dp1 track suspension reinforcements (bushings, links, sways, arms)
 

Pay it forward...

This thread is not about coilovers/springs. It's about suspension reinforcements (bushings, links, sways, arms) that enhance driving experience at the track. If you (1) track your car, (2) often drive near the limit of traction, (3) use track alignment of at least -3f/-2r, (4) already replaced stock dampers, (5) run sticky tires with UTQG 200 or below (r-comps or slicks), (6) don't mind added Noise Vibration Harshness (NVH) in exchange for better feel/control, and (7) have already made upgrades to the stock bushings, links, sways, arms, etc., that made things better...please share your experiences

INSERTS AND BUSHINGS
Bushings
@Racecomp Engineering - "...bushings are often overlooked and I just have to shake my head when I see a dedicated track car with stiff springs and high levels of grip on stock bushings. It should be a fundamental change for every track car. With high grip comes noticeable bushing deflection and unwanted dynamic alignment changes. They're partially a "feel" mod since the car is more consistent/connected/solid but they will make the car faster too."
- "...bushing flex is real. The car actually rolls a little more with the stock bushings on sticky tires even if you're on fancy coilovers. It's nice to know exactly what the wheel is doing and taking bushing flex out of the equation is helpful."
- "...we replaced every bushing on our car...started with Group N STI parts (less NVH penalty, expensive, more difficult to install) and then Whiteline, and a few custom spherical bearing parts."
- "...we've not had problems with whiteline bushings squeaking when installed and properly lubed at the time of install."
- "...replace all bushings with pillowballs."
- "...the often overlooked rear upper control arm is very worthwhile [...bushing replacement]. Whiteline sells an adjustable (camber) and a non-adjustable poly bushing." also "The WL upper control arm bushing replaces a soft squishy OEM bushing in a key location. Adjustments here do not affect anything else either. Real pain in the ass to install and adjust though. I think the ideal way to go is to install the fixed WL bushing for the upper control arm and then get an adjustable lower control arm."
- "...you'll feel some interesting things when you replace soft bushings with poly or solid bushings...enough that you may adjust your damping. Not "equivalent" to increasing damping but some of the things you thought were one thing actually were the bushings deflecting."
@CSG Mike - "...replacing all the bushings with sphericals/solids in the arms, and putting in collars for the trans mount, diff mount, and subframes. It makes EVERYTHING more direct. Also replace the engine mounts, although how stiff you go here is more subjective then the rest of the aforementioned."
@7thgear - "...bushings are the best mod you can do for your car if you're looking at improving feel and response, no doubt about it, the NVH increase is negligible and quite honestly greatly over exaggerated by the online community."
@yomni question "...If you had to recommend a group or set of bushings to a beginner for upgrading, what would you say was the best bang for the buck to eliminate some o that elastic feeling in corners when grippier tires have been added. Is this one of those subjects where you should replace them all or you could do the rear subframe bushings then front control arms...?" was answered 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."
@stockysnail - "...No issues with my car and all the bushings I have from Whiteline in my car (I have all of them) after two winters here. See my build thread for the list. No salt on the west side of 'murica however."

Rear subframe inserts
@gramicci101 - "...watch Whiteline's subframe insert video and look at the two diff carrier bushings. They bounce around like they're on a trampoline. Replacing these bushings or getting inserts for the OEM bushings effectively removes any on/off throttle thump in the rear end."
@7thgear - "...if you're not doing autocross "stock class", then I would highly recommend rear subframe bushings... on ANY car, you will feel the improvement and the NVH is not important, you will be very happy that you've put these in."

