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  #556  
Old 07-12-2007, 11:50 AM
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Originally Posted by Matra et Alpine View Post
In what way ? I've NEVER seperated them. Only you say torque doesn't provide the force that THEN over time provides the power. So without enough torque no power ( ie work done )
You seperate them by saying that you need only a certain amount of torque to overcome this and that... You said it yourself: torque provides an instantaneous force that over time provides power (which isn't work done but rather the rate at which work can be done). Torque is simply a factor for calculating power.


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Originally Posted by Matra
Oops, there we go torque is a must
and therefore so is power

Quote:
Originally Posted by Matra
"locked ratio" ... :burst into tears: It's folly to consider only one gear. A gearbox has a range of ratios and in each of these TORQUE is requried to overcome the "friction" in the closed system - ie hills, air and mating surfaces.
You obviously didn't understand my statement (even though I clearly explained it). I was not referring to the actual gear ratios inside a gear box but rather the ratio with which they exchange speed and torque so as to maintain the power output (minus frictional losses of course). A certain amount of power is needed to overcome the friction in the closed system as opposed to a certain amount of torque. Torque is needed to produce the power but the actual amount to be produced by the engine depends on what rpm you choose to use to produce the required power. (ie high revs will only need a small amount of torque to be produced by the engine while low revs will require a much larger amount to be produced). You could argue that you are talking about torque to the wheels but that is also dependant on the rpm of the wheels and the power needed to over come said obstacles.

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Originally Posted by Matra
No. You are making HUGE assumption.
YOU keep on about it's only power.
Power is a CALCULATION of the application of a force over TIME.
BUT acceleration is determiend by FORCE.
acceleration is determined by energy over time aswell... just like power is a energy over time value.
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  #557  
Old 07-12-2007, 03:54 PM
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Originally Posted by henk4 View Post
I am sure Bob ain't going to like this....
Oh dear
Don't waste your time with each other guys.
My post was trying to integrate both sides of the argument...
In theory, power is all that's needed, and is absolutely essential. You can;t increase your kinetic energy (read speed) at a higher rate than your power production.

Practically, torque is a necessity. Let's just leave it at that. No one is going to run around at 20k rpm in a daily driver.




But, to make this thread just the least bit useful to most people, I tried to explain what torque and hp numbers mean, as advertised. A high peak torque at low rpm signifies a flatter power curve and thus more avg power, and a stronger engine. It also makes more sense practically, in things like overcoming friction, gearing, and starting from a standstill.
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  #558  
Old 07-13-2007, 12:58 AM
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Originally Posted by Bob View Post
O A high peak torque at low rpm signifies a flatter power curve and thus more avg power, and a stronger engine. It also makes more sense practically, in things like overcoming friction, gearing, and starting from a standstill.
that's why we get hot underneath our collar about peak torque figures ......
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  #559  
Old 07-13-2007, 05:03 AM
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Power>Torque. Ask advertisement.
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  #560  
Old 07-13-2007, 05:21 AM
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Originally Posted by henk4 View Post
you are surely aware of the introduction of the diesel powered LMP1 cars in sportscar racing. The comments of petrol engined driven LMP1 cars boil down to: "Because of their massive torque advantage they reach topspeed already after 200-300 meters at the long straights, we can only get to them at the end of the straight, when it is too late to overtake them....."
Another explanation for that is, since LMP diesels have more power, they can put more wing and still have the same top speed as the others this way "masking" their true power advantage and obviously having a great cornering advantage.
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  #561  
Old 07-13-2007, 05:48 AM
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Originally Posted by orne View Post
Another explanation for that is, since LMP diesels have more power, they can put more wing and still have the same top speed as the others this way "masking" their true power advantage and obviously having a great cornering advantage.
that is correct, however, the absolute horse power advantage over the petrol LMP1 cars is not that big. The fact that they have about double the amount of torque makes them so much faster under acceleration out of corners.
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  #562  
Old 07-13-2007, 06:31 AM
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Originally Posted by henk4 View Post
that's why we get hot underneath our collar about peak torque figures ......
But why get excited about the peak torque figure instead of the power advantage (over the whole rev range not just the peak power)....

