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Bigger engine but less horsepower, how?


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Sorry if my question is silly but I want to learn , I also search similar topics but couldnt find answer..

 
Benelli 752S
754cc
Bore - Stroke: 88mm x 62mm
Torque 67 Nm 6500 rpm
Power: 77 Horsepower 8500 rpm
 
and
 
Triumph Street Triple S
660 cc
Bore - Stroke: 76mm x 48.5mm
Torque 66 Nm at 9250 rpm
Power: 95.2 Horsepower 11250 rpm
 

Benelli 94CC bigger and has bigger bore & stroke , how can be Triumph has more horsepower?

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Engine size and horsepower are not linear - you can get small engines that rev highly at high compressions that put out large hp but low torque, and large engines that produce huge amounts of grunt at low rpm but have lower hp numbers. It's an issue that always leads to passionate debate what the terms actually refer to and people get on a high horse about it.

I wouldn't get into a tizz about numbers, it's what the bike does on the road and whether that style of riding suits you that matters.

By the way, there are no silly questions, nor does it matter if you ask something that's been discussed many times before. We all have to start the learning curve somewhere. The only thing that matters is whether you stay on a learning curve or make the mistake of thinking you know all there is to be known. Asking questions always makes things better for everyone.

Edited by Mississippi Bullfrog
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So, if you can get better performance with smaller and lighter engine, (Benelli is 45KG heavier and for sure some of it because of its engine),
what is the point to make it bigger? 


I mean there must be reason or advantage of it , right?
In that example, what is advantage of Benelli ? more economic or what else?

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Have you compared the price of a Benelli versus the Triumph ?  That would be one clue - performance costs money.

Then try buying  the engine for a Moto2 bike (also 765cc).  It will rev higher, make more power and probably be lighter again. But you'd get a shock at what they cost.

You only need to worry about the numbers if you need something light, high-revving and powerful - AND you can afford it.  Otherwise, buy what you can afford, and be happy.

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The headline figures only tell you what the engine can do at its peak. But not many of us ride around all day at 11000 rpm. What happens at 3-5000 rpm and 5-7000 rpm is going to affect normal ride a lot more.

Engines can be tuned to give out loads of power at high revs, or more power - and perhaps importantly - more torque at lower revs.

Looking at the stats, I'd expect the Triumph to be free-revving, but not delivering a lot of punch until the engine's wound up nearer the red line. But I'd guess the Benelli has more to it at lower revs, and this makes a bike more engaging to ride.

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10 hours ago, bonio said:

What happens at 3-5000 rpm and 5-7000 rpm is going to affect normal ride a lot more.

Fully agree, for regular rider 3000 to 5000 rpm are important figures. Those are most used rpms and then up to 7000 where you loosing driving licence and ur savings.

Kawi z1000sx has more hp at 4000 rpm than zx10r (those are figures for few yers old models, not newest ones). 
 

my 1290 gt at 5000 explodes and rip your arm’s off :classic_love:

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2 hours ago, Marino said:

my 1290 gt at 5000 explodes and rip your arm’s off :classic_love:

Yeah exactly. Even my little 400 will pull your arms off if you open it up at 30 mph even though it's only 45hp max. But it runs out of breath at 65, and you have to plan you overtakes carefully cos it's tuned for torque and got no top end. My guess is that the 660 Triumph is tuned for top end, but it going to be underexciting until you redline it... at which point your licence might be heading for the shredder.

Edited by bonio
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What I wrote is a bit unfair. I bet you can have good fun by hooning around in 3rd and saving the the upper gears for when you want to relax a bit.

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2 hours ago, Blackst said:

The saying is..........People buy horsepower, but they drive / ride torque.

As Bonio says above.....torque is the stuff you use in the rev ranges you normally ride at.

Ride safe

 

Don

Naaah - power = torque x revs. You can't use torque, you can only use power. 

 

The saying could be 'check the bhp at lower rpms'. 

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5 minutes ago, James in Brum said:

I thought torque was the expression of power around a pivot? Like Newton metres and stuff? 
 

You're spot on. 

Tiggie's just trying to confuse us. Momentum is how far you take the wall with you.

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17 minutes ago, bonio said:

You're spot on. 

Tiggie's just trying to confuse us. Momentum is how far you take the wall with you.

Is it not a function of mass and momentum ?

i.e a heavy bike at a given speed will have more of an effect on said wall then a lighter one.

Either way attempts to prove or disprove this will probably result in an acquired familiarity with hospital food.

Cheers

Ian

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@Tiggie's post has nothing to do with momentum and weights of bikes etc 

its all about how the power works! bhp is a fast moving power but no pull ie it hits fast but hardly moves it 

Torque is a slower power but stronger ie it hits slow but moves it further 

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6 hours ago, geofferz said:

Naaah - power = torque x revs. You can't use torque, you can only use power. 

 

The saying could be 'check the bhp at lower rpms'. 

You need torque to get moving. Power alone won’t do it. 

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I couldn't give a monkey's about the technicalities, all I'm interested in is the look on the face of the Audi driver on the A41 who thought he was the fastest thing on the road so wasn't looking in his mirrors and was therefore somewhat surprised to find a motorcycle going past him making a rather wonderful noise.

That's what it's all about.

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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 

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1 minute ago, Mississippi Bullfrog said:

I couldn't give a monkey's about the technicalities, all I'm interested in is the look on the face of the Audi driver on the A41 who thought he was the fastest thing on the road so wasn't looking in his mirrors and was therefore somewhat surprised to find a motorcycle going past him making a rather wonderful noise.

That's what it's all about.

It's not just about raw power though, it's also about being a smug twat filtering through a mile long traffic queue :classic_biggrin:

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