CluelessZ

OK,

MY first of many questions...Bear with me as I am a newbie to all this modding stuff (But highly motivated).

I want to eventually install a new suspension. I like the Tien Coilovers. Someone said in another thread that they would never put coilovers on the Z right now, until Nissan, or someone comes out with a way to fix the camber once you install a new suspension.

Camber happens when the wheels are tilted out 1 direction. Question: Why in the hell would you all of a sudden have more camber on your tires/wheels just by lowering the car with a new suspension?

Thanks

Desmo

Whew, that's quite a question really. I'll try my best to hit the high points.

The easy answer is that your suspension is designed to increase the negative camber as it is compressed. Negative camber is when the tops of the tires lean in, positive camber would be the tops leaning out, but you don't see that very often. Lowering your car compresses your suspension (and keeps it there) so by design, the suspension adds in more negative camber.

That leads into why a suspension designer would want more camber as the suspension is compressed. The goal is to keep as much of the tire working for your as possible. Going straight is easy, just run zero camber (tire not leaning in or out). That puts as much of the tire in firm contact with the road as possible, both front and rear, for braking and accelerating forces (assuming the fronts do most of the braking and the rears are doing the accelerating). Zero camber is also good for tire wear, since the tire is going to have even pressure across the entire surface.

So going straight is easy, but in a corner is where the magic happens. First visualize the car going around a pretty fast, even corner. There is going to be body roll towards the outside of the corner. The outer suspension is going to be compressed, and the inner suspension is going to droop. Now if the tires are always at zero camber with respect to the body of the car, that means the tops of tires are going to be leaning towards the outside along with the rest of the car. That isn't good for traction because the tire is gonna sorta flop over and only be in contact on the outer edge.

Now visualize a suspension that adds negative camber as it's compressed (like the 350Z's, and most other cars). As the car rolls to the outside, the suspension adds in negative camber and keeps the tire perpendicular to the road surface, or maybe even digging in just a bit. Now more of the tire is doing work and the car can corner faster.

Camber is usually set on a racecar by running some laps and then measuring the tire temperature across the width. If the inner, outer, and middle temperatures are all about the same on the tire, that means the camber is set well and the entire width of the tire is contributing. Cold temps on the inner edge mean you need some more camber, and cold outer temps mean you have too much. On a side note, cold middle temps mean you need some more tire pressure, and vice versa.

Things get more confusing on the front tires because they also have a caster angle that changes the camber as the wheels are steered left or right. I can't explain caster without drawing pictures. And it gets really confusing on the 350Z because the bottom of the steering hub doesn't rotate on a single balljoint like most cars, but instead pivots about an imaginary point defined by two balljointsworking together.

I would suggest reading a book about racecar suspension design if you are interested in more details. I'd imagine there are some decent ones out there for not more than $15 at your local bookstore. I can also try to answer your questions, but it's hard to do via text only.

JL

CluelessZ

Desmo,

Thanks for taking the time to explain the issue in very good detail! You spent some time making it easy to understand. From a physics standpoint, its actually pretty logical.

I guess I just never thought of the issues such as cornering etc.

Anyway, I think I shall invest some time in educating myself on a couple of these subjects. Time to hit Amazon.com and buy a book or 2.

Recommend any good ones?
Thanks

Desmo

Here's a link to one I've read.

http://www.amazon.com/exec/obidos/tg...glance&s=books

JL

Pedal Pusher

I understand the camber thing. However, I have been told the camber on the 350z is not adjustable. My dealer is willing to help but he has not been able to get the recommended settings from Nissan or the people who made the alignment machine (Hunter).If you have info please share. Thanks

MannishBoy

iTrader: (1)

See the sticky thread at the top of this forum on tire feathering. I posted what the dealer should have in their shop manual.

Pedal Pusher

MannishBoy,
Thanks for the info. I appreciate a person who knows it all.

Pedal Pusher

I'm new to computers. How do I read a sticky thread? Take it easy on me. Thanks

MannishBoy

iTrader: (1)

Sorry, by "sticky", I just meant the thread near the top of this forum that never moves down the post list.

The link is here:

https://my350z.com/forum/showthread....threadid=15758

I'm not sure if you were being sarcastic with the no-it-all comment or really thanking me, but I was just trying to be nice without wasting more server space on this board with another inline image.

droideka

As per the Z33 service manual, the Camber, Caster and Kingpin Inclination angle are NOT adjustable. This has been confirmed by both my dealer and an independent shop with regards to the alignment.

I'm weary of doing the Eibach drop without a camber correction kit for at least the rears at a minimum. 1.2" is quite a drop in the back considering how much camber is already back there.

Obligatory "look at that neg camber" picture.

Pedal Pusher

I sincerely appreciated the help. Thanks

2k3silver350z

if you jack up the car and take the wheel off and look at the suspension there is one bar to the right (if you are facing the passenger side) and one bar on the left (if you are on the drivers side).

this bar can be used to adjust camber on the car. if it lengthens it will create negative camber, if it shortens it will create positive camber. i know this because when my car was curbed that bar was the only one that bent and it caused a ton of positive camber. it's held in by 2 bolts. if someone like ingals would manufactuer a two piece bolt that when you unscrew it will lenthen and when you screw it together shortens this would solve our camber issue and would be done cheaply. the replacement bar is only 30$ so i'm sure that there will be cheaper alternatives to the plates that are just as good.

Pedal Pusher

2k3silver350z.......thanks for the info on the camber idea. I understand what you are saying. It should work.