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holley carb tuning ? #1625274
05/26/14 08:40 PM
05/26/14 08:40 PM
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Kalispell Mt.
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HotRodDave Offline OP
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We have a 650 holley double pumper 4777 on a 392 SB stroker ported magnum heads 10.2 compresison 222@.050 110 LSA 575 lift ported RPM airgap intake TTI headers, 2.5 dual exhaust 2.94 gears, mallolry ign. 32 degrees total in around 2000 RPM 18* idle around 850 idle, electric fuel pump 904 with low 1st and 2nd gears, stock high stall converter. It runs awesome, pulls like a monster at every RPM from idle to 6500 as long as you don't flat foot it. If you go from idle or even a little off idle to WOT it almost dies for a couple seconds then annihilates the tires almost instantly. It is in a 68 cuda. If you ease into it just a little there is no hesitation, only if you just flat stomp it.

Do I need 50CC acc pump? Mabey two 50cc pumps? Different pump cams? They are adjusted to start squirting instantly with any throttle movement. I have the float level set to just barely dribble out the level hole with the engine off and the pump on.


I am not causing global warming, I am just trying to hold off a impending Ice Age!



Re: holley carb tuning ? [Re: HotRodDave] #1625275
05/26/14 08:49 PM
05/26/14 08:49 PM
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY Offline
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I'd increase the squirters first

Re: holley carb tuning ? [Re: HotRodDave] #1625276
05/26/14 08:55 PM
05/26/14 08:55 PM
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IL, Aurora
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ademon Offline
master
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Even mild mopars I have had need big squirters, maybe try mid 30's. And a higher vacuum rated power valve.
Don't think the 50cc will help

Re: holley carb tuning ? [Re: ademon] #1625277
05/26/14 09:13 PM
05/26/14 09:13 PM
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ajcasini Offline
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Put a set of 032 squirters in it. Adjust the pump arms so you have around 040-050 play before the pumps squirt. This is about the size of 2 playing cards. This will help to keep fuel available to the pumps. If you are braking up to 12-1500 then flat foot it you have already pushed some fuel out of the pumps.

Re: holley carb tuning ? [Re: ademon] #1625278
05/26/14 09:27 PM
05/26/14 09:27 PM
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Kalispell Mt.
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HotRodDave Offline OP
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It has 37 front and rear squirters in it.


I am not causing global warming, I am just trying to hold off a impending Ice Age!



Re: holley carb tuning ? [Re: HotRodDave] #1625279
05/26/14 09:37 PM
05/26/14 09:37 PM
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY Offline
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Quote:

It has 37 front and rear squirters in it.




You could be going dog rich with 37s... drop them to
about 32-34

Re: holley carb tuning ? [Re: MR_P_BODY] #1625280
05/26/14 09:40 PM
05/26/14 09:40 PM
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IL, Aurora
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ademon Offline
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Is the air horn milled?

Re: holley carb tuning ? [Re: ademon] #1625281
05/26/14 09:45 PM
05/26/14 09:45 PM
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Kalispell Mt.
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HotRodDave Offline OP
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air horn still there, I will see if I have some smaller squirters


I am not causing global warming, I am just trying to hold off a impending Ice Age!



Re: holley carb tuning ? [Re: HotRodDave] #1625282
05/26/14 10:49 PM
05/26/14 10:49 PM
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Kalispell Mt.
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HotRodDave Offline OP
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I put a 31 in the front and that seems to help, the only other smaller one I have is a 28, should I throw that in the secondary?


I am not causing global warming, I am just trying to hold off a impending Ice Age!



Re: holley carb tuning ? [Re: HotRodDave] #1625283
05/26/14 10:51 PM
05/26/14 10:51 PM
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Posts: 5,894
Florida
Locomotion Offline
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What pump cams do you have in it and what # hole? You appear to not be getting enough initial squirt volume. 50cc pumps will simply prolong the length of the squirt with the same squirter size.

Try pink cam with the screw through the #2 hole in the arm and #3 hole in the nylon(?) cam I the primaries.

Secondaries the same, or green #2.

