Re: Six Pack air fuel ratio results/tuning
[Re: AndyF]
#2139491
08/23/16 07:46 PM
08/23/16 07:46 PM
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Joined: Aug 2003
Posts: 43,157 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,157
Bend,OR USA
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That issue will probably take some work to sort out. First you need to figure out which circuit you are on and then go from there. You can change the jets just to see what happens but I'd be surprised if that fixes it. My guess is that at low speed you are still on the idle circuit and probably in the transition slot. You might need a t-slot restriction to fix the low speed cruise number. You might want to lean out the idle mixtures on the outboards and center carbs so it will idle at or above 14.8, that will affect the lower AFR at your cruising RPM, maybe not enough though I had my old sixpak set up on my 518 C.I. pump gas motor so it would run at or above 15.2 at idle and around 14.8 or leaner at part throttle cruise up to 2500 RPM
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Six Pack air fuel ratio results/tuning
[Re: Cab_Burge]
#2139522
08/23/16 08:42 PM
08/23/16 08:42 PM
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Joined: Nov 2003
Posts: 36,040 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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awhile back someone posted a tuning guide for em, you might see if you can retrieve it or someone might pull it back up, it seemed fairly comprehensive
live every 24 hour block of time like it's your last day on earth
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Re: Six Pack air fuel ratio results/tuning
[Re: ThermoQuad]
#2140278
08/24/16 11:08 PM
08/24/16 11:08 PM
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Joined: Nov 2003
Posts: 36,040 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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that be it, Tom is the man
live every 24 hour block of time like it's your last day on earth
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Re: Six Pack air fuel ratio results/tuning
[Re: 70VcodeCoronetRT]
#2141867
08/27/16 01:45 PM
08/27/16 01:45 PM
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Joined: Feb 2009
Posts: 1,705 Nebraska
70VcodeCoronetRT
OP
top fuel
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OP
top fuel
Joined: Feb 2009
Posts: 1,705
Nebraska
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Ok a little more info. Jet size 64s. Vacuum at idle is right at 14. Power valve is a 6.5. Initial timing is at 18. And this is a 496 not a 440 stroke. I might give 62s a try and see what if anything that does. Thanks
Last edited by 4406forPOWER; 08/27/16 01:46 PM.
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Re: Six Pack air fuel ratio results/tuning
[Re: 70VcodeCoronetRT]
#2141880
08/27/16 01:59 PM
08/27/16 01:59 PM
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Joined: Aug 2003
Posts: 43,157 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,157
Bend,OR USA
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What is your normal crusing RPM and what RPM is it that it is richest at? You can restrict the transition fuel feed circuit to lean that circuit out I've done that in the past to help clean carbs. up. The primary jet will lean the crusie AFR out at the RPM above where the throttle blades are opened more than being on the transition circuit at cruising RPMs ( I hope this makes since ) What are the List numbers on your three carbs? Are your carbs originals or the newer replacement -1 or -2 carbs? I had my old six pak set up to cruise at 14.8 to 15.3 AFR depending on throttle pedal opening at or above 2100 RPM to 2800 RPM Carbs. are tuneable It does take some knowledge and work though, sometimes including errors to learn what that motor likes If your idling the motor with .040 transition slot exposed your not idling on the idle circuit only, your already on the transition circuit Fix that first and then proceed
Last edited by Cab_Burge; 08/27/16 07:04 PM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Six Pack air fuel ratio results/tuning
[Re: 70VcodeCoronetRT]
#2142110
08/27/16 08:37 PM
08/27/16 08:37 PM
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Joined: Feb 2009
Posts: 1,705 Nebraska
70VcodeCoronetRT
OP
top fuel
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OP
top fuel
Joined: Feb 2009
Posts: 1,705
Nebraska
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The only thing I changed was I leaned out the idle mixture with the center carb idle mixture screws. They were around 13.5. Changed them to 14.5 to 15. They are about 1 1/4 turns out. I'm starting to think I have some sort of power valve issue. I did have Scott put in 64 jets per Mr. Six Pack recommendation.
Last edited by 4406forPOWER; 08/27/16 08:40 PM.
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