Re: Fast 164L (and then some)

["David R Johnson" <johnsnd@xxxxxxxxxxx>]

On Feb 15,  7:31pm, Rich Wagner wrote:

> Dave, please don't take this as a flame.  I've just noted a few things that
> I'd like to discuss.  Let me know if my tone isn't appropriate.
>
> Power required is proportional to velocity cubed.  Doubling your speed
> requires eight times the power.  So, if your car can reach 155 MPH on 275
> HP, it would top out at 182 MPH on 450 HP.  That would be it's absolute
> terminal speed.  It's real terminal speed would depend upon gearing.

No problem with your tone Rich.  The error in my WAG formula explains why the
numbers I got seemed inflated.  When I entered 700 HP for the more extreme Z28
I mentioned, I calculated nearly 250 mph - clearly rediculous.  Your correction
gives a more realistic 212 mph.  That car BTW has been geared <up>
substantially (final drive of 2.73 vs. 3.43 stock) in order to be able to reach
its theoretical terminal velocity in 5th gear.

> As you'll see in my following post, the 164 base and L models are actually
> geared perfectly for reaching their terminal speeds.  The S model is in
> fact geared short, and will hit the rev limiter before reaching it's
> terminal speed.  Effectively, it has too much torque for its gearing.

Interesting.  I think in fact we are comparing apples to oranges because the
164 which was on the dyno was modified to raise the rev limiter and of course
was running in the absence of aerodynamic drag.  However, it still would not
surprise me if the 164 could beat many muscle cars in terms of top speed,
although of course it would probably loose a drag race, even if not be as much
as the muscle car driver would expect.  The other question which comes to mind
is why the "muscle-heads" would not have realised the effect of changing gear
ratios on their top speed! :).

Dave J.
1982 GTV6, and other machinery.

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