Quote:
Originally Posted by art leong
It's not about stock. But I remember the old Rat Roaster manifolds for the hemis. The instructions from Chrysler to epoxy popsicle sticks in the manifold to stop fuel puddling.
Fuel injection solves problems like those.
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Actually, big cam and cylinder head racing engines still have this problem, even with efi. ECR engines (sprint cup) went through a ton on development work when NASCAR switched to EFI - they lost a little power at first but with more work to cam/head/intake they eventually recovered the power. Of note though, they tested with a manifold incorporating a window in an intake runner and were amazed to see the fuel from the injector flowing BACKWARDS up the runner toward the plenum at certain speeds. The observation was backed up by readings from individual cylinder O2 sensors showing large amounts of fuel swapping from runner to runner necessitating a large amount of individual cylinder fuel corrections to make them run properly.
As for low speed tuning, I've tuned numerous racing engines with low vacuum and they CAN be tuned to run just fine (not loading up) in speed/density mode.