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**pavan_D_player** · 06-19-2009, 03:20 PM

Originally posted by viv.nomad View Post

but ur gixxr wont be as fuel efficient as a r15 .. in that case that would a waste ... sure it is powerful ... lesser the cc better the millage .. right . dont go for gxxr. it's a less FE engine .. it suckss

ehhhh?????????????????????? dude.. i am not not an expert in bikes but not even dumb enough to expect fuel efficiency from a litre class bike

. Just for racing,stunting and weekend rides

. And thats my one of my dream bikes, not buying it right now.....

**silver_falcon_46** · 06-19-2009, 05:14 PM

Originally posted by hitanshu View Post

Enough gyan - both 2/3.

But 3 is anyday preferable.

Drive a diesel car like the Getz to understand what torque really means.

The friggin thing has a Verna engine down there, it better be pulling like a freight train! That thing shoots like a rocket!

CC: With a certain amount off CC you can choose to tune the engine for torque or hp.

Torque: Twisting force, pulling power. What lacks in the r15 at lower revs, what flows in the bullet at early revs. A touring machine is expected to have good amounts of torque to prevent downshift and to have the engine in a relaxed rpm with enough to overtake/accelerate in the same gear.

HorsePower: Peak power generated by engine. Maybe generated very late making the driveability really low. So an R1 that generates 180 horses maybe slower in a situation where it is required to pull from a lower rpm when compared to the MT which generates half the horses.

Why do trucks have high amounts of torque and similar to the number of horses that a car may produce? A Volvo truck produces about 250 horses and so does an S Class. Why and How? The truck is expected to pull a huge load which requires it to have high amount of twisting force to get the engine up and running at very low rpms. The torque has to be generated from idle, or the truck may not be able to start pulling the load. Hence loads of torque. Why is the HP so low,the same as an S Class? It does not need peak horses. It isn't going to be living at 3k RPm(remember diesels rev way lower than petrols) the whole time. More than 250 horses is no point. Instead if it can generate the 250 full horses at a low rpm, beautiful! It needs all of those horses at a lower rpm to pull that load.

Why do motorcycles have lower torque(compared to trucks) and have 180 horses to pull one person? Peak power! No load makes the requirement of torque really low. Peak power is good to reach 300kmph.

Sometimes you see a Suzuki SV650 awesome for a track and sometime the R6 better although the 650 has much lower peak power compared to the R6 but loads of torque. The SV 650 may be chosen on slower tracks where there are too many tight curves,where acceleration is from a very low rpm. The r6 maybe chosen on quick tracks where you are mostly living in the 8k+ rpm region.

**pavan_D_player** · 06-20-2009, 12:15 PM

@Silver Falcon
That was really useful and easy to understand mann. Thanks for that

. Is there any relation between hp and torque, i mean a mathematical equation that links both??

**viv.nomad** · 06-20-2009, 12:31 PM

Originally posted by pavan_D_player View Post

@Silver Falcon
That was really useful and easy to understand mann. Thanks for that

. Is there any relation between hp and torque, i mean a mathematical equation that links both??

For a given torque, the equivalent power may be calculated. The standard equation relating torque in foot-pounds, rotational speed in RPM and horsepower is:
Where P is power, τ is torque, and ω is rotations per minute. Outside the United States, most countries use the newton meter as the unit of torque. Most automobile specifications worldwide have torque listed in newton meters. The standard equation relating torque in newton meters, rotational speed in RPM torque.

**abhijeet080808** · 06-20-2009, 01:35 PM

^^^ In simple words -

Power = Torque x Rpm x Constant

**pavan_D_player** · 06-20-2009, 03:07 PM

@viv and abhijeet
thanks for that guys

**Cyberpunk** · 06-27-2009, 08:04 PM

Originally posted by viv.nomad View Post

u see , u did a ****in DISRESPECTFUL THING there .. u edited my sentence ... boo ya!

Taking out a "smiley" does not constitute editing. (You need to watch your language if you want some respect)

Originally posted by viv.nomad View Post

hint points to a CB300R which being discussed with full emotion during that time when i posted that reply.. BS

There is no mention of a CBR300R. A Karizma & R15 were being discussed.

