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Old 25th March 2011, 10:57   #151
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Default Re: Torque vs BHP?

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Originally Posted by Sutripta View Post
To match speeds.
...and keep the engine in the powerband for the vehicle's road speed and anticipated gear position. Else you end up with either a gap in power or too much traction, both result in taking the corner slower.
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Old 25th March 2011, 20:11   #152
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Default Re: Torque vs BHP?

^^^
Hi,
Whether one is in the powerband or not depends on gearing, roadspeed, and engine characteristics. Unless one is prepared to fry the clutch, blipping the throttle will have no effect on whether one is in the powerband or not. It is necessary for smoothness.

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Old 25th March 2011, 22:46   #153
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Default Re: Torque vs BHP?

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Originally Posted by Sutripta View Post
Unless one is prepared to fry the clutch, blipping the throttle will have no effect
You mean to say that blipping would fry the clutch?
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Old 26th March 2011, 20:00   #154
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Default Re: Torque vs BHP?

^^^
Just blipping. Of course not.

But if your roadspeed/ gear choice combination takes you out of the powerband, revving the engine to be in the powerband means you are slipping the clutch. How do you like your clutches - scrambled, fried, well done?

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Old 28th March 2011, 10:19   #155
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Default Re: Torque vs BHP?

Next time I'm home, I volunteer to demonstrate There is a technique to cornering using a manual gearbox and a clutch, obviously those not aware of the technique will run the risk of slagging the engine or clutch or both!

Blipping is always with the clutch depressed and to get the revs to the point that disengaging the clutch will not result in dragging or excess revving the engine, and at the same time sending the right amount of power to the driven wheels for that roadspeed.

It's normally used in the entry to a corner before turning in, specially one which involves heavy braking and downshifting. It is not needed for fast corners. Watch a Nurburgring race lap video and listen to the engine note. You'll get it.
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Old 28th March 2011, 14:40   #156
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Default Re: Torque vs BHP?

Blipping sometimes known as manual rev matching, is done while shifting gears, so that the next gear falls in the 'true' power band of the engine.

Depress the clutch > match the rev's and > slot the gear. Ensures +ve gear shift every time. If not properly done, can actually be counter productive, and will mean more time/shift.

Last edited by dhanushs : 28th March 2011 at 14:43.
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Old 28th March 2011, 20:41   #157
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Default Re: Torque vs BHP?

@Cranky
Suppose at the end of a 5th gear straight is a 2nd gear corner. Which for whatever reasons, you decide to take in 3rd, or 4th. How exactly will blipping help you remain in the power band?

Conversely, you are in 2nd, but do not blip the throttle. You fall out of the power band?

Quote:
Originally Posted by cranky View Post
Next time I'm home, I volunteer to demonstrate There is a technique to cornering using a manual gearbox and a clutch, obviously those not aware of the technique will run the risk of slagging the engine or clutch or both!
Sure. And we'll show you how we double declutch on non synchro GBs. Or synchro ones

Regards
Sutripta

Last edited by Sutripta : 28th March 2011 at 20:45.
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Old 29th March 2011, 11:38   #158
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Default Re: Torque vs BHP?

Quote:
Next time I'm home, I volunteer to demonstrate There is a technique to cornering using a manual gearbox and a clutch, obviously those not aware of the technique will run the risk of slagging the engine or clutch or both!

Blipping is always with the clutch depressed and to get the revs to the point that disengaging the clutch will not result in dragging or excess revving the engine, and at the same time sending the right amount of power to the driven wheels for that roadspeed.

It's normally used in the entry to a corner before turning in, specially one which involves heavy braking and downshifting. It is not needed for fast corners. Watch a Nurburgring race lap video and listen to the engine note. You'll get it.
This is nothing but heel n toe revv matching. It is used to match the engine speed with the transmission speed, to avoid unwanted weight transfer while downshifting as you slow down for a corner.

Shifting into the wrong gear will automatically put you out of the powerband, no matter how much you blip the throttle.

Gear ratios are more important, when it's comes to staying in the power band while exiting a corner.

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Old 29th March 2011, 19:17   #159
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Default Re: Torque vs BHP?

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Which for whatever reasons, you decide to take in 3rd, or 4th.
Any wrong decision cannot be helped by any technique, including blipping the throttle. It is only used when moving down the gears, and specially when skipping gears on the downshift to speed transitions.

There are many ways of getting around a corner. One efficient technique is heel-and-toe, there are other methods (such as left-foot braking, as mentioned earlier). One may choose to downshift at the lower range of the powerband and use engine braking.

For racing however, the chosen method (as my first post stated) is usually heel-and-toe, to provide maximum traction by keeping the driven wheels, well, driven - and at the right speed with the right amount of torque.
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Old 7th May 2011, 11:05   #160
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Default Re: Torque vs BHP?

Here's a new approach to understanding Torque and Power:

Consider two people, One really fat (like Yokozuna, the WWE superstar) and one really powerful but agile (like Ray Misterio, another WWE superstar)

Now, assume they are both given an assignment. They have to push a block of 100kg in a straight line for a distance of 100 feet. What happens??
The really fat guy can generate more force and the block starts moving, while the agile guy takes longer to generate the force required to get the block moving.... So, at the 10 ft mark, the really fat guy is ahead of the agile guy.

Now, as they build up speed, the really fat guy (not being agile) cannot move too fast. Hence, to continue to generate good force and not tire out due to speed, he slows down a little or stops accelerating and continues to push at a constant rate of lets say 2 ft per second. So, at the 30 ft mark, the really fat guy's speed reaches an optimum level already!

