Notices
C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

200+ MPH C4

 
Old 02-06-2019, 09:38 PM
  #121  
Red 91
CF Senior Member
 
Member Since: May 2008
Posts: 274
Thanked 13 Times in 12 Posts
Default

Kyle, try to look at it like an ele. motor, I turn on my table saw and before its up to speed I ram a 4x6 into it, it will stall and maybe blow a fuse. If I let it get up to speed it will cut no problem. Ele. motors are known for torque but rated in power. The power in an engine is torque x rpm. Try this torque = amps power = volts Edison lost that fight because he did not want to use high voltage to push the electricity down long lines. If you dump the clutch at too low a rpm you will stall or bog, get the engine up into its powerband and off you go! I hope this helps you to see how torque & horsepower relate to one another.
Red 91 is offline  
Old 02-06-2019, 10:43 PM
  #122  
KyleF
CF Senior Member
 
Member Since: Jun 2018
Posts: 219
Thanked 17 Times in 17 Posts
Default

Originally Posted by Tom400CFI View Post
He's not the only one.



You sure about that? As you go faster, your rate of acceleration increases? IDK about that one.

The rest....too much reading, too poorly articulated to be worth responding to, IMO.
nice engine, would be difficult to swap in to a car though.

typo corrected.
KyleF is offline  
Old 02-06-2019, 10:49 PM
  #123  
KyleF
CF Senior Member
 
Member Since: Jun 2018
Posts: 219
Thanked 17 Times in 17 Posts
Default

Originally Posted by Red 91 View Post
Kyle, try to look at it like an ele. motor, I turn on my table saw and before its up to speed I ram a 4x6 into it, it will stall and maybe blow a fuse. If I let it get up to speed it will cut no problem. Ele. motors are known for torque but rated in power. The power in an engine is torque x rpm. Try this torque = amps power = volts Edison lost that fight because he did not want to use high voltage to push the electricity down long lines. If you dump the clutch at too low a rpm you will stall or bog, get the engine up into its powerband and off you go! I hope this helps you to see how torque & horsepower relate to one another.

Yea... that is simplifying a cutting operation. Which is a lot different than just pushing a car.

If you have a granny gear like an old truck, you can dump the clutch an not bog.

If you didn't read the entire thing, I said HP tells you how much gear multiplication you can use to multiply torque. I never said it wasn't important or useful.

You can't seperate the two.

Is you saw direct drive or is geared through a set of pulleys? Our industrial equipment utilizing electric motors is never direct drive.
KyleF is offline  
Old 02-06-2019, 10:59 PM
  #124  
KyleF
CF Senior Member
 
Member Since: Jun 2018
Posts: 219
Thanked 17 Times in 17 Posts
Default

Originally Posted by Red 91 View Post
Kyle, try to look at it like an ele. motor, I turn on my table saw and before its up to speed I ram a 4x6 into it, it will stall and maybe blow a fuse. If I let it get up to speed it will cut no problem. Ele. motors are known for torque but rated in power. The power in an engine is torque x rpm. Try this torque = amps power = volts Edison lost that fight because he did not want to use high voltage to push the electricity down long lines. If you dump the clutch at too low a rpm you will stall or bog, get the engine up into its powerband and off you go! I hope this helps you to see how torque & horsepower relate to one another.
Again, don't know much about your saw... but I know my Nakamura Lathe. It has a 15hp main spindle... and a hp curve posted right on the machine.

So, when I am setting up a cut, I know how much power is available. Excellent.

You know what the cutting tool guy want's to know... how much torque is transmitted. This is because it takes force not power to sheer the material at the cutting tools tip. If the force is not high enough, it will bog the spindle down and start to slow down. Until it reaches the point where the forces equalize. This also has to take into account not the chuck size but the workpiece diameter... or in the case of milling, the cutting tool diameter.

Now, you know the force to cut, surface speed of the cut and you can calculate the required power consumption utilized to make that cut... but not every cut will be done at the engines peak hp point either. Ideally we would because as I said before, peak Hp is where you can get the greatest mechanical advantage through gearing. The lathe doesn't have but a 2 speed gear box.
KyleF is offline  
Old 02-06-2019, 11:15 PM
  #125  
MatthewMiller
CF Senior Member
 
MatthewMiller's Avatar
 
Member Since: Aug 2015
Location: St. Charles MO
Posts: 1,984
Thanked 284 Times in 238 Posts
Default

Originally Posted by KyleF View Post
That is funny, you want to tell someone else what the point they are trying to make is? Seriously? That makes no sense...
You told me that what I wrote was making your point. But that is not true.

I think you get too angry to think straight and just want to argue. Somewhere down this rabbit hole I think you lost what I said at first... Back to the beginning of what I said....
I'm not angry. I am, however, getting tired of going in circles with you, and I'm not going to keep doing it. I've asked you questions that prove my point exactly (that crankshaft torque doesn't predict performance). I've repeated, ad nasuem, the very definition of power. I've given examples of the ways in which chassis dynos can accurately measure power without knowing crankshaft torque. And today I provided an extremely simple formula that tells you exactly how much force is available to accelerate a car, based on power and road speed and not any torque value. If I know the power the engine is making, and all the resistive forces of the car, then I can tell you how fast the car can go at that power output. You can't tell me that with just crankshaft torque. If I know the mass of the car and the power the engine is making, I can tell you how fast it can accelerate. Again, you can't tell me that with just crankshaft torque. There really is nothing else to say.

