Listers,
The memory may be failing and our 20HP increase at 7000 RPM may have been
due to all of the 'technology' in our Hamburger Pan with the side tank
kickouts and the scraper attached to the pan rail. We also ran/tried an
in-pan dry sump with a remote sump tank that took all of the oil and put it
in a tank in the car (Sprint Car technology). We went to the in-pan dry sump
when even the road race wet sump could not keep oil near the pickup and we
had to run an accumulator to maintain oil pressure on slicks with our
Camero.
Regardless, I went looking for my old copy of Smokey Yunicks "Power Secrets"
where he goes into great detail about how managing the oil in the pan was
critical to achieving his high HP numbers at RPM over 6000. I could not find
the damn thing but as I recall the original reason for the deep sump pans
was to move the oil away from the crank assembly and to obtain more oil
volume for the higher volume pumps being used. Further improvements were
made by restricting oil draining down on the crank from the center lifter
gallery by running standoff tubes that permitted venting from the crank case
but forced oil to return to the pan from the front of the block or the rear
only. Smokey did things like build clear pans to 'observe' what was
happening and as I recall he said losses in HP came from 3 sources; 1 the
oil draining down on the crank, 2 oil spraying from the connecting rods
creating a resistant fog/curtain, 3 oil being 'whipped' into a long oil rope
that wound around the crank (much like swirling water in a tall cup it forms
a conical shape). All oil management activities were focused on removing
(shearing) oil from the crank as quickly as possible to minimize the
parasitic losses and diverting oil away from the reciprocating assembly.
Knife edging the crank helps as well but the most effective arrangement was
a scraper with a side tank that permitted oil to be sheared from the
rotating crank and directed down into the pan reservoir and away from the
crank. The actual windage baffle is to prevent Oil from being whipped into
the crank from the air turbulence by acting as a solid barrier.
Modern methods of HP creation have been focusing on running the crankcase at
a vacuum to minimize any wind resistance/turbulence in the crank case. This
is worth about 8 NET HP according to Hot Rod over the power required to run
the vacuum pump.
It may be smoke and mirrors to some but with a relatively tame motor running
too lean with full QUIET exhaust and the plugs we broke it in on we got
336HP at the rear wheel with even more power likely untapped. That gives
around 390 HP @ 13% drivetrain losses for a nothing special 349 CI Engine.
It is the little things that do increase the overall package. With fresh
plugs and wires and 2 jet sizes I expect that 425HP at the crank below
6000RPM is very realistic.
I would be willing to bet that the pan on the Tiger at 6000 is worth around
10 HP but I am not willing to do the swap pan approach on the dyno to prove
whether it is true. I prefer to just make the leap of faith.
For the non-believers I opted for the Snake Oil.
Best Regards,
Tim Ronak
Business Development Manager
Akzo Nobel Coatings
23961 Via El Rocio
Mission Viejo, CA 92691
Off: (949) 305-5393
Fx: (425) 955-6268
Cell: (949) 289-3357
email: timothy.ronak@akzonobel.com
VM: (800) 234-6747 ext. 2257#
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