Okay... Heres the deal, I have a SBC 305 .030 over low compression, World Torquer 305 heads, Weiand 144 Supercharger with a 625CFM Carter AFB, Crower supercharger hyd. cam designed for up to 10lbs boost, Crane roller rockers with guide plates, fresh double roller timing chain, MSD 6AL, MSD Boost Timing Master, HEI w/ Vac advance...
I have two main issues:
1)My truck is a pain to start on cold mornings...when its cold sometimes it backfires through the carb, doesn't do it warm. Tried messing with the electric choke, its still the same. The distributor was dropped in correctly set in the No. 1 Position with the No.1 position at TDC, so that tells me its not my rotor phasing and I double checked the timing set to make sure its not a tooth off. Timing is set at 8 BTDC. I recently purchased an Innovate LM-1 Wideband Air fuel meter and the backfire is not caused by a lean condition. The distributor has some miles on it, so I ordered a new one which will be here in a couple of days... Im thinking the distributors mileage might be a contributing factor. What can be some other possible causes to the backfire through the carb?
2) I haven't been able to find anything online pertaining to running vacuum advance with a blower. I had it hooked up as usual to a full vacuum port on the carb, but when the motor sees boost, it seems like the motor is working against itself and the top end suffers. I figured out that I would have to run the vac advance off the manifold because the carb is constantly seeing a vacuum signal so it constantly advances the timing when hooked to the carb. When I have it hooked on the manifold, its even harder to start but seems to run better when decelerating and as a plus,the top end is brutal, however the bottom end is really weak. Im thinking the bottom end is weak because the vac advance is seeing boost and not advancing, so I thought about getting a lockout plate for the Vac Advance...But that in itself presents more shorterm problems being, how can I limit my centrifugal advance so I can increase my initial timing to make up for the lack of timing w/o the vac advance? I guess Im just really interested in what others with a similar set up are running for a distributor or what they did to fix these issues.
I eventually plan on getting a Holley TBI projection setup and using that to dictate my timing and fuel issues, but until then I would like to get this set up dialed.
Any ideas or help would be appreciated.
I have two main issues:
1)My truck is a pain to start on cold mornings...when its cold sometimes it backfires through the carb, doesn't do it warm. Tried messing with the electric choke, its still the same. The distributor was dropped in correctly set in the No. 1 Position with the No.1 position at TDC, so that tells me its not my rotor phasing and I double checked the timing set to make sure its not a tooth off. Timing is set at 8 BTDC. I recently purchased an Innovate LM-1 Wideband Air fuel meter and the backfire is not caused by a lean condition. The distributor has some miles on it, so I ordered a new one which will be here in a couple of days... Im thinking the distributors mileage might be a contributing factor. What can be some other possible causes to the backfire through the carb?
2) I haven't been able to find anything online pertaining to running vacuum advance with a blower. I had it hooked up as usual to a full vacuum port on the carb, but when the motor sees boost, it seems like the motor is working against itself and the top end suffers. I figured out that I would have to run the vac advance off the manifold because the carb is constantly seeing a vacuum signal so it constantly advances the timing when hooked to the carb. When I have it hooked on the manifold, its even harder to start but seems to run better when decelerating and as a plus,the top end is brutal, however the bottom end is really weak. Im thinking the bottom end is weak because the vac advance is seeing boost and not advancing, so I thought about getting a lockout plate for the Vac Advance...But that in itself presents more shorterm problems being, how can I limit my centrifugal advance so I can increase my initial timing to make up for the lack of timing w/o the vac advance? I guess Im just really interested in what others with a similar set up are running for a distributor or what they did to fix these issues.
I eventually plan on getting a Holley TBI projection setup and using that to dictate my timing and fuel issues, but until then I would like to get this set up dialed.
Any ideas or help would be appreciated.