Autocross School, 2006 Grenada, MS

1
Autocross School, 2006Grenada, MS

• By James Lee, Lance Coley, Matthew Anderson,
  Teddy Gibson
• Special thanks to
• Roger H. Johnson and Trey Walker

2
Volunteer Organization

• All events are run by volunteers
• In order to compete, you must work the course
• More co-operation means a smoother running event

3
Working the course

• Obtain work assignments from chief of workers
• Report to work station on time
• Station will have some extra cones, fire
  extinguisher, red flag and radio
• One person holds both the radio and the red flag
• Everyone else picks up downed cones
• Watch cones and not that beautiful Saleen Mustang
  thats driving by
• Face cars at all times never turn your back
• Watch out for other workers
• If there is an emergency on course, show the red
  flag and try to get the driver to stop

4
Working the Course

• Each downed cone is a 2 second penalty which will
  be added to your final time
• Person calls in the cone(s) mentioning
• Station number
• Car and class
• Number of cones

5
Working the Course
NO DNF

• 2006 Solo Rule book 7.9.3
• A DNF, or a time penalty if so specified in the
  supplementary regulations, shall be charged for
  any uncorrected deviation from the course, or for
  unnecessarily delaying the event. A course
  deviation shall not be charged if any part of the
  car hits a marker defining the limits of the
  course. A DNF is charged only if part of the
  course is omitted. In returning to the course
  after an off course excursion, it is acceptable
  to drive a part of the course a second time.

DNF Did not finish
National Solo Rules, 2006 Edition by Sports Car
Club of America, Sports Car Club of America,
Topeka, KS, 2006, p. 45
6
Working the course

• Penalties

• Directional cones do NOT count!!!

National Solo Rules, 2006 Edition by Sports Car
Club of America, Sports Car Club of America,
Topeka, KS, 2006, p. 44
7
Working the Course

• No Penalty

• Directional cones do NOT count!!!

National Solo Rules, 2006 Edition by Sports Car
Club of America, Sports Car Club of America,
Topeka, KS, 2006, p. 44
8
Driver Responsibility

• Make sure car passes tech inspection
• Drive quickly and safely
• Bring out the full potential of the car
• on a given course
• Drive car at the limit
• Choose the optimum racing line
• Analyze course conditions

9
Tech inspection

• Seat belts working
• Roll bar for certain classes
• Removable tops / panels
• Brakes / fluids / pedal
• Battery firmly mounted
• Fluid leaks
• Muffler / exhaust
• Loose items removed from car
• Front suspension / steering
• Throttle return / belts / accessories
• Tires / tread / pressure / treadwear
• Wheels / hubcaps / lugs
• Number / class marked on car
• Helmet

10
Class and Numbers

• 14 SM2

8 in
4 in
1.25 in
0.75 in
National Solo Rules, 2006 Edition by Sports Car
Club of America, Sports Car Club of America,
Topeka, KS, 2006, p. 30
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Class and Numbers
National Solo Rules, 2006 Edition by Sports Car
Club of America, Sports Car Club of America,
Topeka, KS, 2006, p. 226
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Helmet Requirements

• Snell foundation standards
• Current and two immediately preceding standards
  (SA, K, M)
• Current Standard is 2005, so 95 and 2000
  standards are valid
• SFI standards
• 31.1A, 31.2A, 41.1A, 41.2A

National Solo Rules, 2006 Edition by Sports Car
Club of America, Sports Car Club of America,
Topeka, KS, 2006, p. 33
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Helmet Requirements
14
Helmet Requirements
http//www.smf.org http//www.motorsportbayern.de/
verschiedenes/reglement/slalom-tipps-helme.htm
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Tires
Maximum load/pressure
Model
16
Tires

• Uniform Tire Quality Grading
• System (U.T.Q.G.)
• Treadwear
• 100 30,000 miles
• 200 60,000 miles
• gt 140 Street Tire
• lt 140 Open Tire
• Traction (AA, A, B, C)
• Testing on wet surface
• Compound not tread design
• Temperature (A, B, C)
• Ability to dissipate heat
• Based on tires ability to operate at high speed
  w/o failure

http//www.hankooktireusa.com
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Tire Pressures
Tread Wear Indicators (TWI)
Tread wear

