powervalve - 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 04-03-2004, 08:06 PM
jtdchevy's Avatar
New Member
 
Join Date: Dec 2003
Location: athens, tennessee
Age: 28
Posts: 28
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Question powervalve

i know a little bit about powervalves but not much, i have a 650 speed demon and i am attempting to tune the car right now, from what i have read you pick a power valve by what your vacume is but what powervalve do you get with what amount of vacume?anybody got a chart for me? thank you

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 04-03-2004, 08:20 PM
DoubleVision's Avatar
Not Considered a Senior Member
 
Last photo:
Join Date: Oct 2002
Location: Heart Of Dixie
Age: 40
Posts: 10,658
Wiki Edits: 0

Thanks: 15
Thanked 60 Times in 57 Posts
http://www.mortec.com/carbtip1.htm
This will tell you what you need to know.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 04-03-2004, 08:50 PM
OddRodder's Avatar
CORNFED and INBRED !?!
 
Join Date: Jan 2003
Location: Springfield, MO.
Age: 53
Posts: 612
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Just when I thought that I could impart my immense wisdom upon the world!! (Yeah, right!) D.V. posts all the information that is needed on this subject!!!
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 04-03-2004, 09:04 PM
Jmark's Avatar
Registered User
 
Last photo:
Join Date: Sep 2003
Location: phoenix
Age: 61
Posts: 4,925
Wiki Edits: 0

Thanks: 13
Thanked 47 Times in 36 Posts
Hmm, I'd have to diss-agree with Mortec on the selecting of power valves.
They say to select the pv with the number 1 to 2 inches less vacuum than the engine has when idling.

To me, having the pv come in 2" below idle is waaaaay to soon. Just touching the gas pedal will drop the vacuum 1 or 2 inches. I"d personally select one that was about 4 to 6" less than idle vacuum. If you get a bog, up it one rating.

I'd probably go one step further and drive the car at normal street speed, keeping a constant throttle and note the vacuum reading. Then try one that is about 4 or 5" less than that.

Mark
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 04-03-2004, 09:09 PM
OddRodder's Avatar
CORNFED and INBRED !?!
 
Join Date: Jan 2003
Location: Springfield, MO.
Age: 53
Posts: 612
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Interesting! I always go right at 2" below idle vacuum and have had few problems! Anyone else?
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 04-03-2004, 09:16 PM
Jmark's Avatar
Registered User
 
Last photo:
Join Date: Sep 2003
Location: phoenix
Age: 61
Posts: 4,925
Wiki Edits: 0

Thanks: 13
Thanked 47 Times in 36 Posts
Well, they also say that there are lots of variables too, and I agree. My current fresh 350 has 14" in gear. If I was running a Holley, i'd have a hard time justifing a "12" power valve.

My sons 400 idles at 4" , but climbs to 13 at cruise. His 286 Comp cam is what is killing the whole thing. But we both run Qjets.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 04-04-2004, 01:56 AM
4 Jaw Chuck's Avatar
Hotrodders.com Moderator
 
Last photo:
Join Date: Mar 2002
Location: Manitoba, Canada
Age: 46
Posts: 5,093
Wiki Edits: 0

Thanks: 2
Thanked 113 Times in 91 Posts
I have found that choosing a PV that is 2" below the vac reading under load at cruise is the best method, you wouldn't want it opening at cruise...mileage would be terrible.

Just my experience.
__________________
Outlawed tunes from outlawed pipes
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:
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



All times are GMT -6. The time now is 05:33 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.