Chris_C wrote:Thanks chaps,
Jani, I've still not got internet at new house, but I'll try to reply to that when I do. You raise a lot of good points that I didn't have clear in my mind and I need to think about!
Just remember that my measurements can always be way off. Also now that I checked I did remember camber gain wrong way around, it is only few millimeters change at edge of tire, but it is better to measure this properly first, my measurement included only top of tire and only when car wheel was on ground and wheel at air, one would get much better results by removing the spring and then measuring full motion range, both top and bottom of wheel and full rebound, neutral, full bump positions, ideal would of course be gain of 1-2 degrees of negative camber when cornering unless one is already running aggressive camber setting, that would work wonders in terms of cornering grip add toe to be neutral or bit toe out and it should be quite nippy and quick with direction changes, that combined with good caster angle there is by default should help to make car bite into corners well.
Rear should have -2 degrees of camber, now camber is affecting how car will turn in and how it will stick into corner and if you set front to be more than rear then you might end up with quick oversteer capabilities, but lack of rear arb and one at front is partly balancing that as is stiffer front springs, but remember with springs that there one must to get weight distribution to be able to know if front really is stiffer than rear.
I don't know how to put spring units to some lbs/in kind of, but GLT standard front were ~26kN and GL standard rear were ~15kN, now I wonder if these were kN/m or kN/m^2, anyway the SI standard ones from my memory, which you know to be rahter poor
Anyway good thing with playing around rFactor and alike is that it makes easier to get what effect different changes are in general sense, also one need to really do the work and learn from real world suspensions to be able to work with rFactor suspension, I doubt it will give precise exact effect but to get what camber and toe does, what different spring and damper setting does, those one can get there, however as there is no exact way to define suspension movement ranges, that is going to cause sim to be bit off among some other issues, especially with tyres, but I think that even live for speed being as free demo would work in there to get to know what each setting would effect, I think it is much easier that way than trying to figure out terms used in fancy books about car handling.
Then there is importance of roll centres, I don't know if you are familiar with those? This image should be helping there:
What ever change you do, if it causes roll center to start moving around more with suspension travel, then handling is going worse, if you can make it stay put then handling should be much better, control of roll center movement separates race car from road car, imo.
There are lot of great articles if one searches roll center with search engine of their choice, that is really important and often overlooked aspect, but if everything else is sorted these can still mess up the handling.
Some links that might be useful.
http://www.circletrack.com/techarticles ... index.html
http://www.neohio-scca.org/comp_clinic/ ... cs2007.pdf
It is lot easier to work out all the angles if one has access to some 3d modeling or cad program, it is much easier to measure from strut to strut distance than trying to figure out distances from side of car or even trying to get measures from imaginary center line of car. Surely one can do that with paper too.
All these measurements will help to some extent. Scrub is one that is giving steering feel.
Trail is effect of caster, this is what makes wheel to countersteer automatically.
There is indeed quite many things to consider when making car to handle, measuring all realiably is going to be quite bit of work, but it is better to make bit of work there than just slap some random pieces together hoping it will work, or slapping pieces together as others too that too, science is there so one can take measurement and plan things ahead then build and measure difference to know if it really did improve as feel of one's butt is alwys subject to errors.
Measuring alone is not the easiest thing, it is so easy to get lot of errors there and doing that on drive or in small garage is quite a pain, however there is lot to be gained from measurements.
These are my measurements, subject to great errors naturally and as I typed names while measuring, they can be bit difficult to understand, refplane is car bottom for example, all are millimeters, anyway it would be good if many of us could do all these measurements and few more if possible, we could put that to some knonledgebase then which would be information that is almost impossible to come by from any books or manuals and still this information is valuable if planning improving handling or putting car to simulation. Should really take photos from measurements some day as that is only way to really tell how I have measured these and from there it would be easier to spot errors in methods so I could make better measurements, it is just bit difficult with only two hands.
This are is such that I think there will be forever something new to learn for me, also because my memory is what it is, sometimes I remember things clearly, only thing is that my memory picks part of one thing and other part from 2nd thing without me realizing, so there always can be errors, just a word of warning if anyone has managed to read this far
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2-5 Scrub
70 trail
185 tire top to inner arch when car is lifted
200 front refplane
205 rear refplane
105 steering arm length
340 effective leverage arb
80 lower balljoint from ground height
320 steering arm to steering rack distance
320 lower arm pivot to lower balljoint distance
215 lower arm pivot height from ground
250 steering arm inside end height from ground
220 steering arm outside end height from ground
115 lower ball joint to wheel hub
245 compressed spring
235 arb link to strut
8 worn brake disc
250-280 strut below spring length
200 strut center to top of brakedisc
215 strut top to bearing cup
1045 strut top to strut top distance
15 strut top cover diameter
140 strut tilted back from vertical
590 strut length
67 strut top above tower
800-802 strut top from front light
450 rearward lower arm length
250 rearward lower arm inner point from front lower arm inner point
210 rearward lower arm height from ground
625 lower front arm pivots from each other
670 steering arm inner end to inner end
1220 steering balljoints from each other
1350 bdisc to bdisc, front
120 steering balljoint from center of wheel
150 contact patch width
40 tire's upper sidewall from inner wheel arch when car lifted along x-axis
130 tire contact patch length
47 tire upper sidewall from inner wheel arch when car resting on ground along x-axis
1346 front track from front of tires
1365 front track from rear of tires
59 width rear leaf
9 thick rear leaf
1250 length rear leaf
Well, hopefully some of this has some help to someone, suspension stuff is not overly difficult once one get hang of it, but there are things that tend to be bit taunting, like when one is going to change suspension arms, that is bit more of work as it is all 3 axles that affect to same things and you get different traits and feats with each, almost anything still works somehow, but to get desired result it is going to be bit of challenge, 1mm off is going to have already some effects so building too is not going to be very easy.
Anyway to get more camber to front one has to somehow get lower balljoint to go outwards more, it is very tiny what one can gain with moving strut top, so only way I know is to move lower balljoint outwards and there is few ways to do it, balljoint itself can be changed or lower arm or crossmember, then there is changes in other geometry too which one would like to avoid is plan is to change only camber, well that dependecy is what makes stuff quite fun as challenging, but it is not really so difficult at what it first may seem and there will be results from all that work.
Still it leaves problem with low amount of bump travel, but one can work around of that by accepting higher ride height and dealing rolling with other methods, that is easier to achieve than making new front of the car as to get more bump travel one would need to move strut tops, move inner wheel arches, design new front suspension mounting points etc. At least I don't think there is easier way to do it, surely making damper piston arm or coil over setup is not going to be enough as wheel arches come to way and lower arm motion range is designed to only so much upwards.
With all that it should be possible to make best out from 300 for sure, don't know if it will then still be quite what wanted, but it is a lot further from standard 300 and probably outperforming most other cars on road, might be bit overkill though
