Hp vs. Torque curves.... - TCCoA Forums
 
LinkBack Thread Tools
post #1 of 4 (permalink) Old 12-30-2003, 12:27 AM Thread Starter
Sheepish
 
AverageJoe's Avatar
 
Join Date: Jul 2002
Location: San Antonio
Age: 35
Posts: 4,085
Send a message via AIM to AverageJoe Send a message via Yahoo to AverageJoe
Hp vs. Torque curves....

This could be an interesting technical debate.

Why do the hp and tq curves seem to ALWAYS cross at 5200 rpms? Does anybody know?

B Team - More skill, more results. A is only a starting point before progressing to B.

Member of the 'B-Team'. Finishing jobs the 'A-Team' can't handle.
AverageJoe is offline  
Sponsored Links
Advertisement
 
post #2 of 4 (permalink) Old 12-30-2003, 01:39 AM
 
Join Date: Jan 2003
Posts: 620
Now I don't know much about the subject, but isn't that the conversion factor to get hp from rpm and torque values. I think the equation is (hp)=(rpm*torque/5225) So setting hp=torque you get rpm=5225. Therefore where the hp and torque curves meet should always be at about 5200 rpms. Hope that's it????

Last edited by Matt S.; 12-30-2003 at 01:45 AM.
Matt S. is offline  
post #3 of 4 (permalink) Old 12-30-2003, 02:31 AM
PostWhore
 
jturmel's Avatar
 
Join Date: Jul 2002
Location: OKC, OK
Posts: 1,848
Send a message via Yahoo to jturmel
Okay here's the short explanation.

First understand there is a difference between ft-lb and lb-ft, ft-lb is the is used to describe work, while lb-ft is used to describe torque. Work being once something has been done, you can have torque on an object without anything actually being accomplished.

Basically when the expression "horsepower" came into play, by James Watts, he observed one hp as the amount of power it took to move (perform) 33,000 ft-lb in one minute. One lb-ft of torque for one revolution is equal to 6.2832 ft-lb of work actually being done. (2 * Pi * r)

The formula for HP is as follows:

HP = (torque x rpm x 6.2832) / 33,000

when you simply this formula you get:

HP = (torque x rpm) / 5252

(you're just dividing the top by 6.2832 and the bottom by 6.2832.)

Since dividing a number by itself always results in 1 then that is why they always cross at 5252. (Inserting 5252 into the "rpm" variable in the equation.)

Hope this makes sense.

-J

1991 Sport 5.0
4R70W Converted, U4P0/SCT Controlled
[email protected], 1.948 60' - 3450 lbs
RIP 1991-2006
jturmel is offline  
Sponsored Links
Advertisement
 
post #4 of 4 (permalink) Old 12-30-2003, 04:11 AM
Braincoating! It's what all the cool kids have!

Administrator
 
tbirdbrain's Avatar
 
Join Date: Oct 2003
Location: South Florida
Posts: 2,725
My professors cap is on
kudos for the post okcbird, you are correct.

a few useless facts, just for the sake of it,

the non-rounded value of exerted force of 1 hp. is 32580 ft-lb per minute.

the hp rating refers to the ability to ‘raise’ a weight, my favorites are
to raise 33 pounds 1000’ or 1000 pounds 33’ in 1 minute.

A+ for everyone

professors cap is now off for the night.

www.BRAINCOATING.com..... Powder & Ceramic Coating

WWW.PRESTONSBOOKS.BIZ..... Books at really great prices!
tbirdbrain is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the TCCoA Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome