>
>
>>Daniel asks:
>>> At Shasta at the 510 show I noticed that a lot of the 510 guys had
>>> a strange airfilter set up. It look like they had a sealed airbox over the
>>> carbs with a large diameter hose ~2" coming off the forward part of it and
>>> going forward to infront of the rad. ending in a little K&N cone air
filter.
>
>John replied:
>>A couple of advantages:
>>1) COOL AIR. The engine is sucking cool outside air instead of the hot
>> stuff from inside the engine compartment. Denser air = more power
>>2) Ram air. At speed, the forward motion of the car is pressurizing the
>> incoming air stream. No cost turbo :-)
>
>
>Hi guys...
>
>this has come up from time to time on the Z car lists as well.
>
>The ram air effect is almost zero - some high falutin engineer type
>calculated
>something obscene like 250 mph needed for a 1 psi boost. Plus, even if there
>was boost, it would foul up the SUs metering, since it's referenced to air
>pressure.
>
>The cool air effect is right on target, though. However, a couple of
>considerations.... the SU carb is supposedly susceptible to turbulence -
>so it's
>important to retain some type of air-horn by the carb. I took all this
>input in
>stride, and promptly disregarded it, as the pretty K&N filters/housings
>have no
>such provision. I don't notice anything goofy from the lack of air horns,
>but
>then again, I'm pretty goofy to begin with.
>
>I think another benefit of the remote intake setup would be decreased
>noise....
>SUs with open air cleaners are pretty noisy; sealing the box except for the
>externally mounted filter would quiet things down a bit.
I've read considerable discussion of these cool/cold air supplies in a
several places. As was mentioned here, they can create problems if closed
off at the back, since the air column hitting the back of the housing
would tend to "bounce back and disrupt the air over the carb throats.
Suggested solution was to leave the back off the "box" open so there
would not be a reflected "wave". Makes since to me, although I'd suggest
using something like a thin Scotch Brite pad to keep the birds and bees
from getting in the back door.
As Kyle (I think) mentioned the cooler air flowing through from outside
works well. FYI, I just bought a couple of the large (6 by 3.5) K&N
setups from APT in Riverside along with a pair of small (less than 1/2
high) CNC shorty airhorns for the 38mm SU's I putting on one of the
510's. Even taller airhorns of a similar design are available and both
heights should work with the flat K&N bases just fine. You could use also
use these in conjunction with a fabricated cold air box. They're
available for Webers and Solexs, too, AFAIK.
FWIW, Ron
________________
Ronnie Day
rday@airmail.net
Dallas/Ft. Worth
'71 510 2-dr (Prepared class autocrosser)
'73 510 2-dr (Street Toy)
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