Captain_Stangin'

Hi guys, I have Sam's front and rear 3 way adjustable bars. I had them set to full soft front and back, medium front and back, and am considering setting them to full stiff front and back, just to experiment. What can I expect? Any issues from too much roll stiffness?

My suspension is as follows:

Steeda Sport Springs 205lb front/175lb rear linear
Koni Yellows 1.5 turns firm front, 1 turn firm rear
Strano sways, medium front, medium rear
CHE K-member brace with torque limiters
CHE Adj. UCA (rod end)
J&M Poly/Rod LCAs
CHE adj. Panhard bar (poly/rod)

I went to a autocross recently with the new setup. I am experiencing understeer, most likely due to too much entry speed. Is there a way to "tune" for this without causing high speed oversteer? Or is driver mod the only way to do this?

Alignment specs:

jahudso2

If you are getting understeer, then leave the front swaybar on middle stiffness and set the rear swaybar to full stiff. If the car still understeers, then keep the rear on full stiff and move the front to full soft. If the car oversteers, then you can try full soft in the front and middle stiffness in the rear.

I have the Stillen swaybars, and to get the most neutral steering for my setup, I have the rear at full stiff and the front at 2nd stiffest (i have 4 adjustments on the front). However, the stillen bars have slightly different rates and I am also on stock springs.

Norm Peterson

I can't see your alignment specs (internet filtering at work blocks most picture hosting sites).

Don't be afraid to experiment with staggered bar settings once you've determined that the understeer is due to mechanical reasons.

Or experiment with different shock settings (maybe soften the fronts by 1/4 turn or stiffen the rears by a similar amount).

Too much roll stiffness will decrease the ride quality over one wheel bumps. It can affect transient handling if you are relying on things like roll steer to help you, and I guess ultimately you'd end up wanting to get more roll damping without adding any damping in pure bump/rebound.


Carrying too much speed, or steering too late/too rapidly/reacting to the course mostly just overloads the outside front tire. As can early apexing (after which you're struggling to haul yourself back somewhere near on line). "Driver mod" is the proper way to fix any of those, assuming that tire pressures were appropriate.


Norm

Captain_Stangin'

Hi Norm, I asked the shop to set my alignment to -2.0 degrees camber, and 1/8th of a inch toe out. I have a auto-x next week on the 27th, and then a open track day on July 9th. I might just leave my settings alone for now, and work on correcting my driving.

I should also note, I've been driving on the stock 17x8 Bullitts with the factory 235/55/17 Pirelli All Season tires. A fellow auto-x club member is selling 18x10 +38mm offset Enkei RPF1s shod in new 285/30/18 R888s. I know the tire height is quite small, and I worry about masking any driving issues I might have with the r-compound, but he's selling the package for $1400 CDN OBO. Think I should scoop it up and run them when my skills have progressed? Or should I just slap em on and see what happens?

Norm Peterson

For the auto-X at least, try running about 4 psi more in the front tires than in the rears. Establish the (hot) pressures by observing how far around the shoulder the scuffing goes and increase (or decrease) pressure to allow less (more) of this scuffing. Your alignment, bar settings, and damper settings aren't too much different from mine, and I'm at about 35 or 36 front, 31 or 32 rear with 235/50-18's on the street. Mostly it's well-behaved and certainly controllable, although it's not very hard to get the tail a bit loose if you drive like an idiot.

Perhaps try out the firmest rear bar setting and tweak the shock settings at the auto-X. The penalty for finding yourself a little too loose isn't as severe there as it could be on the street.

You might want to keep a little more understeer for the open tracking than for auto-X or what you can tolerate even in most street driving.

I think I'd get a little more seat time before moving to R-comps.

FWIW, I think there has been some difference of opinion concerning what pressures to run in R888's (not that this matters much even from a financial point of view when it looks like you're basically getting them thrown in for free with a $1400 set of wheels).


On edit, at least buy yourself a digital angle finder so you can check reasonably closely what settings were actually set. If you have or ever get any sort of camber adjustability, you'll be able to at least rough in whatever camber settings. Just don't forget to check toe.


Norm

Captain_Stangin'

Thanks again Norm,

How do I go about checking the camber and toe? Is it actually possible for me to perform alignments myself? I have J&M Camber plates, I scribe a mark at the "-2.0" aligned setting, and then when I need to go for a long highway trip, I just slam the plates full outwards.

Norm Peterson

All you need for checking camber is some way to measure how far off the vertical the wheels are. Note that you do need to set the car up on a flat surface, preferably a level one (it saves having to add/subtract pavement slope to your readings).

You already are doing some of the alignment stuff. Once you know what the things to measure are and how to measure them, the rest is just moving things around a little and turning wrenches. And doing adjustments in the right order (generally caster, then camber, and finally toe) and re-checking the measurements.

You already have a scribe mark for competition camber, so you don't have to measure that again, just reset to it. If you ever decide you need a little more, you'll already have a reference point to start from.

Better yet would be to measure camber at full outward just to see what it is (R and L may well be different). Then pick a setting that you can set both to, and scribe those points as well. Now you'd have two points to work with if you ever wanted to set something that's different from either your current -2° competition or trip settings.


I've got a couple of more extensive write-ups on DIY alignment that you might be able to use. Word *.doc format. PM me an e-mail address and I'll track the one for aligning Mac Strut suspensions down and send it back.


Norm

Sam Strano

The lack of negative camber is hurting you, badly. You can put the bars wherever you need to. My rear bar is not massively stiff compared to many, so if you need or want to, you can set it full stiff. But remember that balance is combination of the bars, the springs, the alignment and the tires. Any change to any of those will yield a change in balance.

And if you are just too fast into corners, or trying to brake hard and turn at the same time, you will ALWAYS get understeer. Trying to tune the car to fix that kind of mistake will result in a really loose car at speed in transition.

Captain_Stangin'

Norm, I appreciate the help. PM'd

Sam, what is an ideal camber setting to use to auto-x/track use? I heard that too much negative camber can have a negative effect on braking, but I assume that's only in extreme (-3.5' or more) cases.

I do know that whatever suspension adjustment I do, I should make one change at a time.

It's also absolutely possible that I'm simply over driving the **** out of the factory tires during auto-x. I did notice that when I trail braked and got on the gas a little "softer" the car did rotate much better.

As a side note, does anyone know if the 18" RPF1s will clear big brake kits? I don't plan on buying one anytime soon (if ever), but it would be nice to have the option without buying another set of wheels.