Re: [alfa] RE: ES30/SZ stats

[Richard Welty <rwelty@xxxxxxxxxxxxxxx>]

On Thu, 27 May 2004 15:26:35 -0400 reeve_john@domain.elided wrote:

> I still have yet to find a reliable source for the SZ information regarding
> skid-pad tests.  I doubt Car&Driver, Road&Track or any of them have an
> article on the SZ because of the low production and lack of cars in the US.
> I am surprised that I can't find anything from Cars or TopGear.  There is an
> Italian magazine " Quatrroruote" or something similar to that name that
> claims 1.4 G's.  I'd love to see the raw data behind these to get things set
> straight.  Doesn't 1.4G's seem like an ungodly figure for a car built in
> 1991?  The Enzo only pulls something like 1.05 or so, the Viper GTS/R? Pulls
> what 1.25G?  I really want to believe it, but it's really hard to believe
> that if they had a car in 1991 that could pull 1.4G that the latest and
> greatest are only pulling a range of 1.0-1.25.  Seriously, why abandon a
> suspension setup that would handle so well?

i already alluded to this in my response to John Hertzman's post, but
i think i'll amplify it here.

skidpad numbers are of extremely limited value. they are basically
measuring the traction of the tires against a particular asphalt or
concrete skidpad in steady state.

they are sensitve to entirely too many influences, including the choice
of tire, the weather (temp and humidity both), the condition of the
pavement, and the type of pavement. they do not measure such
things as the behavior of the cars suspension in transitional states,
such as entering a corner, leaving a corner, or transitioning from
a left hander to a right hander.

if you were to run on fresh asphalt, and then run on a WWII vintage
concrete airstrip, same car, you would get radically different
lateral G figures. this is because the high aggregate concrete used
50+ years ago for airfield construction offers so much more grip than
modern asphalt that quite frankly, unless you've experienced it you
really won't believe it (50s vintage SAC airbases use roughly the
same stuff, and that's the sort of venue the SCCA has traditionally
used for their national autocross championship. staggering grip,
but it really eats up the tires.)

so take lateral G figures with a grain of salt. they're only really
comparable if the cars were all run on the same skidpad at about
the same time on the same day.

richard
-- 
Richard Welty                                         rwelty@domain.elided
Averill Park Networking                                         518-573-7592
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