Horrible handling

SPOHN

Pretty sure there's nothing wrong from the accident. Been driving perfect on the street even when pushing it. I feel the sway is goingto be the biggest thing. Toe will be check next Friday to ensure. Thanks for everyones help.

__________________

Mike

I told you sway bar from the get-go. Unfortunately, there really is no way of safely testing other than the track.

__________________
NISSAN: 75 280Z / 86 300ZX GLL /87 Sentra SE / 03 350Z / 23 Z
Porsche: 93 968 / 23 Macan GTS / 93 968

Shamu

If you merely pulled car back to factory specs and didn't reinforce rear pickup points you may have some fatigued metal that allows rear suspension to deflect when under loads at the track. I have seen this too. That might explain feels fine on street but then gets funky on track, but too much rear bar is rarely a good thing for a track car. I run stock nismo rear bar with soft springs in rear to keep power down.

Also are bar mounting points all in stock spec? If something was moved in accident you may be getting strange loading of the bar.

__________________
Grant

laze1

Shock settings can also cause this problem for sure...or a busted shock maybe.

Check and record all your shocks settings....

Mt Tam I am

I hope you are on the solution trail. I am surprised you do not have video though.

__________________
Nissan Motorsports 34R Oil Cooler. Stillen CBE. Hotchkis Sport Sway Bars. KW Variant 3 Coilover System. Stillen Gen3 CAI. Michelin Pilot Super Sport. Stillen Brake Ducts. Carbotech™ XP10/XP8 Pads. Z1 Front Rotors. Z1 Stainless Brake Lines. Two degrees of camber

Mike

I suggested the bar because when I went from a street to track only alignment from the same shop, I had to soften my rear bar for the same symptoms.

__________________
NISSAN: 75 280Z / 86 300ZX GLL /87 Sentra SE / 03 350Z / 23 Z
Porsche: 93 968 / 23 Macan GTS / 93 968

laze1

Yep, a full hard rear bar is almost always TOO MUCH rear roll stiffness...that is for Autocross where you need to kick the rear end around to rotate the car. You don't want that to happen at a high speed track like Road Atlanta/Roebling/etc :-(

I "ain't no" Engineer, but sway bars are used to fine-tune a suspension that is already setup correctly. So if you are running a full hard rear bar, you are overcoming a another setup/tuning issue.

My humble recommendation is to start out very soft on all adjustments (shocks/ASB) and them work your way towards a more firm setting. And tire pressures play a part in this adjustment as well. To start go with the manufacturers hot pressure recommendation and then work from there to fine tune feel and total grip. Adjusting tire pressure has the same effect as changing spring rates...higher pressure is like adding higher spring rates...CHECK TIRE PRESSURES ALL DAY LONG...THEY MATTER.

Shamu

I autocross all the time and dont need anything more than stock nismo rear bar to rotate easily. The Grand Am cars were using small rear bar as well. These cars have no issues with turning if they are setup properly. Honestly a larger rear bar on full firm is disater waiting to happen. No wonder this car spun like a top originally.

Only car I would use large rear bar might be a FWD car.

__________________
Grant

martin82

I run stiff up front and softest in the rear for whiteline, car handles great....

M.Bonanni

There's no standard sway bar setting for every car. There's a whole list of things that can affect where your sway bars should be set. The track alone is a major one, I have completely different sway settings for different tracks. What you have done to the rest of your car is also a huge factor: spring rates, dampening settings, tire size, tire compound, alignment settings, suspension geometry, aero, diff settings, and all of that put together and how they react with one another. I guess my point is, there's no way any of us can say that having your rear sway on full stiff is always bad. There's just too many other pieces of the puzzle we don't have.

__________________
MikeBonanni.com
Twitter: http://www.twitter.com/MikeBonanni
Facebook: http://www.facebook.com/MBonanni36
Function > Form

SPOHN

^very true. I had no issues with full stiff in the rear until I added a cage at Road Atlanta. Then when going to AMP which is all down hill off camber turns it threw me for a loop. I guess I took it for granted. More to learn.

__________________

laze1

check you shock settings...

Shamu

Just saying something is wrong if someone needs full firm on larger aftermarket rear swaybar. I'd be looking at every element to assure that wasn't something in my equation.

__________________
Grant

M.Bonanni

If we're speaking in general then I disagree, especially if you don't have a wide array of spring rates/dampers/alignment tools/tire sizes/etc at the track which I am sure none of us do. Sometimes you have to stiffen up the rear sway to compensate for other parts of the setup or even conditions. A super bumpy track with a lot of tight turns might be an example. You wouldn't necessarily want really stiff spring rates yet you would want to stiffen up the rear to rotate through the low speed corners. Keep in mind I am talking in terms of using off-the-shelf parts not fully adjustable fully custom real race car parts. Sometimes we have to make do with what we've got access to which isn't always the ideal situation.

Now if we're talking about the OP's case in particular then I don't think he needs to be full firm on the rear sway at all, I think that is the problem, or a large part of it. Toe issues under load would likely feel more squirmy and unpredictable (like this ) or even result in snap oversteer and not a gradual predictable mid-corner/exit slide. A broken shock would also not be a gradual and predictable loss of traction plus handling would be different in right handers vs. left handers and it would also be felt under braking as the broken side would not be controlling the spring. Shocks settings is the next likely issue but I still still think its a combo of the rear sway being too stiff and application of the throttle being too early which is breaking the rear traction. It's the fact that the oversteer is gradual and predictable that makes me think its handling balance/driving related instead of a mechanical issue.

Anyway, just my two cents. Hard to say anything for sure without data or driving it myself.

__________________
MikeBonanni.com
Twitter: http://www.twitter.com/MikeBonanni
Facebook: http://www.facebook.com/MBonanni36
Function > Form

Shamu

We can agree to disagree. I would argue your baseline setup is flawed if you need to go full firm in rear. Increasing roll stiffness in rear on our cars is big no no. He'll I run 1000 lb fronts and 450 lb rears with stock rear bar. My car still turns well enough that I don't have to touch a thing in ax. Obviously JRZs give me tons of adjustment. I just increase front bump for track. But again with way our suspension dynamics work if you find full firm in rear is only way to turn you haven't set baseline up properly. Believe me I have had top teams work with me in analyzing setup and our cars already have issue getting power down increasing rear bar is just going to lift wheel easier etc.

__________________
Grant