when i first got my 700DP it came with the pink cam and the black cam...and i had a horrible off idle bog... stall the car in a second even in neutral. I should mention my initial timing is at 24 degrees with 32 all in by 2800RPMS
so i started "playing with cams" just going by what the profiles looked like... as i was looking for more fuel just off idle i picked the blue cam as it seemed to have the most initial lift... helped alittle... then i put 37 discharge nozzles on the primarys/secondarys... not to much improvement still bogs just off idle enough that it makes the first 1/4 throttle useless at first and the bog intensifies with more throttle

i have consequently tried upping my PV i went to a 8.5 and then to a 9.5 from the stock 6.5... while i had 10in of vacuum at idle... NO help what so ever...

then in my infinite wisdom... i bought a book "super tuning and modifying holley carbs"

mainly because i noticed a couple of charts on the pump cams

most of all i noticed that the PINK cam delivers the most fuel for the 30cc pump over 10 full strokes

but the green cam in the 2 position has the most lift of any 30cc cam and the most initial...

i have played with both in every position imaginable...

so i guess what i am asking with this novel is

am i being a retard and over looking something(probably) or do i need to upgrade to the 50cc pump

 

I noticed you have a T5, are you trying to launch it hard out of the hole? OR are you trying to lug the motor at lower rpms ? Lugging it with a big cam won't work as it'll want more rpms initially. I'm running pink cams front and rear with 31/35 squirters with 4.5pv If I mash it off idle I have a bog, but if I bring it up to 2500 rpm like I do at the track then launch I won't have a bog, usually the blue cam in the #2 slot works well for most sbc engines. 37 squirters are rather large in fact I would imagine 31/33 to be a more perfect match.

 

no RPM doesnt seem to matter at all i could be at 4k or in neutral and if i dont get into the secondarys it bogs very bad... even if i do open the secondarys it still bogs

also the car is fine with slight throttle openings just anything more than say 20-30 degrees it bogs progressively worse the bigger the angle

i should mention that after the engine gets going it isnt smooth not miss fire but most probably overly rich

i will try going down 4 siezes on the primarys/secondarys on friday as once the carb is out of the transition it is pretty rich... although i suspect the secondary transition also to be pretty rich.... think i get a dark haze as i come into the secondarys hard to tell in the mirror

 

drive around on the primaries alone and pull a fresh set of plugs and see what they look like. This is where a wideband 02 REALLY helps a lot. In fact I'm debating buying a dual wideband 02 setup and charging people to tune them as a mobile service. Your squirters are huge, try dropping down to 31 or so and if that doesn't clean it up then move around jet sizes, but usually out of the box is close, no more than 4-6 sizes off typically.

 

oh id pay you for it... took it to be dyno "tuned" put it on the rollers the "operator" jumped in made one pull said "yup your good 300hpthatwillbe80dollars"... but you didnt do anything... "oh i can tell just by how it smells it is pretty damn close"...yeah not counting that serious bog at 2000rpms...

i kinda had the feeling that if it wasnt a blown mustang they didnt give a crap... lots of photos of mustangs in the shop...

 

I wouldn't have left without a printout and a wideband sheet which shows A/F ratio during the pull. On average any car we hit the dyno with, takes 10-15 pulls for us to monkey around with everything at least, sometimes we come back another day after making more changes at home. Wideband setups are dropping in price, I believe the summit brand one is $240 and seems to be nice, we use the innovative with the 2 1/16" guage and I like that one.

 

Is this on your "vortec 350"? If so, I'd change everything back to stock on the carb and go from there. Sounds like you have a bunch of things changed. Gotta make one adjustment at a time. On my 400 with vortec heads, I'm running the stock jets, cams and 31/31 squirters. It runs good and the plugs are just right *shrug*.

 

okay maybe tell me what you think i should have done...

first i started off with the pink cam... bogged then went through just about every cam... not much improvement stuck with the green

then i went to 31 squirters...front and rear... it helped a bit more than the cams... then i went to 37 no change really over the 31s... again tried out the blue the green and the pink in both positions... blue seemed to be the worst pink and green were hard to tell appart... stuck with the green do to the increased lift at smaller throttle openings... The bog remained... what else could i do to get more fuel on tip in....AH PVs went in 2 step increments...8.5 it was different now it wouldnt bog unless i opened the throttle maybe 15-20 degrees quickly... thinking i found my problem and going against common sense telling me i have 10in at idle why would i need a 10.5 PV and i should have listened... 10.5 was a bad idea no improvement and my eyes where burning...

my next attempt is going to be jets but that is a shot in the dark at this point

btw maybe i am going about testing this wrong...

my method: car up to temp...25mph roll in second a mash of the gas through second and third/ second pass is a 25MPH roll in second rolling into the throttle hard...not so much a mash but a quick smooth depresion

 

Do you have jet extensions?

 

why would i need jet extensions to cure a tip in bog?

 

richen the idle mixture screws 1/8 turn each and see if that clears up your issue.

