Bigger engine but less horsepower, how?

[S-Westerly]

Preferably not on some weird Chinese thing with more tassels than a pole dancer.

[Bender]

2 hours ago, Stu said:

Heres a question for all the Bhp is torque x rpm divided by 5252 arguments 

how can two bikes with very similar engine configuration produce different levels of power? 

Thats what the OP is asking 

Simple, construction, bore, stroke, rotating mass, cam profile, number of valves,  engine configuration, air intake, fuel map.

There are enough variables to give you what ever you want. 

[Stu]

5 minutes ago, Bender said:

Simple, construction, bore, stroke, rotating mass, cam profile, number of valves,  engine configuration, air intake, fuel map.

There are enough variables to give you what ever you want. 

So same displacement and rpm yet different power outputs 

Makes a mockery of that calculation

[Bender]

7 minutes ago, Stu said:

So same displacement and rpm yet different power outputs 

Makes a mockery of that calculation

You cana break the laws of physics jim

 

Displacement is not a factor in that calculation.

[Stu]

3 minutes ago, Bender said:

You cana break the laws of physics jim

 

Displacement is not a factor in that calculation.

In my opinion there is way too many factors

 

[Guest Richzx6r]

2 hours ago, Mississippi Bullfrog said:

So long as you're doing in style.

On the back wheel 

[Bender]

6 minutes ago, Stu said:

In my opinion there is way too many factors

 

Like the engines being completely different 

[geofferz]

12 hours ago, Stu said:

Heres a question for all the Bhp is torque x rpm divided by 5252 arguments 

how can two bikes with very similar engine configuration produce different levels of power? 

Thats what the OP is asking 

Depends on the size of the stroke and bore meaning torque then the rpm I guess? 

[James in Brum]

I’m getting really confused. I thought that horse power is an expression of power, that torque is an expression of effort around a pivot. 
I don’t mean in motorcycles or cars or whatever I mean that is what they are?

like a metre is a metre is a metre, it is an expression of length, a ft/pound it Newton Metre is exactly that. And that in the case of the Newton metre it measure the expression of power around a pivot? I only have my GCSE physics to depend upon.

I’m curious about how does x Bhp lead to different Torques. Does that mean the distance from the pivot has changed?

[dynax]

I would have thought in most cases the torque would be dependant on the gear ratio.

[Mississippi Bullfrog]

Just now, dynax said:

I would have thought in most cases the torque would be dependant on the gear ratio.

And how many pies the rider has shovelled down recently.

[dynax]

6 minutes ago, Mississippi Bullfrog said:

And how many pies the rider has shovelled down recently.

Hmm maybe, and by coincidence we are having a pie for lunch today, a big family size fish pie

[Bender]

10 hours ago, Stu said:

In my opinion there is way too many factors

 

Bhp is a set unit of work over a min based on a horse, now we don't know how big dobbin was or if he had modifications you just have to trust dobbin could work for one minute with a given weight.

Think of it as torque is the power so 2 dobbin is more power than 1 dobbin so twice the power but they just less stressed doing it over a minute.

 

Think of the 2 dobbin like a harley, slow and deliberate.

Now get 4 of  their Italian stallion cousins you now have 4 Lipizzaner dobbins, scare the bejesus out of them, that 1 min of work is now done in 10 seconds and you didn't keep hold of them so there gone, think of them as a ducati hypermotard 

 

Torque is power, bhp is the speed that it's done at, are we all clear now?  No. Good, I'm off to feed dobbin.

[TimR]

Good place to start i would suggest checking out the engine used in 

Kawasaki gpz900 

Kawasaki Gpz1000

Kawasaki GTR1000

It is literally the same engine BUT for a few small internal changes that have an effect on the outputs.

 

[James in Brum]

16 minutes ago, Bender said:

 

Torque is power, bhp is the speed that it's done at, are we all clear now?  No. Good, I'm off to feed dobbin.

Torque does not equal power. They are related. I have no idea about cars and bikes but in physics they are differ t things. Just like volts is not amps.

[geofferz]

50 minutes ago, James in Brum said:

I’m getting really confused. I thought that horse power is an expression of power, that torque is an expression of effort around a pivot. 
I don’t mean in motorcycles or cars or whatever I mean that is what they are?

like a metre is a metre is a metre, it is an expression of length, a ft/pound it Newton Metre is exactly that. And that in the case of the Newton metre it measure the expression of power around a pivot? I only have my GCSE physics to depend upon.

