Yeah, that's the word I was looking for -- steering was much heavier with wider tires in front for autocross.

 

Good info...Im still undecided as to whether I will stay square or not...I never autocross...I do HPDE's and road racing only...so im not sure yet if the 265/285 will benefit my setup...

btw other mods are:
hotchkis sways
bc coilovers
camber arms front and rear
spec alignment
stoptech st40's
and the 275 35 18 dunlops

 

Quicksilver....at my last track event, I switched from a staggered setup to a square and the car felt a little twitchy to me as well. However, after my first session, I adjusted my tire pressure a bit in the rear and all the twitchiness went away. Before abandoning the ship, I'd play with a couple things....sway bars if you have adjustable ones and tire pressures. I'd have to look under the car to be 100% sure, but I'm 95% sure I have my hotchkis sways set to full soft front and rear and run about 2 pounds less air pressure in my rear tires.

And for the record...I'm running a Nitto NT05 275/40/R17 setup.

 

How do you like the NT05's? was thinking of trying them, heard they were great for lighter weight cars, but was curious from a z owners perspective.

 

I liked them. Had another friend put them on his G35C and he liked them as well. I've only done one track day on them, though.

Here's several people's impressions: https://my350z.com/forum/wheels-and-...05-review.html

 

I myself prefer a somewhat close to square setup... I'm running 18x9.5 all around with 275/40 in the rear and 265/35 in the front. On the track, it doesn't take much to get the back end up, especially if coming in a corner a little fast. But it still feels balanced enough that if your really concentrating you can really get around the corner fast, while just barely feeling the back end wanting to let go.

The rear seems to have proportionately less grip with my 265's up front compared to running 245's front. I like it a lot, but you gotta be ready for some tail sliding fun when near your cornering limit. With wide tire's up front you can get higher corner entry speeds, so if you don't have a normal amount of stagger in back, the back will let go. At least that's the way I see it...

I ran 18x8.5 front and 18x9.5, 245/40 front 275/40 rear and I didn't like it... too much understeer for me.

 

I run 275/35's on 9.5 inch wheels all the way around on the street, hotchkis sways set to full stiff rear and 2/3's stiff front. stock it felt like the car would push at the limit no matter what unless you poured the coals to it. I ran 285/30 V710's on 10" wheels at autox & one track event and the car has no problem rotating on brakes if you trail off at turn in especially with a few more pounds of pressure up front. much more neutral in the corner but its easier to run a pretty good yaw angle which you could confuse with sliding and try to correct for if youre not used to it. give it a shot and just give yourself time to learn & adapt to the changed handling (try it at an autox first), but square definately makes the Z mo' funner :]

 

Do people favor a square setup for autox only? or does this apply to road racing as well...Im starting to see a difference in setup for the two types of racing

 

I posted this question in the other thread, but its also relevant here as well...

Do people favor a square setup for autox only? or does this apply to road racing as well...Im starting to see a difference in setup for the two types of racing.

 

Man... you've got two full threads of options and experiences regarding square vs. staggered and you still haven't made up your mind?

 

I ran staggered for AutoX. Square for Track. Don't AutoX much anymore. Why bother...

 

I hear ya man... sit around for 6+ hours only to get 3-5 minutes of "track time"... Not to mention there are just too many people...

 

There's definitely a difference in setup between the two. Loose and quick to rotate makes a lot of sense (and is very fast) at 20-70mph. Loose and quick to rotate makes a lot of scary **** (and is very slow, due to a lack of confidence) at 70-150mph.

Basically, you want a car that tends toward oversteer for autocross and one that tends toward understeer for road racing, as it's a lot easier to deal with being a bit wider than you intended at 100+mph than it is to deal with being backwards at that speed. (note: "tends toward" means has a slight tendency to go toward that handling trait when pushed beyond the limit. Being fundamentally neutral is still the target for most.)

Also, in autocross, there are no walls, cars, or other obstacles to hit like there are in road racing/tracking, so it's fine if you spin the car every few runs. Spinning the car every few laps on a road course is dangerous. Etc etc etc.

 

Your absolutely right here. At Thunderhill this summer I spun out just before turn 6 doing probably 70 mph. Luckly there was no one around me and I ended up going backwards and off the track in a straight line, so no damage at all, just stalled it. I didn't even feel it coming, and if I had hit a car or spun and stopped in a bad spot, it could of been a very deadly situation.

While I found the feeling of my car wanting to drift every corner very entertaining, it certainly is a lot more dangerous at the higher speeds you achieve on a track. The first corner you take at 90-110 MPH and if I spun there... there would have probably been some damage to my car.

Auto-x your not going as fast and have more room to recover, don't have to worry about bouncing off a rumble strip and then have your wheels get caught in ruts or grass and potentially flipping your car. Not to mention other cars... Although some auto-x courses are in parking lots with those stupid concrete islands with trees in them or shrubs or whatever, that could be bad...

 

In truth it really depends on what the driver is comfortable with, their driving style, and the course itself. There is a reason OEM setups favor understeer. It bleeds off more speed in an emeergency situation, creates greater driver comfort and is easier to be aware of impending impact.

But as driver experience, comfort, and styles change most tend to go more abd more to a slight oversteer setup. I slightly loose car is faster on a road course, the data has shown that. But it does require finer tuning of reactions to constantly changing situations and experience in such a setup.

My advice in this matter is start with what the vehicle came from from the factory, then once you feel you have gotten what you can out of it, make small changes and monitor what it has done for you.

 

exactly right^ there really is not a right or wrong answer for everyone, and no one is going to be able to tell you that one is faster than another. It is all situational. Being fast and consistent comes with trying different things, taking copious notes, and seeing what works for you.

 

Good points. But, it's all moot depending on the track. What works for me in Vegas does not hold true, say, in Fontana on the Roval.

So, once again, seat time is gonna be your best bet.

 

I hate to throw another variable in the mix here, but balance also has a lot to do with overall grip - tire compound, pavement type, wet track, green track, heavily rubbered, etc. Generally increasing overall grip (stickier tires, grippier pavement, etc) makes a car tighter (more understeer) and reducing overall grip (worse tires, worse pavement, wet, etc) makes a car looser.

So you might really want to be square with R-comps, but being square on all-seasons might be less comfortable.

Siegel

 

Seeing as it was 2+ years ago when I posted ..... LOL I've come a long way.

Ended up starting off on a square setup with summer (street) tires, eventually moved to Pilot Sport Cups, stayed square. I didn't like the car w/o that much front grip the few times I tried non-square, turn in was "meh" and it understeered a lot - but that was also because we had an alignment setup that was extremely balanced FOR a square tire setup ... wore perfectly front to rear, inside to out, car could be steered with the throttle but not squirrely, and was stable both at high speed and under braking. Honestly couldn't ASK for a better setup, it's something I'll strive to reproduce in my next track/race car (as I've all but sold the Z to a friend of mine).

 

Anybody running 255's all around? If so, what sizes are y'all using to keep VDC and ABS happy?