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question for the autocrossers

Discussion in 'Race Talk' started by dwj, Jan 28, 2009.

  1. dwj

    dwj Member

    Although it is three months away, I am enrolled for a May 4 drivers school/track day at Brainerd International Raceway.

    I will have Kumho XS on the car. My question is that for the first time on a track, how important do you guys think having DOT track tires or full blown competetion tires are??

    Will I enjoy it on street tires or wish I had track tires?

    I have an extra set of wheels but only 8" front and 9" rear. If you feel track tires make a huge difference do you think I can get away with the biggest I can fit on these wheels?
  2. CapnCrunch

    CapnCrunch Member

    You can enjoy it no matter what the tire. I would do the school and first year on stock tires, then over the winter ask Santa for some wide wheels, Team3s are good since you can get custom BS, rim width etc and either Kumho 710s or Hoosier A6s for tires, 315 to 335x17 rear, 275x17 front.
  3. dwj

    dwj Member

    Thanks Cap'n.
    Santa (wife) patients is currently getting tested(new shocks, springs, street wheels, tires) on a car that was drivable. Hopefully a short memory.
  4. Prof

    Prof Member

    The XS will do fine. You will HEAR (and feel) the edge of the envelope coming. (The A6s don't have such an approachable edge--they just break loose eventually. Heat-cycled R6s are the best). "Learn the squeal" from the tires and what it means to your steering inputs. A squealing tire is a slipping tire, and that is good.

    OK, crank the pressure up to 39 or 40 psi and make sure you have at least 1 degree camber up front. If using DOT3 fluid, top off your brake fluid with the DOT3 new 450+ degree stuff. Keep your brakes warm, not suddenly from cold to hot. Cinch those belts as tight as they will go and enjoy. (Tip: If you do a ride along, back up the seat, jerk hard on the belt to engage the emergency catch in the three point system, hold the belt against the lock and move the seat forward til the locked up belt is snug against you--almost as good as a four point harness.)

    After the session, DO NOT USE YOUR EMERGENCY BRAKE when parked. Intense heat will travel up the fluid line to the master, resulting in immediate brake fade. Keep the fins of your radiator clean of crud between sessions.

    The folks in tech are going to scrutinize your battery hold-down/no floor mats/clean brake fluid/snappy throttle return spring.

    I have a set of Falken Azenis 605's if you want to step up to a stiffer sidewall tire. I'm old school: when I choose a tire, it must be drivable to and from the track and purposeful on the track. Others will pipe in and say that an extra set of track tires is a must. Youngsters!

    Mostly, enjoy the day and ride with experienced folks whenever you can. Seat-time is seat-time, whether driving or watching. It gets real fun when the "experienced" person you are riding with looses it at speed...wow, adds new meaning to "along for the ride". Dodge Viper--guy had parked using the emergency brake between sessions.)

    oh--And sign up for a second track day or local SCCA autocross quickly, or you'll lose what you learned.

  5. BPWilliams

    BPWilliams Member

    Glad to see that there are more LSC owners hitting the track! I have only Auto-X'd once so I wont be of much help but here are some tricks that I used for those pesky cones....

    When going down the street or freeway with no traffic run your tires up against the dots on the road and note where your wheels are located to marks on the fenders. This will help in not knocking over the cones and reducing your time any further.

    In auto-cross the track can change so walk it and remember it, that was very hard for me to do comming from the red and white ripple strips...

    Run your rear tires a little softer (-2 to -4 lbs), this will induce under-steer and make the car a little safer...

    CC is correct do not worry about tires now, just go and have fun! there is always someone faster unless you are good enough to be on top of the heap! And all of those guys are seasoned veterans.

    Paul I agree also only one tire is needed "Track Tires" oh of course you will also need a trailer....... :lol:

    Attached files [​IMG]
  6. DaveT

    DaveT Member


    I am a novice and built my LS427 last spring with the 17" Kuhmo 700's Lonestar sold me with the kit. I hit the track twice and probably autox'd 7 or 8 times. There is such a huge learning curve that tires were the least of my worries. It took a handful of times aotuxing before I even felt comfortable navigating the course let alone worry about being competitive. If you have never done it you kinda of need to swallow your pride and just focus on learning to see the course and worry about speed later. The school sounds like a great idea. My plan is to learn to drive the course and tune my supension before I step up to the R compound tire and compete with the big boys.