Diff inserts
@dp1 - "...good next step after the subframe inserts. Can add to the whiny/buzzy ride on highway, especially around maintenance throttle with my OS Giken 1.5 LSD but not very loud and well worth it for track. Not sure if any other of my reinforcements affect this sound."
@DarkSunrise - "...I'm not sure if I got lucky or what, but there's barely any increased NVH [with Whiteline KDT925]. My wife couldn't even tell. I don't have any other inserts or bushings though."
- "...they (WL diff inserts) basically fill the voids in the OEM bushings with polyurethane to minimize flex. Whiteline also makes replacement bushings (KDT924), but those are more expensive and would require you to drop the diff cradle and press them in."
@was385 question "...I keep going back and forth on the diff bushings. Half the people seem to say that the added NVH isn't bad, half say it's awful. Do you have any experience with the whiteline or a similar kit with regards to NVH?" was answered by @Racecomp Engineering "Yes and IMO it's fine. My tolerance for transmission NVH is that I don't mind gear whine that much but can't stand clunks or too much vibration. Others may be different..."
- Whiteline differential insert bushings review
- KDT 925 installed

Transmission inserts
@Who8myrice - "...I have whiteline transmission insert. Inside the cabin got louder but my gear feels great."

Steering rack inserts
@Who8myrice - "...also have Cusco steer rack bushing. Difference is very little but my steerwheel feels tighter, I think I felt more from Trd door stabilizer then this."

Engine mounts
@dp1 - "...limit engine movement and reduce wear on certain parts. Can increase NVH quite a bit depending on solution. Some could melt from proximity to exhaust pipes."

LINKS AND ARMS AND BARS
Adjustable endlinks
@dp1 - "...help fine tune swaybars, especially when trying different mounting locations in aftermarket rear LCAs (i.e., SPL LCA has three link mounting holes to choose from). Two of my four Whiteline endlinks weakened recently and were replaced before failure. After seeing several videos with endlinks failing in turns, I am looking to replace them before the next season with surdier heim joint options."

Adjustable toelinks
@dp1 - "...allow fine adjustment of toe."

Front control arm
@Racecomp Engineering - "...bushings or full replacement control arms with heim joints are excellent."
- thread commenting on fitment of RacerX front control arm

Rear Lower Control Arm (LCA)
@dp1 - "...very useful for dialing in negative camber in the rear and for sway bar adjustments. Strong aftermarket LCAs can aid in bending of a subframe in an accident."
@Sleepless - "...(SPL LCA)...the effective spring stiffness is altered by choosing one of the three shock mounting holes. In other applications this is usually expressed as a percentage relative to stock which I presume is the center hole...Got the answer from SPL. +/- 6% stiffness. Pretty useful LCA"

Swaybars
@CSG Mike - "...sways are used to tune the under/oversteer balance of the car to your preference. In an autox environment, you'll probably want a beefy front sway, since you'll likely value quick transitional speed over sustained cornering speed."
@Racecomp Engineering - "...I don't like running a larger rear bar without a larger front on this car. But maybe try it and see what you think. I suspect you'll like it more with a bigger front bar."
- "...we generally like a 22mm front or a 25mm hollow. Our own RCE bars are 25mm and 19mm (hollow so about 22 front and 16mm solid equivalent). That works well for most set-ups but if you're going very stiff on springs you may want to go smaller. Adjustable bars are recommended"
@ultra - "...On the topic of swaybars I'd be careful what you choose. I'm running the Hotchkis bars, which are very stiff compared to stock (over 200% stiffer at the softest settings). They're good match for full R compound rubber and even more aggressive alignment settings on a track but not so good on the street, with street tires and a less aggressive alignment. They do keep the car extremely flat but I get a lot of crosstalk on bumpy surfaces and the breakaway characteristics are very abrupt. I'll be swapping back to a much milder swaybar combo soon. I'd actually recommend swaybars as an absolute last step in the 'mod chain' but that's just me. If you're super keen offense dialing in your car I'd speak to a pro and get them to recommend something tailored to the other parts already on your car and your own specific use cases."
- Sway bar option list

Rear Strut Tower Bar
@Calum - "...A rear strut tower brace on this car is a complete waste of money. On the front they're still open for debate."

