Hey guys - I had my Challenger to the track for the 1st time at the Mopar Nationals. I only made 2 passes because I was having some carb hesitation. It was mainly breaking up in 1st after I stomped it off the lane, but then it cleared up in 2nd and 3rd. Needless to say my 60ft was less than spectacular (1.68)and the ET wasn't much better (went 11.50 at 118). And it was just too darn hot and humid to care. I just parked it and took in the "show" instead.

So now I'm getting ready to go back to the track locally and hopefully make some clean passes in some nicer weather.

One thing I did try was going from a 33 squirter to a 37. My 2nd pass after the switch was more of the same almost identically. The carb is a quickfuel 950 annular and it does have jet extensions and a 4.5 power valve. Is it possible I need a bigger (than 37) squirter, or perhaps a smaller than 33? The jetting is left as it was on the engine dyno, so I figured it should at least be in the ballpark. Any other suggestions/ideas???

Thanks!

Sounds like the front float level could be to high. If its high when you launch it will come out of the vent tube and splash the carb. Check that. You want to were it is just dribbling out when you shake the car.

50 or 30cc pump?

Could be the primary pump cam is used up before the mains "kick in" or maybe the secondary shot is too late and the "fat" is buried inthe mains...tough to tell without being there but it's something to maybe consider in terms of tuning.

Could be the float level as Duck said but I'll bet you didn't go to the line without checking that first. You'd probably know if you emptied the bowl and it wouldn't have run what it did.

heavy car big motor/auto/street gears usually wants a lot of shot, I always go with 50's and tune the shooter small rather than run a 30 and "shoot up"

I always run with a tube across bowl vents , eliminates any spill overs.

I don't know a lot about your combination,but heavy cars without a lot of gear and convertor,seem to need more pump shot than others.At least in my experience.My wife's old street/strip Duster used 42's front and rear at 3370 pounds and 3.91 gears.This was with with a small block,11:90 car.
Basically,I would have someone watch/video the car and see if it puffs a little black on the initial hit or not,and then you know witch way to go.

Make sure the front float is not too low also. And the idle mixture is not too lean.

my car wants a TON of squirter!!!! 30 degrees if timing under zero boost. I still havent got the hesitation out completly, but im working on it.

I started with 52 squirters and i am all the way up to 78 using a drill bit. I now have to try tightening the accelerator pump arm springs and bending the arm to take up the slop that will cause. If thats not enough I have to open up the squirter circuit to about 89 also with a drill bit

Thanks for all the input. I think I have a pair of 42's and 47's I can try. I'm sure the floats are good and the carb is otherwise in good tune. Btw, I called quickfuel today and they thought the squirter may possibly be too big. Said that sometimes if it squirts too much fuel it can break up or hesitate when it tries to burn/clear up all the fuel. Hmmm, would have never thought that. I have 28's I can try too. I just need to find a low traffic area to do some testing! I want to have the hesitation fixed before going to the track so i can just focus on tuning for power and ET.

Btw Josh, I'm pretty sure you are making a good 500 or so more hp than me, but hope you work your stumble out too

Tony,
Do you leave off idle or do you bring up the rpms before launch?
If you bring the rpms up, then try the #2 pump cam hole on the primary side. This will delay the activation of the squirt and leave you more later on in the throttle. Then remember to put it back on #1 when you drive home.

Can ya post some pics of your challenger??

pump cam!!

heres another pic of the Challenger...

Go with the 'pink' pump cam (no. 1 position) and a #31 pump shooter or squirter.

If you set your pump arm clearance at your idle rpms, and then you leave at around 2k rpms, then you have used up some of your accel pumps fuel capacity.

If you test this, remember to reset your pump arm clearance after rotating the cam to position #2.

What color pump cam are you running on the primary?

Honestly, im not 100% sure, but I think its the pink one. Whatever comes standard on a Quickfuel 950 annular. I'll check when I get home later.

Use the 50cc pumps, bro and reduce the nozzle size, I don't use a 30cc for anything larger than a 37. a 28 or 31 with a 50 will give you a better overall shot than a 37 with a 30