Does the Z have a rear toe-steer problem?

kenchan

You don't value my post?

Guard Dad

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?

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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.

dAvenue

Megan Racing

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Guard Dad

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

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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.

dAvenue

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

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ChrisSlicks

He said he wanted good feedback

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.

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Hotchkis ARB | Stillen CAI | Art Pipes | Berk CBE | Stillen AP Racing Brakes | AE Performance Oil Cooler | BC Racing ER Coilovers | Doran Control Arms

Guard Dad

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.

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

ChrisSlicks

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.

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Hotchkis ARB | Stillen CAI | Art Pipes | Berk CBE | Stillen AP Racing Brakes | AE Performance Oil Cooler | BC Racing ER Coilovers | Doran Control Arms

Guard Dad

In your case did you change the torque arm length or did you set it at the stock length? The implication of the Megan product description is that by adjusting the torque arm length the toe characteristics can be altered-your experience suggests otherwise. 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.

ChrisSlicks

It is more track oriented than street (mine is from SPL). First they eliminate the rubber bushing to get rid of random flex, and second you can use it to alter the bump steer slightly. But like I said before I'm not sure that the suspension is compressing enough to actually induce bump steer in your case, but rather the back end is bouncing off the bumps as a result of the spring rate, or to be more accurate wheel rate as Red pointed out.

__________________
Hotchkis ARB | Stillen CAI | Art Pipes | Berk CBE | Stillen AP Racing Brakes | AE Performance Oil Cooler | BC Racing ER Coilovers | Doran Control Arms

Guard Dad

So your thinking shocks are the first option?

Somewhat off topic (maybe) but I notice that those forum members that install coil overs always seem to comment that the ride has improved. This seems counter intuitive considering that most of these applications involve a 1.5" to 2" drop which, in my experience, usually makes the ride choppy and harsh. Now back on topic. Are our shocks known to be a problem? Is improved ride with coil overs the result of better shocks (I'm not interested in a sloppy ride) or is something else going on here and can any of this in any way be used address my concerns about bump steer?

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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

ha!

softening the rear damp rate will not help, actually will make it worse.
swaybars will not help in this case either.

it's completely related to the amount of stroke, toe-in angle on the rear, and damp rate. ive already experimented with this on my G35C and it's got a similar suspension geometry. it's a programmed design of this kind of suspension. i already mentioned on my earlier post on how to reduce this feel. this is another reason why im not running lowering springs on stock dampers.

Red__Zed

the shortened torque arm and adjusted angle on the 370z changes things a bit vs the g35. The change results in the car generating additional toe-in under corner load, and if you take dynamic toe measurements, you will generally notice that the 370z is prone to over-toe, whereas the g35/350 struggle with stability due to no toe gain. It is a big part of the reason the 350 was unpredictable on corner exit.

kenchan

the principle is the same. the rear toes-out as the suspension compresses. that's why the wiggling butt. the 370Z is much improved vs the G35C, but as i mentioned, the design shares the same principle.

Red__Zed

except the shortened torque arm creates toe-in on compression. the funky wandering feeling described here (and in many other threads) comes from excessive toe-in.


I can't speak for the G35 for sure, but when I did bump steer measurements on my 370, I started at ~1/16*, and went to ~3/32* at full compression on the rear.


You can hook your Z up to a bump steer gauge if you don't believe me.