Roll Center/Bump Steer Correction Kit
@troek - "...i just put on the whiteline roll center kit, with my rsr super down springs, its a very noticeable difference in steering response, and the front end doesn't dip down under sharp cornering like it did before. very worth it in my opinion. i didn't think i would notice anything but i did."
@Racecomp Engineering - "...the bumpsteer kit is not very useful at stock ride height. Front control arm bushings including the ALK would be much more effective. Not sure on which costs more points for you but the bushings are the better choice."
- "...The WL RCK kit will not hurt your handling at stock ride height. There won't be much if any benefit either. I say go for it if you realistically plan on lowering the car later."
- "...The Whiteline roll center kit is NOT primarily for bumpsteer. It is a roll center adjustment kit that includes tie rod extenders. With just the roll center adjustment part of the kit (the ball joints), you induce some bumpsteer by moving the tie rods out of plane. The tie rod extenders minimize that change. Anyway, yes there is a small benefit to the WL kit. It is not very dramatic, but it helps."
@Tor question "...How much lowering before the Whiteline roll center and bump steer correction kit becomes a worthwhile upgrade? How little of a drop before it becomes contra productive?" was answered by @Racecomp Engineering "...It becomes noticeable at 25mm of drop. Even more so at 35mm. I would use it with a 20mm drop, but not any less than that."


Please buy from vendors who support us and who help us make optimal choices (i.e., RacecompEngineering and CounterSpaceGarage). Examples of parts they carry or can source: SPLParts, Cusco, Whiteline, Perrin Performance, Racer X Fabrication, etc.

Additional resources on the topic:
http://blog.modbargains.com/best-sus...-s-brz-zn6zc6/
http://farnorthracing.com/autocross_secrets5.html
http://www.motoiq.com/Projects/Scion/FRS.aspx
Discussion: Upgraded Bushings & Mounts

My suspension reinforcement upgrades (others are on my build page, see sig link):
Cusco 956 464 AV - Front lower control arm front spherical bearing.
Cusco 692 464 BV - Front lower control arm rear bushing.
Cusco 965 464 LV - Rear upper control arm front bushing.
Cusco 965 464 IV - Rear upper control arm rear bushing.
Cusco 965 928 A - Differential mount collar.
Cusco 965 927 A - Rear subframe collars.
Perrin engine mounts.
Perrin transmission support.
SPL Adjustable Rear Toe Arm.
SPL Bumpsteer Adjustable Front Tie Rod Ends.
SPL TITANIUM - Rear Traction Arm.
SPL Titanium Rear Lower Camber Arms (LCA).
Whiteline KLC179 front/KLC182 rear adjustable endlinks.
Whiteline W23448 rear sway bar - mount bushing 14mm.
Whiteline W23447 front sway bar - mount bushing 18mm.
Whiteline KBR38 rear brace - sway bar mount support.


Grouped in Stages...

Stage 0 (stock)
Limited camber adjustments, body lean, some rubber bushing slop, potentially limited lifespan of stock dampers.

Stage 1 (fix few key areas)
- $2k+ damper upgrade.
- Camber plates in front (if dampers don't have them) and rear LCAs to get optimal track/ax camber/toe.
- Transmission/subframe/diff/ inserts or collars and engine mount to remove slop, if NVH is not a concern.

Stage 2 (complete suspension refresh)
- $4k+ damper upgrade
- Everything in Stage 1
- Everything else noted above
- Potentially upgraded sways (i.e., for AX)




What suspension reinforcement upgrades worked best for you or your customers?

The often overlooked rear upper control arm is very worthwhile. Whiteline sells an adjustable (camber) and a non-adjustable poly bushing.

Front control arm bushings (both) or full replacement control arms with heim joints are excellent.

We replaced every bushing on our car...started with Group N STI parts (less NVH penalty, expensive, more difficult to install) and then Whiteline, and a few custom spherical bearing parts.

Bushing flex is real. The car actually rolls a little more with the stock bushings on sticky tires even if you're on fancy coilovers. It's nice to know exactly what the wheel is doing and taking bushing flex out of the equation is helpful.

- Andrew

Not a suspension bushing, but watch Whiteline's subframe insert video and look at the two diff carrier bushings. They bounce around like they're on a trampoline. Replacing these bushings or getting inserts for the OEM bushings effectively removes any on/off throttle thump in the rear end. Whiteline's diff carrier inserts made a negligible difference in NVH, with a slight whine at low speeds in 1st gear.

