Shifting during Auto-X (was: BMW vs. Porsche Auto-X)

[Ron Katona <ron3b@xxxxxxxx>]

Sam Choi wrote:
> Just a comment about auto-x from a relative newbie . . .
> 
> It seemed a lot of the older porsches had a huge problem with the auto-x
> I attended because it seemed like they could never stay in a gear.

You'll notice that a lot of muscle cars have this same "problem."
 
> It's not like I ripped up the track, but I never felt like I needed
> to shift in my E36 M3.  I got into 2nd as soon as I got out of the
> blocks and just stayed there all the way through.

Kudos.
 
> There was one section where I might conceivably have downshifted to
> 1st, but even there the car seemed to have enough pull at about 2000
> rpms that my mediocre shifting probably would have slowed more than
> 1st gear would have helped me.

This was probably the most surprising lesson I learned from the McKamey
instructors when I attended their autocross school. The instructors
urged everyone to take this approach. Basically, unless you come to
almost a complete stop, they wanted you to stay in second gear
throughout... raised a lot of eyebrows then and I'm sure it will now.

"But my Trabant has NO low end torque!" Tough, second gear pal. "But my
Testa Rossa will do 75 in 1st! Listen up - 2nd gear! People actually got
pissed (usually 'Vette and Z28 drivers) about not being allowed to use
1st in the tight sections. Guess what - not shifting was faster every
time whether it was an instructor or student driving. The proof was in
the readouts from the segmented timing of the course.

The shifting that felt so good because it increased the available torque
to the rear wheels had several detrimental effects. It jerked the car if
not done perfectly smoothly. It tended to induce power slides in RWD or
plow in FWD. It left the car with no throttle control for the tenths of
a second that it takes to shift. Most of all, it made it hard to apply
smooth throttle inputs because of the short gearing in 1st. Basically,
it made it REALLY hard to be smooooooth; the key to low ETs.

I know what you're thinking out there with your M motors that don't come
on the power band 'till 9.6 billion rpm. And if you've seen my times at
the auto-x you're probably wondering why you need to listen to me
anyway. Well, I'm just passing on advice from national champs, take it
or leave it...

> I had heard the 944s were very good for auto-x, but when I was doing
> the cone work on the track I noticed them constantly shifting . . .
> 1st, turn, 2nd, 3rd, 2nd, slolom, 3rd, 1st, hairpin, 2nd, 3rd, 2nd,
> slolom, etc.

Not knowing how these cars were set up in terms of gearing and how the
course was laid out, I can't say this was wrong. I suspect they were
shifting too much based on what I've seen from the aforementioned
demonstrations by people who are top notch. It's that old "go slow to go
fast" axiom.

One example... the start of the instructional course was straight entry
to a tight 4 cone slalom followed by a tight skidpad 360. I ran the
whole thing in first and had average times. Brian Priebe jumps in my car
(318ti) and gets about 30 feet from the start line and goes to second!
I'm thinkin' he's nuts because the M44 has no torque at the 2500-3000 or
so rpm we we're now pulling. He stays in 2nd throughout the course. His
times through those first two segments (slalom and 360) were about one
full second faster than mine. Being in 2nd through the slalom and turn
allowed him to work the line without worrying about excessive wheelspin
or losing the rear. Yes, he was cutting a tighter line as well, but this
was also a function of not having the car being upset by the herky-jerky
application of torque while in 1st gear. Smoooooth it was!

Soon after everybody used first for the launch only and left the car in
2nd for the rest of the course. Times dropped all day long through those
segments.

"OK, mister smarty pants, why not run the whole damn course in 5th gear,
THAT would make you smooth now wouldn't it??" Well, there's obviously a
logical limit to this argument. The key is not just to try to be in the
tallest gear that you can muster and not absolutely bog the motor in the
tightest section, but to eliminate unnecessary shifts. That 100 foot
burst into third rather than letting the car coast in 2nd may cost you
more in terms of smoothness than you gain from the few mph increase in
speed before the braking zone.

Sure, there are those 90 mph auto-x courses that demand a shift. There
are those that start with a 500 foot straight where you can get third
gear. But short of that or a hairpin so tight that you've dropped down
to near idle rpms, you're better off never shifting at all after the
first 1-2 upshift. 
- -- 
Ron Katona "One World, one shift"

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