A&Q about 350Z
Q:
Hello all,
So it was my very 1st autocross event at De Anza College and it was fun!
I saw open window triumphs or spitfires, a handful of 510's even the Gunn High School replica BRE 510, 68 & 06 Vettes, WRX, EVO. Some rare ones like a Ford Cortina, Plymouth Satellite and many other cars.
There really is nothing like taking your car through the course and getting a somewhat better feel for how your Z handles.
The one thing I liked is that when the car started to slide (rear fishtailed exiting a corner) i was able to "feel" it and compensate to get it straight.
After watching others (more experienced) run the course, I was like D'oh. I should have stayed in 1st gear like they did for it wasn't a very long course, probably 6 -7 turns in all.
While I ran the course in 62.5 sec. the fastest times were around 49 sec. by the 06 Vette (AUTOXER) and a Lancer Evo.
It got embarassing when the plastic evap connector, the one from the top side of the filler neck that connects to the hose to the evap can cracked and gross leaked gas out the right hand side of the car, good think nothing sparked. This happened on my 3rd and last lap. ( Any anti spit back valve mods for stock gas tank?)
I was also told that I was getting wheel hop in the front end i believe when entering a turn or during a turn. What causes this? Is it because of the stock sway bars.
This was long winded and all, but just wanted to share my experience.
Any thoughts or suggestions, im all ears.
anthony
'73 240z - San Jose, CA
2.4L - 4 Screw, Pertronix, Short Shifter,
Poly-U, KYB GR-2, ZX 6-Spoke, Yok. 215-60-14
Enjoying the ride.
A:
Autocrossing is a cheap way to iron out the bugs in your car's handling. You need to keep a race car in 10/10th shape to avoid any accidents!
Wheel hop is often caused by running a damper (shock absorber) that is too weak to control the oscillations of the spring (both the strut springs and anti-roll bars which are also technically springs). Your KYB struts (which are closer to OEM specs) may need to be replaced by ones with a higher dampening rate. Another cause is a worn out tyre.
The shock absorber is the first to react to the initial weight shift of the car. Your car will not "ride" on the spring unless its driven through a corner in which the car spends time to "settle down." (i.e. long sweeper, wide hairpin, etc.) In many ways the setting of the dampers is more important than the springs.
The spring rates on a racing car's suspension is set up just soft enough to keep the tyres on the road. In other words it is set up to absorb all the bumps and grooves on the road but not softer than it has to be to do the job. Also the stiffness of the spring is always limited by the rigidity of a car. There's a limit on how stiff of a spring you can run on an old 240Z chassis before the body itself starts to act like a spring connecting the front and rear suspension.
Click for a good discussion on spring rates and suspension in general.
The 240Z really comes alive when you drive it hard. The car gives you a lot of road feedback and communicates very well with the driver. That's why it's a joy to drive fast. Even though it has scary high speed (80+mph) handling.
1971 240Z
"Fear is exciting for me." -Ayrton Senna
Post Edited (May 25, 2:20am)
A:
Racing your Z is the moost fun you can have with your clothes on.
If you want to improve your times, get another more experienced autocrosser to ride along with you or you ride along in their car. They can offer valuble advice to improve your lap times from driver position to car setup.
Autocrossing is a great place to test the limits of your Z and the hard use will show you what parts you need to replace. How about some pictures?
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1978 280Z - I wish I had this much money in my 401K.
A:
I don't have a camera so no photos of the event or my car for that matter.
'73 240z - San Jose, CA
2.4L - 4 Screw, Pertronix, Short Shifter,
Poly-U, KYB GR-2, ZX 6-Spoke, Yok. 215-60-14
Enjoying the ride.