Help me fine tunning my suspension setup

[J95]

Hi there,

Id like to hear your thoughts on my setup. Its for track+street
I'm running (1st gen):

• kw v3 with 50/60 springs
• lowered 32mm
• camber bolts + camber plates
• stock sway bars

And these are my questions:

1. Roll Center change because of lowering?

Do you have a number of how much the RC decreases because of X lowering? On my calculations, I'm assuming (for 32mm drop):
Front RC -40mm
Rear RC -10mm
I have no idea about how accurate it is, and this is relevant for LLTD

2. Roll Couple and LLTD

I calculated these numbers: 61.7%, 56.8% (couple, LLT):
I read somewhere that general recommendation is ~65%, I wonder If I'm too low now

(I assumed Motion Ratio does not change with lowering, which is probably wrong)

3. Alignment

Im planning to:
Toe: 0F/0.7R (mm)
Camber: -2.5F/-1.8R (°)

Should I run safer on rear toe?

The other aspect is that my bounce ratio is bad (0.97), I will play with damper settings and try find a good balance


any feedback is appreciated

[Racecomp Engineering]

What tires are you using?
What are you trying to improve from where you are now?

- Andrew

[J95]

Originally Posted by Racecomp Engineering

What tires are you using?
What are you trying to improve from where you are now?

- Andrew

Federal 595 RS-R, 245 40 17

My current alignment is very conservative, I want to make the tail a bit happier but without overshooting

Also I like to have the theoretic numbers so I can play and guess next mods (like ARB ot RC correction)

[BlueWhelan]

If you lowered the car 32mm then your roll centers are probably much much lower than what you assumed.

Generally on the McStruts, the RC will be affected an order of magnitude more than the ride height.

All cases vary. Measure it yourself to be sure.

BUT FIRST - consider Andrew’s question.


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[ZDan]

F/R toe looks fine. 0 front, OK. 0.7mm total(?) rear = 0.06 degrees total, cool. Even 0.7mm per side would be 0.12 degrees, also fine. Generally I'd say 0 to 0.15 degrees total rear toe has worked fine for me over the years (1st and 2nd gen).

Your proposed camber seems way low for track. I've run -3.0 to -3.5 front, with -2.8 rear camber all year, street and track, not a problem.

Regarding lateral load transfer balance f/r, I say run what you have and see how you like the balance before going to any lengths to "fix" things that might not be a problem.

[J95]

Originally Posted by BlueWhelan

If you lowered the car 32mm then your roll centers are probably much much lower than what you assumed.

Generally on the McStruts, the RC will be affected an order of magnitude more than the ride height.

All cases vary. Measure it yourself to be sure.

BUT FIRST - consider Andrew’s question.

Sent from my iPhone using Tapatalk

ok thanks, yes I will try to measure it

It looks like a big enough change to think about correction

Originally Posted by ZDan

F/R toe looks fine. 0 front, OK. 0.7mm total(?) rear = 0.06 degrees total, cool. Even 0.7mm per side would be 0.12 degrees, also fine. Generally I'd say 0 to 0.15 degrees total rear toe has worked fine for me over the years (1st and 2nd gen).

Your proposed camber seems way low for track. I've run -3.0 to -3.5 front, with -2.8 rear camber all year, street and track, not a problem.

Regarding lateral load transfer balance f/r, I say run what you have and see how you like the balance before going to any lengths to "fix" things that might not be a problem.

Great, thanks, I will definitely try more camber, I don't use the car daily anyway. Yes you are right, most probably I will be already happy with the setup, but I like to know the possibilities are and the room for improvement