The Official 370Z Autocross Thread

[theDreamer]

AutoX Z, let me know when/where you are going to Autocross next, I might come out for some Z support and watch/learn for later.

[pgrmstr]

http://scca.com/documents/Fastrack/0...strack-nov.pdf

Looks like its official....CS for 2010

While the 370z is not specifically mentioned, it was classed under the 350z line item so does indeed move to CS for next year.

[AutoX Z]

So I'm getting everything in order to go ahead and start prepping my car for next season.

At this point I don't think I'm going to have enough money for new dampers but I also don't think there are any quality solutions at the moment so I'm ok waiting on that.

I'm just going to get an extra set of sport rims, nismos are too expensive/hard to find and not worth it for a couple pound savings per rim on a car with this much power.

For Hoosiers I'm looking at the 265/35/19 for the front and 295/30/19. Both are a bit smaller in diameter than stock but its the only options at the moment so hopefully it won't have too great of an effect on the gearing which is about perfect right now for autox. I'll crunch the numbers later to see how much top end I'm losing but like I said its the only option so it doesn't really matter right now.

Which brings us to the swaybar. This is where I need some help from yall picking the right one. My feel of the car is that it flops around like crazy in quick transitions and the steady state balance is understeer. I know alot of the behavior in transitions is better fixed with improved damping but again probably out of the picture for this year so how big of a bar would you recommend without making the steady-state balance even worse. I know in theory a big bar can help reduce understeer in camber-challenged cars such as ours but traditional knowledge also says that in general the stiffer front end will reduce front end grip, so where's the balance? Any input/experience on this would be greatly appreciated.

I want to show what the 370 is capable of, I may not be the perfect driver for the job, but I know the car can win so please help me out.

[boosted180]

Originally Posted by AutoX Z

Which brings us to the swaybar. This is where I need some help from yall picking the right one. My feel of the car is that it flops around like crazy in quick transitions and the steady state balance is understeer. I know alot of the behavior in transitions is better fixed with improved damping but again probably out of the picture for this year so how big of a bar would you recommend without making the steady-state balance even worse. I know in theory a big bar can help reduce understeer in camber-challenged cars such as ours but traditional knowledge also says that in general the stiffer front end will reduce front end grip, so where's the balance? Any input/experience on this would be greatly appreciated.

I want to show what the 370 is capable of, I may not be the perfect driver for the job, but I know the car can win so please help me out.

from my experience, the sway bars definitely help tremendously with quick transitions/ slaloms. my first auto-x was stock except for eibach springs. the next was with springs, sway bars, and spc front camber arms. i have the hotchkis, but if i had to do it over, i would go with the stillen as i feel the hotchkis are a bit TOO stiff in the front, which induces some understeer. but most of it is dialed out in my car with increased front camber. at this point, it feels just right for track use, but on tight auto-x courses, it still understeers a bit more than i'd like. i'm ok with where it is now as i see much more track time than auto-x.

so to answer your question, i think you'll see a huge difference with the addition of sway bars (i'd recommend the full set of stillen) and added front camber. you will be much quicker through the slaloms and the understeer problem will be mostly mitigated by the increased front camber.

[pgrmstr]

we can't mess with camber outside factory adjustments, and all we are allowed from a suspension standpoint is front swaybar and dampers that use factory springs, mounts, height, etc.

so swaybar is a must with camber challenged cars to prevent eating costly hoosiers....although I will likely go with Cusco for the adjustability up front

adjustable dampers - koni is supposedly developing SA units but no word, AST is looking at making some but no word, no idea if SA or DA and cost is unknown

was just looking for options and thought about the Nismo units

[pgrmstr]

for the 350z guys with experience, what was your baseline settings for your shocks...front and back?

[Ruff]

Originally Posted by pgrmstr

for the 350z guys with experience, what was your baseline settings for your shocks...front and back?

