Kentetsu

Way too low. Try something like 40 psi next time and see how it feels...

In reference to the sway bar discussion, here's my thoughts on that:

Stock front sway bar: most feel you should remove rear bar. I'm not sure which way I liked it better, but ended up racing with the rear bar on most of the time.

Aftermarket front sway bar: When I installed the bigger front swaybar a couple years back, it was absolutely amazing how level the car would be when cornering hard. If felt much more precise and better poised under all conditions. However, I was experiencing quite a bit of understeer until I reinstalled the rear (stock) swaybar. Then things were much better.

Adjustable rear bar: Installed an adjustable rear bar (ISC maybe?) last fall, have it on the firmest setting, and love it. The car just carves right through the corners now with a definite precision. It's like it just "digs in" so much better. Although now that I think of it, a lot of that could also be attributed to the Bilstein shocks I put on the back end around the same time. lol.


Anyway, on to the mention of tires. I would advise you to hold off on buying expensive tires to race on until afer you fix your driving technique. Sumitomos are only about 50 bucks apiece, so if you burn them up by overdriving them you won't have to feel so bad. But if you treat a set of race rubber that same way, with the softer rubber compound the damage will happen a lot faster.

If you read at all, check out Bob Bondurant's book http://www.amazon.com/Bob-Bondurant-...9568123&sr=1-8

And more than anything else, seat time and practice. But you need the knowledge before you can practice it. I still have so much to learn, I know I've only scratched the surface, even after two years racing. Good luck man...

Rogue_Wulff

I have to agree with Kentetsu. I have used my FB for autox for a couple years now. I removed the rear bar just to see if I could tell a difference, and I did. I can't say it helped, though. I will likely reinstall it.
As for tires, I am using street tires. 205/50-15 Kuhmo SPT on 15 x 7 wheels. I find that 45-47PSI front and 42-45PSI rear works pretty well on this combo.
My suspension setup (if you want to call it that) consists of older ST springs (sagging a bit) and KYB GR-2 struts/shocks, and a homemade strut bar. Otherwise, all stock. Understeer is minimal, usually from braking a little late. Oversteer is a different story. Normally, I get mild oversteer that is easily controllable with the throttle, but it has got away from a couple times. I find that the LSD is a must. Without it, you simply cannot apply much, if any, throttle until the car is going straight, which is way too late.
The 1st two things to upgrade, is good tires and seat time. Tires need not be the best available, just new enough to still have some grip. My 1st season, I was using tires that were 10 years old. Can you say hard as cement?
Adjusting the loose nut behind the wheel is a slow and tedious process. Until you can make consistant runs, any car adjustments are totally useless. Once you can repeat your performance regularly, then you start adjusting the car, and be able to tell what each adjustment does.

vipernicus42

iTrader: (4)

Cool

I'm running Sumitomo HTR-200s from tirerack.com in 205-60-13

They don't count as "cheater tires" or "race tires" so I don't get extra points for them but they're a good tire. I don't know how the PMSC classing system works, but the MCO doesn't give me any points for them.

If you get points for them then you might as well go all the way and try to find a set of rims you can put Azenis on. They don't make them in 13s tho.

Jon

Catatonik

Thanks for all the help. Next event is may 25th, so I'll let you guys know how it goes.

Zyrano

V710 uses a lower pressure, you don't run a high pressure for those, street tires however, 40 would work great. I usually run my v710s at about 29front 31rear and adjust as I go along...

Kill No Cone

iTrader: (6)

C'mon Firebird the Sumitomo just do not compare to the Azenis. They are not sticky or even in ball park. You did make a good point about Hoosiers being available to fit a stock rim.

-=Lil Red=-

iTrader: (24)

How do you know which is the correct way?

I am new to the FB. I installed some new springs and i noticed my strut tops were both in different positions. Which is the correct way?

There is a notch on one of the 4 sides to the strut mount, where is it supposed to point towards in stock form? The front is my guess.

Which way do i turn them for the negative camber?

Thanks

Kill No Cone

iTrader: (6)

Lil Red,
Unbolt the strut tops and rotate them until you find the side that moves the shock inward towards the engine the most. You will give you the most negative camber (or, the least positive).

