Chassis Help! Need a track day set-up.

BGTV8 · 03-06-2017, 04:09 AM

1.0 deg neg at the rear is about right.

If the car feedback is abrupt and giving you a "holy cr4p" moment, then I would put a switch in the car to isolate yaw sensor as first step - takes an hour or so if you have crimper,s some wire and a switch.

If the car feedback is the same with yaw sensor disabled, then I would suspect rear wheel bearing, or rear-steer as a consequence of rear suspension bushing that are FUBAR. You can check wheel bearing by seeing if there is any free play with a wheel unloaded (in the air).

A pry-bar on suspension rods will give you an idea on bushes.

I am assuming that the crab-walk is coming from the rear per your original post.

Other alternatives to look at are rear tyre falling over (what pressures are you running - this can only really happen if pressures are really low - like 20psi)

The other thing is that the tyres are too wide for the rims - especvially at the rear ..

According to my version (Australian) of Tyre and Rim Assoc book, 325 width needs an 11" wheel minimum and 12" max. I would not have thought that 10.5 was too narrow, BUT this may be pressure sensitive, especially if you are really loading the suspension when the car initially takes its set.

If the car is not porpoising, then I cannot see the dampers being the issue.

Park your ars3 on the rear quarter and give the car some weight and step away ... if the car does not settle in 1 or 2 (max) oscillations, that would indicate a damper that is shot, but since you say it is the same in left and right turns, it would be strange to have both go out at the same time ....

I do keep coming back to the residual electronic nannies - Nissan have set the OEM threshold very low, so simplest check is to switch the yaw sensor power, which you will need to do anyway.

Good luck

Over_ReV · 03-06-2017, 07:02 AM

I had this same issue, where the rear would feel like it's wiggling to the side going around a corner even when the tires were not losing traction. I thought something had to be loose in the suspension so I jacked it up and found everything tight. I found a thread on here with someone else having the same issue and they solved by using stiffer rear shocks. Sure enough I stiffened mine and the issue 100% went away.

It also sounds like you may be having VDC intrusion, and if you are capable of driving the car close to the limit you should definitely do the yaw sensor switch mod.

Good luck hope this helps!

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03-06-2017, 04:09 AM	#1 (permalink)
BGTV8 A True Z Fanatic Join Date: Dec 2009 Location: 03350 Australia Posts: 1,516 Drives: 09 Nissan 370Z M6 Rep Power: 39975	1.0 deg neg at the rear is about right. If the car feedback is abrupt and giving you a "holy cr4p" moment, then I would put a switch in the car to isolate yaw sensor as first step - takes an hour or so if you have crimper,s some wire and a switch. If the car feedback is the same with yaw sensor disabled, then I would suspect rear wheel bearing, or rear-steer as a consequence of rear suspension bushing that are FUBAR. You can check wheel bearing by seeing if there is any free play with a wheel unloaded (in the air). A pry-bar on suspension rods will give you an idea on bushes. I am assuming that the crab-walk is coming from the rear per your original post. Other alternatives to look at are rear tyre falling over (what pressures are you running - this can only really happen if pressures are really low - like 20psi) The other thing is that the tyres are too wide for the rims - especvially at the rear .. According to my version (Australian) of Tyre and Rim Assoc book, 325 width needs an 11" wheel minimum and 12" max. I would not have thought that 10.5 was too narrow, BUT this may be pressure sensitive, especially if you are really loading the suspension when the car initially takes its set. If the car is not porpoising, then I cannot see the dampers being the issue. Park your ars3 on the rear quarter and give the car some weight and step away ... if the car does not settle in 1 or 2 (max) oscillations, that would indicate a damper that is shot, but since you say it is the same in left and right turns, it would be strange to have both go out at the same time .... I do keep coming back to the residual electronic nannies - Nissan have set the OEM threshold very low, so simplest check is to switch the yaw sensor power, which you will need to do anyway. Good luck

03-06-2017, 07:02 AM	#2 (permalink)
Over_ReV Base Member Join Date: Jun 2013 Location: Ohio Posts: 43 Drives: 10 370z Rep Power: 123	I had this same issue, where the rear would feel like it's wiggling to the side going around a corner even when the tires were not losing traction. I thought something had to be loose in the suspension so I jacked it up and found everything tight. I found a thread on here with someone else having the same issue and they solved by using stiffer rear shocks. Sure enough I stiffened mine and the issue 100% went away. It also sounds like you may be having VDC intrusion, and if you are capable of driving the car close to the limit you should definitely do the yaw sensor switch mod. Good luck hope this helps!