Six Pack secondary opening rate tuning
#654773
03/29/10 01:09 PM
03/29/10 01:09 PM
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Joined: Jan 2003
Posts: 3,719
Space Station #5
471Magnum
OP
master
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OP
master
Joined: Jan 2003
Posts: 3,719
Space Station #5
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Working on getting the bog/surge out of my Challenger when the secondaries kick. Pulled a diaphragm apart to confirm what springs are in it (yellow). In the process I got to wondering why no one has come out with a quick change spring kit for these, or better yet, an adjustable pod like the QuickFuel set-up for four barrels. Seems like the latter wouldn’t be too difficult to implement on a Six Pack. Just need some sort of adjustable bleed before the Tee on the vacuum hoses. Anybody tried anything like this? 
-Jim
I can fix it... my old man is a television repairman.
He's got the ultimate set of tools... I can fix it.
Currently Mopar-less
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Re: Six Pack secondary opening rate tuning
[Re: 471Magnum]
#654775
03/29/10 10:28 PM
03/29/10 10:28 PM
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Joined: Jan 2003
Posts: 2,001
s. e. pa.
calrobb2000
top fuel
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top fuel
Joined: Jan 2003
Posts: 2,001
s. e. pa.
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hi need more info ! engine , cam, vacuum at idel , ignition timing inital, total , advance rate,center main jet size , power valve no. 
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Re: Six Pack secondary opening rate tuning
[Re: 471Magnum]
#654777
03/30/10 09:30 AM
03/30/10 09:30 AM
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Joined: Jun 2008
Posts: 3,916
usa
lewtot184
master
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master
Joined: Jun 2008
Posts: 3,916
usa
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Quote:
Working on getting the bog/surge out of my Challenger when the secondaries kick. Pulled a diaphragm apart to confirm what springs are in it (yellow).
In the process I got to wondering why no one has come out with a quick change spring kit for these, or better yet, an adjustable pod like the QuickFuel set-up for four barrels.
Seems like the latter wouldn’t be too difficult to implement on a Six Pack. Just need some sort of adjustable bleed before the Tee on the vacuum hoses.
Anybody tried anything like this?
i danced thru this last year. my problem was fuel pressure/volume. do a test. also check float levels and filter restrictions. the opening rate will change about 300-400rpm per spring change. every change to a stiffer spring above the yellows will about a tenth to the e.t.
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Re: Six Pack secondary opening rate tuning
[Re: Mr.Yuck]
#654780
03/30/10 07:49 PM
03/30/10 07:49 PM
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Joined: Feb 2005
Posts: 4,316
Prospect, PA
BSB67
master
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master
Joined: Feb 2005
Posts: 4,316
Prospect, PA
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Quote:
I just bought the kit of springs. I'll be taking them to the track and seeing which works best.
 This is the only way to get the opening rate correct for max power. Tuning to eliminate the hesitation on the street, especially from a roll, may not result in max track performance.
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Re: Six Pack secondary opening rate tuning
[Re: lewtot184]
#654781
03/30/10 07:55 PM
03/30/10 07:55 PM
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Joined: Feb 2005
Posts: 4,316
Prospect, PA
BSB67
master
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master
Joined: Feb 2005
Posts: 4,316
Prospect, PA
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Quote:
...every change to a stiffer spring above the yellows will about a tenth to the e.t.
Lew, I think I know what you are saying here, but it might not be clear to others.
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Re: Six Pack secondary opening rate tuning
[Re: 471Magnum]
#654782
03/30/10 08:34 PM
03/30/10 08:34 PM
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Joined: Jan 2003
Posts: 3,719
Space Station #5
471Magnum
OP
master
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OP
master
Joined: Jan 2003
Posts: 3,719
Space Station #5
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Just to be clear, I have the knowledge and experience to tune through this issue. I know it's just a matter of heavier springs or tweaking the pump shot (or maybe fuel starvation).
I'm just looking to make the spring swap easier/unnecessary. It's very difficult to open up the pods without tearing the diaphragms. I grease the screws on reassembly to help prevent snagging/tears, but they happen, and diaphragms are $30.
-Jim
I can fix it... my old man is a television repairman.
He's got the ultimate set of tools... I can fix it.
Currently Mopar-less
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Re: Six Pack secondary opening rate tuning
[Re: 471Magnum]
#654783
03/31/10 05:56 AM
03/31/10 05:56 AM
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Joined: Mar 2007
Posts: 3,285
West Coast, USA
jbc426
master
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master
Joined: Mar 2007
Posts: 3,285
West Coast, USA
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How do you have your ignition timing set-up? What's your initial and how much mechanical do you have? When does it all come in by?
Check your float levels. Where do you have them set at?
Do you have any vacumm leaks anywhere at all?
1970 Plymouth 'Cuda #'s 440-6(block in storage)currently 493" 6 pack, Shaker, 5 speed Passon, 4.10's
1968 Plymouth Barracuda Convertible 408 Magnum EFI with 4 speed automatic overdrive, 3800 stall lock-up converter and 4.30's (closest thing to an automatic 5 speed going)
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