Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Go Back   Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum > General > Motorsports and Skilled Driving

Motorsports and Skilled Driving Discussion for Organized Racing and motorsports and tips and techniques at becoming a better driver.


Reply
 
Thread Tools Display Modes
Old 12-29-2006, 05:06 PM   #91
turtl631
Zilvia Addict
 
Join Date: Aug 2004
Location: Milwaukee WI
Posts: 900
Trader Rating: (3)
turtl631 has a reputation beyond reputeturtl631 has a reputation beyond reputeturtl631 has a reputation beyond reputeturtl631 has a reputation beyond reputeturtl631 has a reputation beyond reputeturtl631 has a reputation beyond reputeturtl631 has a reputation beyond reputeturtl631 has a reputation beyond reputeturtl631 has a reputation beyond reputeturtl631 has a reputation beyond reputeturtl631 has a reputation beyond repute
Feedback Score: 3 reviews
JZR, I know you used to do some open track stuff with an S2000. It seems that autocrossers use huge tires more than open track guys. Do you think these huge tires would be ideal on a track where rotational resistance is more of a factor and they have more time to cool off between corners? I remember reading some stuff about corvette guys turning faster times on the track with smaller wheel/tire combos than they use for the quickest autocross times. Just curious, thanks
turtl631 is offline   Reply With Quote
Sponsored Links
Old 12-29-2006, 07:09 PM   #92
jzr
 
Join Date: Jun 2005
Location: San Diego
Posts: 18
Trader Rating: (0)
jzr is an unknown quantity at this point
Feedback Score: 0 reviews
Keeping tires in their ideal temperature range is important. For some very small and light cars it may be difficult to get tires fully up to temp, I've seen this on cars like the Lotus 7 (~1100lbs). With big tires and a really hard compound, a driver may not be able to get the tires to temp.

We played around a bit with tire sizes on the S2000, and the fastest setup was always the largest we had (slicks the equivalent of 285/325's) on a car weighing well under 2400 pounds. Took 1-2 hard laps to really get 'em sticky though.

As for the Corvette story, I would consider the source carefully. I would wager that in any serious (say Speed World Challenge or faster) endeavor, you're not likely to find anybody campaigning a production-based car running any tire smaller than either the maximum allowed by the rules, or the maximum size they can physically fit to the car.
jzr is offline   Reply With Quote
Old 12-30-2006, 12:07 AM   #93
turtl631
Zilvia Addict
 
Join Date: Aug 2004
Location: Milwaukee WI
Posts: 900
Trader Rating: (3)
turtl631 has a reputation beyond reputeturtl631 has a reputation beyond reputeturtl631 has a reputation beyond reputeturtl631 has a reputation beyond reputeturtl631 has a reputation beyond reputeturtl631 has a reputation beyond reputeturtl631 has a reputation beyond reputeturtl631 has a reputation beyond reputeturtl631 has a reputation beyond reputeturtl631 has a reputation beyond reputeturtl631 has a reputation beyond repute
Feedback Score: 3 reviews
Hm, interesting. I guess this is yet another case where common sense/logic doesn't agree with experimental results. Thanks for the input, its always great to hear from people who actually know what they're talking about and have firsthand experience.
turtl631 is offline   Reply With Quote
Old 12-30-2006, 11:43 PM   #94
kapower
Leaky Injector
 
Join Date: Feb 2003
Location: washington,tacoma
Posts: 111
Trader Rating: (0)
kapower is an unknown quantity at this point
Feedback Score: 0 reviews
I auto X in the NWR SCCA. I race an s13 in SM, and competed against an s13 with 335mm r compounds all around. I believe they had 12" wheels x4. I have also raced against the PDM 240.

Don from pdm told me that +4 offset would be about perfect for a 10" wheel up front. But his 17x10 +12 5zygens with 275's up front had 2 5mm spacers stacked together.

so for a 10.5" wheel a good offset maybe...

