Autocross questions

Blue Gumby · 06-21-2012, 12:58 PM

Just picked up a Z w/ sports package. Looking for tires for RTR class. Noticed people talk about Re11 in 285/35/19, but how about 275/30/19 size.

Cons are smaller contact patch, 84 bucks more for narrower tire (tire rack).

Pros include better rim fitment, lowers car more than half inch (1.3 inch diff) for more camber and better C.G., better gearing = better acceleration, 2 pounds lighter per corner.

Anyone tried the Koni yellows for autocross yet? Was thinking picking up a set and sending them to Lee Grimes for revalve and degassing. AST are nice but too much money.

cossie1600 · 06-21-2012, 01:08 PM

I am all about saving money, but you have to pay to play. I think you will get tons more wheelspin and the bigger tire will not overheat quite as easily

Shamu · 06-21-2012, 01:50 PM

Can you go down to 18's? I'd go there before going to different 19 setup.

ChrisSlicks · 06-21-2012, 02:03 PM

Quote:

Originally Posted by Shamu

Can you go down to 18's? I'd go there before going to different 19 setup.

In stock class no, not legally.

AutoX Z · 06-21-2012, 07:25 PM

The smaller tire won't have any effect on camber. It will change the gearing slightly but I don't think this will really help. The 295 Hoosiers are 30 series and I end up on the limiter on a lot of national courses. At Blytheville the other week I was going into third for an entire section of the course.

///MSH · 06-21-2012, 08:57 PM

18's and bigger. AutoX Z didn't mention how fun it was hitting 3rd. Most everyone hit third...I believe the gear reduction puts us on a more level playing field.

Blue Gumby · 06-21-2012, 09:11 PM

i'm new to the car but I thought our top of second gear was close to 70 on coupe/sports model

cossie1600 · 06-21-2012, 09:42 PM

I think 66 or something, but everyone is different with different size tires

AutoX Z · 06-23-2012, 07:58 AM

Mine is GPS confirmed 64 mph.

Blue Gumby · 06-23-2012, 05:01 PM

Heads up on a great deal Z1 Motorsports: 19" Lightweight Nismo Silver Wheels $998 Shipped

Sports package size and offset with a little weight saving for stock class autocross.

IMWEZL · 06-24-2012, 05:42 PM

370Z Auto cross GOPR0394.MP4 - YouTube

Had another blast at the Hutchinson Island Auto-X. After the first long right hander going into the crossover I kept on experiencing a slight miss or hesitation. It didn't really feel like fuel cut or clutch slippage but it kept happening at the same spot.

Other than that I probably could have picked up more speed after the slalom by not slowing down as much and taking a different line.

ChrisSlicks · 06-24-2012, 07:22 PM

Quote:

Originally Posted by IMWEZL

After the first long right hander going into the crossover I kept on experiencing a slight miss or hesitation. It didn't really feel like fuel cut or clutch slippage but it kept happening at the same spot.

Minor fuel starvation most likely, although it usually progressively gets worse as the fuel level drops on each run.

03threefiftyz · 06-25-2012, 07:55 PM

Hmmm...

Cut down a hoosier on landing.

mdxj · 06-25-2012, 08:09 PM

Quote:

Originally Posted by 03threefiftyz

Hmmm...

Cut down a hoosier on landing.

Wow.... Must have been fun

06-21-2012, 01:50 PM	#183 (permalink)
Shamu A True Z Fanatic Join Date: Jan 2011 Location: Nor Cal Posts: 1,059 Drives: 370Z Racecar Rep Power: 19	Can you go down to 18's? I'd go there before going to different 19 setup. __________________ Grant

06-21-2012, 07:25 PM	#185 (permalink)
AutoX Z Enthusiast Member Join Date: Jun 2009 Location: Houston, Tx Posts: 314 Drives: 370Z Base, Sport Rep Power: 15	The smaller tire won't have any effect on camber. It will change the gearing slightly but I don't think this will really help. The 295 Hoosiers are 30 series and I end up on the limiter on a lot of national courses. At Blytheville the other week I was going into third for an entire section of the course. __________________ 2013 SCCA Solo National Champion VVV For Sale VVV

