posted this in the autoX forum, but thought you guys may benefit from the info:



I run BSP in AutoX - last year I ran Hankook 275/17's and loved the grip...but this year I wanted a bit more!

I was going for the Max amount of rubber I could fit Front/Rear without moddifing the fenders...here's what I came up with:

tires: Hoosier A6, Front 285/30/18, Rear 295/30/18
Rims: Enkei RPF1 18X10 +38 (I knew the offsets would need a small amount of tweeking, but all the other options were either too $$ or too heavy)

(great price from Billy @ www.vividracing.com – Thanks!!)


Front: needed a 10mm spacer (otherwise the inside of the tire was pushing against the A-arm)...

Rear: no spacer needed. (will need a 5mm spacer to run a 305, but w/ the 295, it’s ok)

*no fender modifications
-Lowered on JIC coilovers about 2”
-Negative 1.5 degrees of camber


next set of tires I may try for a Front 295 (a 15mm spacer should work...but the outside may rub the fender), and a Rear 315 w/ slight fender rolling.

fronts:




Rear:







pic of rim(s):




Tires:


about 10-15mm of clearance to the rear outer fender


about 5mm of clearance from the inner rear shock.



**Can't wait to get these out and see what they can do!

 

Next up...a carwash!

 

BJ @ Vivid hooks it up!!

Nice wheels man

 

You thinking of a 10mm or so spacer out back aswell? Give her a lil wider stance perhaps? Damn nice setup.

 

DAMN you are putting 28s on the rear? BALLER!!!!





That fits damn well, before I read your post I was thinking you had the rears neg cambered out just to fit them but that doesn't look to be the case at all. nice!

 

would rather drive than wash

yeah - super easy to work with, great prices, and got my wheels within a week!


yeah - I'll need to push the rear out about 10-15mm to fit my next set of R-comps...I plan to go w/ a 315 for the 2nd half of the season assuming all goes well (the main concern would be that a 315 wouldn't heat up enough to get to optimal operating temps) - the 315 will also require some fender rolling.

 

oops...fixed.

 

Wow, those fit very nicely! Thanks for the great info. Definitely making me think of going bigger than 275, though like you I have concerns about whether or not I can get enough heat into something as large as a 315, especially since I'm sticking with an NA setup for a while, plus there is a weight and aero trade-off when you start to get into tire sizes that large. For Auto-x there isn't much aero involved given the lower speeds, but lapping days and time attacks a wider tire does generate more drag and accelerating the additional rotating mass of a 315 might be a challenge for a mildly modded G like mine...but since you're running your Z in BSP I can only assume you've got some serious power to go along with all that rubber

If you don't mind me asking, what sort of spring rates and alignment settings are you running? I see you're not running much negative camber -- is that based on feel or data or a street/competition compromise? What about toe alignment? What swaybar setup you running? Appreciate any feedback on this, since I'm sure it'll save me some time sorting out the setup on my G.

 

That is not going to work in the rain.

 

BTW nice rims!

 

true, but my Hoosier wets work wonders

 

Power - I'm at 260 HP at the wheels...BSP doesn't allow FI or any modifications to engine internals (mods: intake/plenum, headers, TPs, exhaust, pullies, flywheel/clutch, ECU tune)

alignment:
camber is around -1.5 all around...tire temps are about 5-10 hotter on the rear inside vs. outside.
Toe: small amount toe in on the front, 0 in the rear. I'll probably go 0 all around this year.

Sways - Med/Med on the hotckis sways. Seems well balanced...over/under steer can occur based upon the loose nut behind the wheel

Coilovers - JIC FLA2...these work really well for smooth surfaces, but I run in a lot that's got a lot of bumps - this causes some issues with traction for me.

Tire Temps: Last year I ran Hankook's 275/17 all around...worked great and was always able to get them up to operating temps (I had to use a water sprayer between runs on any day over 70 degrees to keep them from getting greasy.)

 

I was thinkin about runnin 275/35 Toyo R1R's next time I buy tires runnin a 1" drop on T2 springs...this thread makes me feel a little more comfortable with that idea

 

Awesome, thanks for posting up your setup details. Very helpful!

 

How come you didn't go with 17x10's? They even clear BBK's.

 

I planned to start w/ a 285 Front, 295 Rear...then to step up to a larger size if my fenders could fit them - Hoosier's weren't available in a 285/17, only a 285/18.

*FWIW, I rolled my fenders a few weeks back, and found out that I could fit a 315 in the rear, and a 295 up front - FTW! Tire Rack was nice enough to let me return my 285's...just got these mounted this week!

 

wow.... for the love that is all holy please wash your Z

 

eh ...I'd rather be driving/AutoX/tracking the Z than washing it - with that said, I clean it up when it counts:

 

Come on Peter, that pic is from like a year ago, which was probably the last time you washed it! Was hoping to see those beast at Golden Gardens, but alas it had to snow/rain. Hopefully at the next meet...

 

Damn, I thought my 275s all around was fun... May need to look into a 285/295 setup