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lower a-arm angle? and ride height

Posted: Fri Feb 22, 2008 8:08 pm
by sh0rtlife
ok i want to make sure the chassis is sitting as LOW as is safe...whats the "ideal" angle of a lower control arm?...it will be an aggressive street car so i dont want a huge amount of tire wear and im sure if you go to low you lose some alignment ability

if anyone has a measurement off the frame rails AT or near the lower control arms that would be idea...i adjusted the t-bars and i know the chassis is to low...just dont give me "jack point" references..there long gone lol

Posted: Fri Feb 22, 2008 9:54 pm
by MR2 Zig
If i'm not mistaken you want the lower control arm level (same measurement) from inside to outside. Measure near the inner lca bushings and near the lower ball joint....should be the same.

Race guys may well go lower, but you get into camber gain problems. I do know a fella that will make drop spindles for $350-400 a set, which would allow a lower car without the camber gain issues.

Scott

Posted: Fri Feb 22, 2008 11:15 pm
by GTV27
yeah, I went dead level with mine to optimise the geometry and it ended up sitting pretty high, so some modified uprights (spindles in US speak) would be a good compromise.

Posted: Sat Feb 23, 2008 2:11 am
by Daniel
Outer ends lower than inner ends gives best roll centre and camber gain, the opposite puts the roll centre somewhere below the road and no camber gain in bump.
Greater distance from C of G to roll centre = larger roll couple = more body roll.
I have seen lowered gtvs handle far worse than standard ones mainly due to camber issues.
If you lower, you need to go for a set of extended uprights (drop spindles) so that the roll centre and camber changes are right.

Posted: Sat Feb 23, 2008 2:33 am
by ALFA GTV6 GP
I agree.
Drop spindles are one way to go.

Posted: Sat Feb 23, 2008 5:05 am
by sh0rtlife
well see on the lloyd/milano project i can drop the body further if need be...sooo drop spindles arnt a requirement to get me there :twisted: ..plus the size of the wheel openings forced me down to a 195 50 15 :roll: (or were they 195 45 15)

so a smidge above level or level then eh?

now what about the rear? where abouts "should" it sit in relation to ohh say the crossmember above the transaxle...ive already had to cut off 3 coils and i think it may still be sitting high in relation to the front....HUGE weight loss

Posted: Sat Feb 23, 2008 3:16 pm
by Rookie ROX
General consensus is that the rear should sit about 1" higher than the front to retain the correct rake and geometry.

ROCK ON
R~R

Posted: Sat Feb 23, 2008 3:22 pm
by MR2 Zig
I think you will need different springs. When you cut them down you end up stiffer than you had been before. I think you want thiner wire diameter for the spring coils for a lower rate.

GTV6 sits level along the subframes front to back.

Scott

Posted: Sat Feb 23, 2008 3:41 pm
by sh0rtlife
if a milano is 20 inches shorter in its wheel base, is 1 inch at the rear going to maintain the same rake and geometry?

gtv6 is level?..mine isnt ...right now i cant compare to it as its up on jack stands

Posted: Sat Feb 23, 2008 6:43 pm
by MR2 Zig
Ok i have the car disc open

for lower control arm measure from bottom of ball joint (point a) and from the lower wishbone mounting (point b) then take the difference. the difference should be 39 to 49 mm.

for the rear measure between the rubber bump pad inside the coil spring and the flat of the spring perch (not the groove that the coil sits in). Y ou should get 39 to 49mm.

Keep in mind that Alfa did their suspension adjustments with weight in all the car as follows;
25 kilos in each front footwell
45 kilos in each front seat
25 kilos in each rear footwell
45 kilos in each rear seat

also a full fuel tank

hth,
Scott