FrontEngineDragsters.Org Forum
Technical => Spud Miller's Cave => Topic started by: spookie on September 05, 2022, 08:30:39 AM
-
Have sbc with crower stack injection.I run alcohol fuel.I have had "O" pump checked and is ok. Using .026 nozzle with .054 pill and ran great.Have made changes and now .048 pill is lean [V-P up=faster].Is it time to increase nozzle size,or just change pill Went 5.62,119.71 vp529 Next rd.went 5.60,119.74 vp546. need help on what to do. Thanks!
-
iF DOWN TO 054 PILL i WOULD SAY YOU NEED MAYBE .002 more nozzles. The reason pill so low is pressure needed to get enough fuel thru nozzle.Bigger nozzle will for same fuel less pressure. If me I would go .002 up on nozzles and maybe start with.010 bigger main jat. If you go on spuds site there is tuneup calculator that might give good idea as to how much change one will require of other.
-
That nozzle sounds way too small and with that small of a pill your pump is at max pressure ! An .035 or 37 nozzle might be more tunable for you ! My smallblock is 394 cubes and I use a .037 nozzle with a .088 main . My pump flows around 4.5 Gallons per minute .
-
Agree with Bill on nozzle size.I normLLY RUN .035 TO .037 AVERAGE ON ALL INJECTED MOTORS. I try to keep main jet between 95 and 150 and as I said in first staement that is determined by the nozzle size. If I get to big of jet I just drop nozzles one size which leans motor requiring smaller main. Hopefully explained were can follow what I am saying .I tend to skip a step or two in explanations.
-
you said made changes and now .048 is lean.
What did you change?
-
Thanks for input! Went to .036 nozzle and .064 pill hope to try this set up Sunday. will work on tune-up,but trying to win glory days race at South Mountain Raceway. Rain rain stay away.Will let you know how it works.
-
With .036 Noz & 0.064 MPB you will be 0.009 richer on the MBP than you were with .026 Noz & 0.054 MBP. To put the same amount of fuel to the motor you would need 0.075 MBP. The down side to the .036 Noz will be the drop in fuel pressure.
-
iI agree you will have less pressure and I use to worry about keeping pressure around 150 psi. Found out with injected alky its not huge deal. Have seen really high pressure systems run exactly same as low pressure(below 100 psi).