I'm curious if RCE has done any R&D on the 2015 FRS? Reports seem to point to the 2015 FRS as having revised springs & dampers. I had a 2013 and moved to a 2015 and am quite happy with how the 2015 feels even compared to the 2013. I want to lower my 2015 but it would suck to change negatively in anyway how it handles...because it's amazing!

Bring them your car...

Basic tech info: spring rates, rear suspension, motion ratios, and you.
 

If you think this is amazing from scratch just keep it like this.

Or if you want a little drop maybe yes RCE yellow can do a good job without sacrificing too much the handling.

Correct me if am wrong but I think RCE yellow make the car feel more neutral vs OEM.

This is my feeling also on Mach V springs.

Thanks for the thread!

Same springs as before, shocks are slightly different. Not a very large change.

- Andy

Is this the same case with the 2015 BRZ?

Yes.

So if I just want to lower my car around an inch, as I love the driving dynamics, would the RS-R S/Down do me well? Or would I also need to upgrade other areas of the suspension as well like sways, LCAs, ert?

Basic tech info: spring rates, rear suspension, motion ratios, and you.
 

Only a good set of springs and an good alignment will be fine to start.

No need LCA for around one inch, I don't have LCA and am dropper 1" 3/8...

Of course adjustable LCA are better, but this is to fine tune your alignment.

You can run only lowers springs without any problems don't worry...and if you want, in the near future you have always the time to upstage others suspensions depend on what you will need concerning the handling of this car.

^ Cool thanks. I've had coilovers before, but not sure if I want/need them if I really have no current plans on dropping below 1 1/2".

So which vendors here will provide dyno plots for individual shocks...?

Also thanks for the list, some great reading!

Vendors? Probably few. Some manufacturers will.

I love our 2013 GTS86 auto but at 70+ years of age the wife in particular hates the hard ride. Can anyone advise on modification to make it like (for instance) a Golf GTI which seems about the right amount of suppleness for our taste please.
I am thinking trying different springs first then dampers but have no idea about rates.

A set of new or lightly used 2017 or 2018 BRZ standard shocks would be my recommendation.

Bilstein B6 will ride well too, but a little more "sport" in comparison.

If ride quality is your main goal, I would stick with OEM springs.

BUT the new version of the Ohlins coilovers would also work well, at quite a bit more cost.

- Andrew

I'm also in the 70+ age range. Believe it or not, sticking with the non-PP wheels, tires, suspension AND using a good gel pillow for my wife (who weighs less than 100 lbs), works best. It turns out that the thin padding on the seats transfers the jarring and when that is subdued, the ride seems a lot smoother. I'm thinking about having extra padding put in the bottom of the seat. We actually have a similar problem in our SUV, believe it or not, and she uses the cushion there as well.

Thanks & a simple enough solution to try. She would like to sit higher too.

I trialled a couple of gel cushions and one does exactly what I wanted. The jarring and jiggly ride now feels nicely damped so much so that I think everyone should give it a try. All it cost was $20 Australian and I know I could have spent a heap on spring/damper experimentation and maybe never have got it to feel right. I reckon the o.e. seats could have been tuned by the makers to much better match the suspension. The feeling I get is that the wheels are more stuck on the road even though the suspension is the same and I am inclined to throw the car around more.
The tradeoff is a feeling of being perched up on the seat rather than down in it and not located by it as much resulting in a a slight feeling of wallowing and body roll which you would expect. I have lowered the seat to the max to compensate and got used to it quickly. Previously I had the seat raised about 40mm.
The cushion I like is 430 X 330 X 60 mm and quite heavy due to a generous bag of gel inside a cover of quite soft 30 mm foam both top and bottom and around the sides. It is not memory foam. My feeling is that is the gel that is doing most of the work. Maybe getting rid of the foam and just using the bag in your seat would do the trick and be better than adding extra padding. Widthwise it is a perfect snug fit between the side bolsters but I will be trimming the foam to fit back between the seat-back bolsters. It could do with an hollow for the wedding tackle too and maybe a little foam off the front as it presses on the back of my thighs up by the knees. At $20 I can afford experimenting.

Glad it worked out for you. I guess a more permanent solution would be to get butt implants!!!!!! Both my wife and I sit rather low so raising us an inch or so is actually better....

Hey mate,

Do you have a link where you picked it up or which store you got it from?

I didn't post a link as this is a U.S. (mainly) site but I c u r an Aussie too.

Got it from Cheap As Chips. MA2488 Amazing Gel Comfort Cushion 34. They also have a black car cushion HA9255 Cooling Gel Cushion 4 which was the other one I tried but it didn't seem to do much. I cannot find any gel inside that one despite the description... only a rubbery pad with big holes for air circulation.

Thanks mate, the wife thanks you!

Looking at rear LCAs like the SPL units where there are 3 shock mounting holes am I correct in stating that mounting the shocks in the outermost hole (closest to the hub) will effectively increase the rear spring rate/wheel rate?

Moving the shock mount towards the hub would increase the motion ratio which would put more spring force (weight) on the spring, but the spring rate (on a linear rated spring) would remain constant throughout. It would only compress the spring further than it would if it were mounted on a shock mount more towards the control arm pivot point.



