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{{{{{{{{{{{ VACUUM SECONDARY QUESTION }}}}}}}}}}}}}
#679068
04/24/10 05:43 PM
04/24/10 05:43 PM
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Joined: Jul 2006
Posts: 9,366
Lehigh Acres, Florida
rickstershemi
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360, SB, 8.5 Comp, XE256H Cam, 1 5/8 Headers through 2.5 exhaust, 904 Tranny, 3.55 Peg-Leg  Holley 600 Vac Secondary OK, recently took the kids truck to the track and realized the vacuum secondary wasn't opening.....back home realized it was just barely touching a corner of the spread-bore to square-bore adapter plate and just took a tiny smack to gently bend it out of the way. Now....when you whack the go-peddle in 1st it falls on it's face for an instant and then it's off we go. Have the lightest spring in it (quick change) is it coming in too soon or too late....my thought is too soon and want to try the next spring up....what do you guys think  Rickster
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Re: {{{{{{{{{{{ VACUUM SECONDARY QUESTION }}}}}}}}}}}}}
[Re: Quicktree]
#679072
04/24/10 06:04 PM
04/24/10 06:04 PM
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Posts: 9,366
Lehigh Acres, Florida
rickstershemi
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Quote:
I don't see a 600 vac secondary carb doing that combo any justice.
Either do I, looking for a 750....but it's what I got now 
But I think your right on the spring too light, looks like a little trial and error session
Rickster
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Re: {{{{{{{{{{{ VACUUM SECONDARY QUESTION }}}}}}}}}}}}}
[Re: Sport440]
#679074
04/24/10 06:53 PM
04/24/10 06:53 PM
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Lehigh Acres, Florida
rickstershemi
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Quote:
Like Quick said, the back barrels don't get a pump shot. So if it bogs the spring is to light opening to fast causing it to lean out.
Holley's got about 5 or 6 different springs for tuning the vac secondaries. They are colored for different spring values so you know what your putting in, weaker or stronger. mike
Thanks Mike, I have all the springs, actually it's a Quick Fuel Quick Change Kit, I actually think it might be the short spring, which is like having no spring at all for the 1st 1/4" to 3/8" upon opening, going to try the yellow (long) spring next (second lightest) but taller...we'll see 
Rickster
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Re: {{{{{{{{{{{ VACUUM SECONDARY QUESTION }}}}}}}}}}}}}
[Re: rickstershemi]
#679075
04/24/10 06:56 PM
04/24/10 06:56 PM
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Joined: Jan 2003
Posts: 19,355
Las Vegas
Al_Alguire
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I Live Here
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Las Vegas
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How about some more pump shot????
"I am not ashamed to confess I am ignorant of what I do not know."
"It's never wrong to do the right thing"
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Re: {{{{{{{{{{{ VACUUM SECONDARY QUESTION }}}}}}}}}}}}}
[Re: Al_Alguire]
#679076
04/24/10 07:05 PM
04/24/10 07:05 PM
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Lehigh Acres, Florida
rickstershemi
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Quote:
How about some more pump shot????
I thought about that, but it's adjusted correctly and getting a pretty good shot now....was very crisp on just the primaries, no hesitation at all, gonna try the springs 1st and go from there.....wish I still had the 750 lying around 
Rickster
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Re: {{{{{{{{{{{ VACUUM SECONDARY QUESTION }}}}}}}}}}}}}
[Re: rickstershemi]
#679077
04/24/10 07:09 PM
04/24/10 07:09 PM
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Joined: Jan 2003
Posts: 19,355
Las Vegas
Al_Alguire
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Just saying..If it were me I'd be throwing some squirter at it too...
"I am not ashamed to confess I am ignorant of what I do not know."
"It's never wrong to do the right thing"
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Re: {{{{{{{{{{{ VACUUM SECONDARY QUESTION }}}}}}}}}}}}}
[Re: Al_Alguire]
#679078
04/24/10 07:40 PM
04/24/10 07:40 PM
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Lehigh Acres, Florida
rickstershemi
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Quote:
Just saying..If it were me I'd be throwing some squirter at it too...
I agree, just got back in from two spring changes and the next to stiffest seems to work well, might try the 50CC pump off the Domi and see if it picks up at all...??????
Got a set of 4.10's with Sure-Grip showing up 1st of the week, so Friday night I will be pleased if we can get it to run low - mid 8's
Ran 9.7 a couple of weeks ago with the 3.55 peg-leg and no secondaries at all...
It was my Son's 1st lap and he is stoked to get back out.... 
Thanks for the help guys
Rickster
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Re: {{{{{{{{{{{ VACUUM SECONDARY QUESTION }}}}}}}}}}}}}
[Re: 602heavy]
#679080
04/24/10 08:12 PM
04/24/10 08:12 PM
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Lehigh Acres, Florida
rickstershemi
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Quote:
I doubt whether the secondaries are causing the bog issues , air speed needs to be pretty high in order for the secs to open regardless of spring tension , i can't see they are opening when you hit the gas from a standstill , get hold of a paper clip & wrap it round the secondary arm , go hit the throttle till the motor bogs then go see if the clip has moved up from where you placed it , this will answer you're question , good luck.
