Barrel valve

We are running a 355 ci sml blk,671 on alcohol.cannot get the car to repeat.We start with about 35 degrees timing,lean valve out until the idle comes up,fatten it one flat,let it rock.car runs low 7's.next round change nothing,car won't even get off the line.Barrel valve is way out of adj.yet nothing has moved.Now can't seem to get back that happy med.I have leaned the valve out so far that it tries to cough when you hit it.Fatten one flat ,and it floods at the hit.What am I doing wrong?

 

check to make sure the arm is not slipping on the shaft of the BV. mark it. not tobe rude but why tune by ear? set the BV with a leakdown gauge. stay in the 60-70% range, set the butterflys and lock it. now you shouldnt need to turn the BV more than afew flats to cleanup the idle. you want it FAT. its not a carb on a sreet car. best help i had was written instructions from enderle or check the tech help notes at goodvibes, or if its on this site

 

Make sure your idle check valve is good too!

 

Are the adjusters against the stops with the butterflies closed? If you set the butterflies say at .006 then adj. the barrel valve with a leak down tester with the return ports blocked off and the arms on butterfly shaft and barrel valve are tight with a good return check valve and this happens you need to look somewhere else. It should repete time after time. The only time you would need to readjust the barrel valve opening is to compensate for altitude changes or you just want to try using a fatter or leaner idle at launch.

 

I know/barel valve

Thank you all for the answere's.I didn't want to to get too long winded,but one guy hit it right on the head.I do use a leak down @ 65-70%,Ihave the buterflys set .as i was saying before,when the car came back to the pits barel valve would be showing 40-50%.set it back to 70% and every time you snap the throttle leak down won't return to same setting.I am going to take the valve apart today and check the integrity of the O rings,etc.and I will get back to you guys tonight.I am very excited about this site bacause I love tuning B/A motors,and have helped numorous people run some good numbers.The car I am working on right now is the first one to ever give me this kind of trouble.P.S. I wilalso test the idle check valve.Thanks again guys.Lee