GT car style suspension setup?
 

If you were to setup a twin to feel and act like a GT car, what if anything would you change from stock. Alignment, bushings, dampers, spring rates, ride height, wheel size, tire size, compound... Anything is on the table. I'm looking for something that can chew up highway miles with ease while also having rewarding grip and feel in a corner.

What I liked about my 2013 FRS's stock setup was that it was quiet and comfortable during most driving. What I didn't like was how easy it was to put it on the bump stops and thus how easy it was to get unsettled in a corner, even on the stock tires. I've made several changes since it was stock, and now I'm thinking it's time for a blank sheet approach. This time I'd like to add some science to the decision making process instead of just doing the same cliché things.

I'm thinking a simple set of slightly stiffer springs with dampers that allow more travel, some more caster to give more camber gain and feel, better tires that maintain composure when pushed, 17" rims as they're decently light and allow sufficient sidewall, and an assertive vice an aggressive alignment.

To this end I'm think the ever vaunted B6s for dampers.

I'm consider a couple of different spring setups. RCE yellows is an obvious choice as they increase the front spring rate a significant amount more than the rear. As the rear always seemed to behave well that seems logical. But I'm also considering a set of BRZ front springs mixed with FRS rear springs to keep as much travel as possible and as much comfort as possible.

Pedders strut mounts for the increased caster camber and better SAI, and whiteline control arm bushings for a little more caster without increasing NVH too much, and camber bolts for fine tuning.

Tires is a whole thread in and of itself, so I think I should leave that for now. But I'm wondering if tire width has any noticeable effect on NVH?

Stock or lighter rims.

For alignment settings I'm thinking ~Camber - 1.75 front - 1.25 rear, and toe set to zero everywhere.

Please critique any and everything here.

Kw v3 set to Max height
Toe in on rear for road stability
Conti ecs tires oe size
Leave everything else stock

The spring rates on those are 343 front and 400 rear. I'm questioning if 250 square will possibly be too stiff for my liking. I've read people say that damping can help ride a lot, but I'm having a hard time believing those would ride better than stock.

I also have very little interest in changing damper settings or ride height. If V3s is the best way to get what I want I can set them and then leave them, but I'd prefer to not pay for functionality I'm not using.

The pavement here causes significant NVH on my present setup, I can't see going to solid mounts helping anything with my goals.

Is my understanding incorrect?

going to have to raise the car so it's not hitting the bumpstops as much as it does in stock form for a softer ride.

TRD Rally springs + Sachs dampers seem to be worth looking into based on this glowing review. It raises the car 10mm so you're not hitting the bump stops as easily:

https://www.ft86club.com/forums/show...8&postcount=31

17×8 light wheels with 225×45 tyres for more sidewall and comfort. 2017 MY suspension for softer ride, sound deadening in cabin , doors , quarter panels and boot for a quiet Mile muncher! This will be my ideal GT set up

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I'm pursuing the same goal. Here's what I've done so far:

Chassis

Whiteline Poly Sway Bar bushings front and rear - Slightly better body roll control. Sway bar action is more immediate/linear. No noticeable increase in NVH.

Whiteline Poly Steering Rack Bushings - better feedback through the steering wheel and more immediate/linear response to steering inputs. No noticeable increase in NVH.

Whiteline Differential Mount Inserts - Tightened up shifting a bit and reduced driveline lash w/o noticeable increase in NVH.

Camber Bolts - Alignment set at -1.5 camber front and rear; OEM caster; 0 toe front and rear

Pretty extensive sound deadening in the trunk.

RaceSeng weighted shift knob

Conti 225-45/17 ECS tires on 17x8x40 Konig Ultraform wheels - about 2lbs lighter than oem at each corner.

Lighting:

Added OEM Fog Light Bezels - (the car's a Premium - no factory fogs

Installed Diode Dynamics SS3 - Pro Fog Lights wired to operate on command

LED Turn signal bulbs with DD flasher relay

Not much under the hood:

Sound tube delete
OEM Forester XT oil cooler/temp regulator

To Do:

Bilstein B6s - Unsure about springs at the moment. I may very well stick with the OEMs as I don't want to sacrifice bump travel or obstacle clearance.

