overhere

iTrader: (2)

im having a hell of a time getting my car not to stumble going WOT. i do have a blowthru set up, buy im not even getting in to boost so im pretty sure thats not having alot of an effect on it.

right now i have

mains 73/ 71
squirters 37/45
orange pump cam on primary
pink cam on secondary

ive dropped the secondary mains to 68 no help, ive had the rear squirter from 31-45 no real difference with a bunch of different cams.

if im driving pretty slow and just touch the gas a little i can watch the wideband go slightly lean and there is a small hesitation. it clears up and pulls pretty good drive on just the primary's. if i try to go WOT at any time the car stumbles bad. from a stop it will kill the wideband is off the meter lean when this happens but not sure if its a missfire from rich or actually a lean condition. ive tried all kinds of combination's of squirts and cams. nothing seems to help.

burgers

iTrader: (77)

This is what we have been running on non blow thru 6.0's with 317's and stock cam with 750 dbl pumper.

Front 76-78 with power valve 5.5
Rear 83-85 with power valve blocked

squarters 32 or 33 front
31 rear

What size pumps do you have in the front and rear 30cc or 50?

overhere

iTrader: (2)

my 6.0l is cam only. plus the turbo. ha

i have 30cc front and rear.

your are running alot more primary jet then me. i had the car running great when i had my procharger on it. then i was only running 73 front and 71 rear.

i have my front power valve blocked and the rear is a boost referenced one so thats not helping me at this point.

hifi875

iTrader: (2)

try a 50cc that fixed my stumble w/my 5.3 and a host of others recomended this. that is 50cc for the front

overhere

iTrader: (2)

what cam & squirter you running?

was that a tip in stumble or going WOT?

3pedals

iTrader: (3)

rear power valve is boost referenced ? what is the PV rated at? if it is too low of spec it will be too lean as you get into the secondarys. I'd have an 8.5 to start out.
I dont understand why you'd have the front blocked and the rear referenced, I'd change it around and have the front referenced and the rear blocked, and add 10 jet sizes to the rear.

ZONES89RS

iTrader: (25)

Seems a bigger front squirter might help, i am going to try one soon and see if it helps my stumble issue, if i roll into it at low revs it is fine, but a straight WOT stab and it stumbles then screams into the revs.

overhere

iTrader: (2)

im running a turbo so my PV's work a little different they bring more fuel with boost.

i bumped up the front squirter from a 37 to a 45 it seemed to help a little bit. but still a little hesitation. but if i hit the secondary's it still stumbles and if i stay in it it will die.

ZONES89RS

iTrader: (25)

Dying seems to be not enough fuel, what are the squirters in the rear doing? Have you looked into the carb to see?

overhere

iTrader: (2)

i have not looked into the carb, my hat makes it not possible unless i try doing it at idle just to see if its working.

one thing i did try was hold the prime button down on my meth/water injection and that didn't help either. im so lost efi? ha! i might try a 47 squirter in the rear(biggest i have) and maybe i should put a blue cam in? to really try to get some fuel in it.

3pedals

iTrader: (3)

I did see that you are blow through turbo'd. I still think that the rear PV should be plugged and jetted up 10 sizes. the PV doesnt care if there is a turbo on the car, all it knows is that whenever the vacuum in the manifold is below the rating on it, it will open and allow fuel to flow through the PVCR(power valve channel restrictions), in most cases the pvcr's add aprox 8-10 jet sizes worth of fuel, some carbs less additional fuel. In your turbo app. it would be better for you to just jet the secondarys up 10 and eliminate the PV to ease tuning. the PV would better suit you on the primary so you could acheive a bit of part throttle fuel efficiency - but thats another tuning situation. I beleive the wideband is accurate, you are seeing a very lean situation when the secondarys open, which is why it dies if you stay in it. you have nothing to loose, try it. You have tryed the shooters/cams allready, and as you have found out, they only effect the fuel curve durring thottle position changes - you need more fuel in the main circuit . Go up in jet(primary and secondary) until the wideband starts giving you understandable numbers - then you can use it to get it exactly where you want it.
goodluck
Barrett

sic7camaro

iTrader: (21)

should be power valve thats why when u jetted up it help.common problem with carbs,when running cam low vacum.u gotta match pv to vacum

overhere

iTrader: (2)

ok im going to call rodger at c&s again and see if i can just put a normal PV (vacuum sensitive) in the front of the carb. other wise i will jet the front up a bunch and see if it helps. it idles at 15" where should i start for a pv if i can run one? also how should i just my pvcrs? i have 4 behind the pv that i can jet from .046 to .093

kmracer

iTrader: (1)

www.turbomustangs.com

they'll help out alot.

3pedals

iTrader: (3)

DONT go up in jet on the front!!!!!!! you say it only gives lean reading`s on the wideband, and dies, when you get into the secondary`s, so jet up the SECONDARYS. leave the pvcrs alone for now.
If the rear PV is a special one that only opens under pressure(never seen that, but its possible i guess) then you still need to jet the secondarys up 10 sizes to get that half of the carb close to where it should be, and under boost it will open and add additional fuel.
15"of vacuum at idle, I would put a 8.5"in the front, leave the primary jet alone.

overhere

iTrader: (2)

i talked to rodger again today. and i bumped up my fuel pressure to 6psi. (had a fuel pressure problem with the procharger and never bumped it back up) also raised my front float level a little so it slightly dripping out. then i adjust the rear alot higher. set high as i could then put the plug back in then bumped it up more. was suppose to go untill fuel came out into the carb. then back off 1/2 turn so i might try going a little more. after this i went out and in 1st gear and go WOT it doesn't stumble. it dosn't have the power the D1SC did on the line but im not sure if that is the turbo or if i could get it a little better. but if i put it in 3rd at idle/stop and go WOT it stumbles. its not as bad as it was but it is still there. i tried to kill it by doing this and it wouldn't so it has gotten better.

and yes my PV's are special just for boosted applications. i asked him about the standard PV's and i cant run them because of the modifications done to the carb to make it a blowthru.

after reading your post i think i am going to try upping the secondarys some and see if it helps it a little more? i could always pull fuel out of the pvcr's.