Hi,

I have made a lot of searches and read several threads about Ohlins DFVs, and recently about bump-steer kits.

The situation is:
- I have an AP1 MY2002
- with Ohlins DFV Road&Track Coilovers with Ohlins 10/8kg springs, about 30mm height drop front and rear (maybe I will get back to 20mm drop to avoid street problems...)
- with all the arm bushing (upper and lower, inc rear toe arms) freshly replaced with mugen reinforced rubber bushings
- with fresh UK Spec alignment
- with 18" TE37 on 225 and 255 AD08R tyres
- with fresh TTS Supercharged kit

The problem is:
I drove a nissan 350Z with massive chassis tuning (2-way coilovers, lots of bars and rods, etc..) which was very very very efficient and stable on small bumping roads ! I was really estonished by this car! On the same road, my S needs much more driving skills because it is not as stable and easy to handle.
My car tends to follow the road bumps and grooves, it tends to move on hard breaking, tends to "add" or "remove" steering when I hit the throttle or not. All of this was inexistant on this 350Z (far from stock).

My question is:
For my small height drop, what are the most efficient ways to improve the stability of the car ?
Megan Racing Front + Rear Anti-Bumpsteer kit ?
Lower braces ?
Different Alignment ?

thanks for you advices and feedbacks.

 

Changed my rear springs to match fronts,also when I first installed mine to spec,i was on the rear bump stops and had to adjust preload to around 14mm
https://www.s2ki.com/forums/s2000-br...tings-1163331/
&
https://www.s2ki.com/forums/s2000-br...nside-1166830/

 

Bias/balance for s2000
https://www.s2ki.com/forums/s2000-br...1183541/page3/

 

Your going in the right direction with an Anti-bump-steer kit and getting an alignment done after installation cant hurt.

If your gonna spend that much and do the work yourself new breakpads and rotors / bushings / control arms cant hurt either.

If it steers to one side or the other when breaking its often rotors, less often breakpads.

AP1 can be finicky when air pressure varies on tires too, so keep that in mind.

Just a few things to be mindful of.

 

I have preload the rears like 10mm if I remember correct. Can't get more with 30mm height drop... This is part of my reflection to get back up to 20mm drop for example.
Why not put 10kg rears if I can find them cheap. Don't want to buy brand new swift springs, too expensive for an already expensive ohlins kit.

I will read this. I already have this bias excel sheet

I already have the ohlins, bushings and alignment.
But I am wondering about more mods, like bumpsteer. But for those, I don't know if 30mm height drop is "enough" to make those bumpsteer kits necessary?
I also have stoptech slotted front disks, and ds2500 pads all around with ate typ300 brake fluid. Brakes are ok and don't make the car turn.

 

"UK spec" alignment = way too much rear toe-in at 40 arc-minutes or 0.67 degrees (!). IMO that's at *least* 3x too much rear toe, for me it made the car more nervous and WEIRD handling. While also destroying rear tires at a truly ridiculous rate...

Try 0.2 degrees total rear toe in.

IF street car, maybe -2 to -2.5 degrees camber all around. Caster is a personal-preference thing, I prefer to run at the low end of 5.5-6 degrees. Some will insist that "more is better" though. You might run middle of spec for that or experiment and see what you like there.

 

After all this if you still find the car tramlines/grabs inconsonant road surfaces pulling you left or right, back off on the camber up front to around -1. There is compromises with running a track alignment on the street, and its not just inner tire wear. I find -1 camber up front still gives a good all around performance, with improved handling on street and improved braking is also a benefit with more strait line tire surface on the ground. Rear you can get away with a little more camber without compromise -1.5 -2.

 

UK spec alignment is quite popular, I am surprised with your comment on the rear toe. But to be honest, that level of toe in also surprised my mechanic (he does some drift and does alignment on many drift or Rallye or track cars).




Here is my alignment:




​​​​​​​

 

Get the Hardrace/Megan rear anti bumpsteer toe arms and go for 0.2 degrees total toe in just like ZDan said.
40 minutes is just way to much, if you go back to the same place aim for 12 minutes instead, that is the same as 0.2 decimal degrees.

 

Thanks for advice.
Front anti bumpsteer is useless ?
Also thinking about the well known 10kg rear springs upgrade for the ohlins coil overs...