---
title: 'Why Ducati V4 Engines Are Different from Everything Else'
source: 'https://youtube.com/watch?v=0mU7p4_CbBA'
video_id: '0mU7p4_CbBA'
date: 2026-07-28
duration_sec: 1060
---

# Why Ducati V4 Engines Are Different from Everything Else

> Source: [Why Ducati V4 Engines Are Different from Everything Else](https://youtube.com/watch?v=0mU7p4_CbBA)

## Summary

The video examines four crankshaft layouts for 90° V4 motorcycle engines (screamer with 0° offset, 180° offset, 90° offset, and Ducati's 70° twin-pulse) and evaluates them on power delivery smoothness, exhaust scavenging, secondary vibration balance, and sound. Ducati's choice of a 70° offset is a deliberate compromise that creates a well-rounded engine with good valve train characteristics and a distinctive V-twin-like sound, rather than excelling in any single metric.

### Key Points

- **Four V4 Crankshaft Layouts** [00:02] — Ducati's 90° V4 engines can have cranks with 0° (screamer), 180°, 90°, or 70° offset between front and rear crank pins. These layouts determine firing order and engine characteristics.
- **Firing Order Determination** [01:11] — The crank pin offset dictates firing order and interval. For example, a V4 0 (screamer) has firing order 1-3-2-4 with intervals of 0°, 90°, 270°, 90° relative to crankshaft rotation.
- **Ideal Power Delivery is Evenly Spaced** [04:28] — An inline-four engine fires every 180° of crankshaft rotation, providing perfectly smooth power delivery. The goal for a V4 is to get as close to this as possible.
- **Power Delivery Rankings** [05:24] — V4 180 is best (450° duration, intervals 180/90/180/270), then screamer (450° duration, intervals 90/270/90/270), then Ducati's 70° (380° duration, intervals 290/180/270/250), and worst is V4 90 (360° duration, all fire within 360°, then 360° gap).
- **Exhaust Scavenging** [08:11] — Cylinders on the same bank should have evenly spaced exhaust pulses for optimal scavenging. The screamer (360° apart between cylinders on same bank) is best, followed by Ducati 70° (290°), V4 90 (270°), and V4 180 (180°).
- **Secondary Vibration Balance** [10:44] — Secondary forces occur at twice engine speed. V4 90 has opposite secondary forces canceling, making it best. Ducati's 70° is close, then screamer, then V4 180 (worst due to moments).
- **Valve Train Advantages of 70° Layout** [14:25] — Ducati's 70° twin-pulse design has superior valve train torque and friction characteristics, which are critical for high-revving engines. This will be covered in a subsequent video.
- **Sound Character** [15:31] — Screamer and 180° sound more like an inline-four, while 90° and 70° sound like a V-twin. Ducati deliberately chose the 70° for its V-twin-like burble, which matches their brand heritage.

### Conclusion

Ducati's 70° twin-pulse V4 is a balanced compromise that prioritizes valve train performance and sound character over raw power smoothness, making it uniquely suited for their high-revving motorcycles.

