Does the Z have a rear toe-steer problem?

Guard Dad

Is more toe going to eat the rear tires, or do you just bias it to the factory maximum spec for toe in? Whose dampers do you like?

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2010 Brilliant Silver, Base w/Sport Package, AT7, Katzkin leather, upgraded audio and lots of Dynamat and a bunch of small stuff.

Red__Zed

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.

Guard Dad

What you are describing is toe-in when the rear suspension is in a compressed condition and a toe-out in a rebound condition, am I correct?

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2010 Brilliant Silver, Base w/Sport Package, AT7, Katzkin leather, upgraded audio and lots of Dynamat and a bunch of small stuff.

kenchan

if that was true, dont you think i would've jumped on c/o's 2 yrs ago?

the reason why my car has stock springs and dampers is to maintain balance and stoke for street. the car can use stiffer dampers so this is why ive been thinking about running koni's and using stock springs. lower ride does not = better handling. actually it worsens it on street as it's not a controlled surface like on the track.

Guard Dad

Kenchan, Red_Zed, I'm learning a lot here but if I'm reading your posts correctly kenchan says it toes out under compression and Red_Zed says it toes in under compression. Pick one.

My butt-o-meter suggests that the rear suspension gains significant toe in as it compresses because the car smartly (more like abruptly) steps back in line as the suspension compresses as it lands on the far side off the bump. If the toe change is radical enough that it goes to a near zero toe or (worse) a toe out condition at full droop when it launches off the bump and then gains a lot of toe in on compression we might be onto something as such a behavior would cause the condition I seem to be concerned about.

Comments?

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2010 Brilliant Silver, Base w/Sport Package, AT7, Katzkin leather, upgraded audio and lots of Dynamat and a bunch of small stuff.

Guard Dad

Red_Zed, am I reading that right a total increase of 1/16" additional toe in? Is that from full droop to full compression?

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2010 Brilliant Silver, Base w/Sport Package, AT7, Katzkin leather, upgraded audio and lots of Dynamat and a bunch of small stuff.

Red__Zed

Yes, and yes. The change from full droop to body weight compressed is relatively minor, too, so most of the toe is getting dialed in on compression from rest.

Guard Dad

A little context please: I've done a lot of reading on suspension design over the years and I know that bump steer is generally to be avoided. Since bump steer characteristics, on a production car, are rarely adjustable I have no practical experience altering them, so please help me out, is a 1/16" toe change (most of it on bump) considered to be a lot/excessive for a car such as the Z?

When contemplating the Megan Torque Arm as a possible solution:

1. Changing the inner pivot point (dropping it or moving it in a bit, probably not practical) could alter the bump steer profile.

2. Changing it's length (most likely longer) would reduce the angularity of the torque arm over it's length of travel which should "soften" or reduce the total amount of toe change. This assumes that there is enough adjustability in the torque arm to make a meaningful increase in length and enough adjustability in the rear suspension to bring the static toe and camber adjustments back into spec.

Comments?

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2010 Brilliant Silver, Base w/Sport Package, AT7, Katzkin leather, upgraded audio and lots of Dynamat and a bunch of small stuff.

cossie1600

I bought better tires, redid the alignment and the problem went away. My car felt nervous as I drove home from the dealership too

Guard Dad

Don't keep me in suspense, what tires, what alignment specs?

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2010 Brilliant Silver, Base w/Sport Package, AT7, Katzkin leather, upgraded audio and lots of Dynamat and a bunch of small stuff.

kenchan

I don't know wat happened on your car, but on mine the stock rear toe-in appears pretty aggressive as it is. 4K on the stock tires and 1/2 worn. I'd want more toe-in?

Redzed- I will need to check into wat you posted.

cossie1600

The RE050a just wears fast, half worn at 4K is probably a little high, but not out of the norm

cossie1600

I honestly don't remember off the top of my head. Alignment on new cars can be spotty given the abuse some of them had. I traded in a stock RX-8 that had Direzza Star Specs and a relatively tame alignment on it. The car handle corners with grace and had no drama. On the way back from the dealership, the Z felt nervous at the same exact speed on the stock RE050a. I immediately went out and bought myself a set of RE11 along with an alignment. I basically put together to 1/16 toe in in the front, about 2 degrees of camber in the back along with I believe about 1/8 in toe in in the back. The nervousness I had with the car was gone right after. Heck, it took me a good two years before I had anything close to a spin.

Guard Dad

Interesting. Mine has been rock solid in all modes from the day I got it except for this one issue. That's the reason for my initial post, the apparent bump steer issue stands out because every thing else is so good.

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2010 Brilliant Silver, Base w/Sport Package, AT7, Katzkin leather, upgraded audio and lots of Dynamat and a bunch of small stuff.

Red__Zed

I am choosing my words carefully here to avoid having them misconstrued by some of the overly sensitive members here, so the answer I will give is I believe so
I would agree with both of these. I also agree that the first is likely not practical.
I have no real experiece with the Megan arms, but I am always hesitant to use Megan parts. I know that a longer arm is needed to get good bump dynamic, but at the same time, I don't imagine you have the time/money to play around with a bunch of different parts.

If you do get the Megan arms, definitely post up thoughts though. I'd be curious to see if it sorts out the craziness (and it would be pretty helpful for anyone else that experiences it)