It seems "twisting force to drive the wheels" really bothers you. Your tractive force that you want to hang your hat on and calculate from power is the twisting force at the wheels (Torque) divided by the wheel diameter. This force will not be the same in 2nd and 4th gear, but the power will.

With your CVT, As the vehicle is accelerating Power output is constant, Velocity is increasing and thus wheel rpm, and torque is going down and thus so is the tractive force. The result is as speed increases, the rate of acceleration decreases Acceleration stops when the torque output divided by wheel diameter is equal to the sum of resistance working against it.
Yes, this is correct.

To balance the Free body diagram, you would use forces, not power... but since you have Time, Distance, and Force... you want to solve one side for Power and just damn marry that word. Fine, it works on the conservation of energy principle (Energy in a system cannot be created or destroyed). On the other side you have Speed, Time, Distance of the car moving and a set of forces acting against it. We have already agreed with this information you can calculate power. So, essentially you are converting the resistance forces into a Power and saying the sum of power on one side has to be equal to or greater than the sum of power on the other side. Or should I say the equations you want to use are doing this at a snap shot.
I don't even know what the hell you're talking about here, and neither do you. The tractive force that accelerates the car is determined by the power the engine puts out. There's no marrying of words. It's just super-basic physics. No wedding, no snapshots, no other goobledygock that you like to write.

What you fail or just don't want to agree on is when I say just because you have 400hp (or any number you choose) you won't achieve a given speed if other considerations aren't made.
If the car makes 400hp at 180mph, then it is creating 833lb of tractive force. If the car's total resistive force at 180mph is also 833lbs, then the car has reached its max speed. If the car has less resistive force than that, then it can keep accelerating. If the car has more resistive force than that, then it will not reach 180mph with 400hp.

It's. That. Simple.

Originally Posted by KyleF
...Insert lots more goobledygock here...
If you want to continue to argue about Power versus Torque, just keep in mind Since P is defined by T*RPM/5252... you can always swap it in. Let me borrow someone elses' words..."itís the reason that anyone telling you that horsepower and torque should be considered equally and separately is significantly off-base. The fact of the matter is that horsepower is the product of torque and another value ó RPMs (divided by 5252). Itís not unrelated, separate, or different. In fact, thereís not a single machine in existence that measures a carís horsepower. Itís a man-made number. When a carís performance is tested, its torque is measured using a dynamometer. The measure of an engineís performance is torque. Horsepower is an additional number thatís attained by multiplying the torque by the RPMs." "The mistake most people make when engaging in this debate is considering horsepower and torque independently. Almost everyone argues as if they are separate, unrelated values. They arenít." "The torque at the wheels is the torque at the engine combined with the torque magnification given by the transmission through gearing. So the transmission only sees whatís coming off the engine, while the wheels see the resulting force combination of the engine plus the transmission. Thatís what horsepower represents. Horsepower is the combination of the benefits of the engineís raw abilities combined with RPMs. And RPMs are what allow us to use gearing effectively, which gives us more torque at the wheels." - D. Miessler 12/5/18
Yeah, anybody who says "horsepower is a man-made number" and uses that to justify the notion that torque is all-important is an idiot. I've got news for you: all units of measure are just man-made numbers. Lb/ft is a man-made number, just like miles and hours. OTOH, the things those man-made numbers measure are most definitely NOT man-made. Power is not man-made or imaginary. Neither is force, distance, or time. I can measure power in lots of man-made units, like horsepower or watts. But power is very, very real.

Originally Posted by Red91
Try this torque = amps, power = volts
I know we're on the same side, but I do want to make a correction here for clarity. In electricity: force(torque)=volts, rpm=amps, and power=Watts. Also, I understand exactly what you were trying to point out to Kyle. But the problem is that he can't focus on what's important, and he keeps trying to make things way more complicated than they really are. I've learned the hard way that every time we try to introduce a new example to him, it just compounds his confusion.

Last edited by MatthewMiller; 02-07-2019 at 09:55 AM.
MatthewMiller is online now  
Old 02-09-2019, 12:01 PM
  #126  
jayjones
CF Member
 
Member Since: Mar 2018
Location: Indiana
Posts: 64
Thanks: 0
Thanked 13 Times in 7 Posts
Default

The concepts in this thread aren't simple, and become extra confusing when terms like power an torque are used loosely in some posts and rigorously in others. People with years of experience and great hot-rodding knowledge still throw around sayings like "horsepower is what you read about and torque is what you feel". I think this thread and others like it are very good for the community to learn and dispel fallacies. Newton had to develop an entire new type of math to describe the relationship of applying forces (torque) on objects in motion. Analogies are helpful to a degree but can also lead to bad assumptions.

MM regularly makes very informative posts here and is fighting the good fight, but the frustration starts to show after a while. All I can offer is don't give up, we are all here to learn and share and we wouldn't be here without having the same interests. Someone can be wrong and smart at the same time.
jayjones is offline  
The Following 3 Users Say Thank You to jayjones For This Useful Post:
DGXR (02-09-2019), MatthewMiller (02-09-2019), Tom400CFI (02-10-2019)

Thread Tools
Search this Thread
Quick Reply: 200+ MPH C4


Sponsored Ads
Vendor Directory

Contact Us - About Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: