I was reading an article about Honda's VFRs and how they used both 180 & 360 degree cranks. So I'm thinking the crank would have two common crankpins 180 or 360 apart with each supporting a pair of opposite pistons in the V. So what crank arrangement do they use on the road & race going Ducati V4s and what advantage does one have over the other especially when considering their firing orders?
I believe firing interval is what matters. it’s the gap between spikes in torque to the rear wheel to maintain traction without causing torsional vibration.
The V4 motors run the pins at 90 degrees iirc. As northern monkey says, it’s about power delivery and allowing tyre grip to recover. I can’t recall the numbers, but there is at one point a 270 degree lag in power in the V4. Think of it as two twins running side by side, 90 degrees out of phase. Yamaha did a similar thing with the cross plane crank
Aha... found this on the Ducati web site and I quote "Crank pins offset by 70° combined with the 90° V layout of the engine result in a firing order that Ducati calls “Twin Pulse”, because it is as if the engine were reproducing the firing sequence of a twin. The distinctiveness lies in the fact that the two left-hand cylinders fire closely together, as do the two right-hand ones. On the timing chart, the ignition points are at 0°, 90°, 290° and 380°. This particular firing order makes the V4 sound very similar to the MotoGP Desmosedici." I notice the latter sentence mentions it sounds like the MotoGP engine... but not the same as it So if it's all over in 380° we then have to wait near enough another full revolution i.e. 340° (720 - 380) before the first one fires again.