You looking for dyno charts or what? On my car I only had ots Koni's. I ran them about 90 % full stiff (rebound) and 50% rear.

Glenn's car drove and felt far superior to mine (the car I drove at Nationals) but he has custom valved koni da's. The shocks are Carter Thompson's old shocks. Not sure what settings Glenn runs them on.

[Ruff]

Run 295's square...seriously...

And I'd run as big as bar is available on the market, it will help put the power down.

I'd be suprised if the car can get it done without shocks, the 350z sure as hell can't...

[ChrisSlicks]

I installed the Hotchkis sway bars, full set. The car was dramatically better in transitions, however it made the low and mid speed understeer much worse. I can only imagine that it would be worse still without the rear bar. I corrected the understeer by adding front camber using the SPC replacement upper arms. I'm going to build the car up for BSP as I want to focus on track as much as Auto-X.

[Ruff]

Originally Posted by ChrisSlicks

I installed the Hotchkis sway bars, full set. The car was dramatically better in transitions, however it made the low and mid speed understeer much worse. I can only imagine that it would be worse still without the rear bar. I corrected the understeer by adding front camber using the SPC replacement upper arms. I'm going to build the car up for BSP as I want to focus on track as much as Auto-X.

What size tires were you running front and rear?

The reason I say go square is will help with the low speed understeer, even with the bigger front bar.

For stock class, I really don't think the car can get it done without shocks. But regardless, run a big front bar and a square tire setup.

[ChrisSlicks]

Originally Posted by Ruff

What size tires were you running front and rear?

The reason I say go square is will help with the low speed understeer, even with the bigger front bar.

For stock class, I really don't think the car can get it done without shocks. But regardless, run a big front bar and a square tire setup.

I'm running 275 front 305 rear. Didn't really want the 305 rear but it was the best fit diameter wise. I think the front is pretty much maxed out for the stock size rims. Hoosiers would help but I think you'll be cording them pretty quickly with the stock alignment.

The stock shocks actually seem to work pretty well in conjunction with the uprated sway bars, although probably not quite as well in stock class as you are stuck with the stock rear sway bar.

[Ruff]

Originally Posted by ChrisSlicks

I'm running 275 front 305 rear. Didn't really want the 305 rear but it was the best fit diameter wise. I think the front is pretty much maxed out for the stock size rims. Hoosiers would help but I think you'll be cording them pretty quickly with the stock alignment.

The stock shocks actually seem to work pretty well in conjunction with the uprated sway bars, although probably not quite as well in stock class as you are stuck with the stock rear sway bar.

That's your problem right there with the low speed understeer. And no way in hell are you maxed out on 275s on stock wheels, we run 295 hoosiers on the stock 18x8 350z wheels with no problems, and by far the quickest setup with the car being super neutral. Unless you are talking street tires that are dual purpose. Then you're on your own and the car will kinda suck at autoxing. Until you got to a square setup, you'll going to have tons of understeer auto-xing a Z. And with that much rubber up front, even with stock alignements, they last quiet a while.

[theDreamer]

AutoX Z, when is the next event on the north side of Houston?
I was unable to attend the last event you sent me a link to, but I still really would like to come out and watch, learn, etc.

[Spec Jay]

wow. i like how the nismo 370 got placed into BS and the regulars into cs. i thought the cars were the other way around? :P
anyway. ill be autocrossing again this season its been 3 years since ive done it in my sentra. the 370 should give a interesting learning curve for me hopefully i wont be too far behind with it being the overdog in cs. btw did the cs/bs merger go through?

[Ruff]

Originally Posted by Spec Jay

wow. i like how the nismo 370 got placed into BS and the regulars into cs. i thought the cars were the other way around? :P
anyway. ill be autocrossing again this season its been 3 years since ive done it in my sentra. the 370 should give a interesting learning curve for me hopefully i wont be too far behind with it being the overdog in cs. btw did the cs/bs merger go through?

Yes, and may I please take it for a run or two?