Calling All Chassis Gurus - What's the Best Method for Adjusting Front Camber?
 

Here's a theoretical and practical question for those that understand chassis engineering and setup better than I: For a car like mine that is equipped with SPL Parts adjustable front lower control arms and Raceseng Cas/Cam plates, where is the best location for making front camber adjustments? My car has three places where front camber adjustments can be made:

- The lower control arm
- The strut upper mount
- The strut lower mount (MCS coilovers have an elongated two-position insert allowing adjustment where the strut mounts to the hub)

Obviously, I have a lot of adjustment and will not be maxing out available negative camber - my question is basically if it's better to adjust camber at the bottom with the lower control arm or at the top with camber plate? Which setting should I use on the elongated two-position insert on strut lower mount? In short, does the strut perform better when it's more vertical, or doesn't it matter? Why?

Adjusting with upper mount/camber plate: better roll center

Adjusting with lower mount as with camber bolts or slotted lower strut mount: better steering axis inclination (SAI).

My preference (and that of many in the motorsport world) prefer to get more of your camber from the lower mount.

- Andrew

As a follow up, what is the preferred way to start this tweaking?

i.e. does it make sense to max out the lower mount, and dial back the upper mount to where you want it? Zero out the top mount, adjust lower mount and only touch upper if needed? Is there a different option? What makes the most sense?

Good questions!

I would prefer to have the top mounts "even" if possible. So depending on how much camber you want, you may have to go back and forth. Like you said, starting with the top mounts in the middle then adjusting the lower mount to your desired setting is a good way to go. Then if you need more camber, adjust the tops a smidge and go back to the lower mounts.

- Andrew

@Racecomp Engineering, thanks for the great information - between the follow-up question and your two responses, I've got a pretty good handle on things. Which setting should I use on the elongated two-position insert on strut lower mount?

That I can't say for sure since I haven't seen the MCS coilovers up close, but I would start with whichever gives you more camber.

- Andrew

I have some unfortunate front geometry and can't get all the camber I want without the endlink smacking the inside wall in the wheel well (especially when turning). Had I known this I would've chosen instead to get camber adjustment from the control arm.

For the strut/hub mounting point you want to loosen both strut bolts and push inwards as far as possible to get max camber. I like to use a jack on the brake rotor to provide some positive pressure inwards while I tighten everything up. Make sure you use the torque wrench on the nut, NOT the bolt. Spec is 119 ft/lbs IIRC. I always do 120 because it's one more. :D

I have the exact same parts setup as you do.

I chose to max out the caster and camber at the Raceseng CASCAMs and then do all of the final adjustments at the front lower control arms.

My rationale for this approach was that it is much easier for me to make adjustments at the front LCA rather than going back and forth messing with the CASCAMs. From past experience I've found that the CASCAMs can be tricky to adjust the camber with the car's weight on the suspension. They tended to want to slide all of the way in to max neg camber with the car resting on the suspension. The caster adjustment isn't prone to moving in the same way as the camber with the car on the suspension, but I was concerned about the longevity of the aluminum threads for the mounting bolts since I've made so many alignment changes over the last couple of years.

The SPL front LCAs make it very easy to adjust the caster and camber in small increments with the car resting on the suspension in my opinion and that is why I choose to max out the caster and camber at the Raceseng plates and make the final adjustments at the front LCA.

One thing I think is also important is that by adjusting the camber at the lower lca you are also changing the motion ratio of the suspension.

Also keep in mind if you autocross in STX, you can have an adjustable control arm OR camber plates, but not both. See 14.8.H.2 for more.

Are you using ramps?

I just bring a jack and lift the front, the raceseng plates are incredibly easy to adjust with the suspension unloaded.

I'm on an alignment rack. I agree if you unload the suspension they are easy to adjust.

Very helpful. Thanks so much for your time, as always RCE!