Terminal velocity

[JHertzman@xxxxxxx]

In AD7-468 Rich Wagner took off and ran with the numbers I got from the 164
Product Bulletin, and asked for more- 

"I don't have any data on the 164's gearbox.  If John or anyone else has any
efficiency data on it, please send it on -",
and 
"And this is where John comes back into play.  John has a set of "power
available" curves for these two engines.  The data I've generated here
establishes a set of "power required" curves.  John can now plot, on the same
engine curves, the power required for each of these cars to achieve a given
speed.  In other words, I've defined a set of "gearbox input" curves.  For
example, for the base and L models, gearbox input at 4,683 RPM is 102 HP.
Input at 4,878 RPM is 116 HP.  For the S model, input at 5,211 RPM is 102 HP.
Input at 5,428 RPM is 116 HP.  As long as the power available curve is above
the power required curve, the car can reach that speed.  Where these two
curves cross, is the actual terminal speed of the car, given the gearing.
John, let us know where those points fall."

Whoops. Right now I don't have the Product Bulletin at hand; Colin Verrilli
has one for the 1987 original European announcement and one from '94 for the
USA introduction of the LS and Q, but does not have the one for the '91 USA
introduction, which is what mine is; he wants to cull some info from it for
his 164 Home Page, so I mailed it off this afternoon, together with a
suggestion that he might forward to Rich the relevant data from the earlier
and later Product Bulletins. But I don't believe mine had anything on gearbox
power losses.

I should stress that I am NOT an engineer, or anything close to it. At the
moment, just a spectator enjoying the dust. When the bulletin finds its way
back to me I will have another look. 

Meanwhile, also in 468, Vlad wrote 
"I do believe that the factory advertised speed for the EU 164 - -  is 142.92
MPH.
"As opposed to US, in EU one gets the factory figure as far as max speed and
acceleration and consumption within the owner's manual.
"Speed tests are quite popular there too and usually one sees a significant
deviation between the indication and real speed as far as maximum. Some even
believe this to be a factory designed feature in 90% of the cars for
advertising purposes."

In AD7-466 Jon Herbert had written "Posted (magazine) UK top speeds were 143
for the 12V V6 and 150 for the 12V Cloverleaf." (typo? 12 v or 24V?)  Jon's
143 is pretty close to Vlad's 142.92. Coincidence?

Still earlier in AD7-464 Steve An cast doubt on the precision of the
speedometers: "Or may be the Italian miglia is just *shorter*. I'd be
impressed if the speedo is within 10% accuracy at that end of the dial", which
goes along with Vlad's "significant deviation between the indication and real
speed" 

Conventional wisdom in the magazines I was reading in the 50's was that
optimism was designed in, as an Italian driver would be pleased if his car's
speedometer showed more than the reported timed speed, and upset if it showed
less- 

Coincidentally, 143 + 10% = 157.3, which is about where this started, with
'Nardo's 158 - 

Enjoy yours, 

John H.

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