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

[strat61caster]

@cmiovino sweet glad that's out of the way.

For a first event yeah sounds like it's just getting everything gelling, I certainly wouldn't bother making any judgements, adjustments, or conclusions on 170 run tires, but I usually hit cords around 120 here.

Ride height can make a huge impact, I'd take two turns out of the rear spring perches for the next event imho, no need to go get an alignment or do anything else. i.e. for Vegas Pro we dropped the rear 4 turns and the balance went from undrivable loose to a little push.

I spun my wheels literally for about 2 years chasing alignment and damping issues, threw a dozen combinations of 300/400/500# springs and it meant nothing. Ride height changes helped mitigate problems but never solved them. fwiw we max the KW Clubsports on our Mini, the twin tubes just can't keep up.

edit: pax works out decent for us imho, if I'm in the top 20% I know I'm not sucking.
edit2; more rear camber might help as well, most are 2.5-3 from what I've talked to, not worth running to the alignment shop for 0.3 degrees but next time you're there for other reasons worth a try.

[cmiovino]

Car's fully together with the new 245 A052's and wheels. Still does the same thing. I tried all different settings throughout the day at this test and tune with about 15 runs.

It appears to only be on right hand corners. Lefts are much better, although there's only one slight one here. At last week's event there was a long left sweeper and the car was planted and on point there.

From what I can feel, the inside passenger side rear wheel feels like it's off the ground. The car bounces and bobs, then you go to get on power and it shoots up to redline. In some videos you can hear it skim the surface during this and then hook up. Stock 2017-2020 rear swaybar (15mm). Front is a Perrin 19mm set on stiff (72% increase over stock). I mostly adjusted on the higher end of the settings working my way up in 2 click increments from the recommended 8F/10R from stiff. I tried at near full stiff and it was still doing it. I don't believe it's a setting/rebound issue. It also does it near full soft.

The VERY odd thing is the rear drivers side needed to be set a full 1.5" higher than the rear passenger side to get the same static ride height (~26" from the ground, even. About a 3 finger gap.) I'm current theory is the spring shouldn't be compressed that much and something is going on there. RCE recommend between 5-6" from the bottom of the spring to the LCA bolt. The passengers side is at 5.5" and drivers at 7".

Passenger Side:
https://imgur.com/iCljfB7

Driver Side:
https://imgur.com/U4ep4jj

Driver Side Spring:
https://imgur.com/RHg9JdH

[strat61caster]

Corner weights are probably fucked with that spring jacked up, which would explain good one direction bad the other. You’ll also feel it on a fast shift that chirps the tires, it’ll step out one way consistently as one side grips and the other is light.

I don’t trust the fender heights, a quarter inch one way or the other is more easily fixed by leaning on the fender than messing with the spring perches.

[NoHaveMSG]

Yeah I agree with Strat. Sounds like corners weights are way off.

[Racecomp Engineering]

Definitely thinking this is either a ride height + corner balance issue...let's chat tomorrow. Do you have a picture of how your rear LCAs are set?

- Andrew

[cmiovino]

Originally Posted by Racecomp Engineering

Definitely thinking this is either a ride height + corner balance issue...let's chat tomorrow. Do you have a picture of how your rear LCAs are set?

- Andrew

You're very much onto something. I measured the droop travel at exactly 1" on either side, so I'm pretty sure this is the issue getting on power.

I ended up going ahead and lowering the car 5/8", which got both both sides in spec with the 5-6" measured from the spring perch to LCA bolt in the instructions. The passenger side is right at 5" and drivers at 6" - so there's still that variance. The variance is down to 1" difference from the 1.5" it was before.

I remeasured droop travel at 2" now... which is a big improvement for just 5/8" of lowering. I'll have to double check this as that doesn't fully make sense to me. Should be a 1:1 change I would think.

The ride height before was... high. To get it in my garage. Exhaust was scraping. Not the best measurement, but it was 26" from the floor to the fender to give a ballpark. Probably right at stock height, which was probably out of the coilover's range of travel... mainly not allowing the inside to droop enough.

I can get LCA pictures and any measurements tomorrow.

Before adjustments:

[M0nk3y]

FWIW, I think you're way too high for an STX Setup to begin with. But that's beyond the issues going on here.

