kmvguy83

I recently completed the Prius EPAS swap on my EG, and I'm trying to add some static caster to gain some Return to Center and add more stability to my car.
My preference is the hardened rubber bushings and want stay away from spherical or poly urethane bushings due to the reliability.
Also, I'm not too worried about steering wheel effort nor the bump steer since both of those are remediated with the Prius steering column setup.
I want to aim for around 4-5 degrees of positive caster to my car.

I'm aware there is no way to adjust caster on these chassis from factory but I've seen some aftermarket parts that adds positive caster.
This car will see mostly street time, with occasional AX/HPDE events.

Does any one have experience on any of these setups and would like to recommend?

Couple of options I saw are.
1. Truhart: Front Camber / Caster Kit CAMBER: +2°~-2°/ CASTER: +2°~-2°
This one is the UCA replacement. Seems to add about 2 degrees of caster max.
There are multiple companies that has the same part. From my research Megan, Truhart, Hardrace are all made from the same factory and only difference is the branding itself.

2. Whiteline: Front Control arm - lower inner front bolts
This is the classic shimming the LCA method. Cheap method of adding up to 2.5 degree of static caster.
The kit is cheap but looking at the picture I can probably replace the kit with some high grade washers instead...

3. PCI: ALUMINUM FRONT LOWER SPHERICAL CONTROL ARMS (92-95 Civic/94-01 Integra)
Lower control arm replacement and about 2 degree of static caster. Thank to @Pepe14 , I learned that this part exist.
I'm aware of how capable spherical bushings are for race car application but my biggest worries on these units are the reliability.
Suspension noise I can live with because my STR prepped S2000 has couple of spherical bushings (top hats, front and rear sway bar end links) but the issue is the reliability of these parts.
I rarely put any street miles on my S and I had a pair of bushings that completely seized and broke off.

4. Offset LCA poly bushings. (No links)
I rather not do this because, offset poly bushings will probably be the noisiest and least reliable part out of all the options here...
But if anybody have experience or input on this, please let me know.

spAdam

iTrader: (1)

Define 'best'.

Cheapest/easiest would be the Whiteline kit. It's adjustable too.
The PCI lowers add caster and address a couple of other geometry issues. They are pricey, but high quality.
The upper arm seems like the obvious answer. I don't have a terribly high opinion of the Truhart stuff, but I've never used it either.
Honed makes a set of super trick upper arms that are the best design available, the additional caster is fixed at +1* on them though, and they are pricey.
On EG/DC chassis folks have been known to swap UCAs left to right and gain a couple of degrees. This is free and arguably worth a try.

Probably a combo of parts is the way to go. Like maybe the Honed arms plus the Whiteline kit to allow some adjustability. Keep in mind that adding caster tilts the steering arm down and affects your bump steer curve as well. I imagine you are aware of this if you are already driving a track-prepped S2k.

There is an upper limit on how much caster you want to run with EPS before the increased load starts failing your EPS motor, especially when combined with race tires and/or aero. I'm up against this issue at work right now and it's a race ender for obvious reasons.

kmvguy83

Thanks for the informative reply!
I suppose the term "best" is relative. haha
My definition was getting the setup that suits the car usage. Street-able setup with occasional AX/HPDE events.

Honed UCAs look amazing. And just like you said, combining this with the whiteline kit might be the best way to go about the static caster goal.
Have you ran into anybody using Kingpin Machine: "DC Integra/EG Civic Complete Front LCA Caster Offset Spacer Set"?
Seems like this kit not only spaces out the LCA but also offsets the compliance bearing and shock mounts too.

Also, can you elaborate on your EPS issues you are experiencing? I would love to hear more on this.

spAdam

iTrader: (1)

The Kingpin misalignment spacers are for use with their spherical bearing lower arms. Chris @ Kingpin really knows what he's doing and is passionate about it. Good stuff there.

Can't really elaborate on too much on EPS issues because I'm still investigating... but high caster could be a contributing factor. It's common knowledge that high caster angle increases steering effort, and since you're asking your EPS to deal with that extra effort, it follows that at some point you'll find the limits of what the motor unit can handle.

mattkosem

What did you end up doing? I ended up grabbing the PCI setup (compliance bushing and arm) for my EG. I'll put em in sometime in June most likely.

I initially wanted the Hardrace arms (same as the Truhart but blue) but Hardrace discontinued them. I asked why, and they told me customers had issues with them.

In my searches, I've encountered multiple people citing issues with the hardware on the whiteline kit. Hardrace does sell a similar kit, though, FWIW.

mattkosem

BTW, I had a bunch of noise develop in the first month/1k miles with the PCI arms and had to pull them.

Considering upper arms and the Hardrace caster kit (hopefully better hardware than the Whiteline one) to get the caster back because it did make a positive impact.

--Matt

spAdam

iTrader: (1)

That's unfortunate. Do you know where the noise was coming from? Was it the uniball?

FWIW, the Truhart arms are either coming out of the same factory or they are just straight knockoffs of the Hardrace stuff. I think it's more likely the former. I don't have a lot of faith in the balljoints of either (but I haven't used either because of this). I think the Honed arms are going to become the de facto adjustable upper arm as more people discover them. They're expensive, but all of the shortcomings of other aftermarket arms look like they're well addressed - and they use an oem style ball joint.

mattkosem

Haven't had a chance to diagnose yet. Have a track day I needed to get the car sorted for so back to safe rubber for now. 🤣


Megan, Truhart, Hardrace, and some K-Tuned parts all come off the same line. It is my understanding they are mostly identical apart from color.

Does Honed make an EG adjustable arm? I thought they only make an EK part.

spAdam

iTrader: (1)

Yes, the EG/DC ones came out first actually.

mattkosem

Oh, I see now that the specs say 1 degree. I missed that initially. That's not a lot TBQH.

There are several more options for EKs that don't have EG equivalents, which is a bummer. Neither PCI nor SPC make their variants with caster for the EG. 😔

Some folks swap the uppers from left to right for positive caster, too, but it seems like that route tends to increase it too much and causes problems.

spAdam

iTrader: (1)

Really? It's always seemed the other way around to me, which surprises me due to the higher parts count of an EG/DC arm (because of the separate pivots) but makes sense because it arguably covers more cars.

Didn't realize the Honed arms only get +1° on EG/DC application. Is anyone doing an inner pivot set that allows you to shim the arm back?

I seem to remember that swapping the arms left to right caused more problems than it was worth. Tower clearance, failed ball joints, can't remember the failure mode.

mattkosem

None I can find unfortunately. I'd love it if there was an option that even just had a fixed +2. I don't need the adjustment, honestly.

Probably will just end up trying the Hardrace shim kit since apparently the hardware on the Whiteline kit is not trustworthy and breaks.

--Matt