Hi guys,

Have not been on this site for awhile because I switched focus to tuning my bnr32 instead. However, started to daily my Z again lately, and encountered some suspension/braking woes. Past 120 km/h, the car has a slight wobble that gets progressively worse with speed, along with steering twitchiness. When turning left, the car wants to "shimmy" back and forward (car wants to turn left, then right, then left). I do run quite aggressive camber (-3.2 degrees front, -2.5 degrees rear), caster (10 degrees), and I am lowered a sufficient amount on coilovers, along with a 275 tire up front. I just got my car aligned and running 0 toe all around. However, the car was solid on both street and track before entering storage, and felt very stable at high speeds (besides braking, see below), with that same alignment spec after fine tuning to my liking.

Searching on here, I found some references to worn trailing arm bushings and compression arm bushings that can cause unpredictable, unstable handling. I have not replaced these items yet and are next on my list after I get a chance to check them for play. Also, I have stock end links, I'm thinking these may be the culprit as well since I'm lowered, have whiteline sways, and running large tire sizes but would love a second opinion. There was quite a lot of preload on the sway bars when I installed them, so I'm assuming adjustable end links will be beneficial in my case.

Just wanted to confirm these bushing failures were the cause of my symptoms, any advice would be appreciated. Also, I get a bad vibration and squirrely rear under braking. I have replaced the pads on all four corners, replaced all four calipers, and all four rotors, but the car is still very unpredictable under braking. The rear end will lock up hard with anything over 60% pedal pressure. I have tried bypassing the abs to see if it was my ABS module, but the rear tires still lock up under pressure, and with ABS enabled, ABS initiates much too early in the rear. I tried using a proportioning valve as well to adjust brake pressure to the rear, which helped a bit for the locking issue, but it still locks up with ease and I have no confidence in braking anymore. The braking issue was apparent before going into storage

Cheers,
Dylan

 

anyone have any input? Just bit the bullet and bought some adjustable end links to prevent any preload/sway bar end link binding

 

My best guess would be the bushings, thought so before opening the thread. You should notice a world of difference. With an aggressive drop and setup like you have, they're more than likely torn up. I had a similar shimmy on the highway before replacing all the front bushings.

 

Thanks for the second opinion, I'm going to try out the energy suspension master bushing kit front and rear

 

any luck?

 

Have you checked your bearings for any play? Leaking coilovers? Checked all bushings?

Regarding the brakes, it seems like your brake bias is messed up. Let's hope the experts would chime in. How are the condition of your rear tires tho?