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

[hukdizzle]

Hi RCE/CSG!

Recently installed RCE Tarmac 2 coils and I am looking to get into a lighter/wider wheel and was hoping to get some input on the tire/wheel clearance for the following.

RCE Tarmac 2 (Raceseng Cascam Top Mounts)
17x9 Enkei RPF1 +45mm Offset
245/40/17 DOT Tire (Likely an RS4 or something along those lines)

Installation wise, the car has a crash bolt installed up front from prior classing and since the top hole of the strut mount on the tarmac is slotted I will be maxing out the static camber via that, and then adding additional camber via the top mounts to achieve necessary track oriented camber. I am looking to achieve the following alignment/ride height with adequate strut/tire clearance.

Camber F : -3.5'
Toe F : 0" Total
Camber R : -2.5'
Toe Rear : 1/16" Total
Caster F : 7.0'

Ride Height : Approx 13.56" from top of fender to center of wheel hub. Slight rake with the rear being a 1/16" higher than the front. Car will be corner balanced so static corner heights may change slightly.


Would perhaps a +35 offset RPF1 be the better choice here? It seems like per the ft86motorsports wheelfit calc if I go with the +45 I am going to be extremely close to the damper assembly. If I go with the +35 there is a chance of it rubbing on the fender/liner possibly on the outside shoulder.


Thanks for the help!

[Racecomp Engineering]

Originally Posted by MaverickMonk

Thanks Andrew, I'll have to take you up on that, even if it means crossing the DC Area Supercollider / Capital Beltway. I'm doing my best to get in deep as far as understanding all this stuff, but reading books is no substitute for experience.

Cheers

The amount of traffic at any time of day, any day of the week is infuriating.

Right now I've got a bit of an experimental set up on my SS1s (softer spring rates) but I do plan to return them to the standard 6 kg/mm springs at some point this summer. Just give me a heads up and we'll work something out.

I also really want to host a meet and suspension tech info day sometime!

- Andrew

[Racecomp Engineering]

Originally Posted by hukdizzle

Hi RCE/CSG!

Recently installed RCE Tarmac 2 coils and I am looking to get into a lighter/wider wheel and was hoping to get some input on the tire/wheel clearance for the following.

RCE Tarmac 2 (Raceseng Cascam Top Mounts)
17x9 Enkei RPF1 +45mm Offset
245/40/17 DOT Tire (Likely an RS4 or something along those lines)

Installation wise, the car has a crash bolt installed up front from prior classing and since the top hole of the strut mount on the tarmac is slotted I will be maxing out the static camber via that, and then adding additional camber via the top mounts to achieve necessary track oriented camber. I am looking to achieve the following alignment/ride height with adequate strut/tire clearance.

Camber F : -3.5'
Toe F : 0" Total
Camber R : -2.5'
Toe Rear : 1/16" Total
Caster F : 7.0'

Ride Height : Approx 13.56" from top of fender to center of wheel hub. Slight rake with the rear being a 1/16" higher than the front. Car will be corner balanced so static corner heights may change slightly.


Would perhaps a +35 offset RPF1 be the better choice here? It seems like per the ft86motorsports wheelfit calc if I go with the +45 I am going to be extremely close to the damper assembly. If I go with the +35 there is a chance of it rubbing on the fender/liner possibly on the outside shoulder.


Thanks for the help!

Are you set on the RPF1s? You could consider the Weds TC105X in 17x9 +35 as that is a confirmed easy button fitment for track cars with 245s and camber (and clears more brake calipers). I'm not a wheel fitment wizard, though, I just have my fitments that I know work and stick with them.

The rest of your set up sounds great! Yes get as much camber as you can at the lower mount (safely). Ride heights sound good too. Definitely do some test and tuning since depending on your final tire choice you will want to dial in front camber with a pyrometer if you can. Keep us posted.

- Andrew

[hukdizzle]

Originally Posted by Racecomp Engineering

Are you set on the RPF1s? You could consider the Weds TC105X in 17x9 +42 as that is a confirmed easy button fitment for track cars with 245s and camber. I'm not a wheel fitment wizard, though, I just have my fitments that I know work and stick with them.