Originally posted by viv.nomad View Post

which bullet model is 300cc .. it's 350cc .. more over it is of different class altogether.

Giving an example of 50cc more doesnt change the point & last I checked a Bullet is still classified as a Motorcycle not a "Car"

Originally posted by viv.nomad View Post

if u dont know difference between a bullet and a unicorn or zma or a r15.. donate me ur bike .. and commit suicide.

You want to talk about disrespect?! (You're getting your Panties in a twist over nothing!)

PS: Nice Avatar!

**Aryan** · 06-28-2009, 11:12 AM

@Viv.Nomad: One more such useless post, and you are getting an infraction.

**MaSh** · 07-05-2009, 05:13 PM

Brilliant Thread...

Where does a Suzuki Fiero fit in? What speed should I be riding it for best engine efficiency(Would have asked for RPM if it had an RPM meter

).

Mash

**agra basti** · 05-19-2010, 01:19 AM

Originally posted by abhijeet080808 View Post

We all want torque. After all, torque spins the wheel! The question is where do you want your torque - at the lower end of the tacho and at the higher end of the tacho?

As we know Power = Torque X Rpm. Rpm is the speed at which the power and torque readings are considered. There are theoretically two ways to achieve engine power. Let us discuss both the ways in a simplified manner-

1. Horse power = higher rpm X respectable torque - This type of engine revs higher and has sufficient torque to pull the bike to higher revs. This type of engine has to sacrifice lower end torque. Why? The engine has to be made oversquare to make it rev higher. Lesser stroke results in lesser torque. As the bore is large, this type of engine can use larger valves. So while the engine has fantastic power, it needs to be revved higher. This affect low speed operation - these engines are not relaxed at low speed - in other words, insufficient torque to pull effortlessly from lower rpm. But they are the more powerful engines.

Eg - R15 engine to some extent. Apache RTR 160 to some extent. More examples still to come.

2. Horse power = lower rpm X enormous torque - This type of engine does not rev higher but has enormous torque at lower revs. This type of engine has to sacrifice higher rev power. Why? The engine has to be made undersquare to make it generate higher torque. Greater stroke results in greater torque. It also limits max rpm - due to vibrations and piston speed limits. At higher rpms, this engine looses efficiency. Why? This engine has lower bore, so it must use smaller valves. This affects breathability of the engine. Also, this type of engine has strenghened lower end (like diesel engines). So, more weight too. But, the low end torque enables the engine to pull effortlessly at lower rpm- the engine feels relaxed.

Eg, - Zma engine to some extent. Bullet engine is a perfect example!

Most manufacturers strike a balance between the two extremes.

What do we prefer? While riding flat out, we always stay in the upper revs. So lower low rev torque does not affect us. Hence, we prefer a poweful oversquare engine for flat out riding. If we cruise or ride in the city, we hardly get the chance to rev the engine to higher revs, so low end torque matters. Hence, we prefer a torquey undersquare engine for city riding.

Gearing, Carb, Head Design and Cam profile helps to some extent to modify the characteristics of the engine. But, try to make an oversquare engine behave like an undersquare engine - you loose engine effieciency.

The Internal Combustion engine has lots of improvement to make - only if petrol does not runs out sooner.

An one thing, any engine runs most efficiently at peak torque - so drive a bullet engine at lower rpms and a R15 engine at higher rpms for peak mileage! Don't be surprised if a R15 or Apache redlined through out the day returns decent fuel efficiency! If your bike is not giving you decent mileage, it means the engine is not suited to your riding style!

As with most things in life, what we want to ride is preferably the best compromise of all these factors - power, torque, efficiency, engine life etc.

Sirjee, kitna marks milega?