+2 offset - .25" (6.35mm) = -4.3mm offset or -2.3mm minimuim

I think Don's 275/45/17's bulged out more then a 285/30/18 so there should be a little more clearance with the 18" wheel and tire combo.
kapower is offline   Reply With Quote
Old 12-31-2006, 12:20 AM   #95
kapower
Leaky Injector
 
Join Date: Feb 2003
Location: washington,tacoma
Posts: 111
Trader Rating: (0)
kapower is an unknown quantity at this point
Feedback Score: 0 reviews
Custom made 4 lug 5zygens for the S13 240sx are 17x9 + 20 offset.

The backspacing will vary from wheel to wheel. And clearance will change with tire size, and coil overs but...

-a 10.5 wheel is 1.5" wider (1.5 x .5 = .75) (.75" = 19.05mm)

-19.05mm - 20mm = 0.95mm offset. I think zero offset would be a safe bet, but you could always throw on a quality hub centric 5mm spacer if needed.

On the subject of tire heat. I could heat my rear tires, 225/50/15 V710's, up to 140+ degs in 1 lap the fronts would be about 115-120 deg f. The car had stock everthing sr20 redtop at 14-15psi, Camber 2.5 rear, 4.5 front, with a little toe in on the rear. The 240sx definetly needs 275mm+ for auto X but you'll need a tire warmer (dual driver

IMO a 285/30/18 would be a great tire for an s13 in most auto X conditions.

I think the 275/35/15 will be more affordable, lighter, and lower the car more, but the smaller diameter means less tread contact on the ground so you will have less grip coming out of the corners while accelerating... But may overall be faster...
kapower is offline   Reply With Quote
Old 12-31-2006, 12:41 AM   #96
sideview_180sx
Zilvia FREAK!
 
Join Date: Apr 2005
Location: somewhere north of mexico
Posts: 1,538
Trader Rating: (3)
sideview_180sx is a splendid one to beholdsideview_180sx is a splendid one to beholdsideview_180sx is a splendid one to beholdsideview_180sx is a splendid one to beholdsideview_180sx is a splendid one to beholdsideview_180sx is a splendid one to beholdsideview_180sx is a splendid one to beholdsideview_180sx is a splendid one to beholdsideview_180sx is a splendid one to beholdsideview_180sx is a splendid one to beholdsideview_180sx is a splendid one to behold
Feedback Score: 3 reviews
Send a message via AIM to sideview_180sx Send a message via Yahoo to sideview_180sx
those 5zigen's weren't custom by any means. but if you read up on those who had them, they experienced coilover rubbing issues. I had them and I rubbed up front on the coilover spring, then i took a 5mm spacer to it and it cured that problem.
__________________
feel the rythym. feel the ride. get on up. it's bobsled time. COOL RUNNINGS!!!

formerly sideviewcivic
Save a Horse. Drift This Cowboy.
AirBag Club Member #0014
sideview_180sx is offline   Reply With Quote
Old 01-01-2007, 06:06 AM   #97
jmauld
Zilvia Junkie
 
Join Date: Apr 2003
Location: Cary, NC
Age: 45
Posts: 362
Trader Rating: (0)
jmauld is making a name for him/her selfjmauld is making a name for him/her self
Feedback Score: 0 reviews
Send a message via AIM to jmauld
Since this is relevant to what the original poster was asking about and might be some of the same issues he's going to run into, I'll post my question here.

I've got a set of 285/30/18s that I'm trying to get on my S14 at the moment. Rim size is a 18x9 with 35mm offset. Everything fits fine in the rear. No fender rolling or pulling is necessary.

The front I'm having difficulty with. With no spacers, the rims are hitting the springs on my shocks (bilstein inserts in lowered OEM housing). I can use a 25mm spacer to push the rims out enough to clear the spring, but then the tire hits the fender liners when turning.

I can use a crash bolt to push the top of the rim out some and use a 15mm spacer. However, that only allows me to get about -1.5 degree of camber out of my tein plates. Are there any other camber plates that give more adjustment then the tein plates? Besides slotting the mount holes.

