hippie

iTrader: (9)

uwaeve....Here are the numbers I got when I measured my '03 Track
front toe---Camber....................rear toe---camber
Droop -3 - 1/32 in -- +3/4

........ -2 - 0 -- +1/8 ...........................1/16 in -- -3/4

.........-1 - 0 -- -1/2 .............................3/32 in -- -1 1/4

.......... 0 -1/32 out-- -1 3/8 .................1/8 in -- -2

.........+1 -1/16 out -- -1 3/4 ...................5/32 in -- -2 3/4

.........+2- 3/32 out -- -2 3/4....................3/16 in -- -3 3/4

bump +3 -1/8 out -- -4 ............+2 3/4"......3/16 in -- -4 3/4


I measured all of these numbers the old fasioned way. In the garage with 1" blocks, a camber gauge, and a couple strings. They may not be perfect.

The rear gains camber only a bit quicker that the front in bump, but the one thing these numbers don't take into account is camber loss because of body roll. The front inner pickup points are VERY far apart which contributes to these losses. As a test I dropped the RF 1" and raised the LR 1" (LF and RR were unchanged) and the RF lost 5/8 deg of camber. The LR only changed 1/4deg.

hope this makes sense and helps

mpowers

iTrader: (7)

pirelli pic that I promised




Take it for what you like, I think they are junk.

uwaeve

Hippie, thanks for the data. I've plotted it to return the favor. Maybe I can use the spring rates and cg location along with some g-levels to figure out what I'm looking for.

Stupid question because I've never worked with suspension before: 0 travel corresponds to loaded ride height? Looks like it, to give a static front camber of -1.25 deg.

Thanks again, this is great, I'll see if I can modifiy the numbers using the info above to get the camber the tire sees in relation to the track.

dnguyent

iTrader: (5)

Thanx...sure looks like mine!

hippie

iTrader: (9)

uwaeve...Yes, 0 is my static height with no spare or tools and 1/8 fuel.

Your graphs look good. You can proably smooth out the curves to account for my measurement errors, if need be.

Kolia

iTrader: (2)

I’ve been wondering for a while.

Is the camber curve relevant of the actual spring rate?

I would say that, it’s more related to the actual ride height. Assuming the springs are matched accordingly (stiff enough not to hit the bump stops in the faster corner and hitting the curb).

This makes me think that, assuming current alignment figures where good (I’ll try the -1 deg all around when I get adjustable bits), when lowering the car, we shouldn’t try to adjust camber back to OEM numbers and just use the resulting camber. Because if we do, we would end up have less dynamic camber while cornering as the camber curve will be offset.

That would work against the benefits from the lowered CG.

uwaeve

The following should in no way be construed as an intelligent discussion, as I'm a suspension noob.

To answer your question, to ME, with stock springs, I care about the camber curve because, when I throw on stickier tires, I am counting on the additional suspension travel (from the additional weight transfer from higher lateral g) to afford me dynamic camber. I think. I will have to think harder about the lowering question. It depends on what you're using the car for, too, right? For instance, if you want to slam your street ride, my recommendation would be to try to restore camber, because otherwise you're spending an inordinate amount of time riding on your tires' inside shoulders.

For the track, I'm not sure. As you said, you'll need increased spring rates to keep you off the bump stops. If we look at the extreme case where you lower your car till it's ALMOST out of suspension travel. If you correct back to stock camber, I initially agree that you've just robbed yourself of ALL of your suspension travel, therefore you'll get virtually NO dynamic camber. But riddle me this: you have a lower CG (smaller lever which lateral G acts on to roll your car, therefore less roll), but also insanely high spring rates (you're still trying to keep yourself off the bump stops), so there's going to be much less weight transfer. Due to these two effects, your car will be cornering almost flat. Therefore you don't NEED dynamic camber. It seems that it would be nonlinear.

Does this make sense to anyone? If so, can you explain to me what I'm talking about?

Kolia

iTrader: (2)

Aaah.. Yes !

We’re seeing the same thing. It feels good to know I’m not alone in my cluelessness. I bet if a real suspension designer reads this, he’s either laughing really hard or terribly depressed a our lack of understanding.

I think that the increased lateral forces of a super flat car will justify more camber in itself to align the thread to the resulting force vector.

But more to the point of your original question. Here is what will happen when you put r-compounds on your stock Z. The car will bounce and dart left and right on corner exit as the released loads from the lateral Gs and the relative lack of damping sends the outer front wheels into droop then bump than droop… This is called bump steering... not good.

You will have to be extra careful to let the car go where it wants to go and not “force” the exit in order not to soil your pants. It’s not fun in the beginning, but eventually you’ll work it out. Just the way I did, since my suspension is also bone stock and I have RA1s.

