area under the curve. what the hell? - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 11-24-2006, 08:01 PM
406 ss monte's Avatar
eat a beaver, save a tree
 
Last photo:
Join Date: Dec 2003
Location: greeneville, tn
Age: 43
Posts: 605
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
area under the curve. what the hell?

what does it mean when the cam grinders are talking about the area under the curve?

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 11-24-2006, 08:33 PM
Registered User
 
Join Date: Nov 2006
Location: MI
Posts: 3
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
If they are talking about HP and Torque they probably mean the power you make aside from your peak power.

If you look at a dyno graph of a supra that makes like 1500hp its gonna make no power until all of a sudden when the turbo finally spools up, this has a high peak power but nothing "under the curve". You can modify an engine and end up with the same peak HP but have more power "under the curve" and the latter will be faster

im not very good at explaining things, hope this helps
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 11-24-2006, 10:52 PM
pmeisel's Avatar
Glad the Jeep is on the road
 
Last wiki edit: How to identify a Ford V8
Join Date: Jan 2004
Location: Meridian MS & Vermilion Ohio
Age: 58
Posts: 814
Wiki Edits: 8

Thanks: 0
Thanked 1 Time in 1 Post
Thirty Two is accurate, this is sometimes what is meant....

Or they could be talking about the combination of duration and lift of the camshaft.... how fast it gets to how much lift, and how long it stays there, allowing the engine to breathe.

Either usage would be a common description of the graphical description of what is going on.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 11-24-2006, 11:15 PM
curtis73's Avatar
Hates: Liver. Loves: Diesel
 
Last wiki edit: How to find cheap parts
Last journal entry: 1999-2001: Getting it on the road
Last photo:
Join Date: Dec 2005
Location: Pittsburgh, PA
Age: 40
Posts: 5,128
Wiki Edits: 16

Thanks: 0
Thanked 2 Times in 2 Posts
Right on.

With cams, picture the lobe. For any given duration and lift, there is a curve. If you plot the valve events over time on a graph you would see a bell-shaped curve starting with the valve opening, then reaching peak lift, then dropping down to close. When you grind a cam you can make the lift ramps faster. So, the graph would look the same at the beginning and the end, but the lines would rise and fall more sharply.

The same happens for torque and HP peaks. If you have two engines, both with identical HP and TQ peaks but one has broader curves on the dyno, there is more area "under the curve." Consider this graph in the picture below. They both start and end at 0 and they both peak at 29, but the pink line shows more area "under the curve."

In general, most cams that provide more lift under the curve will provide more power and torque under the curve. If you have two engines with identical peaks but one has more area under the curve, the engine with the broader curves will be faster. As you are accelerating through the RPM range, the broader-curved engine will supply more torque and HP at more points along the way and therefore be faster.
Attached Thumbnails
Click image for larger version

Name:	underthecurve.jpg
Views:	43
Size:	16.5 KB
ID:	16411  
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 11-25-2006, 06:35 AM
CNC BLOCKS NE's Avatar
CNC Blocks Northeast
 
Last photo:
Join Date: Sep 2006
Location: NORTHEAST
Age: 54
Posts: 1,436
Wiki Edits: 0

Thanks: 1
Thanked 17 Times in 17 Posts
Here is a good link to go over.http://speedtalk.com/forum/viewtopic.php?t=1148
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
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:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may 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 Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Anyone in the Phoenix area?? AZ_Ron Body - Exterior 0 01-30-2006 01:27 PM
Dent Repair Randy Ferguson Body - Exterior 25 11-26-2005 09:00 PM
Science Proves the Existence of Hell edge Hotrodders' Lounge 16 12-18-2004 10:09 PM
GM HEI Dist. curve kit?? john69 Engine 4 09-24-2002 07:48 AM
why the hell? axle bastard Hotrodders' Lounge 15 08-14-2002 10:10 AM


All times are GMT -6. The time now is 12:39 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.