It takes some tinkering, but I try to get both squirt durations to finish squirting at the same time for drag racing only applications. You might need a slightly smaller cam. There are charts out there and pink & green are 2 of the biggest 30cc cams. #1 holes usually squirt less volume than #2/3.

Adjust for instant squirt with any throttle movement but keep about .015" additional compression at the pump housing lever when throttle is fully open.

I'll suggest going the other way on the squirters. If it still hesitates, consider .040"/.042"/.045".

I would suggest a power valve rated about 1.5 - 2 numbers above idle vacuum IN GEAR.

My theory is that your converter and gear isn't allowing the engine to rev up as fast as needed. The load requires more initial fuel until the rpm's and vacuum are high enough to get the main jets to take over.

(I normally use .037 - .040" squirters with pump cams as described with a low gear 904, 4.86 gears and a converter that flashes to 5100 - 5400 before starting to lock up.)

Can't guarantee it, but it's worth a try.

If, by chance, it goes when you flatfoot it, hesitates, then goes again, you may need bigger pump cams to extend the duration.

Re: holley carb tuning ? [Re: Locomotion] #1625284
05/26/14 11:14 PM
05/26/14 11:14 PM
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Kalispell Mt.
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HotRodDave Offline OP
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Figured I could throw it in faster than I could get a guess. Now he is gonna have to get some tires that can hook, maybe some SS springs and spring clamps and slant 6 t bars cause it's blowing the tires away no matter how fast I stomp it


I am not causing global warming, I am just trying to hold off a impending Ice Age!



Re: holley carb tuning ? [Re: HotRodDave] #1625285
05/26/14 11:18 PM
05/26/14 11:18 PM
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY Offline
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Quote:

I put a 31 in the front and that seems to help, the only other smaller one I have is a 28, should I throw that in the secondary?




Try it for a test but it might be too small but you
should see a change

Re: holley carb tuning ? [Re: HotRodDave] #1625286
05/27/14 11:32 AM
05/27/14 11:32 AM
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Benton, IL.
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DaveRS23 Offline
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Try a quicker opening power valve first, like a 9.5. Then start the accelerator pump tuning.


Master, again and still
Re: holley carb tuning ? [Re: DaveRS23] #1625287
05/27/14 12:04 PM
05/27/14 12:04 PM
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Quicktree Offline
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Re: holley carb tuning ? [Re: Locomotion] #1625288
05/27/14 12:47 PM
05/27/14 12:47 PM
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Posts: 19,317
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Thumperdart Offline
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Quote:

What pump cams do you have in it and what # hole? You appear to not be getting enough initial squirt volume. 50cc pumps will simply prolong the length of the squirt with the same squirter size.

Try pink cam with the screw through the #2 hole in the arm and #3 hole in the nylon(?) cam I the primaries.

Secondaries the same, or green #2.

It takes some tinkering, but I try to get both squirt durations to finish squirting at the same time for drag racing only applications. You might need a slightly smaller cam. There are charts out there and pink & green are 2 of the biggest 30cc cams. #1 holes usually squirt less volume than #2/3.

Adjust for instant squirt with any throttle movement but keep about .015" additional compression at the pump housing lever when throttle is fully open.

I'll suggest going the other way on the squirters. If it still hesitates, consider .040"/.042"/.045".

I would suggest a power valve rated about 1.5 - 2 numbers above idle vacuum IN GEAR.

My theory is that your converter and gear isn't allowing the engine to rev up as fast as needed. The load requires more initial fuel until the rpm's and vacuum are high enough to get the main jets to take over.

(I normally use .037 - .040" squirters with pump cams as described with a low gear 904, 4.86 gears and a converter that flashes to 5100 - 5400 before starting to lock up.)

Can't guarantee it, but it's worth a try.

If, by chance, it goes when you flatfoot it, hesitates, then goes again, you may need bigger pump cams to extend the duration.




Some good ideas except for the p/v at idle deal. That`s old skool bs and even if it`s open at idle, it doesn`t come into play unless your way in the transfer slot on to the enrichment circuit. The proper way to tune p/v is to cruise the car and get a vacuum reading then go from there. Some guys go further for economy and hit a grade measure the reading and p/v it accordingly. I have bet. 9-10 "`s at a steady state cruise and put a 5.5 in and what a difference compared to the "old" idle theory. It get`s way deeper than this but that`s my position on this fwiw.........