    The track experience was much more stressful than I expected. Believe me these cars are fast enough on street tires to beat most other cars out there running with you.

    Dave T

    PS I've got less than 2,500 miles on 700's and don't expect to get another 2,500 out of them.
  7. dwj

    dwj Member

    Thanks for the advice, saved me some money for now. Got the 4 point harness, have no clue what brake fluid I have, but will flush. I am going to have to live with my 11" disc for now, 12.9 in the future.
    I will be on the track so no worry about cones, just gravel, turf, fences and maybe some of those pesky miota's.
  8. BPWilliams

    BPWilliams Member

    HAHAHA Short memory HAHAHA If your wife is like mine she will expect the same weight in Diamonds that your toy weighs... :lol: :lol: :lol:

    I am just thankfull she really has no clue on how much this stuff really cost :wink: (plus keeping seperate bank accounts helps too!) I was really happy when she said "yes" build the race car and get the Cobra off the track... Now I have two toys for the street!

    Attached files [​IMG]
  9. dwj

    dwj Member

    Ready for the track in about a week. Have not been on the forum in a while. I have been able to get about 500 miles on the car this spring, remember 40F is warm in the spring in MN, today was 80.

    The 210 springs I put on the back were too light under full throttle, they were okay for cruising. Went with 240 and have the varishocks set at 6. I still hit the chasis stop but it does not compress enough to allow the shocks to bottom out. I changed the roll bar, front vents, side vents , quick jacks to powder black.

    Was chassis dyno'ed at 478 at the rear wheels. First rule with KC big block, learn how to work the gas pedal. As you guys know, these cars are rockets from 30 to 120. I promised my wife that I back it down at 120, she read Jody post about 167mph.

    I have decided I am going to drive it as much as possible which means I no longer count to paint chips. Will let you guys know how my first track day goes. Pic after winter makeover.

    Attached files [​IMG]
  10. BPWilliams

    BPWilliams Member

    The first five times or so at the track I put tape on the front end, please protect the paint. I tried to be a racer with a street car and paid dearly. My paint job is chipped pretty bad from the track and if you do not plan on racing your Cobra for a living tape it up to save the paint.

    I do applaud you for going to the track especially with that much HP, it makes since. Learn how to handle that beast so when she gets out of control you can bring her back. We have lost 4 Cobra's this last year due to getting on the freeway alone.
  11. dwj

    dwj Member

    Acquaintance that has instructor certification and just got his competetion license down at road Atlanta told me to put a brick behind the gas pedal and learn how to drive. I kinda figured if I can't out drive em, I will out HP them.

    You are spot on about being careful, when I got the car last fall and it had the little Falkens, binding links and ruined Aldans, it scared me to drive it.
    With the linkage rework, big Kumho's and new coilovers, it is no longer scary, but to be respected.

    If I let anyone drive it, I will disconnedted the secondaries. Do not a panic and the pedal going to the floor.
  12. BPWilliams

    BPWilliams Member

    Well you sure picked a great car to learn how to drive with... hehehe The one thing this car will teach you is how to get out of a turn quickly! These cars do not corner, but are built for straight line speed. I have my instructors license with NASA and get to drive all kinds of cars. The best so far is the WRX what a machine out of the box!

    One word of caution on these cars, and that is the old adage "Slow in , Fast out" make sure you know your brakes and have your bias bar set correctly. When I bedded my pads I found a street in a new development and did 100 mph stops until I could judge my braking distance and the car pulled down nicely. Most people get into trouble because they do not scrub enough speed on corner entry and then the car pulls out from underneath them at the apex.

    Most important is just have fun, do not white knuckle the steering wheel!
  13. dwj

    dwj Member

    Had a great day at the track yesterday, the car is still in one piece and running(kind of).

    Brainerd had us on a 13 turn 2.5 mile course in the morning and a 10 turn 3 mile course in the afternoon. The 2.5 is more tchnical and the 3 is how fast do you want to go.

