~ so how come those cars get by without an air filter? How come little bits
~ of sand and grit and such don't get sucked in and gouge the heck out of the
~ cylander walls, rings, valves, seats, guides etc???
They do. In fact, it's even worse in cars for which the intakes are
inside an engine compartment; what happens there is that little bits
of rubber from modern race tires get wrapped around bits of grit and
sand, and the resulting compound makes an almost perfect grinding
paste when heated up inside an engine.
In the old days (and probably some new days, too), the car builders
often decided that the minute increase in speed that running unfiltered
gave was worth the cost of an extra ring/valve job between races. Once
again: Speed costs money, how fast can you afford to go?
~ How come all the rest
~ of us use air filters and these cars don't? Yeah, that's it, HOW COME?
Because we don't have millions of dollars from rich sponsors
that allow us to pay crewmembers to rebuild the motors between
events. (At least *I* don't. If anyone on the list does, please
send some to...)
~ It's like what the Moss MG catalog says about velocity stacks, "Guaranteed
~ to make your car *look* 5 mph faster!"
A properly designed velocity stack really works, especially on SU
carbs which are sensitive to the 90-degree bend that air has to
make at the mouth of the carb. The trick is to mount it inside a
good, free-flowing air filter. The factory does this, BTW, on
'62-'74 MGBs: note that there's a little aluminium plate that
fits on the front of the carbs, with rounded corners at the
intake. If you use those with a flat sheet of metal (such as
the top of a pair of stock air filters that have been neatly sawn
around the edges), you can pick up a few cubic feet per minute
over even a bare SU carb with no filter at all, *and* save your
motor from internally grinding itself to death.
--Scott
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