Oh, forget trailbraking into a corner, ABS will come on all the time.

I’m hopping the Konis I’m ordering will help with all that.

uwaeve

All I can say is that we are going to have a great time at BAB. BTW, I got accepted to the Friday sessions (whee). I've never had hour-long open track sessions, are you running a larger oil or power steering cooler?

OK back to the matter at hand (obfuscating the suspension issue):

I strongly disagree! But it's only because I don't think I follow you.

So the front will be underdamped when unloaded, eh? I thought bump steer was a change in toe with suspension displacement. Maybe that's what you're talking about also.

I plan to have more than one set of pants with me, this should not present too much of a problem.

I will take the trailbraking (or lack thereof) under advisement.

Will said Konis be on your car at Tremblant?

Kolia

iTrader: (2)

Rock on for Friday !

Look for the Z with "Kolia Z" plates from Ohio! Dark red Titan might be more noticeable...

As for the cornering force thing. It's just a gut feeling. Probably from my motorcycle experience. I'd lean the tire against the cornering force...

Yes, bump steer IS a change in toe with the vertical movement of the car. When we steer with the steering wheel, we're changing the toe of both front wheels... So the car will steer while unloading the suspension.

Kolia

iTrader: (2)

Said Konis will be here early next week. On the car by the following week-end...

dnguyent

iTrader: (5)

Which Koni's...the TCKline, Yellows, or the Truechoice? I'm having a hard time deciding since yellows 'might' not be enough, TCKline w/Nissan Motorsport springs might be too stiff, and the Truechoice set is a bit on the pricey side. Regardless of choice, I'll anxiously look out for your review.

The stock suspension is lovely on r-comps, aren't they?

Kolia

iTrader: (2)

Koni Sports.

The TCKlines look nice. But unfortunately they’ve never got back to me after we had agreed on a quote for a full suspension package, plus seats, harnesses and rollbar…

I’m not sure if they really want to deal with Z guys.

One thing I’m curious though, is if the rear dampers adjustment is on the top or bottom of the damper? I’ll know soon enough. The TCKline ones are adjusted from the bottom.

I luve that smillie! Never saw it before! aha

daveh

iTrader: (9)

That's partially true. Compression is adjusted at the bottom on the TC Klines and the truechoice's, but rebound is adjusted at the top.
The rebound adjustment will be the same on your yellows.

dnguyent

iTrader: (5)

I have no idea what that smilie really means, but for some reason, it looked funny and appropriate. I think that's what I look like trying to keep the car from going into the weeds as I bounce and wobble around on a 95 mph sweeper.

uwaeve

Can you guys comment a little more about the adverse behavior of the stock suspension and R-compounds? I'm about to get my first set of RA1s and I want to know what I'm getting into. Thanks.

uwaeve

dnguyent

iTrader: (5)

I wouldn't say that it's an "adverse" behavior that is inherently dangerous and should be avoided. It's just handling behavior from before that is a bit more pronounced. For me, the car just doesn't settle very well around fast sweepers or shift weight quick enough in transitions. A Z with stock suspension on r-comps going 95mph around a sweeper feels like a buick going around the same turn at 55. That's how I'd describe it.

The good thing with doing the stock suspension and r-comp route, IMO, is that you'll be able to identify the weaknesses of the stock suspension. So, in a sense, I'm hoping that a new suspension, purchased later on, will result in marked improvement in handling and overall feel.

If I did both suspension and r-comps at the same time, I wouldn't have a baseline for the suspension.

Kolia

iTrader: (2)

The R-comps on stock suspension will also teach you to be smoother and to let the car drive itself.

Overall, I think it's a good thing to try it.

Gsedan35

iTrader: (10)

What are you thinking when you say "yellow's might not be enough" ?

Yellow's were specifically designed to have less stiffness (lower compression dampning levels) then oem 03 Z shocks and to have a much greater rebound control range.

I have the Koni's, though I wanted more spring stiffness and Nismo T2 springs are too stiff so I took some advice from Koni and converted the front's into coilovers (running 448lbs).

dnguyent

iTrader: (5)

I put 'might' in quotes because I haven't determined yet whether I need DA over SA (as far as adjustability goes). I haven't ruled them out at all because, frankly, I haven't had any experience adjusting dampers whether they are single or dual. I'd prefer the simplicity of SA, but don't want to end up buying something else a year down the road.

I like the ride in the truechoice set up. I haven't felt the ride/handling characteristics on a T2/TCKline or Koni Yellow set up yet. I'll do a search on your writeup of your Koni conversion, if there is one.