My other option is to put the bilstein inserts into a non-lowered housing and lift the spring back over the tire.

JZR, what are you using to push the bottom of the strut further inboard, and does that screw withthe suspension geometry?


Any other suggestions?
__________________
Jason
'95 240sx SE
jmauld is offline   Reply With Quote
Old 01-01-2007, 07:09 AM   #98
jmauld
Zilvia Junkie
 
Join Date: Apr 2003
Location: Cary, NC
Age: 45
Posts: 362
Trader Rating: (0)
jmauld is making a name for him/her selfjmauld is making a name for him/her self
Feedback Score: 0 reviews
Send a message via AIM to jmauld
Quote:
Originally Posted by kapower
I think the 275/35/15 will be more affordable, lighter, and lower the car more, but the smaller diameter means less tread contact on the ground so you will have less grip coming out of the corners while accelerating... But may overall be faster...
This tire is kind of interesting. I have a set of 15's that they would fit on, so I may give them a try.

My only concern is what they are going to do to the gearing. I've already been running a 225/50/15 which is smaller than the original tires. At most of the local autocrosses, I'm all over the rev limiter in second gear. The 275/35/15 is an even smaller diameter which would end up putting you into third gear. Of course there are some small parking lot courses that these tires would just kick butt on!
__________________
Jason
'95 240sx SE
jmauld is offline   Reply With Quote
Old 01-01-2007, 12:58 PM   #99
jzr
 
Join Date: Jun 2005
Location: San Diego
Posts: 18
Trader Rating: (0)
jzr is an unknown quantity at this point
Feedback Score: 0 reviews
No reason to use the 275/35-15 on the rear except in the case of a relatively low-powered stock car. A turbo 240 is just going to smoke 'em in the lower gears, at least with stock gearing. If you could shoehorn them on the 6" wide stock wheels, could be good for the car in Stock class. There's lots of room in the back to run a tall and wide tire, and it's easy to make even more room with the only sacrifice being the car's overall width.

In the front room is much more limited by the fender seam above and to the rear of the tire. The shorter the tire the better, assuming you can keep the ABS from getting too screwed up. Definitely worth trying up there.

The two ways to get more inboard clearance in front are to increase the length of the strut ears and running smaller diameter springs (2.25" and 2" options are available). Increasing strut ear lengths may compromise things somewhat, but such is life in dealing with strut suspensions.

Rubbing, grinding, and reduced steering lock are facts of life with big front tires on these cars, and it's not limited to strut cars. The Corvette I drove in '05 with 315 front tires, you could only turn the front wheel 3/4 turn before the inside of the rims ground into the control arms. Sure made correcting the all-too-frequent oversteer issues more difficult!
jzr is offline   Reply With Quote
Old 01-07-2007, 11:40 AM   #100
jmauld
Zilvia Junkie
 
Join Date: Apr 2003
Location: Cary, NC
Age: 45
Posts: 362
Trader Rating: (0)
jmauld is making a name for him/her selfjmauld is making a name for him/her self
Feedback Score: 0 reviews
Send a message via AIM to jmauld
Quote:
Originally Posted by jzr
No reason to use the 275/35-15 on the rear except in the case of a relatively low-powered stock car.
For whatever reason, I've got my heart set on DSP. So I'm stuck with a relatively low-powered stock car. (Dyno'd 156hp to the wheels)

However, I got the 18's to fit this weekend.

This week, I'm taking off my shocks and sending them back to Bilstein to be rebuilt. Hopefully they'll be back before the local test & tune. If so, I'll find out how low I can lower the car, and get rid of that slight lean that I have.

Rims: 18x9, +35mm offset. 20mm spacer on the front
Tires: 285/30/18 Hoosier A6s.

No fender mods have been made yet.





__________________
Jason
'95 240sx SE
jmauld is offline   Reply With Quote
Old 01-07-2007, 02:54 PM   #101
nlzmo400r
Zilvia FREAK!
 
