[Supras] Autocross experience

Tue Nov 7 18:41:08 CST 2006

 Hi Tony,
     I really appreciate all of the good information you've given me.  I'll answer your questions first:
q:Have you lost your "N" designation yet?  What class do you run? 
a: I am not sure what designation they gave me, but basically they break up the drivers into four groups.  The first to third, is the insturctors and experienced club members.  The fourths is everone else, I was in the fourth.  The day is split into a morning and afternoon sessions, each session is four runs.  My first four were with an instructor and the last four were without, and that's when I got my best time (as my skill level developed).  For future events, I have to join the Mercedes Club of America in order to participate.

q:What are your goals?
a: That's a good question.  I guess that I wouldn't want an MK3 purely tuned for autocross (there were some BMW and miatas that were just that, pure autocross machines).  I know from my my last track event at Summit Point that the MK3 is a very capable track car (with the proper suspension and brake mods).  So, track is my first priority, but if I can switch to autocross "mode" by making some changes, like the suspension and tire/wheels, then I would consider that the ideal setup.  And if  I could get within 1 or 2 seconds from the fastest time, then I would happy. 

The list of things you've mentioned is very valuable and there are many things that I missed, like tire pressure and keeping the tire sizes same all around.  I do actually have aggressive track pads to improve the stock braking (I forgot to put that in the mods list), which helped, but I need to install braided steal brake lines as well.  I'll put in my to do list getting ST anti sway bars + strut towers for front and rear.   The next season won't start until spring of next year, so I should have time to do these mods.

Thanks again,
/Khalid  

-----Original Message-----
From: TD5133 at comcast.net
To: supras at supras.com
Cc: khalida1 at aol.com
Sent: Mon, 6 Nov 2006 10:34 PM
Subject: re: [Supras] Autocross experience

 Hi Supras,
     I just came back from my first Autocross at Winchester Virginia with the Mercedes Club of America.  I was the only one with a supra (no MKIVs even).  Overall, I think the car did pretty good.  My best time was 35.01 seconds.  To put it in perspective, the best time was in the 29 to 30 seconds range, which was set by a Z06 and moded 06 STi (with experienced drivers).  Most of these cars were purpose tuned for autocross.  I was using Yokahoma AVS ES 100, which were not that great in the cold weather (started in low 40's and ended in high 50's by afternoon).  But I have to say, these tires actually worked very well at the hyperfest event at Summint Point in July, which was 90 degrees plus weather.  So these are just not for cold weather.
    I felt that if had better tires, and perhaps with upgraded anti sway bars, I could have shaved off a couple of seconds from my time.  Also, with more driving experience,eventually my numbers might get within 1 second of the fastest cars.

     I would appreciate suggestions from the group, especially those with autocross experience, on what I can do to make my MK3 more autocross capable.  If you think its a lost cause, I am also open to that ;) 

Thanks,
/Khalid 
90 T  
2mm Greddy MHG+ARP bolts @85ft-lb
Lexus/550 FIs with AFPR and MKIV fuel pump.
upgraded ct-26 with ceramic turbine,
Turbo Smart MBC set to 12 psi
Megamouth turbo elbo
3" exhaust with 3" cat
K&N FIPK with cool air intake mod
stock IC and piping 
XS BOV

stock R154 + aluminum one peice drive shaft = noise + leaky oil seal + headaches!!

Eibach lowering springs with Tokico Illumina adj shocks

f:17x8 5zgen, 235R17 AVS ES100
r:17x9 5zgen, 255R17 AVS ES100

Hi,
Here's my $0.2.
#1 you are right on the money regarding experience, this alone will shave the most time, seat time is the MOST valuable.   Have you lost your "N" designation yet?  What class do you run?  ESP I assume.
It is funny how similar our setups are!  Same wheels and tires, shocks, fipk & other stuff.  So I thought I might chime in.  For autocross grip, brakes and grunt out of the corners are paramount.  I would recommend bigger front tires, I now run 245's on 17x8 5 zigens, but when those wear out will go to 255 all around.  I would prefer 17x9s on the front but I don't want to buy new wheels just for that.  You can go as big as 275 all around but you must roll your fenders, again something I don't want to do.  The 235's put the weight a bit off the front which is good, 245's drop the front a bit and put more weight on the front, which is bad, 2 more reasons I will go bigger in the front.  A good alignment is helpful too.  Go with standard settings until you want to go more aggresive.  You will need to "flip" you front tires regularly or they will wear out much more than the rears.  I was showing cords on (front) my kumhos before I went to the avs-es100's and have had to flip the yokos already.  The rears seem to wear perfectly.  Many people like the koni shocks better than the tokicos.  This would be something for later.  Coilovers are hot, but expensive....
Aftermarket sway bars are definitely the way to go.  I have the ST set and like them alot.  The rear are adjustable and I would recommend the more aggresive setting i.e. more rear bar.  (Is that the outside or inside, I don't remember.)  Make sure you loctite the nuts with red loctite (blue comes off for me).  
I sometimes run with some mk4 na wheels which are the same width as yours but are 16" and way lighter, even than the 5 spoke stock wheels. (you will need a spacer as the wheels will rub the sway bar)  I have some yokohama A083Rs, one of the last sets in 245/45.  My ability precludes me from using them now, so I don't change wheels anymore.  Not worth it at my skill level.  I think I have seen some falkens or new yokos in race rubber that will come in 255 in a 16" and may go with those later, otherwise Hoosiers are available in many sizes, can you say expensive?  
A mk3 na lsd would give you more snap off the bottom, especially with a course only 35 seconds long, wow that is tight!  It won't give the load that the turbo likes to spool, and will KILL your gas mileage, been there done that, broke it, threw it away.
  An electronic boost controller will give you lots of torque that you are missing with the mbc.  I would do that right away.  
Make sure your brakes are in tip top shape, these are another of the mk3's weak points.  Turn the rotors, flush the fluid, and fresh pads are a good start.  Then upgrade as you need.  SS lines, slotted or drilled rotors, porterfield or other more aggresive pads would be phase 2.  Phase 3 would be big brake kit, which might hurt you in autocross as they may not get hot enough.  What are your goals?
Remove some weight from the front, relocate the battery to the trunk, cf hood, lose the diaper, lose the fan clutch, what else?
Tire pressure is important, run higher in the front to lessen push,  38-40 front and 36 in the rear is a good start, but always run more pressure in the front, I even do this on the street, It doesn't affect my tire wear YMMV.  
Targa car?  strut tower braces are probably a good idea, especially if you want to race with the roof off.  I leave my roof on cause I don't have the braces, yet.  
Currently I run with an SS camaro in esp class, and am only a few seconds behind him even being novice class still.
Anyway, HTH.
Tony 92t
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