Suspension Tips, for those who want to lower this car.

[AkaJabari]

Originally Posted by jadewbj

After reading all of this I am still a little confused about if it is possible to lower the car enough to remove the ugly wheel gap with a set of coils without ruining the handling.

I will be upgrading to 18's and using Tein Flex.

"One thing we noticed is that the car has a fairly low roll center and if the car is lowered much at all the lower control arms will point upward with the roll center quickly ending up below ground. This will do two things that are not so great; the car will have a large roll couple and a strong tendency to roll which must be countered with stiff springs and/or swaybar. However the FR-S does have a very low center of gravity due to the low slung boxer engine so perhaps this may still be tolerable.

Next due to the angularity of the lower arm when lowered, the front suspension will lose negative camber under roll which will reduce grip and even lead to understeer in a low car unless a lot of static negative camber is dialed in or roll is greatly reduced with stiff suspension. Big negative camber hurts braking traction and causes the car to be road crown sensitive and tramline on cracks and grooves. Being too stiff hurts mechanical grip. Whiteline if you are reading this, this car really needs your long shank ball joints and tie rod ends to correct the roll center. Make some right away please. Maybe your Subaru kit might fit. The best solution before the aftermarket responds might be to not lower the car more than 1.5” or so."
-Mike Kojima http://www.motoiq.com/magazine_artic...cion-fr-s.aspx

What's a roll center?
Fairly good reference article
http://www.onedirt.com/tech-stories/...r-roll-center/

[jadewbj]

Originally Posted by AkaJabari

"One thing we noticed is that the car has a fairly low roll center and if the car is lowered much at all the lower control arms will point upward with the roll center quickly ending up below ground. This will do two things that are not so great; the car will have a large roll couple and a strong tendency to roll which must be countered with stiff springs and/or swaybar. However the FR-S does have a very low center of gravity due to the low slung boxer engine so perhaps this may still be tolerable.

Next due to the angularity of the lower arm when lowered, the front suspension will lose negative camber under roll which will reduce grip and even lead to understeer in a low car unless a lot of static negative camber is dialed in or roll is greatly reduced with stiff suspension. Big negative camber hurts braking traction and causes the car to be road crown sensitive and tramline on cracks and grooves. Being too stiff hurts mechanical grip. Whiteline if you are reading this, this car really needs your long shank ball joints and tie rod ends to correct the roll center. Make some right away please. Maybe your Subaru kit might fit. The best solution before the aftermarket responds might be to not lower the car more than 1.5” or so."
-Mike Kojima http://www.motoiq.com/magazine_artic...cion-fr-s.aspx

What's a roll center?
Fairly good reference article
http://www.onedirt.com/tech-stories/...r-roll-center/

I think 1.5 would remove the gap just fine. The Flex has camber plates in the front so I can probably get it back to factory specs. The rear I was considering the whiteline camber bolts or GT-Spec rear control arms when they come out.

[Racecomp Engineering]

1.5 inches is a lot and I would recommend the whiteline roll center kit at that point.

It's much easier to deal with things if you stick with a medium/milder drop.

- Andrew

[jadewbj]

Originally Posted by Racecomp Engineering

1.5 inches is a lot and I would recommend the whiteline roll center kit at that point.

It's much easier to deal with things if you stick with a medium/milder drop.

- Andrew

Is this the kit?
http://www.whiteline.com.au/product_..._number=KCA326

[newkid185]

Originally Posted by Moto-P

I've sampled Cusco Street, RS*R Sports-i, and both of them were extremely well behaved and designed for medium grip to high grip tires. Both worked really well at FULL SOFT setting on both ends, even with track radials like the Azenis RT615K. So going stiffer is only needed perhaps, to compensate for wear of the dampers, and also to settle the car at really high speed tracks where stability is in order over quick vector changes.

Both do come at a price of nearly $2000 but with the ability to be 30mm lower, and unlike lowering springs on stock shocks, that allow maybe 20mm max on short rear shocks of the FRS/BRZ, the fully-tapped coilovers can go a full 35mm lower with all of the original stroke range, and has adjustability to actually make the ride more comfortable with more sophisticated valving that is not cost-constrained like the stock shocks.

So if budget is the key, Racecomp's 20mm drop springs are really ideal.

If ride qualities of the stock is a bit harsh for you, you can use either of the more expensive setup to improve that while retaining all the of the nice handling capability with much lower height around 30~35mm drop.

I've also found that 20mm drop is ideal for dynamic alignment (as designed), and 35mm still retaining pretty good alignment as well.

How about Eibach prokit??? I just order it but still not install yet... it just lower the car around almost an inch and they claim that it will work well with the OEM setting...

[WestZ]

How do you address bump stop engagement with certain coilovers, as bump stops do tend to increase spring rates as they engage?

[kiks]

Originally Posted by WestZ

How do you address bump stop engagement with certain coilovers, as bump stops do tend to increase spring rates as they engage?

BumpSTOP

Read and read some more, if you're hitting bump stops you're doing it wrong

[WestZ]

Originally Posted by kiks

BumpSTOP

Read and read some more, if you're hitting bump stops you're doing it wrong

I'm asking OP how certain coilover companies address the bump stop issue. Normally people cut them (which is not an ideal method due to an exponential rise in spring rate when bump stops are shortened esp w/ harsh OEM rubber ones), but there are reputable companies that sell certain bump stops of certain lengths and spring rates to influence ride quality and whether it oversteers or understeers.

Thanks for your quality of insight though. Appreciate the red font .

[kiks]

You dont engage the bump stops...Theyre there as a last line before coil binding. There is no tech wizardry in them, just a harsh stop before that point. You're doing it wrong if you have to hit them or sit on them for some reason.

[Bmore_Raven86]

Hey Moto what brand would you recommend if you just want a lowering springs?

[BRZranger]

Originally Posted by Bmore_Raven86

Hey Moto what brand would you recommend if you just want a lowering springs?

He recommended the Race comp Engineering (RCE) lowering springs, which offers a mild drop. RCE is a vendor on here with a good reputation.

[Racecomp Engineering]

And we're near Baltimore.

Originally Posted by jadewbj

Is this the kit?
http://www.whiteline.com.au/product_..._number=KCA326

That looks like the part number, but I don't know if anyone has tried it yet on this chassis.

- drew

[gmookher]

making a car look good and handle good are two different things

Moto-p has my attention, man knows what he is doing
subscribed

[WestZ]

Originally Posted by kiks

You dont engage the bump stops...Theyre there as a last line before coil binding. There is no tech wizardry in them, just a harsh stop before that point. You're doing it wrong if you have to hit them or sit on them for some reason.

Not necessarily true. There's that aspect of them, but they do serve a purpose both on track and on the street.

Look up "bump stop tuning." I'm not saying you HAVE to ride them the whole time, but if/when they engage, they act as a secondary spring, which actually has a benefit to the suspension's handling.

From Modified: "As for bumpstop use on race cars, according to Peter, Often they are used truly as just a bumpstop, but the progressive spring rates can be used to help cars when they are riding the curbs or jumping them (as is often seen). In a controlled racing formula like a spec or one-make series where every car must use the same shocks and springs, the bumpstop becomes the one tunable spring on the car. It could even be in contact at ride height if a long enough bumpstop is used or the main springs are short enough. Bear in mind that the rate will be rising steeply into compression but will be dropping off into rebound, so the car is likely to roll up a lot on the inside rather than just down on the outside."

As you told me, "read and read some more," I strongly urge you to do the same.

I used to think that bump stops just prevented the shock from totally bottoming out and destroying itself, but I learned later that it serve an underlying purpose. It really does factor in a perfect suspension equation.