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tosoutherncars
Jedi Knight
Offline
Hi all,
As commonly reported, I have a significant stumble on acceleration with my DGV. (see one possible explanation, below.)
Could anyone running this setup post their timing settings? My (california version) '78 has a book setting of something like 2ATDC with the Solex and all the air pump garbage, but I'm wondering whether with the DGV it shouldn't be more like 15-20 BTDC. (Haven't advanced it that far yet to try it out.)
-Duncan
NOTE regarding the use of DGV on the MGB by Doug Jackson of British Automotive (www.mgbmga.com):
"While a very reliable carb/manifold set up, a disadvantage with this carburetor is the fact that the primary venturi accounts for two thirds of the throttle open position (no CFM* figures are given for this position) with the secondary venturi becoming active in the final one third of throttle movement. This carburetor requires excessive initial ignition timing advance to avoid stumble on take off (if the ignition timing was retarded, we would have to open the primary throttle plate to obtain the necessary idle; this would expose the progression bleed holes which in turn would require that the idle mixture be leaned to compensate for this richer mixture condition. The end result being very little progressive richening upon further throttle opening, especially at snap throttle and so the stumble)."
As commonly reported, I have a significant stumble on acceleration with my DGV. (see one possible explanation, below.)
Could anyone running this setup post their timing settings? My (california version) '78 has a book setting of something like 2ATDC with the Solex and all the air pump garbage, but I'm wondering whether with the DGV it shouldn't be more like 15-20 BTDC. (Haven't advanced it that far yet to try it out.)
-Duncan
NOTE regarding the use of DGV on the MGB by Doug Jackson of British Automotive (www.mgbmga.com):
"While a very reliable carb/manifold set up, a disadvantage with this carburetor is the fact that the primary venturi accounts for two thirds of the throttle open position (no CFM* figures are given for this position) with the secondary venturi becoming active in the final one third of throttle movement. This carburetor requires excessive initial ignition timing advance to avoid stumble on take off (if the ignition timing was retarded, we would have to open the primary throttle plate to obtain the necessary idle; this would expose the progression bleed holes which in turn would require that the idle mixture be leaned to compensate for this richer mixture condition. The end result being very little progressive richening upon further throttle opening, especially at snap throttle and so the stumble)."
