Bilstein B8 -> Koni/GC

[mocchi]

I think stock itr front rate is 250lb/in linear and same for the rear but it is progressive which I'm sure you would know
I remember someone saying on HT that running stock itr springs on the spss3 shocks were fine, no bottoming or hitting bump stops.
What shocks are they?

older style ohlins, clip type perches. part number is ct7-s0200-50
ct7 ones, been trying to get some more info but there is so less on the internet.
saw someone asked for more info on these ct7 types on HT but no reply.
made in japan not sweden.

oh, and the perch takes oem style springs, not like your eibach springs.
gc uses eibach yea?

thanks for help btw mike, appreciate it.

[MM89]

The amount of travel after a bump stop has been included sounds quite similar to the spss3's at around 60ish mm.
Would you consider using any coilover sleeves and springs? Running any swaybars?
I would probably run slightly higher rates than stock itr. Just to be on the safe side.

[mocchi]

sway bar is stock eg4 gli front sway bar, rear is 25mm.
when you say just to be on safe side, you mean in case there is a massive pot hole
i ran through it and it destroyed the bump stop and blow the shocks?

if i can get my hands on a spring compressor asap... damn!

but. found this and this calculator, so i might not need to actually jack up the wheels to see
how far it can travel before hitting bump stop.

.... i think i should do both.

[MM89]

So you can remove the perch and retain the circlip on the shock?
If so, then that's pretty easy because the ground control or perhaps most sleeve simply sit on the circlip with a machined lip that covers the circlip. In effect, circlip failure is almost eliminated.

Yeah ground control uses eibach universal 2.5" inner diameter coilover springs.

I'm glad that there is some discussion going on, what has helped me could help others too

[mocchi]

So you can remove the perch and retain the circlip on the shock?
If so, then that's pretty easy because the ground control or perhaps most sleeve simply sit on the circlip with a machined lip that covers the circlip. In effect, circlip failure is almost eliminated.

Yeah ground control uses eibach universal 2.5" inner diameter coilover springs.

I'm glad that there is some discussion going on, what has helped me could help others too

i think i will email the gc guys because they dont have the ohlins options. how did you go with the konis btw.
liking it?

[MM89]

Yeah exactly that. Running up to approximately 8kg/mm all around should still be quite street friendly. I can't see the calculator now as I'm on my phone, but an 8k spring will decrease your chances of bottoming on unexpected potholes. 8k was simply an estimate and also everyone's classification of street friendly will differ.

When you get a spring compressor, try and use the hook type. I used a flat angled surface spring compressor and it would slip alot. It was my first time using one, so perhaps this contributed.

I'm unsure if my assumption is correct, but a bigger swaybar will add roll stiffness/resistance, similar to using a stiffer spring. I would imagine this to be providing extra prevention to bottoming. However with your situation, that would apply to the rear end.

[MM89]

You're right, they don't. Someone may have inquired for ohlins as well in the past, if not they'd be able to fab it up. This would be quite costly though..

The setup is quite good. Won't really find out how good it really is until I hit up winton again.
Would have thought 9k/10k would be quite stiff. But it's on the limit

[mocchi]

Yeah exactly that. Running up to approximately 8kg/mm all around should still be quite street friendly. I can't see the calculator now as I'm on my phone, but an 8k spring will decrease your chances of bottoming on unexpected potholes. 8k was simply an estimate and also everyone's classification of street friendly will differ.

When you get a spring compressor, try and use the hook type. I used a flat angled surface spring compressor and it would slip alot. It was my first time using one, so perhaps this contributed.

I'm unsure if my assumption is correct, but a bigger swaybar will add roll stiffness/resistance, similar to using a stiffer spring. I would imagine this to be providing extra prevention to bottoming. However with your situation, that would apply to the rear end.

yeah swaybars will add spring rate. im thinking of getting 8kg front and 6kg rear.
reason being, the cuscos that m currently using is 8/6kg and i find it good.

would love to feel the difference.

[mocchi]

ok so a friend of mine was so nice to dropped off a spring compressor for me. so..
disassembled the itr shocks.

found out that the stock shocks has 7cm bump stop, 14.9cm shock travel
so it has 7.9cm shock travel before hitting bump stop.

one thing i noticed was the stock itr shocks are softer by about maybe 1/3rd of the ohlins. 1/2 of the ohlins at least.
i need 2-3 times as much force to compress the ohlins. does that makes sense?

maybe the ohlins will be good for track. damn i wanna try it.

what are the effects of having soft springs with stiff dampers?
ans: Overdamping is the opposite, the damping rate is too high in comparison to the spring rate. This is bad because it puts a lot more strain on the suspension mounting hardware, as the bumps are barely absorbed by the suspension and is translated into chassis movement instead. This means that a moderate bump can cause your tires to be airborne for a moment. Obviously not good unless you’re racing on a really really smooth surface. source

or stiff springs with soft dampers?
ans: underdamping, extreme example is blown shocks. bounce up and down until the springs settles itself.

edit: fail. strut hole in itr top hat is too small for the ohlins strut. FAIL.

[mocchi]

update: im stupid. the bushes can be popped out. (-_-)
swapped the top hat bushes and in it goes. now just need to order some lowered and harder springs.
hmm.. H&R or Eibach hmm..

vinny give me some advice! is it hard to get internet in japan? bring me some souvenirs hehe.

[MM89]

could you reuse the stock itr metal cylinder that goes between the two top bushes?
i would've thought that the ohlins use a bigger diameter shaft.

just a word of advice when you're looking around for springs.
if you're gonna be using coilover springs on sleeves, i would suggest going for a spring slightly longer than you think you may need.

for example, i went for a 7" long spring, front and rear. in the front, it's fine, i am able to lower it a fair amount.
however, in the rear, it's not quite long enough to lower the car anymore. there is a bit of difference between front and rear ride heights.

with a longer spring like 8" you will have more flexibility of setting ride height.

[mocchi]

could you reuse the stock itr metal cylinder that goes between the two top bushes?
i would've thought that the ohlins use a bigger diameter shaft.

just a word of advice when you're looking around for springs.
if you're gonna be using coilover springs on sleeves, i would suggest going for a spring slightly longer than you think you may need.

for example, i went for a 7" long spring, front and rear. in the front, it's fine, i am able to lower it a fair amount.
however, in the rear, it's not quite long enough to lower the car anymore. there is a bit of difference between front and rear ride heights.

with a longer spring like 8" you will have more flexibility of setting ride height.

your hunch is spot on. i had to swap the top hat bush because ohlins strut shaft is 12mm, oem is 10mm.
the metal hollow cylinder is also the same, oem has 10mm ID.

me always being unlucky, the metal cylinder on the ohlins bushes are missing, there is only 1 cylinder among all bushes.
as if it's telling me to go on a quest for metal cylinders!! how annoying.

i was thinking of using oem metal cylinders and drill out the ID.

8" is 20.3cm? that is pretty short lol!

i will definitely get at least 8"