Is it possible? Has it been done? Obviously Nissan engineers have our cars running a 1-2-3-4-5-6 firing order for a reason but are there alternatives? There may be advantages to not having cylinders firing sequentially, such as better exhaust gas scavenging and better heat dissipation. Firing cylinder 6 earlier in the cycle may also help with its problems of running lean/hotter than the other cylinders. I guess this would require aftermarket cams and switching injector and coil plugs, or using an aftermarket ECU to control the firing order. I had a play with alternative firing sequences but couldn't find one that didn't involve at least one pair of cylinders firing sequentially (in the same bank, not overall). Perhaps having that sequential pair closer the to the front of the engine would help? Discuss
Crank and Cams would need to be redesigned to the new firing order, then you'd need a A/M ecu as well...
Ignition timing aside, Cylinders fire in the order they hit TDC. And this order is prescribed by the design of the crank, You can't fire cylinders in a different order to when their in position.
The 120deg seperation on the crank makes it tricky. Would be pretty easy on a 90deg V8. Why would you want to change it anyway? It seems to work ok
Of course, I see now. Would there be advantages to changing the firing order though? I'm talking hypothetically here...
Umm, it'd sound different? Probably have a negative effect on flow to the turbo's too. The standard 1-2-3-4-5-6 would give a nice consistent flow through the log manifolds. If you are keen to know more about it have a look on HybridZ. There is a guy on there who wants to make a flat plane crank SBC just to get the awesome sound There is a huge thread on it.
not realy any advantages you could do a big bang motor by having 1-4 2-5 and 3-6 firing at once all you need to do is cut cams and twist them and weld them back up. Would create a whole heap of torque at super low revs. And wouldnt need am ecu just a bit of rewiring of trigger wires to injectors and coils.
You're referring to the fact that the exhaust pulses would be different? OK what about a non-turbo? Looking at it purely from an efficient combustion/longevity side of things...
Yes, in a different order. I don't think changing the firing order would be any more efficient or reliable. Some say that the 1-6 firing order on V6's 'unequally' loads up the crank due to the whole pulsing front to back, but it seems to work.
Due to the crank being so short on a V6 the "unequal load" has really no impact. When you talk longer cranks thats when they alternate firing front to back to "equalise" the load.
Firing 1 6 3 4 5 2 would yeild a slight gain in torque, but would be hardly worth the effort. Conventional 6 cylinder firing order is 1 5 3 6 2 4, front-back-front-back. Doing this on a V engine will repeatedly load one side of the block, then the other, not ideal for fretting of main caps or torsional rigidity. As far as changing it so number 6 isnt the last to fire, your logic there being the other cylinders have already made heat and consumed fuel. It will make zero difference to the #6 lean/heat issue, the cycle doesn't stop at number 6, it continually repeats. #6 maybe be the end of the firng order, but in reality it is 1/6th of a cycle that keeps going.
So machining a new crank and cams for a minor increase in torque would be a complete antonym for 'bang for buck' :rofl: Yeah I can see my flawed logic on cylinder 6. It would only help on the very first cycle... and who cares about that one