06-21-2012, 08:57 PM	#186 (permalink)
///MSH Base Member Join Date: Jul 2011 Location: Owasso, OK Posts: 86 Drives: '11 370Z Nismo Rep Power: 13	18's and bigger. AutoX Z didn't mention how fun it was hitting 3rd. Most everyone hit third...I believe the gear reduction puts us on a more level playing field. __________________ 2011 Nismo with...Stillen Gen3 CAI, FI LTH's, Stillen CBE with Springfielddyno rear section. Stillen under drive crank pulley, UpRev, and LW flywheel. Penske 8300DA Valved by ANZE, SPR FCA's, Stillen F/R adj. sway bars, Enkei PF01's, and Hoosier A6's

06-23-2012, 07:58 AM	#189 (permalink)
AutoX Z Enthusiast Member Join Date: Jun 2009 Location: Houston, Tx Posts: 314 Drives: 370Z Base, Sport Rep Power: 15	Mine is GPS confirmed 64 mph. __________________ 2013 SCCA Solo National Champion VVV For Sale VVV

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06-21-2012, 12:58 PM	#181 (permalink)
Blue Gumby Base Member Join Date: Jun 2012 Location: new york Posts: 31 Drives: 370z Rep Power: 12	Just picked up a Z w/ sports package. Looking for tires for RTR class. Noticed people talk about Re11 in 285/35/19, but how about 275/30/19 size. Cons are smaller contact patch, 84 bucks more for narrower tire (tire rack). Pros include better rim fitment, lowers car more than half inch (1.3 inch diff) for more camber and better C.G., better gearing = better acceleration, 2 pounds lighter per corner. Anyone tried the Koni yellows for autocross yet? Was thinking picking up a set and sending them to Lee Grimes for revalve and degassing. AST are nice but too much money.

06-21-2012, 01:08 PM	#182 (permalink)
cossie1600 A True Z Fanatic Join Date: Jun 2009 Location: californee way Posts: 5,380 Drives: 370, Leaf Rep Power: 29	I am all about saving money, but you have to pay to play. I think you will get tons more wheelspin and the bigger tire will not overheat quite as easily

06-21-2012, 09:11 PM	#187 (permalink)
Blue Gumby Base Member Join Date: Jun 2012 Location: new york Posts: 31 Drives: 370z Rep Power: 12	i'm new to the car but I thought our top of second gear was close to 70 on coupe/sports model

06-21-2012, 09:42 PM	#188 (permalink)
cossie1600 A True Z Fanatic Join Date: Jun 2009 Location: californee way Posts: 5,380 Drives: 370, Leaf Rep Power: 29	I think 66 or something, but everyone is different with different size tires

06-23-2012, 05:01 PM	#190 (permalink)
Blue Gumby Base Member Join Date: Jun 2012 Location: new york Posts: 31 Drives: 370z Rep Power: 12	Heads up on a great deal Z1 Motorsports: 19" Lightweight Nismo Silver Wheels $998 Shipped Sports package size and offset with a little weight saving for stock class autocross.

06-24-2012, 05:42 PM	#191 (permalink)
IMWEZL Track Member Join Date: Apr 2009 Location: HNL Posts: 603 Drives: 370Z/MKVII GTI Rep Power: 17	370Z Auto cross GOPR0394.MP4 - YouTube Had another blast at the Hutchinson Island Auto-X. After the first long right hander going into the crossover I kept on experiencing a slight miss or hesitation. It didn't really feel like fuel cut or clutch slippage but it kept happening at the same spot. Other than that I probably could have picked up more speed after the slalom by not slowing down as much and taking a different line.

06-25-2012, 07:55 PM	#193 (permalink)
03threefiftyz Track Member Join Date: Apr 2010 Location: MD Posts: 536 Drives: 03 350z 6mt Rep Power: 16	Hmmm... Cut down a hoosier on landing.