## Transcript

many great reasons to go with an inline layout, especially in cars. But, in motorcycles, there are many great reasons to go with a V4 layout, as I've explained in my previous video on Ducati V4 engines. Now, once you've narrowed it
V4 engines. Now, once you've narrowed it down to a 90° V4, meaning you've got two cylinders on one bank, and then 90° apart, you've got another two cylinders, well, then there are three obvious options for a crankshaft design, which
will have significant impacts on the characteristics of the engine. So, which one of these three does Ducati choose? Well, none of them. It's a seemingly Well, none of them. It's a seemingly bizarre choice to use a 70° crank pin
bizarre choice to use a 70° crank pin offset in a 90° V4 engine, but it's actually very logical. So, in this video, we're going to explain why Ducati does it the way they do it. This will also help answer the question of why
Ducati bikes sound so good, which is, of course, subjective, but there's a real science behind that sound. All right, so what are the four layouts we're going to look at? And keep in mind, all of these are 90° V4s. Where they differ is how
they have their crank pins set up. So, if we're looking at a V4 0°, or what Ducati calls a screamer, if you look at the crankshaft, it goes over, and then 0° offset from the front pistons versus the rear pistons, so it's going to look
I'll show some images on screen so you can get a better idea of what this crankshaft looks like. But, essentially, you have no degree difference between your front crank pin and that back crank pin. Now, with a V4 180, as the name
implies, you're going to have a 180° offset. So, this bottom set here will look like so, then this top set of pistons here will look like so. So, you're going to have that crankshaft rotated 180°. A V4 90, well, of course,
you've got your crank pin there, and And you've got your crank pin at 90° offset from that. And then finally, what Ducati does with all of their motorcycles is a V4 70. So, instead of this 90° offset like we have here, this only rotates 70°
and so you have a 70° difference between these two crank pins. Now, based on how the crank pins are set up and what angle you choose, this dictates what your firing order is going to be. And this will ultimately decide how smooth the
engine's power delivery is. All right. So, let's walk through an example to order and then how do we get the angles at which each respective cylinder is firing of crankshaft rotation here. So, for example, our V4 0 with a firing
order of 1 3 2 4 with a crank angle rotation respectively of 0 90 360 and 450. So, looking down on the engine and of course, keep in mind this is a V, not So, if you're looking at it from the side, of course, it looks like a V, but
top-down view, you've got cylinders 1 2 2 3 and 4. And as you can see, because of this crankshaft design, both cylinders 1 and 2, the pistons are paired together and cylinders 3 and 4, the pistons are paired together. So,
these two are at top dead center. These two are 90° before top dead center. As diagram, the piston's at the very top. So, that means cylinder 1 can go ahead and fire at 0°. So, this piston fires, then you move over 90° the crankshaft
rotates 90°. That means cylinder 3 and 4 are now the pistons are now at top dead center. So, then we can fire cylinder 3 90° later. Now, we need to rotate this
all the way 270° from where it is here back to so that we can get cylinder 2 at the top of top dead center. So, that means cylinder 2 is firing after 360° of crankshaft rotation or 270° after cylinder 3 has
>> And then because we're already back here, we just need another 90° and cylinder four is then at the top dead center, and so we can fire cylinder four after 90°, and then we have 270° of rotation again before we get back to
cylinder one. All right, so now we understand how the V4 screamer gets its firing order, and then we also understand why it has these intervals between the different cylinders firing. So, we can go through that same exercise
with each of these four different engine layouts, and based on the crank design and where these pistons are, you can determine what your firing order is and what the interval is between different cylinders firing. Now, what is ideal?
Well, ideally, you have your power strokes evenly spaced. That means your power delivery is as smooth as possible. And so, we actually have a reference here to look at to see what is ideal. Look at an inline four-cylinder engine
that has a firing order of 1-3-4-2. Well, in that case, cylinder one fires, Well, in that case, cylinder one fires, 180° later, cylinder three fires, 180° later, cylinder four fires, 180° later, cylinder two fires. So, across 540° of
rotation, you have those four cylinders fire, of course 720 total, in which case you repeat that cycle. So, that is ideal. That's perfectly smooth power delivery because it's very consistent. Every 180° of crankshaft rotation, you
get a power stroke. So, now let's look at our four different engine layouts and determine which one is closest to ideal. So, there's two things we are looking for. First, the total duration between cylinders one and the final cylinder
firing to be as long as possible. So, for our I4, that's 540° between the first and the last cylinders firing. Then, the second thing we're looking for is we want our firing interval evenly split. So, ideal would be 180° of crank
rotation between each cylinder firing. So, how close can we get to this with our different layouts? So, looking at the V4 screamer, you can see the duration is actually pretty good. Between the first and last cylinders
