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

[R2]

Originally Posted by Racecomp Engineering

Front:
Front control arm (front) bushing.
Whiteline ALK
steering rack bushings

Rear:
trailing arm front
crossmember inserts
diff bushings
rear upper control arm bushings (either the camber adjustable or the fixed)

I bolded the ones I recommend most and are the better bang for the buck. The others are good too. Might as well do as many as you can stand at the same time since they're almost all kind of a pain to install.

- Andy

It’s been a few years; do you still feel this list is accurate?

[tane]

I am looking to do a suspension upgrade this winter and this is a really great thread. I have a track oriented ’14 BRZ that sees light daily driving. I have upgraded brakes and exhaust/tuning. I generally like the way the car handles on the track, but am looking to increase overall grip, and reduce some of the understeer on corner exit of big sweepers (I am destroying RF tires on a mostly left turn track). I have Michelin PS4S (225/45 R17) and want to stay with those rather than go to a more focused track tire (Cup 2 or other).

I am thinking of something like Ohlin R&T with camber plates. To target something like -2 degrees camber upfront. At stock height I have -1.25 negative camber in rears right now (and zero camber upfront). I will want to test out stock height vs say a 20mm drop to see the difference.

Here is my confusion. I have been told that Ohlin suggests spring rates of 50N/m (443 lbs/in) front and back. And they say those springs were sized assuming that you keep the OEM anti-sway bars in place (18mm and 14mm).

This was surprising to me. This thread seems to suggest that using a combination of softer springs and stiff bars (like the OEM set up) is an “older” approach to suspension and that it is better to try to get the spring rates right directly and then use bars only to tune balance preference.

At 443 lbs/in, this seemed to imply that without the bars, Ohlin was targeting something that had similar stiffness upfront to the OEM, but 35% more stiffness in the rear (using the really great “wheel rate” data on a related suspension model thread https://www.ft86club.com/forums/show...t=26661&page=8). For a road and track suspension, this seemed like a good place to start.

But if you keep the OEM 18mm/14mm bars attached and just add the Ohlins, that is increasing a lot of stiffness all around (plus adding more in the back).

Which outcome was Ohlin targeting when they recommended 50N/m springs in their coilovers?

Or am I misunderstanding something here?

[Racecomp Engineering]

Originally Posted by R2

It’s been a few years; do you still feel this list is accurate?

Yes....but...I wish there was an easier or different solution to the ALK. It's a fine piece but not what I really want in that spot.

- Andrew

[Racecomp Engineering]

Originally Posted by tane

I am looking to do a suspension upgrade this winter and this is a really great thread. I have a track oriented ’14 BRZ that sees light daily driving. I have upgraded brakes and exhaust/tuning. I generally like the way the car handles on the track, but am looking to increase overall grip, and reduce some of the understeer on corner exit of big sweepers (I am destroying RF tires on a mostly left turn track). I have Michelin PS4S (225/45 R17) and want to stay with those rather than go to a more focused track tire (Cup 2 or other).

I am thinking of something like Ohlin R&T with camber plates. To target something like -2 degrees camber upfront. At stock height I have -1.25 negative camber in rears right now (and zero camber upfront). I will want to test out stock height vs say a 20mm drop to see the difference.

Here is my confusion. I have been told that Ohlin suggests spring rates of 50N/m (443 lbs/in) front and back. And they say those springs were sized assuming that you keep the OEM anti-sway bars in place (18mm and 14mm).

This was surprising to me. This thread seems to suggest that using a combination of softer springs and stiff bars (like the OEM set up) is an “older” approach to suspension and that it is better to try to get the spring rates right directly and then use bars only to tune balance preference.

At 443 lbs/in, this seemed to imply that without the bars, Ohlin was targeting something that had similar stiffness upfront to the OEM, but 35% more stiffness in the rear (using the really great “wheel rate” data on a related suspension model thread https://www.ft86club.com/forums/show...t=26661&page=8). For a road and track suspension, this seemed like a good place to start.

But if you keep the OEM 18mm/14mm bars attached and just add the Ohlins, that is increasing a lot of stiffness all around (plus adding more in the back).

Which outcome was Ohlin targeting when they recommended 50N/m springs in their coilovers?

Or am I misunderstanding something here?

Hmm...I think we're missing something here. First up, you probably meant 50 N/mm (not N/m) and that does not convert to 443 lbs/in...it's around 285 lbs/in.

To make it more simple, are you comparing these 3 hypothetical set ups with your tires?

1. Stock
2. Ohlins with 50 N/mm springs
3. #2 but with stiffer swaybars

- Andrew

[cueball89]

Originally Posted by Racecomp Engineering

Yes....but...I wish there was an easier or different solution to the ALK. It's a fine piece but not what I really want in that spot.

- Andrew

Can you elaborate on that? I don't have an issue pressing the old bushings out. I am a little hesitant putting poly bushings in areas where the old bushing moves in more than one axis.