[ame="https://www.youtube.com/watch?v=IDfJ_zYFPcs"]BRZ / FT86 / FR-S Whiteline Subframe Lock Out Kit - YouTube[/ame]

Replacing all the bushings with sphericals/solids in the arms, and putting in collars for the trans mount, diff mount, and subframes. It makes EVERYTHING more direct. Also replace the engine mounts, although how stiff you go here is more subjective then the rest of the aforementioned.

I've seen videos of (sway bar) end links failing in high G corners, though not on a twin yet. Two of my Whiteline end links weakened from track use and were replaced before failure. I will use them throughout this season but would like to replace with sturdier parts - what brand/model do you recommend?


For example:
- http://www.splparts.com/products/spl...s-brz-wrx.html
- http://racerxfabrication.com/frs-brz...rear-end-links
- http://perrinperformance.com/i-13324...-fr-s-brz.html
- http://perrinperformance.com/i-14660...-fr-s-brz.html
- http://perrinperformance.com/i-14754...-fr-s-brz.html
- http://www.whiteline.com.au/product_...LC179&sq=15936

I've been looking for feedback on engine mounts. I have a set of STi/Group N rubber engine mounts waiting to go in. I also have the Whiteline diff and trans inserts installed already.

I know it's a massively subjective thing but do you think the upgraded engine mount NVH will be worth the gain in feel/directness? Or will there even be as significant of an increase in directness compared to the inserts?
Car's a daily but gets autox'd every few weeks. I'd appreciate any input.

I don't recommend going crazy on mounts on a daily driver, as your engine vibration will get into the cabin.

Stock or barely stiffer than stock is the most I'd do on a non-racecar.

I did the Diff inserts and subframe inserts trying to reduce some movement in the back. Feels great now and compliments all of my Spherical Joints and arms. Lots of NVH, I swear I can hear the damn axles rotating. But car feels so solid and planted. Also diff whine is annoying but oh well.

Thanks, do you track or ax much? Would you mind listing your "spherical joints and arms" upgrades?

Yeah, that's why I'm on the fence about it. I got used to the NVH from the trans and diff inserts very quickly and the engine mounts would be the last mount I'd change. I guess I'll have to find out myself, these don't seem like a popular mod on anything but a full race build.
My last car got a huge driveability boost from an engine mount but the BRZ isn't a Mazda 3 so I'm not sure it'll work the same lol.

Is there any Whiteline bushing that you would advise against, or would not bother using, and why? Assume NVH is not an issue.

I have whiteline transmission insert.
Inside the cabin got louder but my gear feels great.

Also have Cusco steer rack bushing.
Difference is very little but my steerwheel feels tighter, I think I felt more from Trd door stabilizer then this.

I have the Group N/STI engine and trans mounts. Fantastic for a DD and they're really what the car should have come with as you can now tell there's actually an engine under the hood, haha. However they're pretty much a worthless upgrade for a car that sees track or autocross duty, IMO. I'll be swapping to Perrin eventually as I've driven cars with Perrin mounts and they're WAY better on-off throttle with barely any noticeable NVH increase over the Group N/STI mounts at idle or around town.

Thanks, I have Perrin engine mounts and like them. It's good to check the bolts 1-2 times per season, mine got ever so slightly loosened once and my shop (EFI Logics) caught that during one of the fluid change/track readiness checks. I've done quite a few reinforcements at once during the initial build so it's hard for me to tell how big of a difference each of them made.

After exchanging quite a few thoughts with @CSG Mike on my needs and opportunities for improvements, some SPL and Cusco bits will be added. Swaybars will remain stock, there will be less rubber in the suspension, and it should all play nicely with new JRZ doubles.

Good thread!

Here is what's getting added soon, courtesy of CSG via SPL and Cusco:
SPL Adjustable Rear Toe Arm
SPL Bumpsteer Adjustable Front Tie Rod Ends
SPL TITANIUM - Rear Traction Arm
956 464 AV - Front lower control arm front spherical bearing
692 464 BV - Front lower control arm rear bushing
965 464 LV - Rear upper control arm front bushing
965 464 IV - Rear upper control arm rear bushing
965 928 A - Differential mount collar
965 927 A - Rear subframe collars

Looking forward to trying these out with JRZ DA on 500lb/600lb (9k/11k) springs and Toyo RRs...with a little luck, may be ready for 3 days at NJMP with NASANE 6/17-19.

