screw blower problem

took off a roots, went to a screw. BBC with big chief heads. when I stage the car cyl. 1&2 go down to about 200 deg. and do not recover till almost the end of the run. 1/8 mi. any ideas?

 

im constantly fighting #2 and 7 on my chevy. Make sure it's hot when you stage and dump a BUNCH of fuel on the 2 step.

 

we did change the set up and replaced the spool in the bv with the screw type. we have 2 nozzles in the blower and 2 in the back of the hat.

 

screw

The screw piles fuel in the front of the engine and the psi plate and indy big chief manifold don't get along IMO. It's normal to load up with a converter car but if they stay cold way downtrack you have other problems or you're severely rich.

 

Agree with that. It's surprising how much different the front and back nozzles are, like low 40's in the front two (1&2) and 60's in the back (7&8) to get the correct readings. Of course I'm not counting the dribblers. Are you running dribblers or the plate that Mike talked about? If you are, is your launch RPM getting you on the mains or are you below turning the mains on, i.e. is the fuel pressure cracking the main poppet? How are the other cylinders reading?

 

No dribblers and we do have the plate. we have the port poppet set a couple of lbs above launch pressure. other cyl. leave at 800 and get to 1000 to 1050 at end of run. all cyl. are even at end of run. we are dumping fuel with a # 45 jet at 1 sec out and putting it back in at 3 sec out.