Choosing squirter size?

[MyMopar]

Ok I have a huge bog off idle and it is related to my squirter being too small.  So how do I know how many sizes to jump.  My local speed shop sells them at $12-$15 a pop and I ddon't need to go broke just figuring out a size.  What is the best approach? 
Here's my combo:
440 10.2:1 compression
Holley Street Dominator intake
Holley 870 vac. sec. carb

Current squirter size is 40

I was thinking of buying two a 42 and a 44 but I don't know how much a number change will increase fuel flow. 
Like I stated, at idle nailing it off the line the car makes a huge vrouuumppp noise and goes silent, then all of a sudden the tires light up and off I go.  If I rev the motor a few times before taking off the off idle bog isn't so bad.

Any suggestions before I take the advice of someone who needs to make money (the shop owner) 

[Chryco Psycho]

check the float levels first , what size is in there now ? generally unless the cam has massive duration something in the 35-37 is all you should need

[MEK-Dangerfield]

40 is a pretty big squirter as it is, is that what the carb came with? IF this is the problem, I would go up to at least a  44. With a large bog I don't think 2 sizes will help much.


  Mike

[MyMopar]

Floats are set just right, fuel at the bottom of the sight hole, just a little dribbles out. Current squirter is a 40.

Now the speed shop guy told me to go down on the size to make the shot last longer?  Pardon my ignorance but if I am having a fuel starvation problem, why would I want to restrict the amount of fuel input?  I told him thanks for the advice but it just really doesn't make sense to me.  I ordered a 45 and a hollow squirter screw.

I do have a set of accel. pump cams.  What I want to do is get the pump shot right off the bat.  I notice my current accel. pump cam leaves me with more travel than it provides.  Meaning the cam moves the lever half the distance it could move leaving half a shot left.  I haven't figured out how to choose the right one and all but I will wait to see what happens with the squirter first.

Perhaps it is a rich bog, but it doesn't studder or stumble, it goes flat, dead silent as if the car was shut off, I let up on the throttle real quick and then get right back on it and a second later it comes to life 

I guess I'll wait and see, the part is coming in tomorrow. 



Edit: I'll have to double check the squirter size, I could swear it said 40, I'll double check it today undr a ligthed magnifying glass to be sure.  It is the one that came with the carb.

[ntstlgl1970]

You could also try moving the pump cam to the number 2 position and see if that helps. Holley makes "trick kits" with multiple shooters, pump cams etc. that you can get from summit or jegs that might be cheaper in the long run if you go through a few squirters at 12-15$ a pop. I almost agree with the speed shop guy though, a 40 on the primary is a huge squirter. Are you talking about flooring it and it bogs? Maybe you need a stiffer vacuum secondary spring (the more I read your post, the more I think this is your problem), if the secondaries open way too soon, no squirter is going to cover that lean spot.

[MyMopar]

Are you talking about flooring it and it bogs? Maybe you need a stiffer vacuum secondary spring (the more I read your post, the more I think this is your problem), if the secondaries open way too soon, no squirter is going to cover that lean spot.

I know it isn't the secondaries.  I actually will be changing to a lighter spring maybe the yellow short one.  I can feel the secondaries opening and when they hit the car takes off like a rocket.  Right now the purple spring is in there.

So right from a dead idle 780 rpm when I floor it, it dies but then 1.5 seconds later it screams back to life.
I did move the accel. pump cam to the number 2 position and I don't notice any improvement.  I have some parts left from the Holley trick kit, but squirters are not any of them.

[MEK-Dangerfield]

No help Mike here.. 

 Is this bog apparent even when you are driving the car easily?

What the guy at the speed shop was saying is true. You have a certain amount of fuel in the accelerator pump. A larger squirter will allow it to come out quicker. So you have more fuel initially, but hopefully the secondaries kick in before you hit another bog because the accelerator pump went dry. With the size of squirters you are talking about, you should be useing a 50CC accelerator pump instead of the 30CC pump.