Adam, the heavier spring fixed the bog...it's gone and tips in perfectly now, so it was opening way to soon, going to try a bigger pump shot as Al suggested to see if it picks up any on the initial hit
Rickster
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Re: {{{{{{{{{{{ VACUUM SECONDARY QUESTION }}}}}}}}}}}}}
[Re: rickstershemi]
#679081
04/24/10 08:13 PM
04/24/10 08:13 PM
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Joined: Jan 2003
Posts: 32,394
Quicktree
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I Win
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Quote:
Quote:
I doubt whether the secondaries are causing the bog issues , air speed needs to be pretty high in order for the secs to open regardless of spring tension , i can't see they are opening when you hit the gas from a standstill , get hold of a paper clip & wrap it round the secondary arm , go hit the throttle till the motor bogs then go see if the clip has moved up from where you placed it , this will answer you're question , good luck.
Adam, the heavier spring fixed the bog...it's gone and tips in perfectly now, so it was opening way to soon, going to try a bigger pump shot as Al suggested to see if it picks up any on the initial hit
Rickster
if it's not bogging I doubt more pump shot will help
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Re: {{{{{{{{{{{ VACUUM SECONDARY QUESTION }}}}}}}}}}}}}
[Re: Quicktree]
#679082
04/24/10 08:59 PM
04/24/10 08:59 PM
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Joined: Jul 2006
Posts: 9,366
Lehigh Acres, Florida
rickstershemi
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Quote:
Quote:
Quote:
I doubt whether the secondaries are causing the bog issues , air speed needs to be pretty high in order for the secs to open regardless of spring tension , i can't see they are opening when you hit the gas from a standstill , get hold of a paper clip & wrap it round the secondary arm , go hit the throttle till the motor bogs then go see if the clip has moved up from where you placed it , this will answer you're question , good luck.
Adam, the heavier spring fixed the bog...it's gone and tips in perfectly now, so it was opening way to soon, going to try a bigger pump shot as Al suggested to see if it picks up any on the initial hit
Rickster
if it's not bogging I doubt more pump shot will help
I'll let ya know 
Rickster
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Re: {{{{{{{{{{{ VACUUM SECONDARY QUESTION }}}}}}}}}}}}}
[Re: Cab_Burge]
#679084
04/24/10 09:47 PM
04/24/10 09:47 PM
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Lehigh Acres, Florida
rickstershemi
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Quote:
See what squirter size is in it now and try a different size (up and down, down will make it squirt longer, bigger will squirt more in sooner)before swapping out the pump size 
Don't have an assortment of squirters but do have some different pump cams....wonder if we might notice an improvement there...
Rickster
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Re: {{{{{{{{{{{ VACUUM SECONDARY QUESTION }}}}}}}}}}}}}
[Re: rickstershemi]
#679085
04/24/10 09:57 PM
04/24/10 09:57 PM
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Joined: Jan 2003
Posts: 32,394
Quicktree
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I Win
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Quote:
Quote:
See what squirter size is in it now and try a different size (up and down, down will make it squirt longer, bigger will squirt more in sooner)before swapping out the pump size
Don't have an assortment of squirters but do have some different pump cams....wonder if we might notice an improvement there...
Rickster
I doubt it, only way to tell for sure would be having a 60' timer.
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Re: {{{{{{{{{{{ VACUUM SECONDARY QUESTION }}}}}}}}}}}}}
[Re: Quicktree]
#679086
04/24/10 10:15 PM
04/24/10 10:15 PM
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Joined: Jul 2006
Posts: 9,366
Lehigh Acres, Florida
rickstershemi
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Quote:
Quote:
Quote:
See what squirter size is in it now and try a different size (up and down, down will make it squirt longer, bigger will squirt more in sooner)before swapping out the pump size
Don't have an assortment of squirters but do have some different pump cams....wonder if we might notice an improvement there...
Rickster
I doubt it, only way to tell for sure would be having a 60' timer.
Well this week I'm gonna just let him make as many laps as he can, since his 1st time out he only got one, we can play with the carb later, it runs good enough now as is
Rickster
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Re: {{{{{{{{{{{ VACUUM SECONDARY QUESTION }}}}}}}}}}}}}
[Re: rickstershemi]
#679087
04/24/10 10:37 PM
04/24/10 10:37 PM
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Joined: Jan 2003
Posts: 6,591
Canton, Ohio
Sport440
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Im not sure I like the idea of tuning early/fast opening secondaries with more pump shot or squirters. If your running a single plane you could end up over richening the front 4 cylinders while leaning out the back 4 cylinders. While it may eliminate the bog, overall you could hurt its "launch" performance. By X amount of cyl being rich and X amount being a bit lean. If your running a DPlane intake the effects will be less. Id tune the secondary bog with the Springs first, witch you did. Id like to add that even though the Bog is now gone. Id would still try a spring one size heavier at the track to see if it effects ET. Just because the bogs gone doesnt mean the secondary opening rate is at optimum. But it very well could be. At this point with the Bog gone, your probably near the top of the carbs Tune With the combination of Squirters, pumps, pump cams, air jets, main jets, and in your case secondary springs, Do we ever get that perfect carb tune. Probably not but we can get her darn close.  mike EDIT,  Id run as is for now, let the kid have some Fun, mike
Last edited by Sport440; 04/25/10 12:14 AM.
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