Ok, one more question on the Holley jetting.
Now I'm just guessing. Maybe the secondary was cracking or flopping open enough to expose the secondary transfer slot?
Of course I can't find any of the screen shots I made of three springs.
I'll have to open up the dyno files and do over.
Until then, here's a couple of overlaying wide open throttle with and without the secondaries.
Main thing to notice.
Engine accelerates pretty darn well on just two barrels of the '750'.
The carb here has a downleg secondaries and annular primaries. I suppose the thinking was the annular booster restrict flow so using downlegs in the secondaries would make up for it. Nice thought but messes up fuel distribution and never would recommend it. Anyway as you can see the primary AFR is pretty flat and the secondary AFR is rich, lean, richer and drifts lean.
Disconnecting the secondary demonstrated that problem was entirely in the secondary side.
Datalogger shows that more clearly.
Bottom scale is time in seconds.
Blue is vacuum. According to the MAP, vacuum came up to 3.5 "Hg at 5700 rpm using just the primary barrels.
Suppose I should mention a little about the engine:
340 with hughes cam 223/230 at 50.
Now I'm just guessing. Maybe the secondary was cracking or flopping open enough to expose the secondary transfer slot?
Of course I can't find any of the screen shots I made of three springs.
I'll have to open up the dyno files and do over.
Until then, here's a couple of overlaying wide open throttle with and without the secondaries.
Main thing to notice.
Engine accelerates pretty darn well on just two barrels of the '750'.
The carb here has a downleg secondaries and annular primaries. I suppose the thinking was the annular booster restrict flow so using downlegs in the secondaries would make up for it. Nice thought but messes up fuel distribution and never would recommend it. Anyway as you can see the primary AFR is pretty flat and the secondary AFR is rich, lean, richer and drifts lean.
Disconnecting the secondary demonstrated that problem was entirely in the secondary side.
Datalogger shows that more clearly.
Bottom scale is time in seconds.
Blue is vacuum. According to the MAP, vacuum came up to 3.5 "Hg at 5700 rpm using just the primary barrels.
Suppose I should mention a little about the engine:
340 with hughes cam 223/230 at 50.