BPRacer

iTrader: (1)

(Also posted in Suspension forum, but I thought I might get more useful responses here)

Hi guys! I'm new here, and just beginning to learn the intricacies of the Z33 platform. I have a question regarding the rear suspension- is the 350Z rear suceptible to rear toe changes? Did Nissan use soft bushings in the rear arms, as so many manufacturers do, for NVH reasons, that might allow for a lot of it? Do they have something similar to the old Super-HICAS setup, or the toe bushings my old RX-7 TurboII used, which purposefully induce toe change to "enhance stability"?

The reason I am asking is that I sense a toe change or rear steer as I accellerate or decellerate and turn. This is noticeable even under moderate throttle and low g's in tighter turns- i.e. intersections and the like.

There may be some contributing factors. The car (an '05 Enthusiast) is equipped with JIC's(pretty stiff), Hotchkiss sways, and a Cusco 85% LSD. Previous owner also ran Zero toe in the rear. All of these would be likely to be the issue if it was plain ol' oversteer BUT that's not really the issue, it's a confidence thing as I feel the rear end change up quite a bit based on throttle opening. Again, I'm not talking about under hard cornering or aggressive driving, I mean at regular city street speeds.

As I am continuing to develop this car for BSP autocrossing and track duty, I'd like to know if toe change is an issue, so I can factor it into any changes I make.

OK, did I over-explain that enough?

Thanks for the help guys!

Brian Flanagan

stuntman

Usually you'd run a little toe-in for the rear. You're probably feeling the instability and lack of scrub by having zero toe out back.

The bushings in the 350 are pretty good and have a much larger metal center section (narrow rubber) which dosn't allow for a ton of flex compared to most bushings which have a big rubber area and small center pin that can move a lot.

0.02

BPRacer

iTrader: (1)

Thanks for the input! I just wondered if it was going to be something to work around or not.

The more I think about it, the more I believe zero toe and the Cusco LSD engaging and releasing as I play the throttle would logically create the kind of sensations I am experiencing. I will play with different toe settings and see what feels best.

Again, I appreciate the response.

Brian Flanagan

laze1

iTrader: (17)

I track a 2006 Grand Touring all the time, and have never felt any problems with rear-end-flex/toe. In fact it is totally stable under acceleration and deceleration. the rear is planted...even over bumps!

I run Zero toe and 2.5 Deg of camber in the rear, with 275/17 RA-1 all around...

betamotorsports

iTrader: (1)

The diff is the most likely cause of the rear balance changes you're feeling. Rear steer and toe changes are more pronounced over bumps then with throttle changes. Also, if you're able to make significant throttle changes in a corner you're not close enough to the limit to feel roll steer caused by bushing compliance.

SGSash

iTrader: (3)

The cars gain a ton of toe-in during excessive bump travel, but that is common of most properly designed suspensions. However if you're seriously modifying the car it might be a good idea to relocate the pickup points on the toe arm and camber arms if the car is running real low, otherwise even small wheel travel changes could result in large toe changes!

first350

iTrader: (24)

I know what you're talking about - it never did that before I installed that Cusco RS LSD, but after it was installed I noticed it; however, I only notice it at slower speeds, when autoXing or pushing it hard, I don't notice it (but my mental capacity for noticing things like that goes down when I'm autoXing…so it may still do that and I just never realized it.)

Have you gotten any weird looks when you're making sharp turns in a parking lot and the inside tire is chirping b/c fof the LSD? I hated it at first, but I grew to love it…I liked the fact that 99% of people thought that something was wrong with the car, but that 1% (probably less) of ppl who see it, know that you've got a serious LSD!

BPRacer

iTrader: (1)

The most priceless looks were from my girlfriend, first time she rode in it, just after I picked it up from you... "What the HELL did you buy? Are you SURE this thing is going to make it home???" LOL! That, plus the chattering (6-puck full race) clutch, and the fact that we couldn't even get it back into the hotel parking lot (if you recall, your stock Civic CX exhaust drug on the speed hump, so you can imagine)... She was pretty sure I had lost my damn mind!

No, honey, just my hearing!!!

first350

iTrader: (24)

I can honestly say I understand...I think my hearing is still effected from the 4,000 mile trip to kansas and back

BPRacer

iTrader: (1)

WHAT???

RWDBajan

Reviving an ancient thread because people like you to search. Couldn't find anything useful on rear steer.


I have occasional dramatic rear steer. 99% of the time the car drives like a dream, then at somewhere between 45 and 60 on a straight road it'll start wandering, and I have to fight to keep it in the lane. Then after 5 seconds it goes normal again. Almost like if it had malfunctioning Super HICAS (had a R32 Skyline with that and it worked perfectly.)


Wondering if the rear control arms might be sticking and jacking the rear end around. But it doesn't happen on corners and the roads it does happen on are relatively good. Other options I've considered - loose rear subframe, loose lower arms. But I replaced the shocks and springs about 2 months ago and had a full alignment. Didn't see anything amiss. Planning to jack up the rear this weekend to see if there's anything obvious but if anyone has experienced this then any insights would be helpful.

Emski

Did you check the rear diff bushing? When mine got busted the car wandered on the freeway.

terrasmak

iTrader: (8)

Shocks would be one thought, first is alignment. Please post your alignment specs

RWDBajan

Thanks Emski, will check those when I jack it up.


Terrasmak, front and rear shocks are new. Will post specs when I get home tonight if I remember. Alignment was done by the dealer. The previous owner replaced the lower control arms at the back with adjustable ones so I am sourcing some stock ones to replace. I'm going back to stock height shocks and springs from lowered and the arms are the last parts I need to change.

RWDBajan

So am having a challenge finding the bit of paper with the alignment specs. I put it somewhere safe...


It was done by the dealer, so likely factory specs at factory ride height.

RWDBajan

Haven't had the time to deal with this, as my mother in law had a stroke so no weekend time. Thanks for the responses.