Well I pretty much got my ass handed to me at an auto x event last weekend and I rather not let it happen again.

For those of you who are into auto x please help me out…

What tires are you using?
What tire pressure are you running?
Do you mostly stay in 2nd gear?
What other mods are you running that have showin gains for you in auto x?




A few videos from last weekends auto x.

Black Evo
http://videos.streetfire.net/video/Black-Evo_167499.htm

Corvette race car
http://videos.streetfire.net/video/C...car_167500.htm

MR EVO
http://videos.streetfire.net/video/MR-EVO_167501.htm

1988 Turbo Audi
http://videos.streetfire.net/video/1...udi_167502.htm

Ford GT
http://videos.streetfire.net/video/Ford-GT_167503.htm

Turbo Honda Prelude's Auto X
http://videos.streetfire.net/video/T...uto_167869.htm

 

Most of those questions depend on the class you want to run in.
Anything too far from stock throws you in with the big boy modified group... ie) tires, engine mods, suspension mods

 

Well whats the best tire pressure to be running?

 

That depends on the tires.

Some people like to get competition tires, others prefer street tires (again, the class depends).

I've only used street tires. I like to put in around 38-40 psi on the front and 35 psi in the rear.

This keep the car from going into heavy under steer, yet keeps in held on the road as best a possible.

 

Im running street tires.

I'll give your set-up at try and see if Im able to pull some better numbers.

 

I am racing this weekend..... I run 38 front and 30 rear on the stock Pirellis (almost slicks now) and I remove my Anti-Lock brake fuse....
I can not compete on my competitions level w/o the LSD unit

but, I still do OK.... there are alot of EVO's and STI's.... I did be a modified VR6 golf w/ a full cage and came within 1.5 seconds of a Shelby Cobra w/ a 289

 

Do you guys remove your spare tire?

 

Sometimes I take the spare out if I feel ambitious.

 

agreed 2X..... but I usually leave it in 95% of the time

 

my setup depends on the spare tire for balance, best mods in street tire class are koni's, a rear sway bar if it's allowed, and the mother of all mods seat time

 

I run the stock tires with a progress rear sway so my psi will be different than yours, BUT i run 25 up front and 38 in the rear. This allows me to rotate the car with a bit of over steer.

Although most of these guys posting in this forum probably have more seat time than me I would argue against putting a higher psi in the front than in the rear.

 

it really depends on your entire suspension setup and sway bar choice, if youre running an understeer setup then you want what you have lower pressure in the front to compensate(lower pressure=more grip less nimbleness)but you can set the car to oversteer with even tire pressures or even higher in the front tire pressure. it's all about setup and how you like to balance the car while competing(are you an early braker, late braker,trail braker etc..etc...)

 

BUMP!

I need to know what the recommended source is for a set of slicks matching the 205/50R17 size on my 1SS. I'm going to be picking up a set of steelie G6 wheels to run as a spare set.

 

A few pics of me running auto x...I was making the last turn which lead a 1/2 mile runway of the airport we had for the day

TOP SPEEDS DOWN 1/2 RUNWAY
My Cobalt SS hit 107mph
Ford GT 137mph
1988 Turbo Audi 140mph
Evo's were 102-111mph
Mazda Speed 3 hit 104mph

...a few other cars were hitting around 120mph but most were around 100...We had 71 car running in the event that day.

 

what width is the wheel, the scca rules read any tire you can get on the wheel. i don't think anyone makes a 205/50/17 slick, they start out at 225/45/17. if the wheel is at least 7-7.5 inches wide you can fit a 225 wide tire on no problem.

 

Props.

 

why thanks.... some video
https://www.cobaltss.net/forums/autocross-road-racing-53/auto-x-video-chicago-6-29-08-a-121604/

 

They're 7.0" wide, for the record. But I'm trying to stay in the stock class for now, and so far as I understood it you could run any tire compound so long as it's not more than 1/4" variance from the stock size. So if I go from 205/50R17 to a 225/45, isn't that more than that?

 

this is taken straight from the 2008 scca solo rule book. long story short if you can get the tire on the wheel it's legal, the 1/4 inch is for the offset of the wheel used.

here's a link to the pdf of the whole rule book

http://www.scca.com/documents/Solo%2...lo_Rules_2.pdf

13.3 TIRES
Any tire which is OE on a car eligible for Stock Category may be used.
Non-OE tires must meet the following requirements to be eligible for
use in Stock category:
A. The tire must not appear on the following list, which may be
altered at any time by the SEB upon notification of membership.
No tire models are currently listed.
B. No tire models will be approved for competition during the rest
of the year after April 30 of each calendar year. Each eligible tire
model must meet all requirements of Section 13.3 by April 30,
and must continue to meet them thereafter. A tire model will
normally be determined by the designation in the Tire Guide.
However, any of the following changes or similar changes (as
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determined by the SEB) will also be considered to represent a
new model for eligibility purposes, even if the designation does
not change: change of tread pattern at either full or partial tread
depth; characterization by the manufacturer or distributor of a tire
as “new” after April 30.
A tire model which was previously allowed by these rules continues
to be legal until specifically disallowed. This follows
years of precedence on eligibility for discontinued tire models.
If a manufacturer reintroduces a tire model which was previously
discontinued, that tire will be considered a new model.
Therefore, it will have to meet the rules specified in SR Section
13.3 including the April 30 introduction date.
C. The model of tire must be listed in a current or previous two
years of the Tire Guide and Tread Design Guide, or otherwise be
approved by the SEB. The tire model must have Department of
Transportation approval.
D. Within each tire model, the sizes which are available must be
equally available to all competitors. Tire model variations differing
from standard specification, delivered only on a limited
basis, or only to selected competitors, may not be used.
E. No racing tire or recap (on any casing) may be used. Siping or
re-grooving of tires is not permitted.
F. Each tire model must be sold in at least four rim diameters, with
a total of at least six sizes.
G. Tire must fit the allowable wheels and fender wells without
modification.
H. Each tire must have non-zero measurable tread depth (i.e.,
points where it is possible to obtain positive measurement values)
as described in Section 3.3.3.B. Tires may not have cord
visible at any time during competition.
13.4 WHEELS
Any type wheel may be used provided it complies with the following:
it is the same width and diameter as standard, and as installed
(including wheel spacers if applicable) it does not have an offset
more than +/- 0.25 inch from a standard wheel for the car. The
resultant change in track dimensions is allowed.
Wheel spacers are permitted, provided the resultant combination
complies with the offset requirements of this section. Wheel studs,
lug nuts, and/or bolt length may be changed.
Vehicles equipped with rims having metric specifications may use
alternate rims as determined by using the following procedure:
65
Diameter: converting the metric measurement to inches and using
the nearest smaller inch diameter rim.
Width: converting the metric measurement to inches and using
the nearest smaller 1/2-inch width rim. Offset and track must
still comply with the requirements of this section.