Does the Z have a rear toe-steer problem?
 

Those of you who have tracked the Z might be able to fill me in on this question.

When cornering briskly (a 70 mph interchange sweeper) if I hit a bump the front stays planted but the rear steps out aggressively when it gets light at the top of the bump. My other cars (04 T-Bird and 11 Volvo XC60, both IRS) take the corner with much less drama. Is this a toe steer or dampening issue or perhaps something else? Your thoughts would be appreciated.

I've complained about the same thing. I'm curious as to what the other guys will say about this.

The rear toes out as the suspension compresses. To minimize this butt wiggling feel you would want to dial in more toe-in and if you can, stiffen up your rear damper setting.

Btw this phenomenon is called bump steer.

I'm hoping to get some good feedback. It could be toe steer or possibly a damper issue.

This reminds me of a problem Suzuki had with the first generation, long travel suspension, RM 250 MX bike. The rear suspension just didn't behave well on big bumps. Turned out the rebound dampening was excessive and the rear wheel spent too much time in the air before returning to the ground after each bump. A wheel in the air can't generate cornering force. I keep thinking that our situation is something like the Suzuki's problem.

You don't value my post?

Is this condition improved with a change of dampers or switching to coil overs?

I appreciate your response a great deal, I just didn't see it because I was responding to the first responder when your response was posted.

Does anyone offer a bump steer kit to correct this condition?

He said he wanted good feedback :p

Just kidding!

I don't think it is bump steer (although you can get some), I think it is mostly the rear bouncing over harsh bumps as the suspension isn't as compliant as average car due to it's sporty setup.

Not sure of an ideal solution, you can make the suspension softer but then you ruin the sportiness for the smoother corners. Stiff rear sway bar can also make it worse.

Thanks for the link, do the actually do what they say they will do?

I really don't know, but the description fits the problem IMO.

I hear you. I'm hoping that someone has successfully addressed this issue so that we can learn from their experience.

The Megan toe links might be the ticket, maybe someone here has first hand experience with them.

I'm thinking that a good double-adjustable rear shock might be able to moderate the condition, any thoughts?

I'm hoping to avoid just throwing money at the problem.

Most of the dynamic comes from the high wheel rate out back, as well as the dynamic change in rear toe mid-corner (both of which have been jacked up vs the 350)

Nissan basically improved full-on-throttle corner dynamics at the expense of off- and partial-throttle dynamic. The 350 had a tendency to step out under throttle due to insufficient toe in the rear. For the 370z, Nissan dialed in a suspension setup that would increase rear toe more significantly during cornering, and you wind up with a bit of a "floaty" or unstable feel from the excessive toe-in. You couple this with the high wheel rate, and you get exactly what you are talking about.

I have adjustable traction arms, I don't think they really help in this situation (you already have them they just aren't adjustable).

Adjustable shocks tuned for stock spring rates are probably the best option, soften the settings for daily driving and then turn them up for weekend canyon carving.