Re: Air-Fuel Ratio Tuning Questions

[john althaus <althausjbl@xxxxxxx>]

Dennis,
Your changes at WOT are due to the "power valve" opening, part of Holley's  
better idea to richen the mixture as you need more power, as it see's the 
vacuum  in the manifold drop it opens. the numbers are supposed to correspond 
to the  inches of vacuum that it will open at.  Such as a 65 will open when 
 the vacuum drops below 6.5 inches.
 
John  Althaus
64 Savoy Hemi 4 spd
214-673-7540 cell  

 
In a message dated 4/20/2009 9:27:56 P.M. Central Daylight Time,  
big-d@xxxxxxxxxxxx writes:


You  are doing it right. Establish what ratio the car likes and you like 
then  
work towards it. Gnorally speaking most carbs want two jet sizes from the  
old or out f the box settings. but I wuldnt make it a hard fast  rule.
Anymore than 4 jets sizes you are probably off track a bit. never be  
afraid 
to retrace yousteps either.
Don
----- Original Message -----  
From: "Dennis C." <dennis.2914@xxxxxxxxx>
To:  <1962to1965mopars@xxxxxxxxxx>
Sent: Monday, April 20, 2009 4:50  PM
Subject: Air-Fuel Ratio Tuning Questions



Hello,

I  am using an Innovate LC-1 Air-Fuel Ratio meter to jet my carburetor.
I  would appreciate comments from anyone who has used an instrument like
this  or has had experience jetting by Air-Fuel Ratio.

I have not found good  information on what Air-Fuel Ratio (AFR) I should
be shooting for.  I  have seen information ranging from people who are
shooting for the ideal  AFR of 14.7:1 to those who feel that a "Safe"
range is between 12.8:1 to  around 13.4:1.

I have a Holley Street Avenger 670 on my 383.  I  now know that it was
probably not the best choice for a carburetor however  when I got it I
was looking for just street performance on a driver.   I am now a
follower of Don Dulmage.s messages and learning more with each  new
message he posts about tuning and carburetors.

The carburetor  was running very lean out of the box with 65 Primary jets
and 68 Secondary  jets.

At 68 Primary jets I am running 14.0:1 at idle and 13.8:1 to  14.0:1
cruising level ground 65 to 75 mph.

At 70 Primary jets I am  running 13:0:1 at idle and 13.0:1 to 13.5:1
cruising level ground 65 to 75  mph.

To me it looks like #69 jets may be what I need.

I have  some data on WOT with 70 Primary and 74 Secondary jets however I
want to  get the Primary circuit set first.  It is interesting that on a
4th  gear pull on the road from 2000 to 3500 rpm it first drops to around
12.0:1  then around 3000 rpm it drops again to under 11.0:1 and was still
dropping  when I let up on the gas.

Again if anyone has experience in this areas  comments would be
appreciated.

Dennis C.


1996 Dodge Ram  3500 Van Conversion
1964 Plymouth Belvedere 318 Auto
1963 Plymouth Sport  Fury 383 4-speed
1949 Dodge Pickup 289/C4 soon to be changed
1998 Honda  Valkyrie Standard


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Please  address private mail -- mail of interest to only one person -- 
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the  total volume of mail and fine tune the content signal to Mopar topic.   
Thanks!

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Please address private mail -- mail of interest to only one person -- directly to that person.  I.e., send parts/car transactions and negotiations as well as other personal messages only to the intended recipient, not to the Clubhouse public address. This practice will protect your privacy, reduce the total volume of mail and fine tune the content signal to Mopar topic.  Thanks!

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