  Mike

[ntstlgl1970]

"I can feel the secondaries opening and when they hit the car takes off like a rocket". 

Almost sounds like you are too rich/too much shooter 

[MEK-Dangerfield]

"I can feel the secondaries opening and when they hit the car takes off like a rocket". 

Almost sounds like you are too rich/too much shooter 

A bog is either too much air, or too much fuel... we'll get to the bottom of this yet. 


  Mike

[MyMopar]

"I can feel the secondaries opening and when they hit the car takes off like a rocket". 

Almost sounds like you are too rich/too much shooter 

The secondaries are opening up around 3800rpm, so the secondaries have nothing to do with this problem.  According to Holey I shouldn't feel the secondaries opening, it should just be one smooth transition, which it is not.  The car goes good, and as the rpm's climb the car keeps on going good, but once I get to 3800 it almost feels like a shot of nitrous, the car is gone.  I can feel when the secondaries are opening and they are opening too late. 
I did put the black spring in (the heaviest) to confirm the secondaries not being the problem.  The bog stays the same ruling the secondaries out.

And again just going by the info, Holley said I shouldn't have to worry about the accelerator pump being only 30cc with a 45 nozzle.  Who knows, the guy I am in contact with could be a complete idiot steering me in tthe wrong direction.  Perhaps his goal is to get me to buy a bigger carb in the end

Anyway, I hear what you are all saying and it is some good info.  Smaller nozzle allows for a longer duration shot.  Larger nozzle dumps it more or less at once and if the accelerator pump isn't large enough no nozzle will do me any good. 

Lastly, the car does run real good.  Just off idle is a problem, cruising is cool, but when I stomp on it, it will bog out and then go.  Also revving in neutral the motor hesitates a bit from idle, but if I rev it a few times it is good.  Also if I manipulate the accelerator pump lever by hand while revving the motor, I get no bog or hesitation.  This is what led me to believe I need a bigger squirter, as I shot more fuel in by hand and the bogs/hesitations went away.

[ntstlgl1970]

"The secondaries are opening up around 3800rpm, so the secondaries have nothing to do with this problem".

Ok so that part is out, can you share more about your combo? What cam, what is your ignition timing at base and total, what converter (if it's an automatic) what gears, what primary jets, what power valve and so on... w CP "generally unless the cam has massive duration something in the 35-37 is all you should need "

[kudakidd]

the squirters you have now are waay too big. Put in a 'pink' accelerator pump cam (#1 position) and go back down to a #31 (.031) nozzle or shooter. It should come off idle much more smoothly

[MyMopar]

the squirters you have now are waay too big. Put in a 'pink' accelerator pump cam (#1 position) and go back down to a #31 (.031) nozzle or shooter. It should come off idle much more smoothly

I was thinking of doing something similar.

First I want to thank those that stuck it out here.  I want to say that I WAS WRONG.  I put the #45 nozzle in and the problem is still there.  Here are the exact specs of the carb.:
Holley 870 .40 squirter, primary jet #78    secondary jet #82  vac. spring is now brown.  Timing is 14* / 34* total with all in at 3800 rpm.  ntstlgl1970 is right the secondaries are opening too soon, according to Holley the feeling of the secondaries kicking in is actually a flat spot and the engine is trying to catch up.  I put in a heavier spring but that isn't solving the off idle problem, just taking care of the acceleration after the fact.

My plan is to get a #35 squirter and see what happens.  If the bog is better, I will see what changing the pump cam can do.  After that I will go down on jet sizes, probably by 2 to a #76/#80 as the plugs are still black.  Thanks for the input, I should have known better.   

[MyMopar]

Well I can't get any size squirter other than a #31 today.  I'm going to get it and change the pump cam to one that has a full duration.  I want to get this done today as it is suppose to rain tomorrow and then for the next 5 days after that, so tonight is the last time I'll have a chance to play around with it.   

[ntstlgl1970]

Hope you get it done, let us know what happens...