Hi Abhijeet,

I own a TVS Apache RTR 160 (Carbureted) which I bought in 2008, prior to which I was riding a HH Splendor for 10 yrs. The Apache didn't feel all that powerful n responsive - at first - as I was expecting it to be, going by what I had been made to believe by its advertising - the reason I was -only later- able to attribute to my relaxed riding style, wherein I always was easy on the throttle.. ..used to suit my riding the splendor bike but here as you've explained so bloody well I feel like I should have been more active on reading over this forum, so as to not risk the heartache that came when the apache didn't perform the way it'was supposed to

here, I needed to ask you something, the reason I write this post - since the apache 160 makes the highest torque at 6000 rpm should I be taking it to the 6 k mark in every gear before up-shifting? I would do it, and I like the way the bike feels at 6 k but for the clutch application at such high revs and subsequent gear change makes me feel as if the bike is not too okay with it.. the gear change should be ideally performed at what rpm? 3k? Going all the way to 6 k and then coming down to 3k to up-shift, will it not make the bike consume more fuel than me keeping the high revs for the 3rd , 4th and 5th gears only? ..these have been some of my concerns and its been a love-hate-love relationship with my this bike ever since I bought it 2 yrs back.. It's a bit awkward for me on having to ask you or somebody else to explain my bike to me, but thats exactly what I'm doin since I find it necessary..

thanks

**abhijeet080808** · 05-19-2010, 08:40 PM

Hi.. good of you to write in here.. For the Apache, I would say rev up to 4-5k before changing the gear. 3k is a bit short and certainly does not suit the Apache very well! And shift at around 6k for peak engine efficiency but is not always recommended or possible in traffic. Also, dont rev down to 3k to shift the gear - it should shift effortlessly at 5-6k rpms. If the clutch feels different, maybe its not adjusted properly. You can check up with that. But the Apache does have some vibes at around 6k - that is the nature of the engine.

**agra basti** · 05-27-2010, 12:26 PM

thanks for that

what say you about the apache rtr 160 (carb)? and there's another thing that came to the notice while looking up the engine specs for various motorbikes over the internet - why is it that most of the Indian production bikes make the most torque at 6k rpm? even when their bore and cylinder characteristics differ.. comparing an Apache RTR with an oversquare engine with a Karizma with a comparatively longer stroke both making the most torque at 6k??? even the Yamaha FZ..the Honda Unicorn..Max torque at 6k?? with the exception of Enfield bikes at 4k and P220 at 7k..

**rahul9985** · 05-27-2010, 01:12 PM

For me its the Horse Power (BHP) which matters.. I like to rev hard and keep the engine just below the rev-limiter most of the time and hence my love for rev-friendly short stroke engines.. I can gain speeds quicker and can hit higher speeds than the torquier mills ..

**abhijeet080808** · 05-27-2010, 11:58 PM

Originally posted by agra basti View Post

thanks for that

what say you about the apache rtr 160 (carb)? and there's another thing that came to the notice while looking up the engine specs for various motorbikes over the internet - why is it that most of the Indian production bikes make the most torque at 6k rpm? even when their bore and cylinder characteristics differ.. comparing an Apache RTR with an oversquare engine with a Karizma with a comparatively longer stroke both making the most torque at 6k??? even the Yamaha FZ..the Honda Unicorn..Max torque at 6k?? with the exception of Enfield bikes at 4k and P220 at 7k..

Because these are street bikes which are mostly ridden in busy traffic conditions and must satisfy fuel efficiency and engine durability criterias.

**agra basti** · 05-28-2010, 12:23 AM

Originally posted by rahul9985 View Post

For me its the Horse Power (BHP) which matters.. I like to rev hard and keep the engine just below the rev-limiter most of the time and hence my love for rev-friendly short stroke engines.. I can gain speeds quicker and can hit higher speeds than the torquier mills ..

Hi Rahul, since you've said it you owe me a simple explanation on what torque feels like to you in your words.. and what does power feel like (bhp i.e.)

..about torque I have an idea..it's said to be pulling force, so if my Apache makes the max torque at 6k this would mean that she would have the most load pulling capacity, or the capacity of moving up inclines without significant loss of power at 6k

..about power / bhp I still am unsure on how could it be any diffferent than 'torque'???

Originally posted by abhijeet080808 View Post

Because these are street bikes which are mostly ridden in busy traffic conditions and must satisfy fuel efficiency and engine durability criterias.

Thats cool but how come bikes with short strokes and bikes with longer strokes peak at the same rpm? I was comparing the HH Karizma with the Apache. ..whereas an Enfield bike peaks at 4k and that is attributed to its longer cylinder / stroke.

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