• If suspension settings cannot be changed or if
  suspension settings are optimal, adjust tire
  pressures until tire wear barely touches the TWI
  markings

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Contact Patch and Weight Transfer
Front
Front
Front
Rest Equal contact patches on all tires
Accelerating Weight transferred to rear tires
Braking Weight transferred to front tires
Front
Front
Front
Right turn Weight transferred to left hand tires
Left Turn Weight transferred to right hand tires
Brake Turning (Trail-braking) Weight concentrated
on the front outside tire
19
Slip Angles
Direction tire is pointed
Direction vehicle is traveling
Slip angle
Race Tire
Street Tire
20
Slip Angles

• Slip angle and self aligning torque (steering
  centering force)
• Sensitive drivers feel the steering effort
  fall off letting him/her know that they are out
  of the optimum slip angle range

Self Aligning Torque
Drive to win by Caroll Smith, Carroll Smith
Consulting, Inc., Palos Verdes Estates, CA, 1996,
p. 2-7
21
Slip Angles
Overdriving/ Drifter
Optimum (Genius Level)
Novice
Advanced Driver/Talented Novice
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Neutral Steer

• Front tire slip angle the same as rear tire slip
  angle
• Ideal
• 4 wheel drift!
• Might feel like a substantial slide to a novice
• Satisfaction guaranteed!

5o
5o
Front tire slip angle the same as rear tire slip
angle
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Understeer

• Front tire slip angle larger than rear tire slip
  angle
• Causes
• Front tires have less traction than rear tires
• Improper car setup
• Natural handling characteristic of car (FWD, AWD)
• Insufficient weight transfer to the front tires
  before turning
• Entering a turn to fast (Overcooking)
• Remedies
• Unwind wheel
• If front tires over optimum slip angle range
• If front tires lose rotational speed
• Slow down the car gently by lightly letting off
  the gas pedal or by light left-foot braking
• Transfers weight to front tires
• Reduces centripetal force
• Trail braking
• Curse wont do anything but will make you feel
  better, look cool

15o
5o
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Oversteer

• Rear tire slip angle greater than front tire slip
  angle
• Causes
• Rear tires have less traction than front tires
• Improper car setup
• Natural handling characteristics of car (RWD)
• Excessive trail-braking
• Abrupt/jerky steering inputs
• Trailing throttle oversteer (TTO)
• Power oversteer
• Remedies
• Countersteer
• TTO - keep constant throttle or possibly
  increasing throttle input gradually to transfer
  weight to the rear
• Power oversteer - decrease throttle input to
  reduce tire slippage
• Stop watching dvds like drift society,
  dorifuto tengoku, option, etc.

5o
30o
25
Traction circle

• Represents the grip capability of a car
• Can only use 100 of any one action at a time
• Or split duty between two actions
• To maximize the use the traction circle, you need
  to drive smoothly

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Corner sequence

• Threshold braking zone
• Brake turning zone/trail-braking
• Constant throttle zone
• Gradual increase in acceleration while unwinding
  wheel
• Always use smooth steering inputs and smooth
  transitions

Acceleration
Braking
Turning
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Basic racing lines

• The traditional racing line is the widest
  constant arc through a corner
• Maintains momentum throughout corner
• Excellent line for low horsepower cars or for
  large radius corners

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Racing line Early Apex
Wheee!_at_

• Premature turn-in severely chokes corner exit.
• Corner exit speed suffers
• May result in an agricultural excursion

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Racing LinesLate Apex

• Gives up a little speed at entry to gain a
  longer straightaway on exit
• Ideal for straight-line traction limited cars
  (ie. high horsepower) or for tighter corners
• Safer than early apex

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Sacrifice Corners

• Line you would take if corner leads to a straight

• But you need to place car here if you want to
  take the next turn with the widest arc

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Sacrifice Corners

• Cars with lower HP cant accelerate as fast so
  they need to maintain as high a speed as possible
  therefore the fast line for them is a little
  different. Typically they need to maintain a
  higher average speed.

