For my Gymkhana and sprint work, do you think that the R888 or silverstone FTZ type RR would be better in 185/60r14 size! Seeing I can only afford one set of tyres and southland being what it is with unpredictable weather I cant ever know if it will be wet or dry on the day.
socram,
Jan 31, 5:11am
R888s are brilliant wet or dry, but even then, you still need your tyre pressures spot on. With sprints, the age old problem is getting any heat into the tyres before you have finished your run, so that means dropping the pressures a wee bit.(mgmad will have a better idea of how much.)
For your track work, as soon as possible after you come in after a run, check the tyre temps all round.If you don't have a gauge, just check each tyre by hand.They should be fairly warm, but if any tyre is out of kilter with the others, adjust as required as all should be the same temperature.By the sounds of it, your rear tyres might well be cool and the fronts warm.
morrisman1,
Jan 31, 5:46am
I think I will be hard pressed to get some heat into the rear tyres, I don't expect they will be doing much work with only 200kg or thereabouts sitting on them.
Ive just got the good tyres fitted to the rear, but cannot really test yet as I have only got two mounted on rims, the other two are on rims that dont fit this car. That will be a job for tomorrow I think. It will look heaps better with matching wheels all around!
get rid of all that camber on the front for a start.
mgmad,
Jan 31, 10:18am
Sprint tyres will not work for motorkhana, especially on the back. The only time you want good sticky tyres for motorkhana is if you have lots of power, and even then only for the fronts (unless you're going RWD, when you need them on the rear as well). R888s etc will work from cold, if they didn't I'd have hit a lot more banks.
The static weight on tyres means little, it's the cornering load that is important. You will not have any trouble getting good tyres to work on the 121 - so long as the suspension geometry is setup properly.
morrisman1,
Jan 31, 10:34am
I can shuffle around different tyres between events. I had no issues with the 165/70r12 on the rear during the motorkhana. I didn't have any undesirable oversteer and the car seemed to work quite well.
Ill be happy if I can find a setup to reduce the oversteer in the sprints.
smac,
Jan 31, 7:11pm
Right, so as above, it's happening due to weight transfer, so sort that out first. No point putting a wing on a car that's flopping around like a floppy thing.
This may sound a bit obvious, but bearing in mind the dings in the body ahead of the rear wheel, have you had the full alignment checked!It doesn't take much for it to be noticeable on the track.
As regards camber, fitting negative front arms to my Mini was the single biggest improvement I ever made in terms of handling performance.
morrisman1,
Jan 31, 9:31pm
I honestly hadnt thought of that socram, although there was no deformation of the floorpan in that ding, just a slight bend in the pillar structure and panel damage. It may pay to get it checked as you say.
Im going to investigate better springs at the front, the springs from the early Kia Rio fit and they are a higher rate spring for the heavier car. Lowering springs may be available for that car which may be just what I need, or I could cut the stock kia ones seeing as they are a higher rate than the 121 springs it should prevent roll and dive when turning and braking but of course the lowering springs may be even better as they will probably have a higher rate again
smac,
Jan 31, 9:48pm
Lowering the front may counter the gains you make by stiffening it.
elect70,
Jan 31, 10:33pm
Could make a wing a la F1opens on the straights tominimise drag
kevymtnz,
Jan 31, 11:03pm
do u have the spare wheel still in the boot or you take it out in some cases its better to leave the spare wheel in for rear wieght an ajustable rear foil may help but under 100kmh not sure you will get any grace from it being such a small car and FWD you may have to relearn yourself in sideways drifting to see if you can keep it online without going right round and no not the drifting what they call these days which is really the wrong term for it
mrfxit,
Jan 31, 11:32pm
Yep it's a trick getting it balanced all right. Being FWD limits AND concentrates the problems From what I remember about this stuff .
Working from a central line through the vehicle's bidy Common weight transfer problems are .
1: Front springs too soft (nose dropping too fast) 2: Too much rear spring travel (back lifts too high causing weight transfer to & over the fronts center body line) 3: Front & Rear shocks initial expansion/ contraction too soft ( sudden rear lifts cause sudden "shock" weight transfers to the front / sudden front nose dives cause rear weights to lift over THAT center body line & transfer to the front) **** Mmmmm
On the other hand, shocks & suspension too hard on the front can induce tyre slide & the same for the front.
Try the stiffer front springs (leave then std for a start) & if that helps, put stiffer front shocks in OR try shorter & stiffer shocks on the back.
Seems like 1 end is diving & the other end lifting
mrfxit,
Jan 31, 11:39pm
Try this trick but you need a roll of 1" wide masking tape & a good camera
Car at current "stand height" Run the tape at the center height of the body (from the road) full length
Set up camera at THAT same tape height / go for a short run in the car & jump on the brakes just before the location of the camera, Play back at various speeds to see what happens.
You could play around with that idea on straights & or corners, but either way, you WILL SEE whats happening
mrfxit,
Jan 31, 11:45pm
Agree about the wing as above & the same for any "ground effects" body work . waste of time unless you are clocking some reasonable top speeds & in cross winds
morrisman1,
Jan 31, 11:45pm
I found that BNT are able to supply lowering springs for this car, I was quite surprised at that. They are meant to be a 25-40mm drop but Im obviously also interested in the rate. Would it be worth considering these springs to replace the cut standard ones in there currently!
fordcrzy,
Jan 31, 11:56pm
I would try getting a second front sway bar and double them up to get. A bit more understeer. Then balance tyre pressure as required
mrfxit,
Feb 1, 12:00am
Don't lower the front . If anything, stiffen the front (shocks or springs or both but not at the same time) lower the back or stiffen the back or both ^ ^ ^ etc ^ ^
you will know when the front is that bit too stiff because the front will slide too easily under braking (understeer slide & or locking brakes)
mrfxit,
Feb 1, 12:01am
Same "sort" of effect area but more weight
mrfxit,
Feb 1, 12:03am
Try the tape & tripod mounted camera idea you really need to SEE whats happening now before going any further otherwise it's just pure guess work/ seat of the pants stuff. Time to get YOUR eye balls in action (seeing as they are indirectly attached to your "seat of the pants"
morrisman1,
Feb 1, 12:03am
it already has a lowered front, using cut springs. I suspect that putting in lowering springs will possibly even raise the front a fraction and definetely stiffen it up
mrfxit,
Feb 1, 12:06am
I was meaning from what ever height it is now. Front Up could help prove a point either way
morrisman1,
Feb 1, 12:09am
Oh I wouldnt lower it further, I already have more rub than I would like.
Anyone wanna buy a B1 engine off me to help pay for the springs lol.
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