CSG and RCE tag-team suspension Q&A thread! Ask us anything!

[rick s]

Originally Posted by Racecomp Engineering

10 kg/mm up front is too stiff. You don't need that much front spring IMO. And too much front spring bias.

It can feel fast, but a softer set up will be easier to drive, more consistent over different types of surfaces, have a better balance, and be more comfortable as a DD.

- andrew

Thanks Andrew! I tried to find out the TRD spring rates but the best I could find was 3.5/5.8
Should I Shoot for this ratio on the coilovers say 4.8/8 for example or am I comparing apples to oranges.
I would think that stiffer springs on the front would not help understeer tendencies on the FRS
My biggest fear is going backwards by upgrading to coil overs.!

[Racecomp Engineering]

Originally Posted by rick s

Thanks Andrew! I tried to find out the TRD spring rates but the best I could find was 3.5/5.8
Should I Shoot for this ratio on the coilovers say 4.8/8 for example or am I comparing apples to oranges.
I would think that stiffer springs on the front would not help understeer tendencies on the FRS
My biggest fear is going backwards by upgrading to coil overs.!

The same ratio at different overall levels of stiffness won't get you the same overall balance. Different tires or grip levels can change the balance too.

There is to some extent some driver preference but you'll have to spend some time dialing in all of the variables....ride height, alignment, shock settings, swaybars, and spring rates. The 7/7 or 7/8 are popular starting points for springs in STX, but there are plenty of other ways to go too.

- Andrew

[Racecomp Engineering]

Originally Posted by 86league

My '13 BRZ is mostly track use, but some street with ~300+ mile drives to some of the tracks so I want to keep it street friendly.

I'm on RCE yellows, stock shocks/sways - camber bolts and plates up front with SPC LCA's out back to get to -3.5F/-2.4R with 0F / 1/16in R toe. SX2 (200TW) tires, rest stock.

Tires are now wearing relatively uniformly across the tire with this camber setup (MPSS shoulder's absolutely got killed at very similar camber). No consistent reading on tire pyro after I drive off track and back to the pits (cools off a lot) - but nothing that looks bad either -- so I can mostly only go by wear for now...

Pictures from the track show a lot of roll ... e.g. http://www.hart-photography.com/phot...#image=4111227 -- inside front tire contact patch looks to be at 1/3 width or less in lots of the turns.

Will stiffer sway bars improve my cornering traction significantly, or just a little? I think the real answer would be stiffer springs, but that means shocks too so I'm into coilover money... not wanting to go there yet...

I like the car as is and am having fun and tire wear with the SX2's is good across the tire - getting ~10 track days out of a set with proper rotation... But, I kind of like to tinker, and if a (relatively) cheap set of sway bars would improve things a fair amount I am willing to try them...

Also - would stiffer sways mean I'd likely need to (get to) dial out some of the static camber?

Thanks !

If you like the way the car is handling now, I'd be hesitant to change anything! That body roll might not be holding you back all that much. Another season of building experience with a car that does what you want it to do and is reliable/consistent is valuable.

Buuuutt...I like to tinker too. Swaybars would reduce body roll and you may be able to reduce your negative camber slightly. Keep in mind most front + rear swaybar sets will increase front roll resistance more than rear due to the motion ratio of the swaybars. So you may have to fiddle with the alignment to get things just the way you want them.

- Andrew

[FLYFISHR]

This likely to be a stupid question, but when you set the front negative camber, is there any thought to compensating for the weight of the driver or whether you have to compensate for right or left hand turns. What I mean by that is, I think some people are more likely to take more speed into a left hand turn as a posed to a right hand turn while daily driving.

[churchx]

FLYFISHR: if one is being very pedantic, then yes, very "ideal" alignment for specific use/location/track may take into account of there being or not passenger, of track being clockwise or counter-clockwise. Then there also is corner balancing/alignment if one has height adjustable coilovers. But imho these tweaks are into category of where one can spend 90% of time for 10% of gain, so unless it's for highly-competitive racing where every slight extra advantage counts, i wouldn't bother. If anything, you may ask to deal alignment while you are sitting in car.

[Foxy Grandma]

Would you guys recommend your Tarmac springs be paired with the Bilstein B6 or B8? I've seen reviews of people who have gone either way with good results.

[Racecomp Engineering]

Originally Posted by Foxy Grandma

Would you guys recommend your Tarmac springs be paired with the Bilstein B6 or B8? I've seen reviews of people who have gone either way with good results.

You could go either way, but I would prefer the B6.

- Andrew

[Pat]

Originally Posted by Foxy Grandma

Would you guys recommend your Tarmac springs be paired with the Bilstein B6 or B8? I've seen reviews of people who have gone either way with good results.

FWIW, I spoke with someone at Bilstein about this and they said B6 is preferable, but both would work fine.

[sato]

Any particular reason why B6 over B8, and why?

Sent from my Pixel 2 using Tapatalk

[Pat]

I think there is just a longer shaft, which allows for more droop travel. Andrew would probably be able to confirm or deny this.

[jamal]

Originally Posted by FLYFISHR

This likely to be a stupid question, but when you set the front negative camber, is there any thought to compensating for the weight of the driver or whether you have to compensate for right or left hand turns. What I mean by that is, I think some people are more likely to take more speed into a left hand turn as a posed to a right hand turn while daily driving.

Yes, definitely. Firstly, it is better to corner balance and align a car as close to the way it will be driven as possible. So with the driver in the seat or an equivalent weight there, plus maybe 1/2 tank or less fuel, all the extra stuff out of the interior, race wheels and tires on, etc.

As far as changing the alignment from left to right, that depends on the specific track and driver. You usually figure this out by measuring tire temperatures, but if you were on, say, an oval track, obviously you would want more negative camber on the outside wheels.

[strat61caster]

Originally Posted by sato

Any particular reason why B6 over B8, and why?

Sent from my Pixel 2 using Tapatalk

B6 is cheaper.
B8 offers less droop travel which can help short springs stay under pressure when the car is lifted off the ground but offer no other advantages.
With some google-fu you can find the specs someone posted on this forum.

[H1C]

Originally Posted by Pat

FWIW, I spoke with someone at Bilstein about this and they said B6 is preferable, but both would work fine.

Interesting. When I spoke with someone at Bilstein USA tech support about a year and a half ago about which shock to get for RCE Tarmac springs, he told me the exact opposite. I told him the RCE's spring rates and expected drop. In fact he was quite insistent that, for any spring that is shorter than OEM length, I should get the B8s. So that's what I did.

[new2subaru]

Originally Posted by H1C

Interesting. When I spoke with someone at Bilstein USA tech support about a year and a half ago about which shock to get for RCE Tarmac springs, he told me the exact opposite. I told him the RCE's spring rates and expected drop. In fact he was quite insistent that, for any spring that is shorter than OEM length, I should get the B8s. So that's what I did.

Maybe they were out of B6's