[churchx]

Whiteline ALK may fail for some, with metallic insert separating from poly bushing. Well, at least it did fail this way for me. Currently replaced it with non-eccentric power suspensions front LCA front poly bushing. There is extra caster from pedders top mount, so not seeing extra caster from front bushing of front LCA that needed. Also there might be "too much" caster, as everything, that makes steering heavier, eg. increasing scrub radius, lot more caster, imho may put more load on our electric power steering, which was prone to overheating on older twins (IIRC fixed .. not sure though if on MY2015 or MY2017), recalling reading post where for someone reducing caster helped/fixed with EPS overheating/switching off problem.

[Racecomp Engineering]

Originally Posted by cueball89

Can you elaborate on that? I don't have an issue pressing the old bushings out. I am a little hesitant putting poly bushings in areas where the old bushing moves in more than one axis.

That's exactly it. It's fine...but...I would love a sealed offset pillowball.

- Andrew

[RotARy15]

I've somehow finished reading this entire thread and I have a few questions remaining.

Slight crosspost from another thread>

Originally Posted by RotARy15

My plan at the moment is to keep it mostly stock. I'm in an interesting situation with my FD. I was slowly building it to be track worthy (must control thermal runaway...) but at this point, I need proper facilities to complete some of the work. So for now I am going to keep things simple as the BRZ is not intended to be a track toy, yet. It replaced my 03 NB as a daily driver. And will be serving as a track-able daily until I get the FD finished or give up and sell it at which point I will start making spectacularly stupid decisions with the BRZ.

I haven't decided on width for track wheels yet and my biggest hangup is that it depends on suspension mods. I'd like at least 245's but best I can tell, a 9 inch is hard to fit on an OE setup and that gets more difficult if you gain camber at the hub. 17x8.5's are rare and 17x8 isn't really a large increase over the stock 7.5's so I might as well hunt down another set of stock wheels and slap sticky 215's on those in that case. It is hard to justify $1000 in wheels for only another .5 inch when I could hunt down stock wheels for around $500.

The main goal suspension wise is track/street alignment. I don't really want to hop off the PP setup yet. Camber bolts alone aren't enough. Raceseng plates are the goal but buying plates for the OE coilover and then deciding I want V3's or Tarmac2's is an unnecessary re-fitting cost attributed simply to indecision and poor planning...

How much are 245's worth compared to 215's? Enough to deal with the headache of squeezing a 9 inch wheel in an OE setup?

With regard to camber. I'd like to save the money on plates and go with bolts but that alone won't get me enough camber. Does slotting the OE strut and adding camber bolts to the top hole sound as crazy as I'm afraid it does? If I mirrored the slots from something like the T2's what ballpark would that get me to? Looking for -2 to -2.5.

If the rear turns out to be heavily mismatched or too low then I will spring for SPL's and just get that problem solved without too much thought.

May eventually do subframe and transmission/diff bushings but I feel like I will "forget" to do these if I don't end up with a personal 2 post lift.

[timurrrr]

Originally Posted by RotARy15

With regard to camber. I'd like to save the money on plates and go with bolts but that alone won't get me enough camber. Does slotting the OE strut and adding camber bolts to the top hole sound as crazy as I'm afraid it does? If I mirrored the slots from something like the T2's what ballpark would that get me to? Looking for -2 to -2.5.

You can get -1.75º with just SPC Performance camber bolts for ($20 on Amazon). Some folks swap the other bolts too and get even more, so perhaps your goal is achievable with just bolts; although I personally avoided using two pairs of bolts.

I've also seen Pedders offset strut mounts but don't know anyone to confirm how well they work. They are pretty cheap though, so worth a try?

[churchx]

timurrrr: they work fine. Not that cheap though (price is for one, you need two).

[HaXx]

Hey CSG and RCE. I know many are on air when doing overfenders, but i want to go coils. Can you school me on what coils to get so i can get the right ones the first time? Tracking is not in the equation for me.

[strat61caster]

inb4 racecomp superstreet and csg tein flex

[i8ur911]

Originally Posted by HaXx

Hey CSG and RCE. I know many are on air when doing overfenders, but i want to go coils. Can you school me on what coils to get so i can get the right ones the first time? Tracking is not in the equation for me.

A specific coilover is not needed for over fenders. The large majority of the coilovers for the 86 chassis accomplish very similar ride heights.

What's your concern?

Sent from my Pixel 3 using Tapatalk

[HaXx]

Originally Posted by strat61caster

inb4 racecomp superstreet and csg tein flex

there were a set of csg flex a's for sale a while ago but i missed them. theres a set of rce zero's up for sale right now, u think theyd be well suited? i suppose im looking to buy nice, not buy twice. but also im not a performance driver, i dont want to be the guy showing up for tryouts with pro level gear. i just looking to get whats par for the course.