Paras

Current ride height = 26 3/4" front and 27 1/2" back. I recently had my car aligned and it doesn't seem to be as planted as I'd like it--especially on high speed sweepers and just when I'm changing lanes going at speed > 80mph in fourth gear (when the car is torquey). It seemed to be better before I had it aligned... I used specs similar to the "advanced street" on the VB&P website... Here's my before and after (current) alignment specs:

Left front:
Camber: Before: -.82, After: -.67
Caster: Before: 8.07, After: 7.81
Toe: Before: -.09, After: .07

Right front:
Camber: Before: -.82, After: -.67
Caster: Before: 7.71, After: 7.75
Toe: Before: .05, After: .11

Front:
Cross Camber: Before: .24, After: .00
Cross Caster: Before: -.36, After: -.07
Total Toe: Before: -.04, After: .18
Set back: Before: -.03, After: -.06

Left back:
Camber: Before: -.76, After: -.47
Toe: Before: -.02, After: .02

Right back:
Camber: Before: -.81, After: -.51
Toe: Before: -.14, After: .04

Rear:
Total Toe: Before: -.16, After: .06
Thrust Angle: Before: .06, After: -.01

(I know, runflats suck but I got 'em till I wear 'em out...) Also, crappy freeway quality isn't better for a stiffer suspension... Could I use more toe in front and less in back? I think that I still have plenty of caster...

Paras

ttt

Paras

ttt?

Umrswimr

Less "planted" how? Front end lets loose, back end lets loose? Straght line stability? Does it do the sideways "hop" iover rough stuff?
You don't have a lot of camber and caster looks good. I'd blame the toe if anything.... :cheers:

Paras

**Keeping in mind that its a lot better than when I had the F45 suspension...

When I'm going from freeway to freeway and there's a long left sweeping turn that's a little banking... I'm going 85-90 (maybe I'm not supposed to be able to go faster but I think I should) and it feels like the entire car wants to go to the outside of the turn (it isn't holding down as much as I'd like it to)--kinda like the tires just want to let go. I feel like I have to adjust the front a little bit too much and the back doesn't seem to follow the front as closely and securely as it should (I notice that moreso when I'm changing lanes).

I've noticed one thing with the coilovers though--if I start to skid and its very minor and controllable on my part, the active handling does not come on and the car lets me handle it--much, much moreso than when I had the stock suspension where the back would much more easily fishtail and the active handling light would come on and I'd feel the assistance much more quickly...
There is no sideways hop and I've been trying to determine if its the front or the backend that wants to come loose but I can't tell...

Paras

ttt? Last time...

Umrswimr

Are you still running the Runflats?

I know the best way to get grip in a corner is to add more camber and/or more tire. If the whole car wants to drift outwards uniformly, you're pretty much just reaching the limits of the tires, I would think. Sorry I can't be more help.

Try posting over to the RR section since this will also apply to those folks running coilovers on the track... :cheers:

West Coast Chris

Keep the Camber around 3/4 Negative and the Caster between 7.5 -8.0 Positive. Toe is the most critical for wear and drivability it should be 1/32" of toe in between the two, That goes for Front & Rear. That is how I line up corvettes and did my 02" Z06 after lowering it to factory maximum. Car corners like it is on rails and goes perfectly straight. We tend to give the right side a little extra Caster 1/4 -1/2 of a degree here in Canada to compensate for the crowned roads, don't know how many in the USA


[Modified by Hefty, 7:27 PM 4/28/2004]

Paras

Umrswimr, yeah, I'm still running runflats (can't justify changing them till they're worn out)... I had the feeling that since the whole car wants to move outwards uniformly, maybe I am reaching the limits of the tires but I was/am hoping that's not the explanation!

Hefty--Thanks for the specs. Can I have that much camber on runflats and be ok? Is .75 for front and back? Also, I have toe in of .1 in front and about .04 in back... Is there too much toe in at the front tires? Did you mean toe in of 1/32 front and toe in of 1/32 back?

Umrswimr

I'll let you know the answer to that in about 2 months. I'm running a full degree of neg camber on my runflats now. I predict adverse tire wear. :jester

TheDarkKnight

Well I'm running the following on runflats (PilotSports):
Front
left/right camber: -1.3/-1.1
left/right caster: 5.5/5.7
toe: -0.06/-0.08

front cross camber/caster: -0.2 actual
front total toe: -0.14

Rear
left/right camber: -0.7/-1.0
L/R toe: .15/.13
Rear total toe: .28 actual

I've been running this for about a month, including two days of autocross and a wicked run on a very very very twisty road for about 160 miles --aggressively driven. Tire wear looks nothing out of the ordinary. Indeed, still have nubbies along some parts of the tire. Granted these are a 400 treadwear rating, bit this was close to the specs a fellow racer set out for me to run street/autocross with -- without shredding tires on the street.

I guess I shoudl finish off with saying "Your Mileage May Vary" :lol:

Paras

DarkKnight: Does the toe out in font make your car feel like it goes for the edges? What would happen with too much toe in? And how does toe out feel at high speeds?

Umrswimr: I'll be expecting your answer in 2 months!


[Modified by Paras, 1:10 PM 4/29/2004]

TheDarkKnight

Hmm what do oyu mean by go for the edges? What happens with toe out depends on the other settings (even air pressure) and if we are talking front versus rear. Too much for one person is about right for another depending on the other's settings. So I'm afraid I can't answer you too well other than to say: If you have "too much" it will suck. ;)

As far as at high speeds (120 or so) it feels smooth and straight so far. I'll be able to give you a better answer after the Pony Express at Battle Mountain (http://www.openroadracing.com/html/pony_express.html). :D

Paras

DarkKnight,

I meant toe out in the front. I was wondering if the car will wind up pulling too much to either side as the wheels catch something. When I first had my car it was a handful to keep it going straight but when I got the toe in up front, it made the car easy to steer striaght...

Smooth and straight at 120? Cool. How about when changing lanes at 120?
And wow the roadracing thing looks cool!

Richin Chicago

I think this has been covered before but watch your wheel bearings. What I was told, when the Z06 came out, was that any negative camber on a run flat car would signifigantly reduce wheel bearing life. The sidewalls were just too stiff. I don't have this on anything other than a coversation with a GM guy up at Gingerman in Michigan. He said they had always wanted to go with negative camber since first production.

James G

You don't have near enough camber

West Coast Chris

Think of your tires going in a perfectly straight line that would be a zero toe setting , the reason you give it a little toe in is to compensate for inertia. so when under acceleration your tires should be going perfectly straight. On byass ply tires I set 1/8 of an inch of toe in because the side wall isn't as strong so the tire flexes and then runs straight. Driven wheels are a different story. Basically you should always have the tires going as straight as possible . Do not put excessive toe in or toe out. With 3/4 negative type of Camber settings you should have nominal tire wear but excessive toe is the major contributor to wear.

Avanti

:eek: :eek: :eek: Runflats with coilovers? Get new tires before anything else... please, then go from there. I couldn't believe the difference in going from RFs to F1s!

All the best. :yesnod:

Paras

Hefty-so do you think that 0.1 toe in for the front tires is too much? And should I have more than .04 toe in for the back tires? Lastly, is there a big difference between say .03 toe in and .1 toe in? Sorry for all the questions but it baffles me why my car doesn't seem to handle as good after it has been aligned...

And thanks all for all your help.

'97 C5

If I missed it somewhere above I apologise...but, what sway bars are you using, does the car feel unbalanced on both left and right hand cornering, did you corner weight the car? What are the spring rates and shock rebound and compression rates?