im going to attempt 200 in my 99 H/C/I coupe MN6 3.42 adding spray soon. Car has seen arround 180MPH for a few miles stock w/ 122k miles Running it out a long time to get there, I spun a rod bearing after that.

Im going to use motor power to get to 165+ as it does without a sweat, then saving my spray for up high. I have really good oil pressure now and upgraded rod bolts and about 15k on the bottom end so Its ready for the challenge

 

YOU ARE CORRECT 6th gear is not intended nor is it strong enough for a top end blast especially if you have stuck more HP to make 200MPH

 

Torque is a vector of force in one direction causing twisting or rotation along another vector(s). HP is a nebulous concept from the 1700s trying to equate pony power to steam engines to affect sales for Mr Watt. It's a concept of power and in our world is related by mathmatical formula to torque which actually measures the ability of an engine or vehicle.

Just because HP is a mathematical construct doesn't mean its not real but attempting to figure out which powers a car when and where is not working with the data.

Yes, obviously the more an engine can torque something the faster and greater the amount of force applied or acceleration and speed. And HP has traditionally been equated with speed. In fact the power of the engine is what does the trick and the more gas and fuel properly combusted around adequate engineering the more fun we have. You can't divorce one from the other in cars.

 

I wouldn’t say HP is a "nebulous concept", as it is a measure of a real phenomena called work. HP is force (torque) times velocity (speed - ie, RPM). Think of HP as "torque at speed". Torque without speed is just a force and does zero work.

In an engine, the more torque you can produce at any given RPM, then the more HP will be produced. An IC engine produces some level of torque throughout it's RPM range, so if it can produced more torque per power stroke, then the more HP you will also produce throughout it's RPM range.

 

HP is generally a constructed number. From one pony pulling ore up a mine shaft to steam engines to what we have today. HP is a concept to try to standardize the power output of an engine. Today we use torque to 'measure' HP. In the end the words we used are defined and are constructed to help us communicate concepts from one word to things much more complicated. And all via a word or so.

The power of an engine is not really a torque or HP number. What I'm saying is exactly what you said. They are inter-related. It's the fuel and air combustion which makes cars go and not torque or speed. And I'm not saying dynos aren't important. Or that speed and torque aren't either.

 

Taking it up another notch for anybody serious about gearing for 200 mph. The MN6 is used because the internal gearing of the MN12 will change the net effect of the G-Force cogs to .9 & .8 for 5th & 6th (or something very close). RPM Transmissions can get you the "hook-up" on this combo

 

Not to "get wrapped around the axle" here, but yes HP is a "derived unit" of measurement ... just like many other engineering units of measure.

Actually, we use torque times speed to measure HP ... as that is the definition of work (force x velocity) ... it's a basic engineering definition of work that is used in many many applications, not just the power output of an IC engine.

Actually, the "power of an engine" really is measured by HP ... if it's really not torque or HP then what is it really in your opinion?

Torque is just one component of the HP measurement. Why do you think all the manufactures give HP ratings on their engines? Because without a HP number, nobody would really know what the engine was capable of. The torque output number is just a way to show how much twisting force the engine's crankshaft is capable of. How much torque it puts out at a given RPM is the HP (amount of WORK) is can do. Yes, they are definitely "interrelated" as you can not have HP without torque AND velocity.

It certainly IS the torque and HP that makes the car go ... it's the "fuel and air combustion" that pushes the piston down which makes the torque and speed, which makes the HP. Speed and torque better be important ... otherwise you wouldn't have HP and your car wouldn’t move at all.

It amazes me on how many people are so confused on what torque and HP really are and how they are related. Anyone who can grasp the engineering concept of work will understand torque, speed and HP.

 

... the only way to take advantage of 6th gear would be to custom gear the tranny 5th & 6th gears. But the other "easier" way would be to just gear the differential to give just over 200 MPH in 5th gear ... and of course having near 475 RWHP or more to get the car to 200 MPH.

 

 

I can do the math and I certainly know the equations. Give me a lever long enough and I'll move the world. You don't understand what I'm getting at but it's all good.

 

No offense, but I guess I didn't get your message. This stuff is cut and dried only one way, but people have different concepts in their heads and sometimes express it in not so clear of terms. But yeah, it's all good.

 

I was just trying to say not worth arguing over torque and HP moving a car.

 

I was determined to not get back into this thread, but I have to say you are flat out wrong with respect to your initial observation.

Work is force over a distance. Force on an object with no movement, as you said, equals zero work.

However, just a cursory look at units tells us that Torque = Force x distance. Torque is work (or energy) plain and simple.

HP is power, and is work per time. It is NOT work, as you implied.

Just had to correct that little bit.

For clarification on many of my previous posts: I meant to imply that in a non-linear system, such as the power/torque curve of an ICE, for matters of top speed, it is critical to look at the curve. For example, there may be a dip in the curve where all factors add up to a net zero and the car is incapable of accelerating more. If it were to get past a hypothetical "dip" in curve, than it could continue to accelerate towards max power. Each point along the curve needs to be evaluated along with external conditions to ensure that there is a positive net force being delivered to the mass, otherwise, there will be no acceleration.