72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
Re: holley carb tuning ? [Re: Thumperdart] #1625289
05/27/14 01:02 PM
05/27/14 01:02 PM
Joined: Jan 2003
Posts: 32,394
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Quicktree Offline
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Quote:

Quote:

What pump cams do you have in it and what # hole? You appear to not be getting enough initial squirt volume. 50cc pumps will simply prolong the length of the squirt with the same squirter size.

Try pink cam with the screw through the #2 hole in the arm and #3 hole in the nylon(?) cam I the primaries.

Secondaries the same, or green #2.

It takes some tinkering, but I try to get both squirt durations to finish squirting at the same time for drag racing only applications. You might need a slightly smaller cam. There are charts out there and pink & green are 2 of the biggest 30cc cams. #1 holes usually squirt less volume than #2/3.

Adjust for instant squirt with any throttle movement but keep about .015" additional compression at the pump housing lever when throttle is fully open.

I'll suggest going the other way on the squirters. If it still hesitates, consider .040"/.042"/.045".

I would suggest a power valve rated about 1.5 - 2 numbers above idle vacuum IN GEAR.

My theory is that your converter and gear isn't allowing the engine to rev up as fast as needed. The load requires more initial fuel until the rpm's and vacuum are high enough to get the main jets to take over.

(I normally use .037 - .040" squirters with pump cams as described with a low gear 904, 4.86 gears and a converter that flashes to 5100 - 5400 before starting to lock up.)

Can't guarantee it, but it's worth a try.

If, by chance, it goes when you flatfoot it, hesitates, then goes again, you may need bigger pump cams to extend the duration.




Some good ideas except for the p/v at idle deal. That`s old skool bs and even if it`s open at idle, it doesn`t come into play unless your way in the transfer slot on to the enrichment circuit. The proper way to tune p/v is to cruise the car and get a vacuum reading then go from there. Some guys go further for economy and hit a grade measure the reading and p/v it accordingly. I have bet. 9-10 "`s at a steady state cruise and put a 5.5 in and what a difference compared to the "old" idle theory. It get`s way deeper than this but that`s my position on this fwiw.........


thats the way you would do it for a street car but not drag only

Re: holley carb tuning ? [Re: Quicktree] #1625290
05/27/14 01:18 PM
05/27/14 01:18 PM
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Thumperdart Offline
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What? Not sure I understand your point Quick..........


72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
Re: holley carb tuning ? [Re: Thumperdart] #1625291
05/27/14 01:41 PM
05/27/14 01:41 PM
Joined: Jun 2003
Posts: 9,225
Charleston
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sixpackgut Offline
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Charleston
blue cams and 32 squirters. I also wont run a PV lower than a 6.5. I want it to open as soon as I mash the go pedal

Last edited by sixpackgut; 05/27/14 01:45 PM.

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Re: holley carb tuning ? [Re: sixpackgut] #1625292
05/27/14 02:26 PM
05/27/14 02:26 PM
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Kalispell Mt.
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HotRodDave Offline OP
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Thanks guys! It is already running 10 times better, I am gonna have to get it to hook up now before I can do any more tuning on pump shots

I also remember why I hate holleys, got to pull the fuel bowls and dump gas all over the engine to check PV and jet sizes


I am not causing global warming, I am just trying to hold off a impending Ice Age!



Re: holley carb tuning ? [Re: HotRodDave] #1625293
05/27/14 03:29 PM
05/27/14 03:29 PM
Joined: Dec 2006
Posts: 1,178
Indy
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Indy
Quote:

.....

I also remember why I hate holleys, got to pull the fuel bowls and dump gas all over the engine to check PV and jet sizes




I use an empty play doh cup, pull one of the lower bowl screws...drains in seconds...no mess.


67 Barracuda street car, 408, e85, 1.38 60', 6.44 @105.9 in the 1/8 mile, 10.19 @130.5 in the 1/4...so far....
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