Does that make sense?
JEB

aFBatw!

thats what i thought/tried at first but it felt awful i get way more lateral traction with low pressure (and 25 - 30 is cold pressure they get to around 32 -35 by the end of my last run)i have some camber and that might be why. i guess its because it just feels better and it shows in my times

Kentetsu

I believe the strut position you want is with the arrow pointing in, and toward the firewall.

Rogue_Wulff

That's how I have mine set. The SA had strut tops that were different. Those need to be pointed towards the front outside. The FB units are exactly opposite of the SA, so check them close. You can see the offset of the strut, when viewed from above.

Kentetsu

Good to know Rogue. Thanks.

Kingbob

try setting them to 32ish for the first run and letting them heat up and rise to your desired pressure and dropping the pressure when it gets too high. For example on our RX-3 with kumho v710s (basicly the same suspension as an RX-7. It's fairly softly sprung with huge swaybars) We begin the day with 32 all around if the track is cooler, or 34 if it's already hot. We make our first run to decide on what pressure differential to run front or rear for balance (depends on the pavement and the course that day) and run that from there on out.

Not a lot of use in setting the tires low when they're cold and just letting them ramp up to where they should be, atleast in Autocross. Set them where you want them to be on run 1 or a little lower so they can get some heat in them quicker. You should be bleeding air out after most runs.

aFBatw!

32-35 is a guestimate i do bleed them. i guess its my driving style, but these tires do have extremely stiff side walls it took me alittle over an hour to mount them on the wheels.

mikey D

you can tell by looking at the strut tops.
or measure them. you want the most metal to the outside close to the fender.
that give max camber.

I run 35-40 psi but I run hankook z214's

I tried lower settings and the car just got sloppy.

With r compounds you go so fast your stock rear suspension will bind in hard corners, no rear bar helps in these cases but increases low speed understeer.
really tight low speed courses definatley put the bar on.
I just on hooked 1 link on that car to disable it. I could put it back on in a few min if it was needed.

try a victoracer v700 for your first r compound. it fits on the stock 13 inch wheel and is usually cheep plus will last 2 seasons or more.

wecycle

The following chart may help you sort out the car.
Hopefully it will format correctly. If not you can go to http://polybushings.com/pages/handlingtips.html

Adjustments To increase Understeer To Increase Oversteer
front tire pressure lower higher
rear tire pressure higher lower
front tire section smaller larger
rear tire section larger smaller
front wheel camber more positive more negative
rear wheel camber more negative more positive
front springs stiffer softer
rear springs softer stiffer
front anti-sway bar thicker (stiffer) thinner (softer)
rear anti-sway bar thinner (softer) thicker (stiffer)
weight distribution more forward more rearward

RacerX7fb

Yes. This guys original problem was too much understeer, which is why I do not understand why he is being told to get a bigger front anti-sway bar and remove the rear one. Removing the rear anti-sway bar softens the rear of a car. That increases understeer/ reduces understeer.

Suspension tuning is universal for virtual all cars:

http://www.ffcobra.com/FAQ/handling101.html http://www.msrlracing.com/setup_guide.htm http://www.s2000.org/articles/suspension/
http://www.rogerkraustires.com/TechS...verunder.shtml

The most likely cause of understeering as a beginner is driving into a turn too fast. Go by the old racers mantra: Slow in = fast out. This rule applies especially to our 1st gens. Your stock RX-7 is already a good platform to begin with. At less than 5 minutes of run time out there just go have fun and drive smooooooothly. Don't worry so much about modifying your car (like $$$ on parts, tires, etc...) yet. Ask an experienced instructor to ride along with you and you will learn alot. To those who have not yet autocrossed, try it. You'll be surprised at how slow you are!

one320fc

Another thing I didnt see mentioned or I missed it. CG lock or a harness, keeping your own *** planted helps you keep control of the car as well. If you can spend the extra cash pick up a racing seat. And practice!! no point building a car that out performs the driver.

mikey D

racerx7fb obviously didnt read everything.


Quoting myself

"With r compounds you go so fast your stock rear suspension will bind in hard corners, no rear bar helps in these cases but increases low speed understeer.
really tight low speed courses definatley put the bar on.
I just on hooked 1 link on that car to disable it. I could put it back on in a few min if it was needed."

I suspect I also mentioned he was probably entering turns to fast and braking at the same time. Rx7's dont really understeer much unless your doing something wrong.