Spouting just a max HP number, without considering the curve, would do nothing to determine a car's maxiumum potential speed.

 

The easiest way is to slap a taller tire on the back. With the 19s on the rear and my 5th gearing I should be able to hit 220ish. I have only seen 200 once though.

 

Sorry if this has already been said since I only read the first page, but Road and Track did a 0-200mph test maybe a year ago and they had a good article on how much horsepower is required just to overcome drag at very high mph. I found it to be a very interesting article as an engineer. I will try to dig it up when I am back home in 2 weeks. They made an interesting point that the aftermarket rims on the lambo they tested lifted it up about an extra 1/4 inch off the ground and knocked maybe 15mph off its top speed. If anyone is interested PM me.

 

Excellent point. Put rims on, but lower the crap out of the car with the aftermarket bolts. Not only does it look better, but it helps aero too!

 

I admit after looking at my terminology that I didn't use it quite correctly. But the statement "Torque without speed is just a force and does zero work." is still valid if you think about it. The more accurate way of saying it would be "Torque without moving a distance does zero work." And of course if you have zero speed you have zero displacement which in turn gives you zero work and zero power. Yes, work if force times distance and power is work per time.

http://en.wikipedia.org/wiki/Mechanical_work

"Work can be zero even when there is a force.

Force and displacement are both vector quantities and they are combined using the dot product to evaluate the mechanical work."

http://en.wikipedia.org/wiki/Torque

Torque has dimensions of force times distance and the SI unit of torque is the "newton meter" (N m).[4] Even though the order of "newton" and "meter" are mathematically interchangeable, the BIPM (Bureau International des Poids et Mesures) specifies that the order should be N m not m N. N•m is also acceptable.[5] Because "mN" is the symbol for the "millinewton", it must not be used to refer to the newton meter. In applications that are not case-sensitive, it is also necessary to avoid "NM" and "nm", because "nm" is the symbol for the nanometer.

The joule, which is the SI unit for energy or work, is also defined as 1 N m, but this unit is not used for torque. Since energy can be thought of as the result of "force dot distance", energy is always a scalar whereas torque is "force cross distance" and so is a (pseudo) vector-valued quantity. The dimensional equivalence of these units, of course, is not simply a coincidence: a torque of 1 N m applied through a full revolution will require an energy of exactly 2π joules.

This means in order for a torque force to do work, it must move some angular distance. For instance, if you put a torque wrench on a tight bolt and checked the torque but the bolt didn't rotate (move) at all, you just did zero work ... all you did was put a force on the bolt. If the bolt would have moved, then you just did some work, and if the bolt rotated very quickly, you just produced some power. If you took 2 years to move the bolt very slowly, then you basically produced zero power ... but "technically" you did produce a super small amount of power since it still took some time to do the rotation.

And of course power definition.

http://en.wikipedia.org/wiki/Horsepower

Work = force x distance
Power = work/time = (force x distance)/time

When a force moves something over a distance, it's going to take some amount of time to do it, so when doing work you are really also producing some power, unless you take 2 years to move something ... but in that case you still have a time factor, but since the denominator would be so large the power value would basically be zero.


... but that would have to be quite a HP curve dip to cause a car to hit a wall and not head towards it's real peak HP point while accelerating towards top speed. I don't think I've ever seen any power curve that has dips that large, but maybe it could happen if the engine's tune was entirely messed up on the top end.

 

Zee0six,
Just what in all that wikipedia quotes contradicted what I said? Sounds exactly like confirmation.

Yes on a technical level, application of force without any angular motion isn't work, but by definition, torque implies that angular motion has occurred. I think you have the implications of the terminology mixed up.
In your torque wrench example, when the bolt stops turning, you are no longer "torquing" it, you are only applying a force to the bolt that counteracts its frictional/tensile strength so it stops turning.
Without work, power is also zero, and with zero power, no ones going 200mph, so what's the point arguing any more over this?

Entirely possible if it hits that wall during a gear change, for example, when the engine and corresponding torque/hp curve suddenly dip with a correspondingly lower RPM.

 

On a more practical note a C5 with the right gearing and about 750RWHP with a specially made air dam will go 225MPH.

 

Come on now ... did I say those links "contradicted" what you said?

No, torque does not "imply" anything. Torque can be with or without motion ... one has to be specific and clarify the application.

Did I say you were wrong? (you're "reading between the lines") ... can't someone just clarify with examples on what's going on? I was actually trying to give you an example where torque is just a force without any displacement which in turn equals zero work and hence zero power. If you read and comprehend the flavor of my input you will see we are on exactly the same page here.

Yes, I could see where that could happen if the tranny was not very close ratio ... like shifting from 5th to 6th gear for example.