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Re: GEEZ!, Equal cars and Drivers

To: bshort@AFSinc.com, geez@autox.team.net
Subject: Re: GEEZ!, Equal cars and Drivers
From: Todd Green <tag@cs.utah.edu>
Date: Mon, 08 May 2000 09:04:22 -0600
Hey Bryon (and all)

>I would like to make this run the topic of an article in
>NAP.  I'd like to address some of your questions there, as
>well as a few others.

You have my most welcome permission and *many* thanks for the run
analysis!

>Don't worry, Todd, you'll look like the great driver that you are when
>I'm done!

Good yes, great....maybe in a couple of years if I can keep
progressing, but I thank you for the compliment :)

I'll add in my recollections from the run.  Hopefully my thought
processes will be of help to other drivers.  (And I freely admit I'm
horrible about taking (even constructive) criticism, so if I seem a bit
defensive in places, my apologies.)

>The dip in the lateral chart at 11.4 is caused mostly by
>over braking at 10.6.  This results in the small foot fake
>at 11.2.

Bingo.  Traditionally as I go into my later runs and carry more speed, I
forget to move my braking point earlier to compensate for the speed, and
overcook the corner.  So rather than overcooking the difficult corners,
I mentally tried to brake a bit early.  Clearly I was too early here.
Also by this time in the event, I knew that I wasn't going to catch Bob,
but if I just put in solid runs, 2nd place would be mine.  (I was
currently in 3rd due to cone damage, but had 2nd by ~.5 on scratch.)  So
I was shooting for 9.8/10ths to make sure I didn't cone, yet put in the
times that I needed to have an M3 1-2 finish ;)

>These are very minor, but look at 17.3, 22.0, and 29.9. 
>These last two are gas foot fakes, which are even more
>costly to your time.  All ding both smoothness and
>aggressiveness.

I was having a really hard time putting down the power and was getting
quite a bit of wheel spin on the big left-hand arc.  (I had set my
shocks rebound to be much softer after the morning runs which helped
quite a bit, but not enough.  (Of course the softer springs I ordered
weeks before the event are still on intergalactic backorder.)  Anyway,
the lifts are from me trying to restore traction in the rear.  This is
where I think GH's excellent observation about a different line comes
into play.  You'll notice that I'm still pulling 'big' lat G's at 22.0
(1.10 G's).  I'll bet Bob had the car much straighter at this point in
time and was able to use more of the car's traction for acceleration.
(On this particular run I understeered at 17.4 and wasn't able to take
that turn as tightly as I had wanted, and thus struggled to straighten
the car for the whole return trip until ~23.4)

>Another little curiosity is the extra hand movement at
>24.8.  Since I wasn't there I don't know if the course
>required you to turn around a cone there, or if a better

That was a three cone slalom, that generally could have been taken
(almost) straight.  If I remember correctly I was a little out of shape
coming into it and had to make a small correction to catch the car to
straighten it out for the braking zone after the slalom.

>And the biggest loss in Usage score on the entire run is
>also interesting.  It's the 1-2 shift at 2.6.  We all tend
>to ignore the importance of shifting, and how much that
>coasting while the clutch is in costs us.  Not that Todd's
>0.7 second shift is all that bad, but once you start driving
>at this level, every possible tenth gain matters.

This was actually conscious.  Most of my shifts are a wee-bit quicker,
however the shifting point came right when we had to make a right hand
turn.  I found that I had to slow slightly to make the turn (in order to
set up well for the next turn leading onto one of the longest
"straights" on the course.)  Since I couldn't be on the gas going into
the turn, I didn't really worry about the power shift, trying to focus
more on setting up for the next turn.  I did consider short shifting
even earlier, but I was still busy trying to control wheel spin from the
start etc.  This probably would have been a better solution towards the
end of the event when the surface was finally rubbered in and the loose
grit was finally swept away, as the first turn probably could have taken
more throttle.

On a side note, I've always measured "shifting time" from the point when
the acceleration starts to drop (i.e. off the gas) until the
accel curve's slope becomes positive (i.e. on the gas) no?  The .7 that
you have noted seems to be from when the accel starts to dip, until when
it is maxed again.  If I understand this correctly, the .7 would
represent the total accel time lost due to shifting, but not the
physical time it actually took to shift, no?

>It's GREAT to see this kind of discussion on the GEEZ list! 

Agreed!  As usual, thanks for the great input and support of GEEZ!

Todd

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