firing, you've got 450° of crank rotation, but the interval is not that then a long interval, then short, then long. So, if we look at the V4 180 with comparison to the Screamer, you can see it maintains that duration, 450° between
the first and last cylinders firing, but it does so at a more even interval. So, it does so at a more even interval. So, instead of that 90 270 90 270, it's 180 90 180 270. So, this is a bit closer to an inline four-cylinder in terms of
power delivery. It's going to be a smooth power delivery. Now, here's where we get into some not so great power delivery. If you look at a V4 90, all delivery. If you look at a V4 90, all four cylinders will fire within 360° of
crank rotation. Then you wait a whole additional 360° of crank rotation until your cylinder one fires again. So, this is not going to be a smooth power at once, and then wait, all at once, and then wait. And then if you look at a V4
70, the design that Ducati uses, they extend that duration versus a V4 90 a little bit. Instead of 360°, it's now 380° between the first and last cylinders firing, and then slightly better intervals where they're not so
long between waiting. So, only 340° of waiting from four to one versus 360° of waiting from four to one with the 90° V4. So, a little bit better in terms of power delivery, but still not great. so we have fully made it through power
delivery, which is just one of many characteristics of the engine that is determined based on the crankshaft design. So, for each of these these engines against each other, with the best ranking one and the worst
ranking four. So, in terms of power delivery, you've got the longest duration and the smoothest spacing with this V4 180. So, that will get number one for power delivery. Second place will go to the V4 Screamer. Same
duration, not not as great of spacing. And then third place will go to our Ducati twin pulse engine. And then fourth place, all of them firing within fourth place, all of them firing within 360° of crank rotation. So that is going
to the V4 90. And now you're thinking, "What the How long have I been here? We've only got one characteristic down?" Good news, the rest of them will be much quicker. Okay, the next characteristic we'll
discuss is exhaust scavenging. And this is particularly important for peak exhaust pulses interfering with each other in a negative way. Instead, you want them helping each other with exhaust flow. Now, as far as exhaust
scavenging, what's important to look at is the two cylinders that are on the same bank. So these two cylinders here, their exhausts are going to join up fairly quickly. So it's important that their exhaust pulses don't interfere
with one another or do so in a positive way. So we look at when with cylinder one fires versus when cylinder two fires, we can of course look at our firing order. One and two are firing 360° apart. And then one of course is
going to fire 360° after that. So you can see that even spacing of one, two, one, two, and so on. And so if you look here at two full firing cycles, combustion cycles, so four total rotations of the crankshaft, you've got
360, 720, 1080, 1440. If you look at that, of course cylinder one is firing that, of course cylinder one is firing at 0°, 360° later cylinder two, 360° later cylinder one, 360° later cylinder two, 360° later cylinder one. And so you
can see this really even spacing of these exhaust pulses, which is perfect. That is ideal. Now, if you look at a different layout, say this V4 180, you can see that between one and two, you only have 180° of crank rotation. So
cylinder two is firing immediately after cylinder one. And so, you can see then you have a long pause until cylinder one. So, what this means is as you have a cylinder one firing, shortly after cylinder two is firing, so you can have
that high pressure impact those exhaust gases releasing from cylinder two. So, that is not ideal. And then what you want really is this real even spacing. So, as you look at a V4 90 and even a V4 70, you start to extend that duration
between cylinders one and two firing. So, here cylinders one and two, that's a 270° split in crank rotation. And then for the V4 70 that Ducati uses, one to two is 290°. So, slightly longer. So, a
slightly longer duration between one and two firing. So, this is ideal. This is worst case. This isn't so bad. And again, this is getting closer to getting to our worst case here. So, as we look at our engine characteristic rankings,
of course, this V4 screamer is going to be the best. Uh then we have the twin pulse, the Ducati engine, then the V4 90, and then the V4 180. All right, the next engine characteristic we're going to get into is the second order
vibration balance or the secondary balance. All right, so in order to understand secondary balance, we need to understand primary and secondary forces. if you don't understand them at all, I would highly recommend checking out
little cheat sheet here and I'm going to review very quickly. So, our primary forces are basically happening first order forces are happening at the same frequency of this piston moving up and down. So, as this piston is going up
you of course have that primary force going up. As this piston reaches bottom dead center, as it's going down and then hits the bottom, you have that primary force going down. So, you counter these using counterweights on a crankshaft.
