Engine Types - Inline vs V-type vs Boxer

[bruce71]

Wow this is interesting. I started off reading the thread from post 1. Informative, very layman explanations and stuff. Except for the small tiff in the middle. Haha, no offense.

 

But back to the point of engines, inlines as opposed to v-layout engines. We are, talking about and comparing the layouts right? Then we should know that we should be comparing engines with the same number of pistons, just different layouts (inlines vs Vs). Like comparing v4s and inline 4s, not v-twins and inline 4s. I guess this has been addressed by our brothers/sisters earlier.

 

So now i shall just mention that the engines with same number of pistons in different layouts will have different characteristics. Assume the rest of the engine is identical (valve size, number of valves, cam profiles, bore x stroke etc.), a V engine will generally have a lower centre of gravity. They are also more compact. Generally also, they will have different firing sequences, which will have a huge effect on the power curve. Firing sequences are the major differences between ducati's "big bang" setup and their "screamer" setup. They are also responsible for the lumpy, thumping sound you hear for 09' and above Yamaha R1s, as compared to the smooth, creamy sound of the pre-09' R1s. Of course they changed the whole crank system but ultimately, it's the firing sequence that's altered. This is what yamaha did to counter the power "surge" that inline 4s have, to make it a torquier bike throughout the curve. The firing sequence is also the reason why harleys have that signature pulsing sound.

 

Yes and talk about the power curves. We start from the basics. Torque is just a way to measure the amount of turning force that something has. The reason why inlines generally have higher horsepower figures on paper is simply because they can reach insanely high revs. Horsepower is actually torque, in relative to your revolutions per minute. There is a formula to calculate hp from a torque curve, google it if it interests you. V engines have generally a smoother torque curve, like a plateau, which means that it will produce the same amount of torque throughout the revs. Inlines generally have more torque as the revs go higher, which explains why there is a steeper gradient for their horsepower curves.

 

The explaination above is why bikes like the mt-01 have huge amounts of torque but unimpressive hp figures. However, crack open the throttle anywhere along the powerband and you will find yourself having a hell of a fun time trying to hold on to the handlebars. Torque is awesome.

 

There's alot more to your discussion than just "cbr/s4 vs rvf". I believe what we talk about is just the surface. I can sit down with you the whole day and just talk about engine configs, what changes in the angle of the v engine do, with all the proof i need just by googling. It won't end

 

Oh btw, i don't have a license so don't flame me for riding a small bike. Knowledge doesn't depend the number of years the license has been in your pocket

 

Chill bros, we're all here to learn.

 

Sent from my GT-I9300 using Tapatalk 2

 

haha, thanks to mechwira & you, you guys just state all i had wanted to say. you 2 are very patient leh!

 

i am too lazy to be so technical & i can't do it even when i want to. you 2 guys are more technically knowledgable than i am. i admit i am not as smart as you people.

 

i am lazy & take the easy way out of summarizing it when discussing V-twins vs inline 4s & V config vs inline. ie.

 

4P wins 2P. . V-irgin or no virgin.

 

but when it is 4 vs 4 or 2 vs 2, then V-irgin wins. easy & simple to remember. But V-irgins needs more attention & taking care. old uncle like me too lazy, i leave the small girls for young men.

 

i am not angry, just too lazy to get angry. i old liao, if i got so much energy i go drool at hot girls, hehehe!

 

anyway, i am very impressed that you are 1 of the very few people out there who is NOT confused with Torque. i had given up explaining it when many people out there use torquey to actually mean more pull ( power ) at low revs. i too lazy to talk so much, so i use torque in the same way as most so that most people understand but actually it is technically wrong. ( just like 'topo' used in the army is actually navigation & not topography , but what is the point of being too anal? )

 

big thanks to you & mechwira, i have to go out & beo chiobu-s liao! no worry, i only look at all legal one, the V-irgin Xiao Mei Mei ( small girls ) i leave to very Matured riders who ride big bike, i no qualified with my small 2b bike. i can only hit on zeh zehs, hahaha!

 

PS: happy CNY to all chinese, if yiu are not chinese then happy public holiday break for you! bye!

Edited February 7, 2013 by bruce71

[ticks]

Lol. In summary.. Torque is what moves you, horsepower is what u talk about.

[dwh12]

Very interesting and informative thread ^.^

 

I'm not a mechanic, but i can try to explain power and torque theoretically since i studied aircraft engines and theyre quite similar.

 

Mathematically speaking,

 

Force = mass x acceleration

Torque = force x moment

acceleration = Torque / (moment x mass)

 

So given a bike that produces, say, 19N.m, weighs 126kg, and the effective moment from the engine, through transmission, to final drive (plus the diameter of the rear wheel) is 0.04. (Aprilia RS125, maybe?)

 

So the acceleration of the bike at peak torque would be

19 / (0.04x126) = 3.8 m/s^2

which means that if the engine were to continuously produce that torque, it would go from 0-100 in 3 seconds!

 

But, in reality it doesnt, because of air friction, transmission losses and etc.

 

 

For the same bike, say there is a power output of 15hp, or 11kW.

 

Rolling resistance and friction in wheel bearings, engine and other parts are usually quite constant, say 5N.

 

Air resistance however, increases with the square of velocity, also related to coefficient of drag, say 0.2. (affected by its aerodynamics, e.g fairings, boxes, panniers)

 

Power = Force x Velocity

= (kV2 + k) x V

P = (kV3 + kV)

= (0.2V3 + 5V)

 

so a bike with 11kW of power will be able to travel at a top speed of

11000 = (0.2V3 + 5V)

(Solving a cubic equation)

V = 38 ms or 138km/h.

 

Note that the weight has nothing to do with the top speed.

 

So in short,

Weight and torque -> acceleration.

Power and aerodynamics -> top speed.

 

I may be wrong here, but I hope this helps! I'm clueless about the difference between the engine configurations effect on bike performance. Will need you guys' expertise and experience in this! Me nerd, like to study maths only, lah!

 

btw, this is my first post! hee

[Jehuty]

Ahhh lemme put this into perspective.

 

1)V4s do not make more power than Inline 4s, V4s just have lower center of gravity, which equals better mass centralisation thus the bike feels light even if its 180kg and handles better. You can make them more oversquare than Inline 4s

 

2)Inline 4s have more top end than V-twins, V-twins have bigger pistons thus more reciprocating mass, thus they can't rev as high, their peak horsepower comes well down the revs but they also have more torque throughout the rev range hence more pick up, V-twins fire in pulses, so you'll get that pull. Hence why your Ducatis need an extra 200cc to compete though even then it will still lose out to Inline 4s on top end

 

Bikes have terrible coefficient for aerodynamics, I hear aerodynamics doesn't affect much until speeds excess of 200km/h.

[ooitn]

Simple answer to the TS question.

Sample cc, same piston numbers, same valve, same COMPRESSION ration..same firing sq...same..same..same..

 

V or Inline or Boxer = same power, torque

 

Only diff layout and CG...

[ben1112]

Simple answer to the TS question.

Sample cc, same piston numbers, same valve, same COMPRESSION ration..same firing sq...same..same..same..

 

V or Inline or Boxer = same power, torque

 

Only diff layout and CG...

 

I must politely let you know that it is not all the same. Different layouts do not produce similar power/torque as they are inclined to one or another for the reasons previously discussed. Feel free to look over page 1 again to recap on it.