For my car I've only spec'd out the rear for coil-overs, but with the factory control arms the motion ratio is .76. The way I measured this was:



https://enderw88.files.wordpress.com...2/diagram1.gif


On the rear of my (2013) FRS D1 is 13.50" and D2 is 17.75". Dividing 13.50" by 17.75= .76


I haven't weighed my car on scales, but all this means is that (say for example) each rear corner weighed 630 lbs. on scales. You would subtract the unsprung weight of wheel/tire/brakes/half of control arm, let's call it 100 lbs., giving you 530 lbs. on that corner. With the motion ratio that 530 lbs. divided by .76 would give you the actual force the spring would see of= 697 lbs.



Typically on a street car you'll want to see 25%-30% of the springs free length compressed by the weight of the car, so changing the mount position inboard or outward on a control arm will effect the compressed spring length. Ultimately, it's the dampening of the shock that controls the motion/ride quality of the car, though.

What is the ideal motion ration? Do you want it as close to 1 as possible?

There is no "ideal motion ratio". Depending on car body, suspension design, clearance, dimensions, it just happens to be some specific one for that car. And manufacturer chooses spring and damping rates to be used with that ratio, as it changes resulting rates one actually will get "at wheel".

I'm pretty sure they changed the spring rates with the face-lift BRZ and the "new" GT86.

Do anyone know the latest oem/stock spring rates for both or at least the BRZ of 2017+

Would be great!

Hopefully someone can help me in here instead of starting a new thread.

I just got Eibach pro kit lowering springs and I'm about to install it but wanted to know where to find torque specifications for control arms, sway bar links and top hat and strut top bolts? Also lug nuts would be great. I just want to get everything right from the first time. Btw I will be using my car most of the time for DD.

My car is 86 2018 with 10,000KM (not sure of it matters).

Thanks in advance.

Sent from my SM-G975F using Tapatalk

Here’s an excellent DIY to get you started

http://www.ft86club.com/forums/showthread.php?t=10842

Necro addict
 

As mentioned, there are many factors at play so sharing a snapshot of the whole setup would have helped.
Was it lowered? Any sway bar change? Any reduction or increase in unsprung weight? Any aero?
I have a 2022 BRZ that I'll track a lot, but will be a semi-DD.
I'm doing the Cygnus Racing shock version of Fortune shocks. Hyperco 7K springs. Digressive valving.
Voodoo 13 rear lower control arms.
APR GTC200 wing. I intend to have a splitter, so some aero on the front to balance it out. Have 245 888R's on 17X9" ET42 APEX ARC-8 rims. Plan on a 1 to 1.5" drop.

'22 BRZ Question. I see most persons using the Gen1 rear LCA and coilovers. We know the '22 RLCA is around 0.5" different: https://www.ft86club.com/forums/show...54#post3495854

How does that affect the motion ratio? Additionally, the track between Gen 1 and 2 is different (staggered)? It appears most suspension offerings for Gen2 are the Gen1 parts and spring rates. Should this matter?
Additionally, the MCA traction mod ( best mod i've ever put on a car) really tames the rear end step-out and adds comfort. It does not affect alignment, but does changing the anti-squat characteristics affect motion ration at all? I do feel like I can get away with much higher rear spring rates now that the rear end is predictable. I am currently on stock suspension but am looking for performance oriented suspension parts for track and auto-X and most of what I find is looks oriented.

I'm curious about the 1st gen LCA too. I think I'll wait until all this stuff gets ironed out before doing any suspension mods.

I wrote up this little discussion of the 1st vs 2nd gen differences:
https://www.racecompengineering.com/...ension-changes

Rear motion ratio is a tiny bit higher with the 2nd gen. The example I gave in the article is that a 300 lbs/in rear spring would be about 10 lbs/in stiffer in wheel rate on 2nd gen compared to 1st gen. Not huge, but it's there. Then there's the slightly increased track width in the rear that works against that.

One thing that's interesting is that most 1st gen adjustable rear LCAs actually already have the 2nd gen geometry. This is because the 2nd gen BRZ rear LCAs are the same part number as they are Subaru VA chassis (2015-2021 WRX and STI) and many aftermarket companies have been using the same LCAs for both 1st gen BRZ, VA chassis, and a whole bunch of other Subarus (for better or worse). The act of adjusting the LCAs changes the motion ratio a tiny bit anyway. For me it's not a large concern. I do not expect anyone to make an adjustable 2nd gen specific rear lower control arm, but I'm not in the rear lower control arm business. :)

The MCA traction mod should not affect motion ratio as far as I'm aware.

- Andrew

Interesting, which adjustable gen1 arms actually use the gen2 geometry?
I know Verus isn't one of them.

It's hard to tell, but my guess is most (not all) that are listed as for 2008 to 2020 WRX/STI in addition to BRZ were originally developed for the WRX/STI.

Gets complicated with the arms that have multiple mounting holes and the Cuscos that have 2 position mounting key thing.

Again the difference is small and when you adjust camber with the LCA it changes the length of the arm and the motion ratio slightly anyway.

- Andrew

Totally!
I'm more worried about legality in the autox STR class than motion ratios at this point though.

If you ever confirm, please share!

If anyone is curious.
2013-2020 BRZ (2013-2014 wrx & STI) RLCA part#20250FG042.
2022 BRZ (2015-2017 WRX & STI) RLCA part #20250AL011.

The Verus 7000 series LCA's are listed as fitting 2008-2021 WRX/STI in addition to the BRZ/FRS/86, so maybe they can accommodate the 2nd gen geometry as well?

"Accomodate" is not the same as "use".
You can find my posts on this forum where I measure these Verus arms and they don't match the geometry of gen2 cars, and thus are not legal in SCCA STR.