Adam -
Anyone who is driving 35 MPH won't win at Sebring ot Le Mans! I think
that's the point...
Cheers,
Alan
On 1/19/12, A <adamnolde@yahoo.com> wrote:
> Thanks for replying Alan.
>
> I'm not normally contrarian, but...
>
> I've been studying heavily on the subject(s). Going so far as to dig up and
> read a 1969 NASA study on the subject of perpendicular orifices to fluid
> dynamics.
>
> I have come to some indisputable data points that suggest either further
> computation or/and modeling should be applied to determine the true
> goings-on.
>
> I have always planned on having the protruding CAB through the grill. Not
> just for the ram air effect, but because it looks great too. I've even seen
> a guy taking it in through the left head lamp orifice using a bell mouth,
> which must give even greater effect.
>
> In short I agree with the conventional wisdom EXCEPT at mid to low speeds.
> At say 4-5.5k rpm the air being drawn by the engine through the 4" CAB has a
> velocity around 30-45mph. Thus, no ram air effect until over say 40mph and
> that's before considering the possible shortcut-comings of the box itself.
>
> Thus, what's really troubling me is the questions of turbidity and scavenge
> inside the box. The '69 NASA study proved that the following items had
> significant effects on perpendicular ducted flow:
>
> 1 a flat vs round opposite wall to the orifice
> 2 a flat vs radius orifice edge
> 3 parallel inline orifices
> 4 orifice distance in relation to feeder duct termination points and
> opposing wall.
>
> Basically the OEM air box incorporates the most negative aspects of the NASA
> study. If you look at the b
>
> Adam Nolde
> Whitney Metals, LLC
> 203-606-4675
>
>
> On Jan 19, 2012, at 1:55, Alan Seigrist <healey.nut@gmail.com> wrote:
>
>> Adam -
>>
>> Any flow inefficiencies in the cold air box design are overcome by the
>> positive air differential created by having the front end of the CAB
>> paper tube face directly forward into the oncoming air stream when
>> driving at high speed. In fact, the speed ram effect will provide
>> more HP improvement than having cold dense air going into the carbs.
>>
>> If you look at pictures of some 100S/4 racers in the day, many of the
>> cars have run the paper air tube past the grill or even through the
>> shroud into the oncoming air stream to maximize positive pressure in
>> the CAB.
>>
>> It's about the air pressure, not the air temperature. Basically it's
>> a cheap supercharger when you are driving fast.
>>
>> Alan
>>
>> On 1/14/12, Adam Nolde <adamnolde@yahoo.com> 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
>>>
>>> [demime 1.01d removed an attachment of type image/jpeg which had a name
>>> of
>>> 100M.jpg]
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>>
>> --
>> Sent from my mobile device
>
--
Sent from my mobile device
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