Secondary well size

[novadude]

Were all Q-jet Secondary wells the same size, or did the secondary well diameter vary by application?  Roe talks about making these larger in his book, and that got me wondering whether GM ever "tuned" the size for specific applications?

[Cliff Ruggles]

That's one of those modifications that is very difficult to measure your success with.  I see no restriction between the secondary disks and the supply passages up to the nozzles, but like everything else with this hobby could it hurt to "message" them a bit so the fuel flows smoother....most likely it couldn't hurt anything......Cliff

[novadude]

I wasn't referring to that passage, I was referring more to the size of the well ABOVE that passage.  Larger volume gives more of an initial shot as you are holding more fuel on the "backside" of the jet that controls steady state flow. 

[Cliff Ruggles]

Considering we have Q-jets in use on FAST Class cars (and other racing applications) running into the 9's in the 1/4 mile WITHOUT touching any of that, I'd say they are adequate as-is for most of the applications they will be used on.......Cliff