The rest of your set up sounds great! Yes get as much camber as you can at the lower mount (safely). Ride heights sound good too. Definitely do some test and tuning since depending on your final tire choice you will want to dial in front camber with a pyrometer if you can. Keep us posted.

- Andrew

Thanks for the recommendation Andrew, I will take it into consideration!

[Icecreamtruk]

@Racecomp Engineering
Can I get an idea of what the stiffness of your sway bars are, if possible by adjustment position (sku BSK020) and also, would they work with endlinks that currently work on my stock bars? I have the rear stock endlinks but front ones are shortened (non ajustable) that came with my coilovers. Thanks.

[Racecomp Engineering]

Originally Posted by Icecreamtruk

@Racecomp Engineering
Can I get an idea of what the stiffness of your sway bars are, if possible by adjustment position (sku BSK020) and also, would they work with endlinks that currently work on my stock bars? I have the rear stock endlinks but front ones are shortened (non ajustable) that came with my coilovers. Thanks.

Front is 25mm hollow, which comes out to be roughly equivalent to 22mm solid. This means on the soft setting, it's roughly 2x stiffer than stock.

Rear is 18mm hollow, roughly equivalent to 16mm solid. It's about 1.75 x stiffer than stock.

Remember that rear swaybar motion ratio is not the same as stock, so increasing bar rate by the same amount front and rear does not translate to the same amount of wheel rate increase front and rear. This is true with all swaybars, not just ours.

Adjustable endlinks do help with adjustable bars, but you would be able to reach the soft settings fine with OEM endlinks.

- Andrew

[Infinity]

I have seen people mention damage to rear axles from lowering the car. I believe this is caused by the diff being too low relative to the wheels.

The only solution seems to be solid sub-frame and diff risers from PBM. This is not ideal because it is not a simple mod to install/uninstall and solid bushings will increase NVH.


1. How low do you need to be for this to become an issue?


2. Do rear lower control arms that lower the shock mounting point like PBM or Stance keep the diff higher and help preserve axle life? If yes, what are the downsides of lowering the shock mounting point like this?

[CSG Mike]

Originally Posted by Infinity

I have seen people mention damage to rear axles from lowering the car. I believe this is caused by the diff being too low relative to the wheels.

The only solution seems to be solid sub-frame and diff risers from PBM. This is not ideal because it is not a simple mod to install/uninstall and solid bushings will increase NVH.


1. How low do you need to be for this to become an issue?


2. Do rear lower control arms that lower the shock mounting point like PBM or Stance keep the diff higher and help preserve axle life? If yes, what are the downsides of lowering the shock mounting point like this?

1. It's not how low, but the range of motion you're using. A low car with very little roll won't be stretching the axles.

2. They do not affect the axles.

[blown]

what do you suggest for stock ride height, street/track driving. I have the ohlins road and track, and looking for something different. Need coilover for the extra space for wheels.

[Vital]

Originally Posted by blown

what do you suggest for stock ride height, street/track driving. I have the ohlins road and track, and looking for something different. Need coilover for the extra space for wheels.

RCE SS1 Coilovers or the CSG Tein Flex A.

[Racecomp Engineering]

Stock ride height is tough. You can't really get to stock ride height with SS1s or many other coilovers. A 15-20mm drop is about the highest you can go.

- Andrew

[OwlDance]

Hey guys, can't seem to find OEM alignment for 2017+ refresh cars between documents and searches. Would anyone happen to know them for a base model Toyota 86? I assume there are slight variations between Subaru and Toyota's iterations.

[rustymuffler]

Hi @Racecomp Engineering

I have Koni sports with OEM 2017 springs on my '13 BRZ. It has removed the harshness of the stock setup. Now I am looking for a modest ~1" drop while also reducing roll for spirited driving. Would the Racecomp Yellow, or Tarmac springs be a good fit with the Koni dampers without making the ride as harsh as the stock '13 setup?

[Racecomp Engineering]

Originally Posted by OwlDance

Hey guys, can't seem to find OEM alignment for 2017+ refresh cars between documents and searches. Would anyone happen to know them for a base model Toyota 86? I assume there are slight variations between Subaru and Toyota's iterations.

OEM alignment isn't very good anyway.

Is your car stock? What kind of tires do you have? How would you describe your driving style?

- Andrew