Re: [alfa] SPICA air box/ Leave well enough alone

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

Hi Andy:

Just a guess, but I'd say that ping (preignition) has been there all along, 
masked by the roar of the K&N's.  I have measured an air temp at the 
throttles that is at least 50F cooler (on a 90F Florida summer day) with 
the Spica airbox in place, as opposed to the K&N's or no air filters.  This 
was independently verified by Jim Steck, with his additional comments to me 
that the Spica airbox actually runs at a slight positive pressure, due to 
the tuned resonance of the intake runners.

I'd also question the use of 87 octane, but I'm no expert.  The way my '74 
Spica Spider is tuned, it only runs on 93, with gross reductions of 
ignition advance needed to run on even 89.  Preignition can also vary with 
compression and mixture, along with ignition timing, but again, that's all 
experiential and not the result of proper research.

I'd keep the Spica box, opt for some better gas, and re-tune the fuel and 
ignition systems if needed.  YMMV.  I've got a paperweight on my desk that 
used to be a 1750 piston, until it had a hole blown in its crown by 
prolonged preignition and lean mixture, way back in '79.

Regards,

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


At 01:08 PM 7/19/2004, you wrote:

> Date: Mon, 19 Jul 2004 10:01:25 -0500
> From: "Andy Menapace" <Andy.Menapace@domain.elided>
> Subject: [alfa] SPICA air box/ Leave well enough alone
>
> Hey Y'all,
>
> The Spider is fantastic!  All I need to do now is enjoy it as long as I
> can before something goes wrong.... but wait I could add a sump guard!
> Oh yeah, I could take those K&N filters off and put the stock air box
> back on!  I hear they work better anyway!  Then the voice of reason
> says, "Leave well enough alone".  What the hell does he know!
>
> Well, the sump guard sits so low that I bottom out everywhere and I
> cringe at every hill and dip I see!  It's coming off!  And the SPICA air
> box is causing a bad ping!  Well, I assume that is the problem.  And so
> my post:  Could the SPICA air box cause a ping due to the restriction of
> air when compared to K&N air filters?  Can I tune the ping out (ignition
> timing)? Should I?  I was running on 87 Octane with no problems using
> the K&Ns.  Unless convinced otherwise, I'll switch back to the K&N
> setup.
>
> Andy Menapace
> 79 Spider
> Brandon, MS
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