Quote:
Originally Posted by Akimbeau
Runs fine except I'm having an issue with the engine stalling on hard braking. I'm suspecting fuel slosh is killing the engine.
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-You can test this hypothesis by going out with an observer, and replicating the condition while they watch for black smoke... smoke puffs mean your assumption is correct, no smoke puffs, mean you are going the wrong direction, and you might be going too lean on the primaries...
Either way, lots of great advice above- vent whistles and extended jets on the primaries should probably both be considered "mandatory equipment" on a holley that is going to be tossed around hard on the track.
If you have a mechanical fuel pump, then one other thing to check is your low-load fuel pressure (rev the engine hard, let the throttle snap shut, and watch the fuel pressure gauge as the RPM's drop.)
fuel sloshing in the bowls during decal (or hard cornering) can slosh around the outer edge of the float, allowing just enough space beneath the float to allow the supply needle to crack open, and if you have a higher (or variable) pressure fuel pump, then it can push past the needle.... Once this extra gas is in the bowl, it has to go somewhere...
Do you have a fuel pressure regulator? From my own experience, Holleys seemed to like no more than about 7 psi maximum for severe off road or road racing/autocross uses. Now, there might be a more current point of view on this (the last time I track raced a car with a carb was in the early-mid 1990's
); but I'll throw it out there for conversation's sake...
Using a good high volume (but low pressure) fuel pump, along with a good high quality pressure regulator, should help with stabilizing your fuel delivery into the bowls during hard braking and severe off-camber maneuvers.
Lastly, (and again, this is just a personal opinion)- If you know any hard-core drag racers who try to give you any advice on how to set up your fuel system for track use, then walk away man, walk away...
In a drag racer's mind, a carb only has two settings: idle, and WIDE-OPEN
Constant fuel delivery, at a consistent pressure, should be your goal.