If you winter drive your FRS be prepared for a workout getting the OEM toe arms off.

I did during the 2014/2015 winter but it's been tucked away off season since. I'm sure that EFI Logics has seen their fair share of baked in parts. Thx for the heads up :)

I was very surprised how nice the car is for daily driving even with all the mounts and bushings. Our cars are great at having the frame take it all and not have stuff vibrating all over the place like some cars. I would recommend doing all the stuff I've done even for non-track canyon carving enthusiasts. I barely feel any vibrations. I do feel what the car is doing much more and things are more responsive and solid feeling.

I have my eye on the "Whiteline KCA 435 front roll center bump steer correction kit" but haven't bought it yet as I'm undecided if I need it.

Here's a list of what I have so you don't need to visit my build thread, even though you should. ;)

Whiteline KCA416 Front Camber adjusting bolt 16mm
Whiteline Rear Control arm - upper inner bushing (camber correction) KCA326
Whiteline Front Control arm - lower inner front Anti-Dive / Caster Correction Kit KCA434
Whiteline Front Control arm - lower inner rear bushing W0509
WhiteLine Rear Crossmember Mount Bushings KDT922 Positive Traction Kit
Whiteline Front Sway Bar with bushings Front 20mm Fixed BSF45
Whiteline Rear Sway Bar with bushings 16mm Adjustable BSR53Z
Whiteline Front Steering - rack & pinion mount bushing KSR210
Whiteline Rear Trailing arm - lower front bushing W63414
Perrin Poly Rear End Links
Front strut tower bar
Perrin front control arm brace
Subaru Impreza OEM Conical Washers (Subaru P.N # 20326AA000)
RCE TARMAC 2 COILOVERS
Whiteline Gearbox Positive Shift Kit KDT926
Perrin Rear Shifter Bushing
Whiteline KDT925 Rear Diff - mount in cradle & support outrigger insert bushing
MTEC Shift Spring Kit
Chase Bays stainless steel clutch line
Autozone slave cylinder (smaller than stock)

Your roads must be nice up there (actually a friend from OR here this weekend commented how terrible our roads are).

I'm Ground Controls, solid mounts front and rear and 255/35 Star Specs. The ride is atrocious and loud. And I'm about to put SPL LCAs on the car to get some travel back and be able to adjust the camber.

They are usually good.

The less flex/play your bushings have, the more load/work gets passed on to your dampers. It'll really reveal the quality of your dampers...

You seriously have to see the quality of our roads. It's atrocious.

I'm visiting Portland in about 8 weeks to see if I want to get out of this corrupt, underfunded conservative hell hole!

Love the suspension upgrades on track, very tight and precise between JRZs and metal-on-metal joints instead of rubber bushings but not snappy

It would be helpful if these individual pieces were bundled into packages where each component compliments the other and represents the most logical progression order.
I hate to use an over used term but in effect Stage I Stage II etc.

That's exactly what I wanted to do with this thread after more feedback. Having gone though a major change, I do see it more as Stock/Stage1/AllOut - you either leave it close to stock and change dampers and a few items that give you camber, eliminate larger movement, and similar...or go all out to chase the razor sharp handling that this platform can be after a large enough investment.

Would be very happy to get votes on options that belong to Stage 1/2/3 and compile into the top post.

It is happening also on our cars. Reason is not the high G corners, but the height difference in the car. When you change the suspension, you usually decrease also the wheel fender gap. Factory end links were designed for the OEM height and if you keep the same links, then the stress on them is much bigger. It is just likely to happen failing in high G corners.


Too bad that most of the aftermarket coilover brands (even big names) don't provide updated end links. They just take your money and leave you alone to think about all these details. :(

I put a baseline for oem and two upgrade stages in the top post, will update with best suggestions.

FRS gone, thread closed

damn! how come? Really found this build exciting.

Moved onto 2014 Cayman S, with PDK and track upgrades