4160 to 4150 - 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 02-21-2013, 06:08 PM
Registered User
 
Last photo:
Join Date: Jan 2013
Posts: 61
Wiki Edits: 0

Thanks: 3
Thanked 0 Times in 0 Posts
4160 to 4150

I have a holley 4160 750cfm vacuum secondary. I have the primary running pretty good. I have 72 jets in the front. But probablly need to go to 70 or 68. I want to convert it to a 4150 to have a little more adjustability. What would be a good starting point for the secondary jets? I think the secondaries are generally richer than the primaries but not sure on that. Should I get a secondary metering block with a power valve? I would assume not since my other 4150 carb doesn't have one. What would be the disadvantage to a secondary power valve? Anything else you guys can point me in the right direction on?

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 02-21-2013, 10:00 PM
lg1969's Avatar
Google "Tunnel Ram 406"
 
Last photo:
Join Date: Oct 2007
Location: Bohemia, L.I.N.Y.
Age: 64
Posts: 1,059
Wiki Edits: 0

Thanks: 1
Thanked 21 Times in 18 Posts
Use another Holley Carburetor of similar CFM as a point of reference. I did the same thing on my pair of 390 VS Holley for my TR setup. I Change it from a sec. plate to a block.
Holley carb specifications, list #'s, jetting and tuning tips.

Last edited by lg1969; 02-21-2013 at 10:08 PM.
Reply With Quote Quick reply to this message
The Following User Says Thank You to lg1969 For This Useful Post:
bowtie44s (02-22-2013)
  #3 (permalink)  
Old 02-22-2013, 05:23 PM
ericnova72's Avatar
More for Less Racer
 
Join Date: Jan 2007
Location: S.W. Lower Michigan
Age: 48
Posts: 9,800
Wiki Edits: 0

Thanks: 48
Thanked 603 Times in 540 Posts
No powervalve in the rear block, Start with #80 jets and tune from there. This is Holley's starting point for 750 vacuum secondaries with no powervalve provision in the rear and a rear metering block with replacable jets.
Reply With Quote Quick reply to this message
The Following User Says Thank You to ericnova72 For This Useful Post:
bowtie44s (02-22-2013)
  #4 (permalink)  
Old 02-22-2013, 07:39 PM
Registered User
 
Last photo:
Join Date: Jan 2013
Posts: 61
Wiki Edits: 0

Thanks: 3
Thanked 0 Times in 0 Posts
Just wondering why I don't want a powervalve in the rear. My theory is if i'm at low vacuum with just the primaries open the 2nd powervalve will open and cause it to run rich. Am I correct or way off? Is that why the secondary jets are so big?
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 02-23-2013, 03:54 AM
Registered User
 
Join Date: Feb 2013
Posts: 5
Wiki Edits: 0

Thanks: 1
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by bowtie44s View Post
Just wondering why I don't want a powervalve in the rear. My theory is if i'm at low vacuum with just the primaries open the 2nd powervalve will open and cause it to run rich. Am I correct or way off? Is that why the secondary jets are so big?
Yes and no. The power valve in the primaries are sufficient enough on that carburetor to keep that hesitation out when you romp on it.

If you put the same power valve in it as the one in the primaries, you wouldn't have a problem, except it'd still run rich because the primary power valve is doing the job well enough. More isn't better.

13.8:1 air to fuel ratio is perfection for power.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 03-01-2013, 05:17 PM
ericnova72's Avatar
More for Less Racer
 
Join Date: Jan 2007
Location: S.W. Lower Michigan
Age: 48
Posts: 9,800
Wiki Edits: 0

Thanks: 48
Thanked 603 Times in 540 Posts
Also, under hard accelleration the fuel in the rear bowl sloshes to the rear of the bowl, away from the pick-up point of the rear powervalve, it is slightly higher on the metering block than the jets are. This is the main reason Holley discontinued use of rear powervalves in most on thier carbs.

Rear jet extensions are used on hard launching cars for the same reason, to move the jet back to where the fuel is forced to be due to the G-force of the launch.

You're correct, the rear jets are bigger because there is no additional fuel being added by a powervalve like there is in the front.
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


Similar Threads
Thread Thread Starter Forum Replies Last Post
holley 4160 to 4150 conversion help needed eric32 Engine 10 12-19-2009 06:12 PM
help with holley 4160 sam_bo3 Engine 2 03-11-2009 07:10 AM
4160 600cfm StevenC Engine 1 01-04-2006 05:50 AM
Powdercoating a Holley 4160 rick458 Engine 6 03-21-2005 02:26 PM
Flanges on 4160 Holley's the same as 4150's? unstable Engine 5 06-28-2004 09:54 PM


All times are GMT -6. The time now is 10:38 AM.


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.