I recall reading a magazine article--probably one of the club mags--about a guy
that raced a 100M. He got better
performance with a couple velocity stacks on the carbs. Dunno if he proved it
with a dyno or track times, but he was
convinced. Also, the box is mildly pressurized by the air under the valve
cover that vents into the box (at least
ours is).
OTOH, the box looks pretty cool.
Bob
On 1/13/2012 8:56 AM, Adam Nolde wrote:
> All,
>
> Has anyone conducted or read the results of anyone else's research
> regarding the fluid dynamics of the 100M cold air box?
>
> I'm no engineer, but a
> keen mind looking at the 1956 cold air box design can quickly work out the
> fact that it may have some ill effects on air delivery at higher RPM's. I'm
> specifically concerned about the size and depth of the box causing delivery
> issues for both, but more likely the rear carb.
>
>
> I've done some very crude
> calculations and crude bench testing just as a base to understand the flow
> involved and the possible scale. I've learned my engine can suck as much as
> 263CFM at 100% VE, but obviously it should be less, so I use this as a max.
> That puts the velocity at each carb above 85mph static, but much faster during
> intake stroke. The velocity at the air box inlet is above 65mph static. The
> box depth in front of each carb opening is only 1.75". I can see potential
> for not only vacuum creation and inefficient atmospheric replacement, but add
> to that the inefficient dynamics of the flat and non radiused orifices.
> I've also discovered a fair amount of scavenging occurs between carb orifices
> in-spite of the wide and presumably ample open ended box.
>
> Anyway, I've
> theorized that the probable advantage of thermodynamic control supplied by the
> air box, may be negated by its inefficient design and inability to supply
> sufficient volume.
>
> If anyone has done or knows of some CFD (computational
> flow dymanic) modeling and, better yet, 3d image modeling. Please let me know
> where to access the information.
>
> Thank you and kind regards,
>
> adam nolde
> 203-606-4675
>
>
>
--
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Bob Spidell San Jose, CA bspidell at comcast.net
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