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Discussion Starter #1
Currently having trouble getting our drag car off the line. The car is new to us and only completed two meets. Its a 540ci BBC running a 780 DP Holley - 2500RPM Stall - Manual shift T400 - 4.11 9Inch rear. In a Holden One toner!

On our first outing we broke a rocker at the 60ft mark and that was it for the day. It did manage to roll thru for a 13.8 at 97mhr and 1.8 60ft. How ever on our return we did 12.8 at 107mhr, 1.87 60ft - first pass. On the next passes we performed larger burnouts to warm the slicks, however this resulted in an engine that would not idle and stalled or heisitated badly on launch. On our last pass we did no burnout and easied the throttle on for a 13.5 at 107mhr and a 2.2 60ft.

What could it be?
1 We were thinking that the carbi was flooding following the burnout. Its running a holley black mechanical fuel pump unregulated. Should be internally regulated to 8-9psi, this may be too much for the holley needle and seats. Would explain why it runs ruff following the burnout.

2 Could it be the other way and in fact be running lean off idle hence why it stalls of the line. May need to up the shooter size to cover the air hole.

The plugs read well after each run, there is a large amount off black smoke after the engine restarts (after it stalls).

Hope you can understand this, any ideas!!!!

Cheers
PINKO351

2 Could
 

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Pinko351 said:
Currently having trouble getting our drag car off the line. The car is new to us and only completed two meets. Its a 540ci BBC running a 780 DP Holley - 2500RPM Stall - Manual shift T400 - 4.11 9Inch rear. In a Holden One toner!

On our first outing we broke a rocker at the 60ft mark and that was it for the day. It did manage to roll thru for a 13.8 at 97mhr and 1.8 60ft. How ever on our return we did 12.8 at 107mhr, 1.87 60ft - first pass. On the next passes we performed larger burnouts to warm the slicks, however this resulted in an engine that would not idle and stalled or heisitated badly on launch. On our last pass we did no burnout and easied the throttle on for a 13.5 at 107mhr and a 2.2 60ft.

What could it be?
1 We were thinking that the carbi was flooding following the burnout. Its running a holley black mechanical fuel pump unregulated. Should be internally regulated to 8-9psi, this may be too much for the holley needle and seats. Would explain why it runs ruff following the burnout.

2 Could it be the other way and in fact be running lean off idle hence why it stalls of the line. May need to up the shooter size to cover the air hole.

The plugs read well after each run, there is a large amount off black smoke after the engine restarts (after it stalls).

Hope you can understand this, any ideas!!!!

Cheers
PINKO351

2 Could
You need a regulator for fuel pressure, the black smoke tells you its flooding for some reason, I also think the 780 might be too small, 850 or larger maybe might help. Also it depends how you are leaving the line, foot brake, trans brake etc. A bog on sudden flooring the throttle,could be squirters too small.
There are many possibilties. One thing that might help is after the burnout, put it in neutral and give it slight even throttle,12-1500 RPM and let it smooth out, and don't keep womping the throttle, every time you stomp on it raw gas is shot into engine, and it don't help anything. Stage it and then Hammer Time!
 

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Discussion Starter #3
engine stalls of the line

We are in the process of fitting a regulator and jet extensions to the secondaries. We will give it a try as soon as the diff center returns from the shop, it's being fitted with a mini spool.
 
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