 

will give it a try tomorrow afternoon... any recommendations on header mufflers. the police have been complaining about the cherrybombs...

 

Can't a hard launch cause starvation in the rear bowl?

 

Are you sure that the accelerator pump arm is adjusted correctly? You should see fuel come out of the squirters immediately when you bump the throttle. If not, and you're sure the linkage is set, the check ball in your pump diaphram housing might not be working.

That book you bought is very good, read the section on accelerator pumps and make sure yours is set to spec.

One more thing, what are you running for jets in the primaries?

 

yes a hard launch could cause fuel starvation... except i am keeping the car on the primarys only...momentum is sorta working in my favor

right now i am 69/78

my pump arm is adjusted properly i tightend it untill i had just taken up the slack... surprisingly it left me with about the right clearance to not bottom out the pump...

and the fuel is instant i ment even a degree or 2 and there is fuel coming out of the squirters...

 

how'd richening the mixture screws work out?

 

the mixture screws seem to help but also shoot my idle up to about 1000rpms...to get the idle down i would have to close the throttle blades or close down the mixture screws either would seem to put me almost back where i started
right now i am only out a little less than 1 turn...that is including the extra 1/8 turn
so i figured it might be easyer to fight with my idle mixture.. took the carb off
and opened both blades to expose .015 of the transfer slot... was at .010 closed down the mixture screws to 1/2 turn fired the engine idle is at 2200
so i started closing down the idle mixture screws.. no real effect on the idle maybe 2100 with both of them fully closed... figuring i have the blades way to far open i closed both of them to just barely see the shadow of the transfer slot and gave it another go... forgot to open the idle screws this time but still idled at 1700...

my next plan will be to remove the rocker arms and carb and seal up the intake see if it holds vacuum... i have tried the propane, carb cleaner, ether...

i just dont get it really i know i am rich all over christ i am probably dumping enough fuel to run methanol

i mean i am not running a big plenum... just a dual plane/high rise air gap...
one thing i have been wondering is could i simply be to rich and the airgap isnt hot enough to atomize the fuel?

 

you want to adjust the idle speed screw as you richen the mixture screws. Drop it back down a bit, fyi mine idles at 1100 or so out of gear and 850-900 in gear, so an idle that high for a bigger cam won't be an issue. If rpms picked up when you richened it then you need to drop the speed down again and road test. Just trying to see if your initial tip in could be cleared up with a slightly richer idle. Is this a 4 corner idle system or 2 corner?

 

it is a 2 corner idle... and i have richened it up another 1/8 and my idle speed didnt change and the bog is almost gone... now it is a little GO, little bog, big go.. i am going to continue opening them until it goes away... then start trying cams again i guess unless you think i should do something else.... i should also mention that the engine seems to get really noisy in the valve train under this type of load/engine sounds a little rough... when the secondarys open it is more smooth

 

Reminds me of what I went through with my carb. I have a 700 dp, and I went through a lot of trouble tuning it.
It's good now. I'm running a decent size cam also. I have a 6.5" power valve, 74 primary jets, 82 secondary, and I have the pink cam in the first hole on the front and rear. I have 31 squirters front and rear, and a 50cc pump. It was an eBay special and I got screwed big time, so I had to learn how to fix it myself. Maybe that will help.

 

so richening the mixture screws worked out real well no more bog... my idle is sitting at 800 rock solid... to do that however required almost completely closing the secondarys as there seemed to be a point where my idle was either 2000 or 500rpms with both open to .015 of the transfer slot... if i tried closing both secondary and primary blades evenly it would sit at 2000 until finally it would just drop right to 500 same goes with the primarys... tried just closing them down to bring the idle down and it fell to 500...

right now i have the primarys open about .020 and the secondarys open just enough to keep the blades off the bore... any attemp to change it seems to shoot me back into the 2000 rpm range...

so i guess my next attempt will be to adjust them evenly while completely ignoring the amount of transfer slot exposed and just keep it under .010 for each? seems logical

 

both blades are typically only open if you are trying to idle above 1000 rpms, i'm pretty sure I already mentioned that. If you want to idle below 1000 the primaries alone is usually sufficient depending on air bleeds. Glad to see the slight richening cleaned out the bog....glad I helped to fix something.

 

AH that was what i didnt understand.... i was under the impression that they were always supposed to be equal

i went back down to the 31 primary /secondary squirters still no bog... but still running the green cam in the #2 hole seemed like it wasnt happy with the blue

i think my "valve train" noise is do to a lean condition on the primaries... think i am going to try some 73s just to see if the sound goes away... as it used to happen off idle and carry into the upper rpms under load wont make the noise if there isnt a load now it is gone off idle only to return by 2500

 

If you have 4-corner idle, they should be equal. If you have 2-corner idle, you should adjust the primaries so the transition slots are exposed properly, then use the secondaries to get proper idle speed. A pain to get right the first time, but pretty simple after that.