pipe, you can feel a sort of "puffing" feeling, meaning that its not a constant stream of vapor coming out of the tail pipe, but rather a series of pulses. If we can get this stream of vapor coming out to be as close to a solid stream as possible, we maximize the efficiency of the gas flowing out of the cylinder.

if you want 8-4-1 headers join 1-6-7-4 and 2-3-5-8. If you want 8-4-2-1 headers join 1-6, 7-4, 2-3, 5-8 then 1-6-7-4 and 2-3-5-8.

8-4-2-1 would be best for a twin turbo setup with twin scroll turbine housings. In this instant you would put 1-6 on one scroll of one turbo and 7-4 on the other. Then the same for 2-3-5-8 on the other sid