Here's a video of my car on the same surface, years years old...but you get the point.

[cmiovino]

Do you have a picture of how your rear LCAs are set?

SPC, wet look is from fresh Fluid Film.

[Racecomp Engineering]

Originally Posted by cmiovino

You're very much onto something. I measured the droop travel at exactly 1" on either side, so I'm pretty sure this is the issue getting on power.

I ended up going ahead and lowering the car 5/8", which got both both sides in spec with the 5-6" measured from the spring perch to LCA bolt in the instructions. The passenger side is right at 5" and drivers at 6" - so there's still that variance. The variance is down to 1" difference from the 1.5" it was before.

I remeasured droop travel at 2" now... which is a big improvement for just 5/8" of lowering. I'll have to double check this as that doesn't fully make sense to me. Should be a 1:1 change I would think.

The ride height before was... high. To get it in my garage. Exhaust was scraping. Not the best measurement, but it was 26" from the floor to the fender to give a ballpark. Probably right at stock height, which was probably out of the coilover's range of travel... mainly not allowing the inside to droop enough.

I can get LCA pictures and any measurements tomorrow.

Before adjustments:

Yeah stock height is just too high and you will not have the droop you need. Should actually ride better with correct lowering and more droop too on certain bumps at least.

So that's a step in the right direction. Did you lower the car 5/8 of an inch or the spring perch? What are your current center of hub to fender measurements?

The uneven perches is confusing to me...was wondering if it was somehow related to how your LCAs were set but I'm not that familiar with the SPCs to be honest. There's a couple of things it could be but hard to tell from here.

- Andrew

[cmiovino]

Originally Posted by Racecomp Engineering

Yeah stock height is just too high and you will not have the droop you need. Should actually ride better with correct lowering and more droop too on certain bumps at least.

So that's a step in the right direction. Did you lower the car 5/8 of an inch or the spring perch? What are your current center of hub to fender measurements?

The uneven perches is confusing to me...was wondering if it was somehow related to how your LCAs were set but I'm not that familiar with the SPCs to be honest. There's a couple of things it could be but hard to tell from here.

- Andrew

SPC is identical to stock, minus the ability to adjust camber on the hub side via an eccentric bolt setup.

5/8" of ride height each side. At the perch it was literally ~1" removed on the driver side, ~1/2" removed passenger side to get that change.

Center of hub to center measurements are 13 1/4" rear. Same side to side. It would have been near 14" before during the event.

I measured the droop at exactly 2" now, both sides. Before it was 1". Should 2" be enough for autocross purposes?

The car felt like it rode a hair better at the same settings last night during the test drive.

[Pat]

Originally Posted by cmiovino

SPC is identical to stock, minus the ability to adjust camber on the hub side via an eccentric bolt setup.

5/8" of ride height each side. At the perch it was literally ~1" removed on the driver side, ~1/2" removed passenger side to get that change.

Center of hub to center measurements are 13 1/4" rear. Same side to side. It would have been near 14" before during the event.

I measured the droop at exactly 2" now, both sides. Before it was 1". Should 2" be enough for autocross purposes?

The car felt like it rode a hair better at the same settings last night during the test drive.

Off topic: I saw your old WRX a couple hours ago while driving Tanks car.

Sent from my Pixel 7a using Tapatalk

[autoracer86]

If it was me I would set the shock collars to the same length with one of the end links disconnected and see if there is any difference in height on compression and droop.

If there is still a difference then remove the shocks and see if there is any binding when moving the suspension components.

You kinda want to remove as many variables as possible.

[Racecomp Engineering]

This forum is so damn clunky it's getting outrageous. Having so much trouble posting and and PMing lately.

Anyway, we have definitely seen our share of "uneven" Subarus in our time including from the factory. The left rear especially can be quite a bit heavier and you can see it in the various corner weights posted over the years, so that makes some sense here.

The full inch difference for the perches is a little more than usual...there may also be something bound up.

It's a pain but swapping the assemblies side to side would be 1 test (seeing if you need to adjust the perches the same way to get the even height).

If you're able, getting the car on some scales would be a good test as well.

Your new lower ride height should make a big difference.

- Andrew

[Tokay444]

I don't see hardly any point in going to an adjustable height shock without corner balancing.