[alfa] Re: Re: Quadra flow and horsepower

["Dean W. Cains" <dwc@xxxxxx>]

Hi Group:

I absolutely have to agree with Jim, and I've collected the data.  Last 
Summer I measured intake temps on both Tim Lentz's and my '74 Spider's, 
comparing the Spica air cleaner and the Shankle.  The readings were taken 
on a day with 90 degree ambient temp, with the temp probe inserted in the 
#3 intake runner on the manifold.  With the Spica box installed, the intake 
temp only measured 95+ degrees when stopped at a traffic light.  Otherwise, 
it was always within several degrees above ambient.  With the Shankle, even 
at speed, intake temps measured anywhere from 145 to 170+ degrees.

Aside from the temp issues, I'd have to guess that the design of the Spica 
box has other benefits, too.  For one, there is likely a beneficial 
resonance that occurs within the box, that helps to fill the cylinder whose 
valve has just opened, because of the back-pressure created by the cylinder 
whose valve has just closed.  Further, the longer intake runners my result 
in more torque at rpm's that are more useful for street driving.  Of 
course, similar results should apply to cars with carbs, comparing the 
original air cleaner to some of the aftermarket alternatives.

I also couldn't live with the increased noise of the Shankle system, which 
droned loudly at highway speeds and hissed even louder under acceleration, 
but that's more a matter of personal taste, I suppose.

Regards,

Dean
Lutz, FL
'74 & '87 Spider Veloce's


At 04:24 PM 10/9/2003, you wrote:

> Date: Thu, 9 Oct 2003 12:09:29 -0400
> From: "Jim Steck" <4sfed@domain.elided>
> Subject: [alfa] Re: Quadra flow and horsepower
>
> I don't doubt John Norman's dyno study . . . but it doesn't represent
> the real operating conditions.  To compensate for day-to-day
> weather conditions, dyno results are generally corrected to reflect
> expected results at standard temperature and pressure.  That's
> 70 degrees F and 29.92 in Hg . . . so the Quadra flo is better at
> high RPM when inlet temperatures are the same.
>
> In the car, the Spica airbox is easily 50 degrees cooler than the
> Quadra flo . . . a cold air box in Colaizzi's Giulietta vintage racer
> dropped the inlet air temperature by 70 degrees.  Fifty degrees will
> make a _5%_ difference in Hp.  If we accept Stevan's premise that
> the Quadra flo only helps with high output (airflow) engines, we
> have to conclude that on a stock engine, the Spica airbox is
> 5% better because of the difference in temperature.  The truth
> probably lies somewhere in between with the Spica still ahead.
>
> - -- -- --
> Jim Steck, AutoComponenti
> 8906 Darke County Line
> Brookville, OH 45309
> ph: (937) 884-5142
> fax: (937) 884-5144
> email: jim@domain.elided
> web:  www.autocomponenti.com
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