Join Date: Oct 2003
Location: louisiana
Posts: 1,248
Trader Rating: (0)
nlzmo400r is just really nicenlzmo400r is just really nicenlzmo400r is just really nicenlzmo400r is just really nicenlzmo400r is just really nicenlzmo400r is just really nicenlzmo400r is just really nicenlzmo400r is just really nicenlzmo400r is just really nice
Feedback Score: 0 reviews
Send a message via AIM to nlzmo400r
Quote:
Originally Posted by jmauld
For whatever reason, I've got my heart set on DSP. So I'm stuck with a relatively low-powered stock car. (Dyno'd 156hp to the wheels)

However, I got the 18's to fit this weekend.

This week, I'm taking off my shocks and sending them back to Bilstein to be rebuilt. Hopefully they'll be back before the local test & tune. If so, I'll find out how low I can lower the car, and get rid of that slight lean that I have.

Rims: 18x9, +35mm offset. 20mm spacer on the front
Tires: 285/30/18 Hoosier A6s.

No fender mods have been made yet.





looks friggin sick, what kind of tires? Look like slicks
__________________
'my drinking team has a racing problem'


[email protected] - gt32 .6bar
nlzmo400r is offline   Reply With Quote
Old 01-07-2007, 02:55 PM   #102
nlzmo400r
Zilvia FREAK!
 
Join Date: Oct 2003
Location: louisiana
Posts: 1,248
Trader Rating: (0)
nlzmo400r is just really nicenlzmo400r is just really nicenlzmo400r is just really nicenlzmo400r is just really nicenlzmo400r is just really nicenlzmo400r is just really nicenlzmo400r is just really nicenlzmo400r is just really nicenlzmo400r is just really nice
Feedback Score: 0 reviews
Send a message via AIM to nlzmo400r
oops, nvmd, reading pwns me. How does the 285 fit on the wheel? Any closer pictures of the actual tire on wheel
__________________
'my drinking team has a racing problem'


[email protected] - gt32 .6bar
nlzmo400r is offline   Reply With Quote
Old 01-07-2007, 03:07 PM   #103
jmauld
Zilvia Junkie
 
Join Date: Apr 2003
Location: Cary, NC
Age: 45
Posts: 362
Trader Rating: (0)
jmauld is making a name for him/her selfjmauld is making a name for him/her self
Feedback Score: 0 reviews
Send a message via AIM to jmauld
Is this what you're looking for? I think the tire fits on the rim pretty good. To be honest, I was expecting it to bulge out a little more.

__________________
Jason
'95 240sx SE
jmauld is offline   Reply With Quote
Old 01-08-2007, 08:00 PM   #104
nlzmo400r
Zilvia FREAK!
 
Join Date: Oct 2003
Location: louisiana
Posts: 1,248
Trader Rating: (0)
nlzmo400r is just really nicenlzmo400r is just really nicenlzmo400r is just really nicenlzmo400r is just really nicenlzmo400r is just really nicenlzmo400r is just really nicenlzmo400r is just really nicenlzmo400r is just really nicenlzmo400r is just really nice
Feedback Score: 0 reviews
Send a message via AIM to nlzmo400r
yea, thats what I was talking about, it does fit really well. Makes me think it would want to stretch on a 10.5
__________________
'my drinking team has a racing problem'


[email protected] - gt32 .6bar
nlzmo400r is offline   Reply With Quote
Old 01-08-2007, 11:54 PM   #105
jzr
 
Join Date: Jun 2005
Location: San Diego
Posts: 18
Trader Rating: (0)
jzr is an unknown quantity at this point
Feedback Score: 0 reviews
That fitment isn't *bad* per se, but it would be better with a wider wheel. You can see the tread edge is rounded a bit, a wider wheel would flatten out the tread surface somewhat. I'll try to get a pic of mine on an 11" in the next day or two...

You car looks great Jason! I think it could be a great choice for DSP, go kick some BMW ass!
jzr is offline   Reply With Quote
Reply

Bookmarks


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -6. The time now is 10:54 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
vB.Sponsors
Copyright © 1998 - 2019, Zilvia.net™