I’m curious about how does x Bhp lead to different Torques. Does that mean the distance from the pivot has changed?

Torque is effort. A long stroke cylinder (in a twin for example) has a long lever so it can produce a lot of turning effort so lots of torque. Rpm is the rate of effort - how quickly it can do the work. So torque x rpm (there's a number of 5252 to drop in but ignore it for this) is how much work and how quickly it can be done which is effective power or bhp. 

So twins produce lots of torque because of their long stroke, but also because of this it takes longer for the piston to move up and down in the cylinder so it's hard for them to rev so fast. A 1000cc twin has 2 big 500cc cylinders. 

 

Compare this to a 4 cylinder 1000cc which has 4 250cc cylinders - much smaller, shorter stroke (so yes, less torque), but the piston can move up and down so much quicker meaning faster rpm and therefore possibly more bhp. 

 

Clear as mud?! 

 

 

 

[Bender]

4 minutes ago, James in Brum said:

Torque does not equal power. They are related. I have no idea about cars and bikes but in physics they are differ t things. Just like volts is not amps.

OK I was trying to keep it too simple, torque is the capacity to do the work, power is how quick it gets done, hence bhp, happy now. Probably not.

 

Without itorque your going no where.

[geofferz]

Anyway personally I don't bother looking at the torque figure - it's bollocks. I rode a Harley with loads of torque but super low revs so tiny bhp. It was horrifically slow - I couldn't appreciate any of its torquey goodness, it was slow in every gear at every rpm. 

 

Bhp matters. 

[Mississippi Bullfrog]

4 minutes ago, geofferz said:

Anyway personally I don't bother looking at the torque figure - it's bollocks. I rode a Harley with loads of torque but super low revs so tiny bhp. It was horrifically slow - I couldn't appreciate any of its torquey goodness, it was slow in every gear at every rpm. 

 

Bhp matters. 

You haven't ridden the Triumph 1200 twin. Loads of low end grunt but a relatively small bhp figure. But for passing lines of traffic on A roads the grin factor is huge. The downside is that accidentally twitch the throttle on a greasy roundabout and it gets very very interesting very very quickly. The power range is at a very usable 3000+ which makes instant acceleration in traffic a rather wonderful thing. The unwary BMW/Audi driver hears it coming, assumes it something like a Harley, thinks they won't get passed. They are wrong.

[Stu]

6 minutes ago, geofferz said:

Anyway personally I don't bother looking at the torque figure - it's bollocks. I rode a Harley with loads of torque but super low revs so tiny bhp. It was horrifically slow - I couldn't appreciate any of its torquey goodness, it was slow in every gear at every rpm. 

 

Bhp matters. 

Torque is not bollocks! You ride on torque you race on bhp 

A Harley is not a good comparison to be honest but then it depends on the Harley too 

Get the right bikes to compare and you can tell the difference 

The TL I had would stomp out of corners leaving all sorts of bikes but get in to the higher revs you would get reigned in 

[Marino]

56 minutes ago, Bender said:

Now get 4 of  their Italian stallion cousins you now have 4 Lipizzaner dobbins

Just to correct one small mistake, Lipica (Lipizza) is in Slovenia, but close to Italy 

[Bender]

28 minutes ago, Marino said:

Just to correct one small mistake, Lipica (Lipizza) is in Slovenia, but close to Italy 

They originated from Lipica in Italy.

[dynax]

7 minutes ago, Bender said:

They originated from Lipica in Italy.

https://en.wikipedia.org/wiki/Lipica,_Sežana

[Bender]

29 minutes ago, dynax said:

https://en.wikipedia.org/wiki/Lipica,_Sežana

Haha ok I concede  

 

 

AlthoughSpanish, Italian, German and Danish studs were used and later studs from the orient.

And Lipizzaner is the Italian name

I'm jus waffling to cover my tracks  

 

I don't know what dobbin is in Slovenian, mind you I don't know what it is in Italian either  

[Mississippi Bullfrog]

20 minutes ago, Bender said:

Haha ok I concede  

 

 

AlthoughSpanish, Italian, German and Danish studs were used and later studs from the orient.

And Lipizzaner is the Italian name

I'm jus waffling to cover my tracks  

 

I don't know what dobbin is in Slovenian, mind you I don't know what it is in Italian either  

i know what dobbin is in French. 

 

Dinner.