So, as this piston goes up, you can see this weight goes down, so it counters that primary force. As the piston goes down, the weight the counterweight on the crankshaft goes up, so it counters the force of that piston. So, primary
forces we're not going to worry about here from a balancing standpoint because counterweights. What we're concerned with here are the secondary forces. And so, second order forces happen at twice the frequency of primary forces. And so,
that secondary force is up. When that piston is halfway down, that secondary force is then down. And then when that piston reaches bottom dead center, that secondary force is up. Again, I have videos explaining why this is if you
care to check them out, but this is going to act as our cheat sheet right going to look at the different layouts, and what we want to see is the secondary get into moments, but I will take moments into consideration when I give
balance. So, what we want to see is these arrows pointing in different cylinder here, and then there's another cylinder behind it. So, both of those unison. So, of course, that means their secondary forces are going to line up.
That's not good. They're both going to be going that direction. Then here where this piston is halfway down for both of these, that means halfway down, we can look at our cheat sheet, the secondary force is pointed down. So, both of those
there are pointed down. Both of these here are pointed up. That is not good from a secondary balance perspective. Same with the V4 180. So, as we look at this, both of the forces here where there the piston is at the top and the
one behind it is at the very bottom, both of those secondary forces pointing the middle, so both of those secondary forces pointing down. As we look at our V4 90, you can see one piston is at top dead center, while one is 90° after top
dead center. And so, looking at that, you can see that means one is pointed up, one is pointing down. So, those secondary forces canceling out, and that is happening on both sides. So, from a secondary balance perspective, the V4 90
is very good. Now, I haven't drawn it for the V4 70 twin pulse, but it's going to be very close. Of course, that angle of the crank is just going to be a very close to this. It's not going to be as well balanced as this, but it will be
the rankings, of course, the best one's going to be this V4 90, then Ducati's V4 twin pulse, then this top one here, the screamer, and then the V4 180. And the
reason why this is worse than this, even though they look identical, is actually because you can do some magic with some counterweights here to help reduce the moments from that secondary balance, whereas you cannot here. And so, this
one is going to have the worst overall secondary vibration characteristics. And whiteboard, and you're thinking, "We're only halfway?" Nope, we are almost done. One of the most critical reasons why Ducati chose the 70° twin pulse layout
is because of its advantages in valve train torque and friction. This is a very complicated topic, so it's going to be my next video. And it's part of the secret of how Ducati engines are able to rev so high. It is absolutely
fascinating, but it is also quite complicated. So, we will get into it in my next video. But just know that in terms of combined valve train torque and valve train friction, this V4 70 twin pulse engine has the best
characteristics. And so, as you get the more complete picture, you can see that this is such a well-rounded engine. Ducati's not here to say that this is the best and the only way to make an engine, right? In fact, actually, Ducati
has used the V4 screamer previously in MotoGP, thanks to the really good exhaust scavenging, which lends itself well to having a high peak horsepower. But this is the design they currently use for all of their engines, and it is
because it is such a good well-rounded engine with a lot of really good characteristics. And it has really good valve train characteristics, which are critically important for high-revving engines. But there's still one subject
we haven't touched on, and that's sound. Now, of course, sound is subjective, but Ducati has a long history with V2 or V-twin bikes, and they like the way V-twin bikes sound. There's kind of a raw, rough burble to a V-twin that's
much different than, say, the monotonous rhythm of an inline four-cylinder. So, as far as the sound, the V4 screamer and the 180, they sound kind of more similar the 180, they sound kind of more similar to an inline four-cylinder versus the V4
90 and Ducati's V4 twin pulse that sound kind of more similar to a V-twin engine. And so, I actually generated sound files for each of these, and so I'm going to play them at 800 RPM so you can kind of get the cadence of these firing orders.
I feel like at 800 RPM, you can really distinguish the different sounds, so we'll go through them. So, first playing this one. So, it has that nice rhythm to it. Then playing this one.
little better, the difference in these. So, I'm going to play this at 400 RPM. to it. And then playing the V4 twin pulse, the Ducati engine. Both of these
sound basically the same, so just going to play this one. And then going through them all one more time at 800 RPM.
like the screamer where you have that kind of more rhythmic like brrr. differences between them. Ducati, of course, likes the sound of their bikes and the way that they've done it. So, in the next video, we will cover why
Ducati's crank design is so good for valve trains, and we will close this out with some lovely sounds of Ducati's actual V4 twin [music] pulse engine.
feel free to leave them below. Thanks for watching.