cups v. coilovers? Now weight & 4spd. vs. 5 spd.

[rapieper@yahoo.com (Ron Pieper)]

--- Dan Bubb <jdbubb@ix.netcom.com> wrote:
> I haven't really known how to respond to this what with the trend to
> more
> and more gears in the latest high performance cars.
> One suggestion is to lay out a graph of torque or HP vs. MPH
> available for
> all the gears and then overlay the two graphs. This should give you a
> good
> idea of which combination will give better acceleration in the speed
> range
> of interest and if there are going to be huge holes in acceleration
> if the
> gear spacing is too wide.

The 0-60 figures I'm predicting based on Jason Camissa's spreadsheet
all point, naturally, to the 4K setup: 3.94 F/D, 3.45, 2.12, 1.44 (1st
- 3rd are the only ones of interest) being the fastest.  I can build
that into a 4-speed I'm sure, but highway driveability becomes a big
issue.  

> As far as the difference in handling and braking as a result of
> saving 20lb.....?

IMO the advantage of a 20lb savings would be significant for autocross
purposes only.  There are many factors in this decision including my
own automotive future.

> One other thought, (since you must have available any f/d you care to
> pick from) is why use a 3.89? The 3.89 gear set has 93 teeth vs. 84 >
 teeth for the 3.94 or 3.67 gear sets. Bigger teeth are stronger!

Interestingly, the 2H I just built for Tobias (via Eric S) had a 3.94:1
made of a 63R + 16P = 79 total.  The choice of which ~3.9 R&P combo
would be an issue if rings and pinions tended to fail, but IMO they're
pretty robust.  But to dive in anyway, are few big teeth really
stronger? or more small ones (less polar moment on each tooth, less
time engaged, although less material supporting it)?  Since my
knowledge of mechanics and gears is waaaay old, I'll defer to one of
the ME's on the list...(is that you?).  

Practical observation: why didn't VW continue the use of the 63/16 2H
3.94 combination above if it was stronger?  Fewer teeth = less gear
grinding therefore cheaper to make.  

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