tyres are at 19psi, 6clicks clockwise on prorace shocks, 0 deg. toe, -1.5ish deg. camber at the front...
any ideas? its really kinda scary, ive got no confidence driving anything near fast on the nice country roads...
been here before....went for a drive today, the cars perfect on smooth stuff, but then on country roads with uneven srfaces she becomes really hard to
keep straight, and kinda grabs at any ruts and flings you all over the place...
tyres are at 19psi, 6clicks clockwise on prorace shocks, 0 deg. toe, -1.5ish deg. camber at the front...
any ideas? its really kinda scary, ive got no confidence driving anything near fast on the nice country roads...
Have you checked for bump steer?
how do you check for bump steer?
the rears parrallel as i remember, its fixed too...
Check for bump steer:
Springs too heavy/hard for a bec?
would having a big angle on the rod ends create bump steer? ive outlined it in the pic...
checked the spring rates, theyre what mk suggest...dont think theyre set too hard, seems like a nice ride.
[Edited on 13/4/09 by A1]
Sounds like bump steer to me as cloudy says.Sorted one a couple of weeks ago for a customer. Moved the rack,set toe at 1.5 degrees in and 2 degrees
neg camber.
Different car!!! Hope this helps Woz
^ clicks clockwise on the shocks, i would soften them up a bit and see if that helps.
Have you got any preload on the springs? my back end is a bit skippy so i will wind down the springs at the rear to give a bit of a softer start if
you see what i mean.
quote:
Originally posted by snapper
^ clicks clockwise on the shocks, i would soften them up a bit and see if that helps.
Have you got any preload on the springs? my back end is a bit skippy so i will wind down the springs at the rear to give a bit of a softer start if you see what i mean.
All the symptoms of the dampers are set too hard.
Also your car would benefit from some toe-in front and rear.
Bumpsteer like the poor is always with us the only way to deal with bump steer without a front end redesign is to plot the bumpsteer curves and try
corrections to the streering rack and ball joint height to reduce it.
[Edited on 13/4/09 by britishtrident]
quote:
Originally posted by zilspeed
FLAME PROOF JACKET ON.
(But it's all true).
The concept of 'preload' to alter effective spring rate is a myth.
The spring is not rising rate, therefore it is linear.
You can play with the spring seat heights to adjust the effective corner weight at each tyre footprint (but not the actual weight distribution, that's fixed) by adjusting them individually.
You can adjust them collectively at one end to alter ride height and consequently rake.
You cannot alter spring rate by altering ride height. If you want the spring to be softer or harder, 'preload' is the wrong way to go about it. You need to change the spring.
Can we assume these are pretty normal radials too? if they are then the toe in/camber suggestions sound good, after changing your dial in shock settings first as they are easiest.
I have hear/read/listened to gossip that the best settings for shocks is to have the lowest damping effect that works.
I set mine to fully anti-clockwise (least damping) and added clicks until it felt started to feel harsh, then went back one click from that point.
The fronts are just 1 or 2 clicks from the lowest, and the backs are about 3 or 4.
Works for me - your mileage may vary!
A well handling track car will never perform as you want it to on a typical road. Especially as the roads lately are absolutely not worth paying
for... but hey-ho, we get what we get!
We are in a similar position and still working on it...
Steve
Winding up the spring platforms does increase preload if the damper unit is fully extended.
It means that a certain amount of force is required above static force before there is any movement of the spring/damper.
Apart from giving very strange unpredictable cornering, it gives a very harsh ride over bumps and the wheel tends to become airborne a lot as
it's already at maximum extension.
We had this problem trying to get enough clearance for the sump. We had to extend the spring unit to bring the damper-rod extension back towards
half-way statically.
Edit: It's also been suggested that even though the dampers have 20+ clicks, only 3-4 of them actually do anything. 10 clicks may actually
be fully hard.
I run 2 on the front and 3 on the back. 1.4 deg camber on the front, slightly less on the back, slight toe-in on the back and slight toe-out on the
front (about 0.5-1mm). Castor is measured at 5 deg.
It has no problems with tram-lining or darting on rough roads and has excellent self-centering.
[Edited on 13/4/09 by BenTyreman]
I'm glad to hear that I didn't imagine it! 
Mine are all set close to full soft, in fact I think the rears ARE on full soft, and could do with being softer yet. I also run soft springs (140 lb rears and 260 fronts, which are a tad heavy to be honest)
i changed the track rod ends so their now lower, seems to have made it better on the country roads, to quite so 'skip and fling you into the oncoming traffic' as it used to be, although you can feel the wheels pulling on the road. its relatively easy to control though. one thing i have noticed is that i have to turn the wheel more to turn corners and it feels much lighter??