Quote:
Originally Posted by henk4
that is correct, however, the absolute horse power advantage over the petrol LMP1 cars is not that big. The fact that they have about double the amount of torque makes them so much faster under acceleration out of corners.
I am pretty sure that when it comes to peak power that the diesels are less powerfull then the petrol engines... But they have a huge advantage when it comes to average power over the used rev range (which is smaller for the diesel engines)

more torque means more power and power is what is important.
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  #563  
Old 07-13-2007, 06:45 AM
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Originally Posted by hightower99 View Post
But why get excited about the peak torque figure instead of the power advantage (over the whole rev range not just the peak power)....



I am pretty sure that when it comes to peak power that the diesels are less powerfull then the petrol engines... But they have a huge advantage when it comes to average power over the used rev range (which is smaller for the diesel engines)

more torque means more power and power is what is important.
the diesels are quoted at 700 BHP and 1200 NM, the Judd engine in the Creation has 640, and somewhat over 630 NM.
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  #564  
Old 07-13-2007, 07:09 AM
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Racecar Engineering had a good article on the Peugeot 908. They discuss the current rules and indicate there a net advantage in power for the diesels. Their bases was that even though the diesel is limited in operating speed and some advanced valve timing techniques, the effective restricted displacement was much larger. Basically the diesels end up getting about 50% more air, although this doesn’t end up giving them 50% more power.

The Peugeot is claming about 700 bhp for the 908 of RE is suspects it is capable of more. If I understood the article correctly their basis is on the fact that ACO regulations don’t allow the diesel engines to produce visible sooty particulate matter. So the engines are currently running lean to minimize incomplete combustion and the resulting exhausted particulates. So RE is speculating that potential improvements in air:fuel ratio will allow them to get closer to 800 bhp mark.
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  #565  
Old 07-13-2007, 07:13 AM
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Originally Posted by Alastor View Post
If I understood the article correctly their basis is on the fact that ACO regulations don’t allow the diesel engines to produce visible sooty particulate matter. So the engines are currently running lean to minimize incomplete combustion and the resulting exhausted particulates.
Both the Audi and the Peugeot run with particulate filters which reduce soot emissions by about 99%. (I have one too...) There is no need for specific lean running of the engine, so I think you either may have misunderstood the article or Racecar Engineering got it wrong. Was the article written by Ian Wagstaff?
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  #566  
Old 07-13-2007, 02:59 PM
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Originally Posted by henk4 View Post
Both the Audi and the Peugeot run with particulate filters which reduce soot emissions by about 99%. (I have one too...)
Well la-dee-dah henk4.

My car has power steering but you don't see me gloating.
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  #567  
Old 07-13-2007, 04:00 PM
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Originally Posted by Kitdy View Post
Well la-dee-dah henk4.

My car has power steering but you don't see me gloating.
particulate filters were initially seen by the German industry as not relevant, after Peugeot introduced them in 2001.....only lately they have started to catch up. My car was produced in August 2001.
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  #568  
Old 07-13-2007, 07:25 PM
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Originally Posted by henk4 View Post
Both the Audi and the Peugeot run with particulate filters which reduce soot emissions by about 99%. (I have one too...) There is no need for specific lean running of the engine, so I think you either may have misunderstood the article or Racecar Engineering got it wrong. Was the article written by Ian Wagstaff?
The article was written by Ian Bamsey. Since they mention the Dow particulate filter later in the article they seem to be aware of it.
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  #569  
Old 07-13-2007, 07:43 PM
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Originally Posted by -What- View Post
Power>Torque. Ask advertisement.
no.

For example- the rotary. For these, Power =/= torque (sorry Matra!)
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  #570  
Old 07-14-2007, 02:24 AM
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Originally Posted by henk4 View Post
the diesels are quoted at 700 BHP and 1200 NM, the Judd engine in the Creation has 640, and somewhat over 630 NM.
Well then the diesels have a huge advantage (basically more power everywhere!)

And having a higher peak power means that with gearing they should be able to have a higher top speed then the petrol engines...
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