• The sacrificial line taken by a high HP car if
  the second turn leads into a significantly long
  straight

Miata
Miata
Miata
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Advanced TechniquesTrail-braking/Heel and
Toe/Left foot braking
These techniques smoothes out braking-turning/acce
leration-braking transitions

• Trail-Braking
• Instead of completing braking before turn-in,
  braking is initiated slightly later and continued
  through turn-in to take advantage of the traction
  circle
• Once turn-in begins, braking must be decreased to
  prevent wheel lock-up
• Can be used to help rotate car at turn-in
• Left Foot Braking
• Can be used in conjunction with trail-braking
• Allows better mid-corner balancing of cars
  steady-state attitude
• Allows quicker transition from brakes to gas
  after turn-in
• Normally only done when a downshift is not
  required to take the corner
• Excellent autocross technique, but some great
  drivers dont use it
• Heel/Toe Downshift
• Utilized when a downshift is required in the
  braking zone
• Match revs without lifting off brakes,
  maintaining control of cars attitude.
• Rarely needed on an autocross course

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Seating Position

• Seat should be upright to slightly reclined.
• Arms should have slight bend at elbow so that the
  steering wheel can be turned about 180 degrees
  without completely straightening arms
• Hands should not hit legs at severe steering
  angles
• Always use both hands to control the steering
  wheel
• Legs should be slightly bent at the knee

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Course Walking

• Objective
• Familiarize yourself with general course lay-out
• Identify key cones
• Define driving lines
• Find places to gain an edge on competition
• Course should be walked twice at a minimum
• Once with experienced person or group to discuss
  lines
• Again by yourself to define your own line and
  memorize course.
• Should have a good enough visual image of course
  to mind drive it

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Locating Key Cones
Key Cone

• Locate key cones
• Key cones dictate the racing line
• Choose line based on car, key cones and how wide
  the gates are
• Wider gates allow for sloppier lines which are
  not necessarily faster

Key Cone
Key Cone
Key Cone
Key Cone
Diagram Courtesy of Roger Johnson of the Houston
Region SCCA
36
Choosing a Line Recognizing Visual Deceptions
Diagrams Courtesy of Roger Johnson of the Houston
Region SCCA
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Slaloms
Diagrams Courtesy of Roger Johnson of the Houston
Region SCCA
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Slaloms
Examples slaloms in disguise

• Recognize certain course features as slaloms
• Focus on key cones when walking/driving the course

Diagrams Courtesy of Roger Johnson of the Houston
Region SCCA
39
SlalomsPacing Slalom cone distances
Slalom cone distances may vary. Therefore its a
good practice to always pace them
Diagrams Courtesy of Roger Johnson of the Houston
Region SCCA
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Slaloms
The Gap will make a tight maneuver faster
Version "A"

Speeding things up
With an increasing gap, you will be able to drive
faster through the slalom. A small increase
(e.g. one foot) will have a surprisingly large
effect
Diagrams Courtesy of Roger Johnson of the Houston
Region SCCA
41
Slaloms
Diagrams Courtesy of Roger Johnson of the Houston
Region SCCA
42
Other Visual Deceptions
Look painful - but are not
Truly Painful
solutions keeping the same flavor as the original
Narrow, walled in sharp turns
these areas
cause the
All can be driven as one flowing turn
maneuver to be
painful
The problem associated with this narrow walled in
turn is that the placement of the wall forces the
turn to be made up of 2 or more painful turns
instead of a flowing turn
30' gates
18' gates
Diagrams Courtesy of Roger Johnson of the Houston
Region SCCA
43
Looking Ahead

• When you are here
• You need to be spotting this key cone

• When you are here
• You need to be looking at this key cone

• When you are here
• You need to be looking there

Diagrams Courtesy of Roger Johnson of the Houston
Region SCCA
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Revolving magical gates
Walnut Ridge, AR, National Tour 2005
Watch these cones
Racing Line
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Revolving magical gates
Walnut Ridge, AR, National Tour 2005
Now they look like a slalom
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Revolving magical gates
Walnut Ridge, AR, National Tour 2005
But wait, If you take the correct line, they open
up into a short straight!