I'm waiting to see what the RCE rally spring/B6 pairing has up its sleeve.

I've considered 949 Xidas - Dead sexy kit. But their development path seems to have taken them away from what I'm looking for - and they are probably way beyond my price range.

Edit: After I get the shocks sorted, I think I'll be finished. I do have a few more suspension/chassis bushings/inserts that I may play with, but I'm quite happy with the car as she sits and don't want to add unnecessary NVH.

I've considered and am still on the fence about flex fuel. A few more ponies would be fun to play with now and then, but ... I'll probably just keep procrastinating. :)

Kw v1 then
Kw uses oe mounts unless you get the clubsports
More about kws focus on gt ride quality then adjustability

I have the pedders strut tops and I don't think you'll need more castor than that. At the very least install them without the whiteline bushes and give it some time to see if you still want more.

If you go the B6 with RCE yellows, make sure you open up the front struts and trim the bumpstops to a similar height to the RCE ones.

You may even want to look at some 16x7.5 wheels instead of the 17s for a smidge more comfort that with the right tire will still feel good.

As written by RCE about B6:
"Where are the bumpstops in the front?
Since it's inverted, the bumpstop is inside the lower part of the strut body. Yes you can open these up and have a look, but I don't really recommend replacing the internal bumpstop. The non-inverted rear uses a regular bumpstop you can see (you reuse stock)."

https://live.staticflickr.com/4834/4...12ebae5d_h.jpg
^ My car back when it was in GT mode.

This was RCE SS1s, Perrin steering rack lockdown, Cusco rear lower control arms, adjustable toe arms, Whiteline rear diff inserts, Whiteline rear subframe inserts. And Braid Fullrace A 17x8 with 225/45/17 Michelin Pilot Sport 4s. And a very good alignment.

That was pretty terrific all around. A little low in this pic, but a better overall ride than it was stock.
The rear diff and subframe inserts do add some noise (gear whine). Not that annoying to me, but it would be nice if it were a little quieter for a true GT car.

All pre-2017 OEM dampers are just too stiff and very easily unsettled. I've been swapping back and forth between 2016 OEM and Bilstein B6 during our RCE Rally lift springs testing and the Bilsteins are such a big step ahead. The roads I drive on are terrible crap, and the OEMs can't keep up in certain sections.

So swapping in Bilstein B6 on their on makes a really nice difference. Add RCE Yellows if you want something a little lower and a performance improvement.

The Bilsteins add a lot of "composure" when there's a series of bumps or section of rippled and broken pavement. One intersection near me has massively rippled pavement alllll the way across. On OEM suspension right now you do a "oh...geez...ow...dang!" On Bilsteins it's more of a "oh...geez." A section like that in a corner gives the skating sensation on OEM stuff that is not confidence-inspiring.

On a single bump, say a small speed bump or a single ripple the Bilsteins are noticeably better, but it's not that terrible on the OEMs.

I'd be hesitant to go with a poly front control arm bushing, and would either stick with fresh OEM bushings or STI Group N front control arm bushings.

I'm putting my SS1s back on this Thursday as we await the next prototypes of the Rally springs. Really looking forward to taking off the OEM struts.

- Andrew

Shortening the internal Bilstein bumpstop is optional with lowering springs. Basically, I don't want everyone opening up their Bilsteins if they don't have to...

- Andrew

I didn't do that, didn't seem nesssary from what I read on here. Though it can't hurt.

For purely comfort goals 2017+ dampers or the entire spring/strut assembly as a takeoff if you can find them used. Cheap and will improve ride.

I am on B6+ yellows. Ride is firmer than stock but far from typical coil setups. My comparison is to 2017 suspension.
Strikes a happy medium of sportier feel without being racecar.