General info for an uneducated AX'r, Primarily tire pressure Options

[jd66921]

Hi,

I've been doing AX's for a little more than a year.

Currently I'm driving Howard's old car "Suzi". She's a pretty much
stock 914 2.0l. She's been lightened a little. She has fiberglass hood and
bumpers. All her heat and ventilation has been removed. Weight is 2050 lbs

The engine is a stock 2 l as far as I know, and has an unmolested MPS.
The transmission is stock.

I do not know what kind of shocks are on her. The rears are yellow and do not
seem to have any adjustments. The rear springs seem fairly soft to me? There
are sway bars front and rear, I do not know what size they are. The fronts are
adjustable with a number of holes in the horizontal arms. They are set to the center.

I typically run about 10-12 seconds behind Corvettes, A Birkin, and a well
setup Mustang Cobra. I am typically 3-4 seconds behind set up Miata's,etc.
This is on courses that I would generally say favors the high powered cars.
Generally, the courses are two 180's at each end, fast stuff down the middle,
and most of the courses I can take flat out or with minimal lifting., except for the
real corners, of course.

Wheels are 5.5 inch Fuchs, with Falken Azeni RT-615's.

My big questions is: I am now running 25 psi front and rear in the tires.
Is that in the right ballpark? Should I go higher/lower, and why? The car
feels good most of the time, with a little bit of mostly controllable oversteer. I
can get some wheel spin off the line, and a little on right hand sweepers.

What will changes to the front swaybar make? I've never understood them! I
would prefer an answer like "increasing the front rate will increase grip" instead of
"decrease over steer".

Anyway, I seem to have reached the limit of my improvements without help, so
I 'd like any help I can get!!

Thanks,

Jeff




My first question is

[koozy]

Here is my take on it.

Raise the pressure to 35 (or even higher) and see how it feels. The Faklen tires get slippery when hot so low pressures will contribute to a "greasy" feeling tire. I ran mine at 44 and did quite well. They seemed to like the 44. I didn't see much roll on the tires at any pressure since they have a reinforced sidewall.

Have the car aligned. Best $70 you'll spend on AX prep. (if you don't do all that much street driving go with 1/16th toe out and have them add a bit of negative camber. This will help in the twisty stuff at AX. I have the car at 1/16 toe out and street driving isn't all that bad. it likes to find the grooves on the highway but it's not uncomfortable.

Try to disconnect the rear bar and see how that feels. (just disconnect one side and use some wire to hold it up)

Figure out if the front looses grip before the rear, or vise-versa and then you can make adjustments to combat the issue at hand. (only one thing at a time)

Very important: Only change one thing at a time so you know what the result of the change is. More than one change and ya end up chasing your tail tryin to figure out what the heck happened. (ask me how I know...)

Look out... this is the beginning of what some call the "slippery slope" and if ya get the bug it can be the most fun ya ever had changing stuff on the car every couple of months... ha ha ha

Don't sell yourself short. After 15 autocross events you know what you are doing. If ya didn't, you wouldn't know ya needed anything at all.

Have fun and keep us posted on your changes, results and progress. Remember, the closer ya get to the fast guys the farther away it looks.