here's what happened
to measure the tyre tread area i need a flat level platform so i stacked layers of marble tiles
so the cars sitting flat
placed 80kg of rice to simulate my weight
slip two thin pieces of cardboard under the tyre to measure the length & width of the patch from 1-3bars then calc the area and looks like this
i set the fronts to 2.8bars and rears to 1.2bar so they all have roughly the same patch and same distance from wheel centre to floor
tire place puncture repair
coilover covers kept most of the major muck away. just a dusting of fine dirt left behind
removed rear springs so i could push the axle up till i hit the bumpstop
the rear damper has standard rear bumpstop fitted. its 62mm long, the damper has a travel of 110mm so only leaves 68mm of travel.
when hitting the bumpstop the wheel barely reaches the arch, the rim is only 80mm from the arch lip. this may explain why the rear end feels so punchy when going over speedbumps cos the rear hits the stock bumpstop prematurely.
rear swaybar misses the fueltank
the issue at the rear axle is not the wheels touching the archs but the exhaust striking the right swaybar mount bracket
the stock bumpstop takes up like half the damper stroke so i fitted the original coilover bumpstop which is 35mm so giving 95mm of travel
dust boot tied down so it doesn't pop off n let dirt through
wheel stops much higher at 67mm from the arch but found the axle already hits the exhaust when its 80mm away so i had to increase the damper height from the axle by 16mm to stop the wheel at that point.
the rear spring is 204mm long and calculated its binding length is at 73mm.
with standard bumpstops and damper at its lowest height, the preload ring is only 90mm from its highest setting to the spring top support.
with coilover bumpstops its still only 78mm away so no chance of complete spring binding.
now to set the front bumpstop point by adjusting the lower ring. take springs out n jack the wheel up.
the current setting allows the wheel to get this close
but its mainly when turning and braking hard that the wheels move this far so i turn the steering and it rubs the arch so no wonder it used to make a racket during hard right turns
to test what camber does i set it all the way
and it pulls the top of wheel in
enough to just clear the arch. this strut top camber adjustment maybe good for clearing the arch when really lowering but handling wise, i dunno if it actually affects the camber where you need it most in terms of handling i.e when the wheel steers, compared to increasing the castor.
lowered the bottom ring till the gap is better
the front spring is 220mm long and binding length is at 80mm.
front damper has a travel of 118mm.
when hitting the bumpstop, the wheel rim is 60mm from the arch and the preload rings max height setting before spring binding is 68mm from the top of the damper casing.
with damper fully extended, the spring is at zero preload when the ring is bout 100mm from the damper casing top.
now to corner balance.
first i set the preloads like before and equal both sides.
(preload measured from top of damper casing, height from wheel rim to arch)
RL: preload 55mm, height 97mm
RR: preload 55mm, height 101mm
FL: preload 90mm, height 100mm
FR: preload 90mm, height 109mm
i lower the preloads to get a level ride height and weighed the front
(preload, height, weight)
RL: 47mm, 100mm
RR: 49mm, 101mm
FL: 107mm, 100mm, 254kg
FR: 95mm, 100mm, 303kg
50kg difference between the front wheels. was gonna fit ballast but don't have any so had to sacrifice uneven ride height in order to load the corners.
I stiffen the FL preload 5mm several times to increase load
RL: 47mm, 105mm
RR: 49mm, 98mm
FL: 101mm, 101mm, 258kg
FR: 95mm, 98mm, 306kg
RL: 47mm, 105mm
RR: 49mm, 96mm
FL: 95mm, 107mm, 261kg
FR: 95mm, 101mm, 306kg
RR height is getting lower so i stiffen it 10mm to raise it up and transfer load over to the FL
RL: 47mm, 110mm
RR: 39mm, 102mm
FL: 101mm, 108mm, 269kg
FR: 95mm, 102mm, 300kg
stiffen FL some more
RL: 47mm, 110mm
RR: 39mm, 101mm
FL: 90mm, 113mm, 271kg
FR: 95mm, 107mm, 301kg
soften the RL to try transfer load away from the FR to the others then weigh all the wheels to see the whole picture
RL: 57mm, 104mm, 166kg
RR: 39mm, 100mm, 211kg
FL: 90mm, 114mm, 268kg
FR: 95mm, 103mm, 295kg
car was definately RH heavy. i tested putting 10kg bag at the RL
RL: 57mm, 101mm, 172kg
RR: 39mm, 98mm, 215kg
FL: 90mm, 113mm, est 272kg
FR: 95mm, 102mm, est 299kg
minimal effect. seems like in this unbalances chassis i could only balance either the front or real axle so would handle left/right turns differently
looking back i figured i could stick the preloads back to their equal values and sort out the varying ride heights & corner loads with ballast to push down on each corner. so i brought five 7.5kg dumbell plates from tesco for £60
7.5kg in RL
22.5kg to be bolted to passenger floor
and just bout stuff one in FL engine bay
set all preloads equal. wanted to measure from top of damper but spring is in the way so i use a thin screwdriver to represent the level for the tape measure
results from adding 30kg in FL and 7.5kg in RL
RL: 45mm, 100mm, 190kg
RR: 45mm, 105mm, 197kg
FL: 98mm, 98mm, 277kg
FR: 98mm, 98mm, 314kg
looks good. ride heights and rear balance pretty much equal, front needs more work.
try increasing FL ride height to load up the FL and RR wheels
RL: 45mm, 107mm, 187kg
RR: 45mm, 97mm, 200kg
FL: 98mm, 102mm, 278kg
FR: 98mm, 97mm, 311kg
abit uneven so i lowered the FL back down and move the RL ballast with the others in the FL footwell
RL: 45mm, 103mm, 189kg
RR: 45mm, 100mm, 200kg
FL: 98mm, 97mm, 279kg
FR: 98mm, 94mm, 318kg
think thats as near as i'll go. just need to bolt down the weights n refit everything
found a lil trick if the cars moved to one side too far after using jack in tight garage. slip a rice bag or equivalent under the wheels and a good shuv moves it with ease