On the other hand, the agile guy's body is more tuned for higher speeds. He can generate lesser force than the fat guy, but this force is available to him at a much higher speed, say 5 ft per second. So, at the 30 ft mark, while the fat guy has already reached optimum speed, the agile guy, still behind the fat guy, is still accelerating to reach his optimum speed.

As this continues to, lets say the 70 ft mark, the agile guy reaches his optimum speed of 5 ft per second and is able to overtake the really fat guy....


Now, lets change the assignment a little. If the requirement was to move a 1000 kg block by 50 ft, following the above logic, the really fat guy will be the winner...


Comparing this with torque vs BHP, force = torque and power = BHP...
A high-torque engines (the truck engines, dirt-bike, off-roaders etc...) are like the really fat guy and high-power engines (F1, SBK etc...) are like the agile guy...


Again, i am only talking from the 'ENGINE' perspective, not considering the transmission, vehicle weights etc.. which are equally important to determine the final effect.

@Experts, this is purely an example i have created based on my understanding... please correct me if i am wrong... thank you
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Old 7th May 2011, 14:31   #161
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Default Re: Torque vs BHP?

Quote:
Originally Posted by bzr77k View Post
Here's a new approach to understanding Torque and Power:

Consider two people, One really fat (like Yokozuna, the WWE superstar) and one really powerful but agile (like Ray Misterio, another WWE superstar)

Now, assume they are both given an assignment. They have to push a block of 100kg in a straight line for a distance of 100 feet. What happens??
The really fat guy can generate more force and the block starts moving, while the agile guy takes longer to generate the force required to get the block moving.... So, at the 10 ft mark, the really fat guy is ahead of the agile guy.

Now, as they build up speed, the really fat guy (not being agile) cannot move too fast. Hence, to continue to generate good force and not tire out due to speed, he slows down a little or stops accelerating and continues to push at a constant rate of lets say 2 ft per second. So, at the 30 ft mark, the really fat guy's speed reaches an optimum level already!

On the other hand, the agile guy's body is more tuned for higher speeds. He can generate lesser force than the fat guy, but this force is available to him at a much higher speed, say 5 ft per second. So, at the 30 ft mark, while the fat guy has already reached optimum speed, the agile guy, still behind the fat guy, is still accelerating to reach his optimum speed.

As this continues to, lets say the 70 ft mark, the agile guy reaches his optimum speed of 5 ft per second and is able to overtake the really fat guy....


Now, lets change the assignment a little. If the requirement was to move a 1000 kg block by 50 ft, following the above logic, the really fat guy will be the winner...


Comparing this with torque vs BHP, force = torque and power = BHP...
A high-torque engines (the truck engines, dirt-bike, off-roaders etc...) are like the really fat guy and high-power engines (F1, SBK etc...) are like the agile guy...


Again, i am only talking from the 'ENGINE' perspective, not considering the transmission, vehicle weights etc.. which are equally important to determine the final effect.

@Experts, this is purely an example i have created based on my understanding... please correct me if i am wrong... thank you

You'll be absolutely right if it were the engine driving the wheels directly - in the event there is a gearbox between the engine and the wheels, things change.
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Old 7th May 2011, 21:58   #162
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Default Re: Torque vs BHP?

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You'll be absolutely right if it were the engine driving the wheels directly - in the event there is a gearbox between the engine and the wheels, things change.

yes, and thats why i mentioned that this comparison is from the engine perspective only... not considering any other parameters.
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Old 8th May 2011, 20:33   #163
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Default Re: Torque vs BHP?

Quote:
Originally Posted by bzr77k View Post
Here's a new approach to understanding Torque and Power:

Consider two people, One really fat (like Yokozuna, the WWE superstar) and one really powerful but agile (like Ray Misterio, another WWE superstar)
....
Hi,
Why do we need such convoluted analogies when there is a simple mathematical relationship between torque and power.
Torque (force) moved through certain revolution (displacement) is a measure of work done.
Work done in unit time is a measure of power.

A gearbox can change the torque, not the power.

Regards
Sutripta
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Old 8th May 2011, 20:39   #164
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Default Re: Torque vs BHP?

Quote:
Originally Posted by Sutripta View Post
Hi,
Why do we need such convoluted analogies when there is a simple mathematical relationship between torque and power.
Torque (force) moved through certain revolution (displacement) is a measure of work done.
Work done in unit time is a measure of power.

A gearbox can change the torque, not the power.

Regards
Sutripta

I think our friend is a martial arts fan , and his definition of "power" may be very different from the science and engineering definition
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Old 8th May 2011, 22:45   #165
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Default Re: Torque vs BHP?

Quote:
Originally Posted by Sutripta View Post
Hi,
Why do we need such convoluted analogies when there is a simple mathematical relationship between torque and power.
Torque (force) moved through certain revolution (displacement) is a measure of work done.
Work done in unit time is a measure of power.

A gearbox can change the torque, not the power.

Regards
Sutripta
Well, absolutely... i understand that.
I was trying to explain this to a friend and couldn't proceed beyond explaining concept of force and work done! Hence, the analogy.
Its just a more real-life scenario for the non-techies to compare with.

The 'simplest' explanation is still the text-book definition

Quote:
Originally Posted by vina View Post
I think our friend is a martial arts fan , and his definition of "power" may be very different from the science and engineering definition
i was a huge fan of the WWE (actually the erstwhile WWF), and its not martial-arts!!!

I was not attempting to 'define' Power, merely providing an analogy to compare power and torque! let me know if you see any loop-holes in the analogy, will be glad to correct them for my own understanding
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