Wide band AF. Holley carb adjusting? - 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 06-28-2013, 02:21 PM
staleg's Avatar
Registered User
 

Last journal entry: Hand brake
Last photo:
Join Date: Dec 2005
Location: Norway - Europe
Age: 47
Posts: 778
Wiki Edits: 0

Thanks: 0
Thanked 2 Times in 2 Posts
Wide band AF. Holley carb adjusting?

The '34 Roadster works pretty well. Ignition is adjusted. It's easy to start, pulls evenly and good, no stumbling. The idle is maybe a little high, even with the adjusting screw all the way out, but all in all the engine works well.

But the AF ratio is way too rich. Crusing around 12-1500 rpm shows 12-12,5:1.

QFT Super Street (Holley based) 650 CFM DP carb.
Engine is a Chevy small block mainly standard except air gap intake, headers and 2 x 2,5" exhaust, straight thru mufflers.
6 speed trans.

What do you suggest? Lean down the primary jets a bit?
If so, how much? 3 steps?

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 06-28-2013, 02:40 PM
How fast is fast enough?
 
Last photo:
Join Date: Jun 2005
Location: St. Louis, MO
Age: 29
Posts: 8,673
Wiki Edits: 0

Thanks: 16
Thanked 280 Times in 261 Posts
first lean down your idle until it stumbles at transition, then go back just a hair to cure the stumble. then lean your primaries, but only go 1 step at a time. for cruise 15:1 is about ideal, but sometimes its needs to run richer with a carb to compensate for uneven distribution.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 06-28-2013, 02:48 PM
staleg's Avatar
Registered User
 

Last journal entry: Hand brake
Last photo:
Join Date: Dec 2005
Location: Norway - Europe
Age: 47
Posts: 778
Wiki Edits: 0

Thanks: 0
Thanked 2 Times in 2 Posts
Sounds like a good start. Thanks
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 07-10-2013, 01:33 AM
Registered User
 
Last photo:
Join Date: Mar 2009
Location: Burton, MI
Posts: 782
Wiki Edits: 0

Thanks: 34
Thanked 15 Times in 14 Posts
i put a $20 narrow 02 gauge, and an old spare 02 sensor I had laying around in my car... best $23 I ever spent (forgot the $3 for the 02 bung)

I had to go down something like 6 or 8 jet sizes to get my holley 650 (vac secondary, dual feed) to run 14.7-ish:1 at cruise.

1200-1500 rpm cruise seems a tad low.. what ground speed are you doing that at? 55mph with an o.d that wouldn't surprise me much :>
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 07-10-2013, 10:27 AM
Slammedsi's Avatar
Registered User
 
Last photo:
Join Date: Feb 2013
Location: Vernon, TX
Posts: 257
Wiki Edits: 0

Thanks: 118
Thanked 4 Times in 4 Posts
Quote:
Originally Posted by staleg View Post
The '34 Roadster works pretty well. Ignition is adjusted. It's easy to start, pulls evenly and good, no stumbling. The idle is maybe a little high, even with the adjusting screw all the way out, but all in all the engine works well.

But the AF ratio is way too rich. Crusing around 12-1500 rpm shows 12-12,5:1.

QFT Super Street (Holley based) 650 CFM DP carb.
Engine is a Chevy small block mainly standard except air gap intake, headers and 2 x 2,5" exhaust, straight thru mufflers.
6 speed trans.

What do you suggest? Lean down the primary jets a bit?
If so, how much? 3 steps?
Been wanting a wide band. What brand are you using? And are you runing only one sensor in one side of the exhaust.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 07-11-2013, 04:28 AM
staleg's Avatar
Registered User
 

Last journal entry: Hand brake
Last photo:
Join Date: Dec 2005
Location: Norway - Europe
Age: 47
Posts: 778
Wiki Edits: 0

Thanks: 0
Thanked 2 Times in 2 Posts
Only one sensor, yes.
The brand is AEM:
http://www.summitracing.com/parts/avm-30-4100

AF gauge to the right with vacuum gauge left of it. Good information for both ignition and carb adjustings.

Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 07-11-2013, 04:37 AM
Andy79Z28's Avatar
Registered User
 
Last photo:
Join Date: Jan 2009
Location: Shirley, NY
Posts: 20
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
air fuel

I have 2 AFR wide band meters. My problem is that the O2 senors do not last. I use leaded race fuel and the O2 sensors clog up right away and go bad. Any suggestions?
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 07-25-2013, 07:51 PM
Andy79Z28's Avatar
Registered User
 
Last photo:
Join Date: Jan 2009
Location: Shirley, NY
Posts: 20
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
Guess no one has an answer for my last post......
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
Wide Band A/F Tuner Controller SSedan64 General Rodding Tech 1 09-01-2010 06:08 AM
Wide band or narrow band A/F...? staleg Engine 6 08-12-2008 02:10 PM
adjusting floats on holley carb inquiring_mind2 Engine 1 04-24-2008 09:29 PM
looking for wide band sensor pt no. 0258007057 sc2dave Engine 9 05-10-2007 10:15 AM
Anyone use this wide band A/F meter? dirtydave Engine 5 05-15-2005 08:35 AM


All times are GMT -6. The time now is 01:25 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.