OWTKAST cpt

iTrader: (1)

Went to my first auto X today with another buddy and his Z...

SUPER tight 30 second course (video's later)

Guys in the vipers, vets, miata's were turning 25's I was 27's.


ANYWAYS....

-Im street tires with coilovers, intake, and sways.. what in the heck class am I in??? LOL They were all confused.. and causing me more confusion.

- Im running invo 245/275 on RPF1's

-Car udnersteered then immediately snapped loose.... Where should set up the sways??? Seems I need to soften the rear???

-Air pressure?? whats best for the street tires??

-Rev limiter???? course was sooooo tight I was having a touch time on the 1 or 2 decisions.


I am sure some of these questions are answered but I have been reading soooo much I am only getting more confused trying to sort it out.

I REALLLLLY appreciate any information you all give me.. thank you..


Thanks

OWTKAST cpt

iTrader: (1)

Stiff front.. soft, OEM, or no rear sway bar... got that.

scotts300

iTrader: (46)

Class CSP I believe.

In 95% of autox cases you can (I do) run just 2nd gear. Sometimes I'll need 3rd, but there is enough low end torque that you shouldn't need first at all.

OWTKAST cpt

iTrader: (1)

CSP would run R comps though right?? Im new so excuse my ignorance =)

STR Is fine on street tires but not over 255???

So IF i ran in STR what would I aim for 18 9.5's like +12-15 with a 255 tire?

n8dog11914

iTrader: (1)

Just did two events recently (one just two hours ago). I'm pretty sure most 350Zs go into B stock. and BSP if you have an intake, suspensions mods, etc. Just springs alone can put you in the BSP class for example.

Edit: This also varies region to region. You might just want to ask someone when you get there because I haven't seen a 350Z in CS yet.

OWTKAST cpt

iTrader: (1)

Its CS for stock Z's in 2010
I've already got coilovers and sways..=)... maybe =( lol

n8dog11914

iTrader: (1)

CS was mostly Miatas today where I went (2nd gen). Like I said, I think it varies.

06platinumG

iTrader: (1)

Your BSP with the mods that you have done. Here is a link to the SCCA rules


http://www.scca.org/contentpage.aspx?content=61

OWTKAST cpt

iTrader: (1)

BSP is R comps though??

I could swap to 255's and stay STR?

guitarist

iTrader: (1)

Max wheel width in STR is 9". 9.5s would put you in BSP, as noted above. The rest of your mods are STR legal.

As for handling: it sounds like you're just exceeding the grip limit of the tire. Dunlop Star Specs, Bridgestone RE-11s, or something similar would be a huge improvement. Nitto Invos are fine for the street, but they're not autocross tires.

And I'd run a square, 17" setup (17x9), with a near-stock offset (not more than +20) to keep out of the fenders once you get it as low as you'll need to go. The 17" wheels won't look as "cool" but the tires are a lot cheaper, and the wheels will be lighter, too.

Z1NONLY

iTrader: (2)

The Z is now a C-stock car but the " street prepared" class hasn't changed for the Z.

As your car sits now, it's an (under-prepped) BSP car. That's the class I'm running in now.

Even though the spherical bushings on my A-arms technically bump me up to SM2, none of the competitors in my local class care because they don't make that much of a difference and I'm on street tires while they are on race tires. (my front bar was at full soft before I got some negative camber on the front wheels)

As for your setup, I know nothing about your driving style so I am going to make recommendations based on what you wrote and what I normally see.

*Meaning this is just an educated guess*

The understeer on entry could just be the result of overcooked entry speed. The snap oversteer could be throttle induced, (you mentioned 1st gear and the rev limiter).

However, a lot of people like the sporty feel of a super-tight suspension and set their cars up as such.

If you are low on grip, (street tires) and run your suspension too tight, your overall traction will suffer and the line between "stick" and "slide" will be very thin. (although crappy street tires can cause a similar problem)

I run some pretty aggressive, sticky street tires, (275/285 Kumho XS) but my settings are on the soft side. My RSR springs are just about stock spring rates. My Koni "yellows" are close to the middle of their adjustment range, and my front Hotchkis bar (4-holes) is set just one hole from full soft and the rear bar is at full soft.


As for tire pressures...

Different tires like different pressures, but the Z is kind of heavy and most street tires like higher than normal pressure when driving hard. The chalk or shoe-polish trick is an easy way to set the pressure to ensure you are using all the tread. Just mark the tires before you run and look at what's left when you get back. If the marks are still on the tread, lower the pressure. If you are scrubbing the mark off the sidewall, put more air in. (eventually, you may want to consider alignment settings and tire temps when dialing in air pressure)

About the rev limiter;

I only recently started experimenting with staying in the higher gear. (3rd, in my case)

It sounds and feels slower, but my times are usually better when I stay in the higher gear. (This is when choosing a gear is a close call)

Two side effects (that I have noticed) of staying in the middle of a higher gear rather than the top of a lower one are; A)Smoothing of throttle inputs, and B) Forces you to look ahead, setup, and maintain momentum a little better.

OWTKAST cpt

iTrader: (1)

Thanks for the input. Right now it's just strictly fun but I really enjoyed it. I didn't realize the wheel width thing either.... Hmmm ditch parts for stock class?? Lol or buy wheels and tires for str.


Most cars hardly left first gear today... 25 seconds was fast lol... Uber tight.

I'll adjust the sways check tires and have fun for now.

Z1NONLY

iTrader: (2)

The venue I run on tends to have courses that are more open. Most of the SCCA stuff I have seen was second gear stuff.

And I wouldn't ditch parts for the stock class. That's a race-tire class too.

Have fun, and enjoy your car. The seat time is worth more than any parts you can buy anyway.

OWTKAST cpt

iTrader: (1)

Very true... 13 yrs of kart racing puts a little bit to much competitive spirit in me lol

May go back out next sunday on a bigger course.

Ill adjust the sways and see how it feels..

Guilty1s

iTrader: (12)

The stock 350z sits in CS... but anything modified outside of that, it BSP. BSP can run R-comp but dont have too. You can run TBSP, which is a Paxed street tire class.

In my region, the is a an awesome class called STM. Pretty much anything goes as long as they are street tires 140 wear and up. Like STR but i think no limit on tire width.

Also oddly enough.. modifed 370z still stick in the CSP... it dont make sense sometimes.

nismofreak1208

iTrader: (30)

i'm pretty sure i'm in the wrong class for my region in hawaii, but they have me under the SSM class being two door coupe unlimited street modified. All i'm rocking is full urethane bushings front and rear, gt spec braces all around, full exhaust and cats, and a osiris flash. They said it is the right class but i'm not too sure, never really cared too much about it.

SmoothZ

iTrader: (13)

I also usually stay in 2nd gear once I get going. Rarely do I go into 3rd.
I'm in BSP. I have springs, sways, intake, plenum, and upgraded brakes.

OWTKAST cpt

iTrader: (1)

Yah it's the wheel and tire width that seems to knock us into bsp quickly

n8dog11914

iTrader: (1)

The lure to the CS class is strong, but you have to ask yourself is it worth it to sell off your mods just for a few autocrosses a year? From what I can tell, a really nice set of street tires and a bunch of seat time is really what matters the most.

INTIMAZY

iTrader: (15)

Truth.

That's the only reason why I put up with the abuse by rx7s in SM2.