    Learning your entry point, focusing on the apex and aiming to your exit point was interesting to learn. In the begiining, I was paying attention to everything except that(going off the road, blowing the engine, etc), Later on I became zeroed in on those points and was running faster and smoother. I was only focusing on my marks and the flag men and occassioning checking my rear for for a particular blue vette. The three mile course I would hit 120 easy in two spots, but just kept it there.

    I lost a breather cap somewhere on the cource, not good. When I was strapping the car on the trailer, i noticed 80/90 gear lube all over the rear and metal shavings on the drivers inside wheel. Did notice any different with the rear but something is not good.(Brain, where is the IRS?????)

    Even at the track people ask if it is a real one. I know I do look like a millionaire???? I have just started telling people yes.

    Have new respect for the pros and their ability to focus for hours.
  14. BPWilliams

    BPWilliams Member

    Great for you DWJ! I am glad you had fun and there was no major damage! It takes a long time to sort out a car to be track worthy and this is the first step! On my first weekend I could not have imagined how hard it was to keep that kind of concentration and how the pro's make it look so easy....
  15. dwj

    dwj Member

    What rear end set up are you using? I may decide to have major surgery on mine. I have 28 spline, 370 gear and according to Currie a limited slip. I am pushing the 28 spline with the torque I have, the 370 gear is too low and when I turn one wheel, the other turns the opposit direction which means it is not limited slip or clutches are shot. It does leave two even patches.

    I do not want to band aid this and then worry about the rear on track day.

    Found my breather cap between the transmission and top of the tunnel.
  16. 2KWIK4U

    2KWIK4U Member

  17. BPWilliams

    BPWilliams Member

    I am using a DPI Gold Track lock racing diff set at 1/2 tight. It is a worm gear diff that is torque sensing. You can see all the good stuff from DPI at www.dpiracingproducts.com and it has 31 spline’s.

    I am pushing over 450 lbs of torque at the trans and had to make sure the drive train could handle all the pressure of the track. I have already locked up the diff because of low oil in the diff (sloshing in the axle tubes) and the best advice I have is to get inner tube seals to keep the oil in the carrier area. I run Red-Line Shock Proof gear oil with additive. My axles are Currey 31 spline upgrades that are larger in diameter and the gears are 3:50's with a red line of 180 at 7K RPM. I have the TKO355 beefed up (2nd, 3rd, and input spline’s) with the .80 fifth for road racing.

    The standard for the track used by most that is cost effective is the Detroit locker, it is used by all that do not want to spend the money for the Gold Track or similar diffs.

    PS stay away from the IRS on the track.. everyone I know of with an IRS can never get thier chasis tunning correct, they fight it all the time..
  18. dwj

    dwj Member

    Thanks Guys,
    Time for a little research and budget check. Heading out of town so will not even look for the damage until this weekend.
  19. dwj

    dwj Member

    Turns out the big mess on the rear end was all coming out the vent. I extended the vent about 1 inch, Not sure where the shinny shavings came from except maybe the rotors and it was noticable because the film of oil everywhere, rotors look good. If I still get sloshing out the vent at the track , I will extend it with flex hose and mount it very high.

    No leaks anywhere on the street, rear end that is.

    Bought a 350 gear and am going to install it and take apart the rear end and figure out what positration unit I own and measure the axles in preparation for future changes.

    BP, DPI has a platinum track, I assume this replaces the gold track.?

    Back to the track in a couple weeks, cruising on the street is okay, but this car wants to go.
  20. BPWilliams

    BPWilliams Member

    DWJ yes that is correct, mine is already out dated! But it still rocks! and is very predictible on the track. On my rear-end and trans I ran puke tanks into the trunk and mounted the lines up to them, they work nice and they drain back into the trans and rear-end after they puke.

    First time on the track my vent tube which was mounted to my roll bar lost about a qt of oil everywhere, after I moved it so that would not happen (to the roll bar)... I will try to get a picture of them later...

    Attached files [​IMG]
  21. dwj

    dwj Member

    Looks like the green moster lost some clothes.

    If you have an opportunity to take a pic of the puke tanks that would be appreciated.

    Did not appear to have any unusal lube leaks with the transmission, better check the level again.

    Thanks again for the help, my guess is that each trip to the track will result in questions that you or some of the other guys have been through.

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